Phenomenology 2020 Symposium

4 May 2020, 02:00 → 6 May 2020, 21:30 US/Eastern

University of Pittsburgh

IMPORTANT INFORMATION REGARDING PHENO 2020 IN LIGHT OF THE COVID-19 PANDEMIC

We thank you for your ongoing interest in the Pheno symposia. Unfortunately, due to the ongoing COVID-19 pandemic, we must cancel the physical version of the Pheno symposium. We were very excited to continue this great series and host you in Pittsburgh, but we are unable to do so while ensuring the safety of participants and the Pittsburgh community. We will refund any registration and banquet fees that you have paid. Please be sure to cancel any travel bookings that you have made. There is no fee to cancel your hotel booking if you booked using the Pheno code.

We are planning instead to host a virtual Pheno symposium. The full details of this virtual meeting will be made available soon. Registration for this virtual symposium will be free. The talk schedule will roughly follow the planned schedule for the physical meeting and will be held May 4 to May 6. We would like to encourage you to register and submit an abstract for a parallel talk. Registration can be done at https://indico.cern.ch/event/858682/registrations/ or by following the registration link on this page. If you already registered for Pheno, you do not need to register again. We hope to see you online in May!

 

PROGRAM

The 2020 Phenomenology Symposium will be held May 4-6, 2020 at the University of Pittsburgh.  It will cover the latest topics in particle phenomenology and theory plus related issues in astrophysics and cosmology.

 

Registration and talk submission for Pheno 2020 have closed

 

Confirmed plenary speakers and topics:

• Nima Arkani-Hamed (IAS): Something relevant
• Anadi Canepa (CMS, FNAL): Prospects for LHC physics
• Christophe Grojean (DESY/Humboldt University): Strategy in pursuing high energy physics
• Daniel Holz (University of Chicago): Multi-messenger probes for fundamental physics
• Jarek Kaspar (University of Washington): Muon physics at FNAL
• Zhen Liu (University of Maryland): BSM Opportunities at the LHC
• Francesca Di Lodovico (King's College London): News from neutrino experiments
• Pedro Machado (FNAL): Neutrino physics: the theory and phenomenology
• Katharina Müller (University of Zurich): Physics Highlights from LHCb
• Tilman Plehn (Heidelberg University): Physics at hadron colliders
• Stefano Profumo (UC Santa Cruz): What is the Dark Matter?
• Jianming Qian (ATLAS, Univ. of Michigan): LHC update: New results, new techniques, and new ideas
• Jianwei Qiu (Jefferson Lab): Physics at the Electron-Ion Collider (EIC)
• Matthew Reece (Harvard): New Physics at the TeV Scale
• Adam Riess (Johns Hopkins): Developments in cosmological measurements 
• Andreas Ringwald (DESY, Germany): Axion physics
• Martin Savage (University of Washington): Quantum computing
• Scott Watson (Syracuse University): Cosmology and new physics

Mini-Reviews:

• Joachim Brod (University of Cincinnati): News on flavor physics
• Giacomo De Pietro (Belle II, University of Rome III): Dark Photon searches at B-factories

FORUM ON EARLY CAREER DEVELOPMENT

Invited Speaker: Dr. Midhat Farooq, Careers Program Manager, American Physical Society
Physics Careers: the Myths, the Data, and Tips for Success
May 4, 1:00-2:00 PM

VIRTUAL COCKTAIL HOUR, AWARDS CEREMONY

As is a Pheno tradition, we will have an award ceremony after the parallel sessions on Tuesday, May 5 at 6:45 PM EDT.  Though we cannot share a drink together, we encourage you to join with your favorite beverage in hand! We will present awards to several participants to be redeemed when it is safe to do so.

PHENO 2020 ORGANIZERS: Brian Batell, Joshua Berger, Ayres Freitas, Joni George, Tao Han (chair), Adam Leibovich, Natália Maia, Cédric Weiland, and Keping Xie.

PHENO 2020 PROGRAM ADVISORS: Vernon Barger, Lisa Everett, Kaoru Hagiwara, JoAnne Hewett, Tae Min Hong, Arthur Kosowsky, Yao-Yuan Mao, James Mueller, Vittorio Paolone, Tilman Plehn, Vladimir Savinov, Xerxes Tata, Andrew Zentner, and Dieter Zeppenfeld.

More information to come.

PHENO 2019

overview_map2020.pdf

pheno20schedulesafe.pdf

points_of_interest.pdf

Poster_pheno2020_final_version.pdf

Poster_pheno2020.pdf

restaurantsmap2020.pdf

Monday 4 May

Plenary: I

Convener: Marc Sher (William and Mary College)

1 Welcome

Speaker: Prof. Kathy Blee (University of Pittsburgh)

2 LHC update: New results, new techniques, and new ideas

Speaker: Jianming Qian (University of Michigan (US))

Pheno2020.pdf

3 Prospects for LHC and HL-LHC physics

Speaker: Anadi Canepa (Fermi National Accelerator Lab. (US))

AnadiCanepa_Pheno2020.pdf

4 Physics at hadron colliders

Speaker: Tilman Plehn (Heidelberg University)

pheno_20.pdf

10:30 Coffee Break

Plenary: II

Convener: Hooman Davoudiasl (BNL)

5 Developments in cosmological measurements

Speaker: Adam Riess

pheno_agr.pdf

6 Multi-messenger probes for fundamental physics

Speaker: daniel holz (University of Chicago)

Holz.pdf

7 Cosmology and new physics

Speaker: Prof. Scott Watson (Syracuse University)

Pheno.pdf

12:45 .

12:45 Lunch

Career Forum

8 Physics Careers: the Myths, the Data, and Tips for Success

Speaker: Midhat Farooq

14:00 .

BSM I

Convener: Lisa Everett

9 Topologically stable, finite energy electroweak-scale monopoles

The existence of a magnetic monopole, if it exists, remains elusive. Experimental searches have been carried out and are continuing in this quest. Of great uncertainty is the mass of the monopole which is model-dependent and ranging from some Grand Unified scale to the electroweak scale. In this paper, we propose a model where topologically stable, finite-energy monopoles {\em `{a} la} 't Hooft-Polyakov could exist with a mass proportional to the electroweak scale. This comes about in a model of neutrino masses where right-handed neutrinos are {\em non-sterile} whose electroweak-scale Majorana masses are obtained by the coupling to a complex {\em triplet} Higgs field. Custodial symmetry which insures $M_W=M_Z \cos \theta_W$ requires the introduction of another triplet Higgs field but {\em real} this time. It is this {\em real Higgs triplet} that is at the core of our proposal.

Speaker: Prof. P. Q. Hung (University of Virginia)

PHENO20_pqhung.pdf

10 Non-linearly realized discrete symmetries

While non-linear realizations of continuous symmetries feature derivative interactions and have no potential, non-linear realizations of discrete symmetries feature non-derivative interactions and have a highly suppressed potential. These pseudo-Goldstone bosons have a non-zero potential, but the potential generated from quantum corrections is inherently very highly suppressed. We explore various discrete symmetries and to what extent the potential is suppressed for each of them.

Speaker: Mr Saurav Das

Non-linear_discrete.pdf

11 Mirror color symmetry breaking in Twin Higgs models

We investigate extensions of the Twin Higgs model in which the twin color gauge symmetry and the Z2 mirror symmetry are spontaneously broken, by introducing a single new colored triplet, sextet, or octet scalar field and its twin along with a suitable scalar potential. This spontaneous Z2 breaking allows for a viable electroweak vacuum, and leads to dramatic differences between the visible and mirror sectors in terms of the low energy residual gauge symmetries, color confinement scales, and particle spectra. Several of our models feature a remnant SU(2) or SO(3) twin color gauge symmetry with a very low confinement scale in comparison to QCD. Couplings between the colored scalar and matter provide a new dynamical source of twin fermion masses, and lead to a variety of correlated visible sector effects that can be probed through precision measurements and collider searches.

Speaker: Wei Hu (University of Pittsburgh)

Pheno_1c.pdf

12 A new mechanism for Matter Anti-Matter asymmetry

We propose a new mechanism for generating matter-antimatter asymmetry via the interference of tree-level diagrams only. We first derive a general result that a nonzero $CP$-asymmetry can be generated via at least two sets of interfering tree-level diagrams involving either $2\rightarrow2$ or $1\rightarrow {\cal N}$ (with ${\cal N}\geq3$) processes. We illustrate this point in a simple TeV-scale extension of the Standard Model with an inert Higgs doublet and right-handed neutrinos, along with an electroweak triplet scalar field. The imaginary part needed for the required $CP$-asymmetry comes from the trilinear coupling of the inert doublet with the triplet scalar. Small Majorana neutrino masses are generated by both the scotogenic and type-II seesaw mechanisms. The real part of the neutral component of the inert doublet serves as a cold dark matter candidate. The evolutions of the dark matter relic density and the baryon asymmetry are intimately related in this scenario.

Speaker: Arnab Dasgupta (School of Liberal Arts, Seoul National University of Science and Technology)

arnab_PHENO-2020.pdf

13 Strong First-Order Electroweak Phase Transitions in the Standard Model with a Singlet Extension

A common assumption about the early universe is that it underwent an electroweak phase transition (EWPT). Though the standard model (SM) is able to restore the electroweak symmetry through a smooth cross over PT, we require a strongly first-order PT to ensure electroweak baryogenesis, requiring us to look at new physics beyond the SM. The simplest case to extend the SM is to add a real singlet field, which allows first-order EWPTs (FOEPT) to occur.

Starting with the most general higgs+singlet lagrangian, we then fixed four of its coupling constants as functions of parameters whose range of values had more experimental motivation. Then by requiring a FOEPT and performing a Monte-Carlo scan over five free parameters, we were able to study the parameter space in this allowed region. Most notably, we observed the triple higgs coupling ($𝜆_3$) take on values between 1.2 and 2.5. The possible values of $𝜆_3$ could serve as motivation for future collider experiments to improve sensitivity in this range when looking at the cross sections of $pp\rightarrow hh$ versus $𝜆_3$.

Speaker: Mr Anthony Hooper (University of Nebraska-Lincoln)

FOEPT_in_the_SM_with_a_Singlet_Extension.A.Hooper.pdf

14 Minimal model of torsion mediated dark matter

We present a minimal model of fermionic dark matter (DM), where a singlet Dirac fermion can interact with the Standard Model (SM) particles via the torsion field of gravitational origin. In general, torsion can be realized as an antisymmetric part of the affine connection associated with the spacetime diffeomorphism symmetry and thus can be thought of as a massive axial vector field. Because of its gravitational origin, the torsion field couples to all the fermion fields including the DM with equal strength, which makes the model quite predictive. The DM is naturally stable without any imposition of ad hoc symmetry, e.g.,
$Z_2$. Apart from producing the correct thermal abundance, a singlet fermion can easily evade the stringent bounds on the spin-independent DM-nucleon direct detection cross section due to its axial nature. However, in the allowed parameter space, strong bounds can be placed on the torsion mass and its couplings to fermions from the recent LHC searches. Assuming a nonuniversal torsion-DM and torsion-SM coupling, smaller values of torsion masses may become allowed. In both cases we also study the reach of spin-dependent direct detection searches of the DM.

Speaker: Dr Debottam Das (Institute of Physics, Bhubaneswar)

torsion.pdf

15 Phenomenology of CP-Violating Higgs Portal Dark Matter

The Galactic Center gamma-ray Excess (GCE) is one of the most statistically significant experimental anomalies to date, with one possible explanation in annihilating dark matter. In this talk we discuss a realization of a Higgs portal thermal relic, such as preferred by the GCE, with a CP-violating Yukawa coupling. The phase of this coupling sets the hierarchy between annihilation and scattering, allowing evasion of stringent direct detection constraints. We present phenomenology of the model and explore prospects of future detection.

Speaker: Linda Xu

CPV_Higgs_15min.pdf

DM I

Convener: Antonio Delgado (University of Notre Dame)

16 Dark Matter searches with the ATLAS Detector

The presence of a non-baryonic dark matter component in the Universe is inferred from the observation of its gravitational interaction. If dark matter interacts weakly with the Standard Model it would be produced at the LHC, escaping the detector and leaving a large missing transverse momentum as their signature. The ATLAS detector has developed a broad programme to directly search for DM. The results of recent searches on 13 TeV pp data, their interplay and interpretation will be presented.

Speaker: Julian Wollrath (Albert-Ludwigs-Universität Freiburg)

DarkMatterSearchesATLAS.pdf

17 Search for dark matter at CMS

A large body of cosmological evidence points to the existence of dark matter in the Universe which cannot originate from standard model (SM) particles. Hence unraveling its origin remains one of the outstanding problems of particle physics and cosmology. The dark matter search program at the LHC covers a wide range of final states and targets a variety of possible interactions between dark matter and SM particles. A summary of the dark matter searches performed at the CMS experiment, using proton-proton collision data collected at a center-of-mass energy of 13 TeV, is presented. Searches performed in various final states are described, and results interpreted in terms of several dark matter models are presented. These results are also compared to the results from direct and indirect dark matter searches.

Speaker: Simranjit Singh Chhibra (Vrije Universiteit Brussel (BE))

20200504_DMatCMS_Pheno2020_schhibra.pdf

18 Collider probes of real triplet scalar dark matter

We study discovery prospects for a real triplet extension of the Standard Model scalar sector at the LHC and a possible future 100 TeV $pp$ collider. We focus on the scenario in which the neutral triplet scalar is our dark matter candidate. When produced in $pp$ collisions, the charged triplet scalar decays to the neutral component plus a soft pion or soft lepton pair, yielding a disappearing charged track in the detector. We recast current 13 TeV LHC searches for disappearing tracks, and find that the LHC presently excludes a real triplet scalar lighter than 287 GeV with $\mathcal{L}=\rm36\,$fb$^{-1}$. The reach will extend to 608 GeV and 761 GeV with the collection of $\mathcal{L}=300\,$fb$^{-1}$ and $3000\,$fb$^{-1}$ respectively. We extrapolate the 13 TeV analysis to a prospective 100 TeV $pp$ collider, and find that a $\sim3$ TeV triplet scalar could be discoverable with $\mathcal{L}=30$ ab$^{-1}$, depending on the degree to which pile up effects are under control. We also investigate the dark matter candidate in our model and corresponding present and prospective constraints from dark matter direct detection. We find that currently XENON1T can exclude a real triplet dark matter lighter than $\sim3$ TeV for a Higgs portal coupling of order one or larger, and the future XENON20T will cover almost the entire dark matter viable parameter space except for vanishingly small portal coupling.

Speaker: Yong Du (University of Massachusetts-Amherst)

pheno2020-Yong Du.pdf

19 Next Generation Dark Matter Models

Speakers: Linda Carpenter (UC Irvine), Linda Carpenter (Ohio State University), Prof. Linda Carpenter

PHENO20.pdf

20 Mirror Twin Higgs Portal Dark Matter

Direct and indirect detection experiments have excluded large regions of parameter space for many of the simplest models of sub-TeV WIMP dark matter. However, the predictions of these models can be altered through the introduction of non-equilibrium events in their cosmological history. In this study we explore the implications of an energy-dominating, asymmetric, out-of-equilibrium decay on Twin Higgs Portal Dark Matter (THPDM), a Mirror Twin Higgs (MTH) model extended by a singlet scalar acting as dark matter. Asymmetric decays are highly motivated within the MTH framework since Planck bounds on $\Delta N_{\text{eff}}$ severely restrict the amount of extra radiation that can be present during big bang nucleosynthesis (BBN). In THPDM, the asymmetric decay has the secondary effect of diluting the frozen-out dark matter population, which implies that the observed relic abundance today may be only a fraction of its original value. This leads to smaller direct detection cross section predictions compared to conventional models of Higgs Portal dark matter. We examine two models of asymmetric reheating in conjunction with THPDM to determine whether either scenario yields predictions accessible by the next generation of direct detection experiments.

Speaker: Shayne Gryba (University of Toronto)

Shayne_Gryba_MTHPDM.pdf

21 A sub-GeV dark matter model

We propose an extension of the Standard Model gauge symmetry by the gauge group $𝑈(1)_{𝑇3𝑅}$ in order to address the Yukawa coupling hierarchy between the third generation and the first two generation fermions of the SM. Only the right-handed Standard Model fermions transform non-trivially under the $𝑈(1)_{𝑇3𝑅}$ group. In addition to the new dark gauge boson, we have a dark scalar particle whose vacuum expectation value (vev) breaks the $𝑈(1)_{𝑇3𝑅}$ symmetry down to $𝑍_2$ symmetry and also explains the hierarchy problem. A vev of $\mathcal{O}$(GeV) is required to explain the mass parameters of the light flavor sector naturally. The dark matter (DM) particle arising from the model naturally has mass in the $\mathcal{O}$(1−100)MeV range. The model satisfies all the current constraints. The dark matter obtains the correct thermal relic density by annihilation. We also consider the effect on early Universe cosmology of the dark photon associated with the gauging of $𝑈(1)_{𝑇3𝑅}$. We find that cosmological constraints on this scenario are qualitatively much more severe than on other well-studied cases of a new 𝑈(1) gauge group, because the dark photon couples to chiral fermions.

Speaker: Sumit Ghosh (Texas A & M University)

pheno20_SG.pdf

22 Phenomenology of Singlet-doublet Fermionic Dark Matter

At present the Standard Model (SM) of particle physics is the best theory to describe the fundamental particles and their interactions in nature. After the Higgs discovery, the particle spectrum of the SM is almost complete. However, the SM does not possess a candidate that can mimic the nature of dark matter (DM) inferred from astrophysical observations. Moreover, the SM does not explain the sub-eV masses of the active left-handed neutrinos which is required to explain observed solar and atmospheric oscillation phenomena. Amongst many possibilities to accommodate DM in an extension of SM, a simple possibility is to extend the SM with two vector-like fermions: a SM gauge singlet and a doublet.

In this talk I shall elaborate how such singlet-doublet mixing can save a WIMP-like DM from stringent direct detection exclusion limit. At the same time, I shall elucidate, depending on the scalar sector, such DM models can also address light neutrino mass, paves path to a stable electroweak vacuum and give rise to strong first order phase transition producing detectable gravitational wave.

Speaker: Basabendu Barman

DM_BB_Pheno_2020.pdf

Neutrinos I

Convener: Peter Denton (Niels Bohr International Academy)

23 Looking forward to Neutrinos at the LHC

Neutrinos are copiously produced at particle colliders, but no collider neutrino has ever been detected. FASERv, a recently approved subdetector of FASER, is designed to detect such collider neutrinos for the first time and study their properties. In this talk, I will show that the small and inexpensive emulsion detector will be able to detect thousands of neutrino interactions with TeV energies. I will then discuss how FASERv will measure neutrino cross sections at energies where they are currently unconstrained, will bound models of forward particle production, and could open a new window on physics beyond the standard model.

Speaker: Felix Kling (SLAC)

Pheno2020.pdf

24 Long-lived heavy neutrino searches at the colliders

A gauged $U(1)_X$ extension of the Standard Model is a simple and consistent framework to naturally incorporate three right-handed neutrinos (RHNs) for generating the observed light neutrino masses and mixing by the type-I seesaw mechanism. We examine the collider testability of the $U(1)_X$ model, both in its minimal form with the conventional charges, as well as with an alternative charge assignment, via the resonant production of the $U(1)_X$ gauge boson $(Z^\prime)$ and its subsequent decay into a pair of RHNs. We first derive an updated upper limit on the new gauge coupling $g_X$ as a function of the $Z^\prime$-boson mass from the latest LHC dilepton searches. Then we identify the maximum possible cross section for the RHN pair-production under these constraints. Finally, we investigate the possibility of having one of the RHNs long-lived, even for a TeV-scale mass. Employing the general parametrization for the light neutrino mass matrix to reproduce the observed neutrino oscillation data, we perform a parameter scan and find a simple formula for the maximum RHN lifetime as a function of the lightest neutrino mass eigenvalue $(m_\rm{lightest})$. We find that for $m_\rm{lightest}\leq 10^{−5}$ eV, one of the RHNs in the minimal $U(1)_X$ scenario can be long-lived with a displaced-vertex signature which can be searched for at the LHC and/or with a dedicated long-lived particle detector, such as MATHUSLA. In other words, once a long-lived RHN is observed, we can set an upper bound on the lightest neutrino mass in this model.

Speakers: Dr Arindam Das (Department of Physics, Osaka University, Toyonaka), Arindam Das (Osaka U), Arindam Das (KIAS)

Das_PHENO2020.pdf

25 Scalar and Tensor Neutrino Interactions

We study the constraints on the General Neutrino Interactions (GNI) based on the framework of the Standard Model Effective Field Theory extended with right-handed neutrinos N (SMNEFT) from low-energy probes (neutrino scattering, nuclear beta decay, and meson decay), and high energy electron-proton and proton-proton colliders. We compute the one-loop anomalous dimensions of the low-energy effective Theory (LEFT) below the electroweak scale and SMNEFT above the electroweak scale. The tree-level matching between LEFT and SMNEFT is performed at the electroweak scale. Currently, the most stringent limit on scalar and tensor interactions arise from pseudoscalar meson decays and the LHC measurements, which are probing 10^{-3} level. In the future, the upcoming High-Luminosity LHC (HL-LHC) has the potential to reach 10^{-4} level and LHeC can play an important role with certain theoretical assumptions.

Speaker: Hongkai Liu

Hongkai_pheno20.pdf

26 Neutrino Non-Standard Interactions: Complementarities Between LHC and Oscillation Experiments

Physics beyond the standard model may induce significant deviations in the couplings involving neutrinos generally referred to as Non-Standard neutrino Interactions (NSI). We present a complementarity study between LHC and oscillation experiments to probe NSIs. We perform the analyses in a simplified model and an illustrative ultraviolet completion. The present and high-luminosity LHC sensitivities to NSIs are derived with jets plus missing energy searches. We show that besides constraining the allowed NSI parameter space, the LHC data can break relevant degeneracies from oscillation experiments. The results will be presented.

Speaker: Dr SUDIP JANA (Max-Planck-Institut für Kernphysik)

Pheno2020.pdf

27 Neutrino Non-Standard Interactions via Light Scalars

Non-standard interactions (NSI) of neutrinos with matter mediated by a scalar field would induce medium-dependent neutrino masses which can modify oscillation probabilities. Generating observable effects requires an ultra-light scalar mediator. I'll talk about general results for the scalar NSI using techniques of quantum field theory at finite density and temperature, including the long-range force effects, and discuss various limiting cases applicable to the neutrino propagation in different media, such as the Earth, Sun, supernovae and early universe. By combining all the constraints on the NSI parameters, it is shown that observable scalar NSI effects, although precluded in terrestrial experiments, are still possible in future solar and supernovae neutrino data.

Speaker: Garv Chauhan (Washington University in St. Louis)

Chauhan_Pheno2020.pdf

28 How well do we know neutrino-electron scattering? EFT approach for neutrino interactions

Neutrino-electron scattering provides a clean tool constraining the neutrino flux at accelerator-based neutrino facilities and requires precise theoretical predictions. We determine the effective theory of neutrino-electron and neutrino-quark scattering and provide the most precise up-to-date prediction for neutrino-electron scattering cross sections quantifying errors for the first time to be of order $0.2-0.4~\%$. Radiative corrections in the theory with electron and neutrinos can be determined from three effective couplings as an input. One is the Fermi constant which is known with sub-ppm accuracy. Another one has a small error of order $0.02~\%$. The uncertainty of the third one is limited by the knowledge of hadronic contributions to charge-isospin vector-vector correlation function. We also discuss tests of the Standard Model exploiting inputs at different scales and provide the most precise neutrino-electron and neutrino-quark couplings. The latter can be useful for evaluating the Standard Model processes and constraining new physics scenarios.

Speaker: Dr Oleksandr Tomalak (University of Kentucky)

talk_Oleksandr_Tomalak_Pheno2020.pdf

29 Muonium-Antimuonium Oscillations in Effective Field Theory

It is widely accepted that the standard model is not a complete theory and there is new physics to be found. One example is the experimental finding that neutrinos oscillate between flavors which is only possible if the neutrinos have non-zero mass. The flavor mixing of massive neutrinos is described by the Pontecorvo-Maki-Nakagawa-Sakata (PMNS) matrix leading to charged lepton flavor violation. Since flavor violating processes have highly suppressed branching ratios in the standard model mainly due to the tiny neutrino mass, observing lepton flavor violation (LFV), would be a clear indication of physics beyond the standard model. One possible way to search for LFV is muonium-antimuonium oscillations. This process violates muon lepton number by two units making it an important test of new physics. Using effective field theory (EFT), we calculated the mass and width differences of the mass eigenstates of muonium. Here the width difference is calculated for the first time. We believe future experiments searching for muonium oscillations would put further constraints on possible new physics.

Speaker: Renae Conlin (Wayne State University)

Pheno_2020_Renae_Conlin .pdf

Cosmology I

Convener: Arthur Kosowsky

30 The Gravitational Waves from the Early-Universe Turbulent Sources

I will review the results of our direct numerical simulations of magnetohydrodynamic turbulence in the early universe: I will discuss the stochastic background of gravitational waves and relic magnetic fields produced from the early-universe turbulence. These simulations do not make the simplifying assumptions of earlier analytic calculations. If the turbulence is assumed to have an energy-carrying scale that is about a hundredth of the Hubble scale at the time of generation, as expected in a first-order phase transition, the peak of gravitational wave power will be in the mHz frequency range for a signal produced at the electroweak scale. The efficiency of gravitational waves production varies significantly with how the turbulence is driven. Detectability of turbulence at the electroweak scale by the planned Laser Interferometer Space Antenna (LISA) requires anywhere from 0.1 to 10 percent of the thermal plasma energy density to be in plasma motions or magnetic fields, depending on the model of the driving process. At frequencies below the peak value, our results predict a new universal form of the spectrum with more power than previously thought. The enhanced low-frequency tail makes turbulence at significantly higher energy scales detectable.

Speaker: Tina Kakhniashvili

GWs-Pheno2020.pdf

GWs-Pheno2020.pptx

31 Gravitational Waves from Cosmological Phase Transitions in an Expanding Universe

In this talk, a discussion of gravitational wave calculations from an expanding universe will be presented. Details include changes to the dynamics of a cosmological first order phase transition, behaviors of the sources for gravitational wave production and the modified gravitational waves. Possible
applications to a non-standard cosmological history such as the existence of an early matter domination will be discussed.

Speaker: Huaike Guo (University of Oklahoma)

Huaike.pdf

32 A wrinkle in spacetime: searching for gravitational wave signatures of multiple hidden sectors.

I explore the possibility of detecting gravitational waves generated by first order phase transitions in multiple dark sectors. Nnaturalness is taken as a sample model that features multiple additional sectors, many of which undergo phase transitions that produce gravitational waves. I examine the cosmological history of this framework and determine the gravitational wave profiles generated. These profiles are checked against projections of next generation gravitational wave experiments, demonstrating that multiple hidden sectors can indeed produce unique gravitational wave signatures that will be probed by these future experiments.

Speaker: Mr Paul Archer-Smith (Carleton University)

Pheno2020.pdf

33 Spin Effects in Non-relativistic General Relativity Beyond the Leading Order

Understanding spin effects in the evolution of compact object binaries is essential to proper interpretation of waveforms from gravitational wave observatories such as LIGO. Spin degrees of freedom can be incorporated naturally into a post-Newtonian expansion during the binary’s inspiral phase. During this regime of a binary merger, there is a clear separation of scales between the radius of the compact object, the radius of the orbit, and the radiation wavelength that lends itself to an effective field theory description, known as non-relativistic general relativity. In this talk, I show how to include spin in this framework and how to extract physical observables relevant to producing analytical gravitational wave templates. In the process, I will discuss several subtleties of this method, including the need to impose proper spin supplementary conditions, and compare with calculations using alternative approaches.

Speaker: Mr Brian Pardo (University of Pittsburgh)

Pheno2020_BrianPardo.pdf

34 Phase Transitions as Cosmological Witnesses

We study the gravitational wave background from a first order phase transition generated during standard and nonstandard cosmological histories. We analyze the hydrodynamic properties of the plasma to define a self-similar invariant velocity profile to be utilized in the Sound Shell Model for acoustic gravitational wave production. We show that the relevant equations in an expanding universe take on the usual Minkowski form when the quantities are appropriately scaled. This allows us to investigate the impact an Early Matter Dominated era or a period of Kination before the Standard Radiation Dominated era will have on the stochastic gravitational wave background.

Speaker: Dan Vagie

Daniel_Vagie-Pheno_2020.pdf

35 Signatures of complex scalar field with chemical potential in primordial non-gaussianities

Oscillation in the bispectrum of density perturbations uniquely signifies the production of heavy fields during inflation, making it an important probe of physics at high energy scales. However, the magnitude of this non-gaussianity suffers Boltzmann-like suppression in models with minimal interaction between the inflaton and heavy fields, limiting the range of masses that can be probed close to the inflationary Hubble scale $H$. In the case of fermions and gauge bosons, it has been shown that a certain non-minimal derivative coupling of the inflaton to the massive field can lead to the development of a chemical potential $\lambda$. This boosts particle production, and hence the signal strength $f_{\text{NL}}$, by many orders of magnitude. We extend this chemical potential mechanism to the case of massive complex scalar fields. We show that $f_{\text{NL}} \sim O(10^{-2})-O(1)$ can be obtained for a large parameter space through tree-level diagrams. An important feature of the model is that detectably large signals can be obtained for masses up to $O(\lambda) >>H$, which is significantly larger than the case of other spin fields. We outline a procedure to extract the effective mass of the heavy field from the non-Gaussian signal, which is generally difficult in this mechanism due to the presence of additional parameters. Finally, we present an analysis of this mechanism in the curvaton paradigm.

Speaker: Ms Arushi Bodas (University of Maryland, College Park)

pheno20paralleltalk_ArushiBodas.pdf

36 Thermal Loop Effects on Large-Scale Curvature Perturbation in the Higgs Inflation

It is known that the Higgs potential in the Standard Model can drive successful inflation as long as the Higgs field couples non-minimally to gravity. It is then inevitable to take into account the loop corrections of the Standard Model particles to the Higgs potential in the Higgs inflation. In this talk, we discuss the one-loop corrections at finite temperature to the curvature perturbation generated during the Higgs inflation. We find that the thermal loop effects can suppress the power of the curvature perturbation at large scales, thus resulting in a low quadrupole of the temperature anisotropy in the cosmic microwave background.

Speaker: Mr Po-Wen Chang (The Ohio State University)

Po-Wen Chang_Thermal loop_Higgs inflation_Pheno2020.pdf

Axions & ALPs I

Convener: Bhupal Dev (Washington University in St. Louis)

37 Dark Photon searches at B-factories

Speaker: Giacomo De Pietro (INFN - National Institute for Nuclear Physics)

Presentazione_DePietro_PHENO2020.pdf

38 X-ray Searches for Axions

Axions are a generic expectation in many extensions of the Standard Model. Astrophysical objects have long been used to search for axions through, for example, cooling of white dwarfs or neutron stars. In these objects, axions can be created through scattering processes in the core and escape the star. However, the emitted axions can then be detected in X-ray observations if they convert into an X-ray photon on the way to Earth, either in the magnetosphere of the star or in the galactic magnetic fields. Here I present a summary of recent works searching for evidence of these particles from X-ray observations of white dwarfs, neutron stars, and late-stage massive stars. In particular, I focus on the recent discovery of an excess from nearby isolated neutron stars consistent with the axion expectation for an axion with the product of photon and nucleon couplings $g_{a\gamma\gamma}g_{ann} = 4.7 \times 10^{-21}$ GeV$^{-1}$ and mass $m_a < 10^{-5}$ eV. I discuss a variety of followup efforts to further characterize the nature of the excess.

Speaker: Christopher Dessert (University of Michigan)

Dessert_Pheno_2020.pdf

39 Axion Constraints from Quiescent Soft Gamma-ray Emission from Magnetars

Axion-like-particles (ALPs) emitted from the core of magnetars can convert to photons in their magnetospheres. We study such emissions in the soft-gamma-ray range (300 keV to 1 MeV), where the ALP spectrum peaks and astrophysical backgrounds from resonant Compton upscattering are expected to be suppressed. Using published quiescent soft-gamma-ray flux upper limits (ULs) in 6 Magnetars obtained with $\textit{CGRO}$ COMPTEL, $\textit{INTEGRAL}$ SPI/IBIS/ISGRI and the $\textit{Fermi}$ Gamma Ray Burst Monitor (GBM), we put limits on the ALP-photon coupling obtained from conversions, assuming that ALP emission from the core is just sub-dominant to bounds from neutrino cooling. For core temperatures ($T_c$) of $10^9$ K, the constraints on the ALP-photon coupling coming from 1E 2259+586 and J170849.0-400910 are better than the current limits obtained from the CAST experiment. We show the dependence of our results on the magnetar core temperature. Our results motivate a program of studying quiescent soft-gamma-ray emission from magnetars with the $\textit{Fermi}$-GBM.

Speaker: Mr Sheridan Lloyd (University of Durham)

AXION_MAGNETAR_TALK_2020_ISS1.pdf

40 Fast radio bursts from axion

Recent years there are more and more observed fast radio bursts (FRBs)
Their origin is still unknown. We propose a new origin of FRBs from the
well-motivated axion.

Speaker: Dr Fa Peng Huang

FaPengPheno2020.pdf

41 Axion cooling of neutron star mergers

Axions may be produced in nuclear matter via neutron bremsstrahlung. We calculate the mean free path of axions in neutron star merger conditions, and find that axions created in a merger would free-stream through it, leading to cooling of the merger. We calculate the emissivity of axions over a wide range of temperatures, densities, and axion-neutron coupling constants, and translate that into a characteristic cooling time due to axion emission. We find that in certain thermodynamic conditions, axion emission could cool nuclear matter in timescales less than ten milliseconds, which makes axion cooling relevant for neutron star mergers.

Speaker: Steven Harris (Washington University in St. Louis)

steven_harris_pheno_2020_axions.pdf

42 New Directions for Axion Searches via Scattering at Reactor Neutrino Experiments

Searches for pseudoscalar axion-like-particles (ALPs) typically rely on their decay in beam dumps or their conversion into photons in haloscopes and helioscopes. We point out a new experimental direction for ALP probes through their production via the Primakoff process or Compton-like scattering off of electrons or nuclei. We consider ALPs produced by the intense gamma ray flux available from megawatt-scale nuclear reactors at neutrino experiments through Primakoff-like or Compton-like channels. Low-threshold detectors in close proximity to the core will have visibility to ALP decays and inverse Primakoff and Compton scattering, providing sensitivity to the ALP-photon and ALP-electron couplings. We find that the sensitivity to these couplings at the ongoing MINER neutrino experiment exceeds existing limits set by laboratory experiments and, for the ALP-electron coupling, we forecast the world's best laboratory-based constraints over a large portion of the sub-MeV ALP mass range.

Speaker: Adrian Thompson (Texas A&M University)

thompson_ALPs_PHENO2020 (1).pdf

SUSY I

Convener: Konstantin Matchev (University of Florida (US))

43 Searches for strong production of supersymmetric particles with the ATLAS detector

Supersymmetry (SUSY) provides elegant solutions to several problems in the Standard Model, and searches for SUSY particles are an important component of the LHC physics program. Naturalness arguments for weak-scale supersymmetry favour supersymmetric partners of the gluons and third generation quarks with masses light enough to be produced at the LHC. This talk will present the latest results of searches conducted by the ATLAS experiment which target gluino and squark production, in a variety of decay modes, with final states including jets, leptons, and missing transverse momentum. It covers both R-parity conserving models that predict dark matter candidates and R-parity violating models that typically lead to high-multiplicity final states without large missing transverse momentum, and includes results which use new techniques to target compressed regions which have historically been difficult to access due to small mass splittings between SUSY particles.

Speaker: Marco Valente (Universite de Geneve (CH))

StrongSUSY_MarcoValente_Pheno2020.pdf

44 Searching for pair production of top squarks at the CMS

Results are presented from the most recent searches for pairs of supersymmetric top quarks with the CMS detector. The searches are performed in the in final states with and without leptons benefitting from the tagging of hadronically decayed boosted W or top quarks wherever applicable. The results are based on proton-proton collisions recorded at sqrt(s) = 13 TeV with the CMS detector using the full Run 2 dataset of 137 fb-1.

Speaker: Andrea Trapote Fernandez (Universidad de Oviedo (ES))

pheno2020_def.pdf

45 Searches for electroweak production of supersymmetric particles with the ATLAS detector

The direct production of electroweak SUSY particles, including sleptons, charginos, and neutralinos, is a particularly interesting area with connections to dark matter and the naturalness of the Higgs mass. The small production cross sections lead to difficult searches, despite relatively clean final states.The ATLAS experiment is exploring this experimentally challenging frontier with the large integrated luminosity of Run 2, multiple signatures, and new experimental techniques. This talk will highlight the most recent results of searches performed by the ATLAS experiment for supersymmetric particles produced via electroweak processes. Models are targeted in both R-parity conserving as well as R-parity violating scenarios.

Speaker: Jason Oliver (University of Adelaide (AU))

ATLAS_EWK_SUSY.pdf

46 SUSY phenomenology circa 2020

Recent LHC Run 2 limits on SUSY particles and null WIMP search results lead some to believe that SUSY is largely excluded save for some remote regions of parameter space. This ignores several developments in the past 20 years, including 1. the emergence of the string landscape and its solution to the cosmological constant problem, 2. the importance of the strong CP problem and the axion, 3. the role of discrete R symmetries in solving the SUSY mu problem and generating both R-parity and a gravity-safe global PQ symmetry and 4. an improved understanding of naturalness including the notion of stringy naturalness. I briefly summarize each of these, then show the resulting most promising avenues towards SUSY discovery at collider and WIMP and axion detection experiments.

Speaker: Howard Baer (University of Oklahoma)

Pheno2020_Baer.pdf

47 Stop and Gluino Searches at the LHC and Future Colliders

The analyses over the new supersymmetric particles by the ATLAS and CMS collaborations have revealed quite sensitive and strict results, which exclusively shape the fundamental parameter space of low scale SUSY models. These analyses usually make some assumptions over the mass spectrum and particle species such as bino-like LSP neutralino, left-handed lightest stop, stau etc. Even though results from such analyses constrain the low scale SUSY models, some of the assumptions may not hold, when the low scale spectrum is obtained in the framework of the SUSY grand unified theories (GUTs). In this talk, we present similar analyses performed within a class of SUSY GUTs and the exclusion curves for the stop and gluino from the current experimental results. We also perform the similar analyses to analyze the mass scales for stop and gluino, which can be probed in near future collider experiments.The work represented is supported by the Scientific and Technological Re- search Council of Turkey (TUBITAK) Grant no. MFAG-118F090.

Speaker: Dr Cem Salih Un (Bursa Uludag University)

CemSalihUn_Pheno2020.pdf

IMG_0136.MOV

48 Simple Hidden Sector Dark Matter

A hidden sector that kinetically mixes with the Minimal Supersymmetric Standard Model provides simple and well-motivated dark matter candidates that possess many of the properties of a traditional weakly interacting massive particle (WIMP). These supersymmetric constructions can also provide a natural explanation for why the dark matter is at the weak scale - even if it resides in a hidden sector. In the hidden sector, a natural pattern of symmetry breaking generally makes particles and their superpartners lie around the same mass scale, opening novel possibilities for a variety of cosmological histories and complex indirect detection signatures.

Speaker: Zachary Johnson (University of Michigan, Ann Arbor)

Pheno2020_Zachary-Johnson.pdf

15:45 -

QCD & EW I

Convener: Dr Daniel Wiegand (University of Pittsburgh)

49 Signal-background interference for digluon resonances at the Large Hadron Collider

We study the interference between the amplitudes for $gg \rightarrow X \rightarrow gg$, where $X$ is a new heavy digluon resonance, and the QCD background $gg \rightarrow gg$, at the Large Hadron Collider. The interference produces a large low-mass tail and a deficit of events above the resonance mass, compared to the naive pure resonance peak. For a variety of different resonance quantum numbers and masses, we evaluate the signal-background interference contribution at leading order, including showering, hadronization, and detector effects. The resulting new physics dijet mass distribution may have a shape that appears, after QCD background fitting and subtraction, to resemble an enhanced peak, a shelf, a peak/dip, or even a pure dip. We argue that the true limits on new digluon resonances are likely to differ significantly from the limits obtained when interference is neglected, especially if the branching ratio to $gg$ is less than 1.

Speaker: Prudhvi Nikhil Bhattiprolu (Northern Illinois University)

pbhattiprolu.pdf

50 Leading Fermionic Three-Loop Corrections to Electroweak Precision Observables

Future electron-position colliders, such as CEPC and FCC-ee, have the capability
to dramatically improve the experimental precision for W and Z-boson masses and
couplings. This would enable indirect probes of physics beyond the Standard Model at
multi-TeV scales. For this purpose, one must complement the experimental measurements with equally precise calculations for the theoretical predictions of these quantities
within the Standard Model, including three-loop electroweak corrections. This article
reports on the calculation of a subset of these corrections, stemming from diagrams
with three closed fermion loops to the following quantities: the prediction of the W-boson mass from the Fermi constant, the effective weak mixing angle, and partial and
total widths of the Z boson. The numerical size of these corrections is relatively modest, but non-negligible compared to the precision targets of future colliders. In passing,
an error is identified in previous results for the two-loop corrections to the Z width,
with a small yet non-zero numerical impact.

Speaker: Lisong Chen

pheno2020.pdf

51 Master Integrals for the mixed EW-QCD corrections to the Drell-Yan production of a massive lepton pair

We present the calculation of the master integrals needed for the two loop mixed QCD-Electroweak virtual corrections to the neutral current Drell-Yan processes $(q\bar{q}\rightarrow l^+ l^-)$. The dependence on the lepton mass is expanded such that potentially large logarithmic contributions are kept. Finally, the canonical master integrals are given as a Taylor series around four space-time dimensions with coefficients given in terms of generalized polylogarithms up to weight four.

Speaker: Syed Mehedi Hasan (INFN Sezione di Pavia)

Pheno 2020_Syed(v2).pdf

52 The proton radius puzzle

For almost 10 years now we are facing the proton radius puzzle, the difference between the proton charge radius extraction using electrons and muons. Taken at face value, the puzzle might be an indication of a new force in nature coupling to muons, but not to electrons. Recently PRad, a new electron-proton scattering experiment at Jefferson Lab, reported a proton charge radius that agrees with the muonic value. We perform a model-independent extraction of the proton charge radius from the PRad data. We find that the model-independent statistical error is more than 50% larger compared to the statistical error reported by PRad. We discuss the implications for the proton radius puzzle.

Speaker: Gil Paz (Wayne State University)

Proton_Radius_May_3_2020.pdf

53 Large electron electric dipole moment in the standard model

The electron electric dipole moment (EDM) is a very good probe of new physics beyond the standard model, and it is currently measured in many experiments.
It also receives contribution from the standard model, but this was estimated to be very small in previous works.
In this talk, we show that the short distance (quark-level) contribution to the electron EDM is suppressed by factors of quark masses.
We then calculate the long distance (hadron level) contribution, and show that the one-loop level process generates an EDM of O(10^{-39}) e cm, which is many orders of magnitude larger than the short distance one.

Speaker: Dr Nodoka Yamanaka (University of Massachusetts)

2020.05.04_yamanaka_electron_EDM.pdf

54 Integration By Parts like identities in Schwinger-Feynman-Lee-Pomeransky parametrization

The use of Integration-By-Parts (IBP) identities is currently an unavoidable step for the computation of scat-
tering amplitudes. IBP identities have been traditionally constructed in momentum space and, more recently, by employing Baikov parametrization. In this talk, we show the construction of a system of IBP-like equations over parametric space, namely using Schwinger-Feynman parameters within Lee-Pomeransky representation (SFLP). Unlike traditional IBP approaches, in the SFLP framework, we obtain non-zero contributions from the surface term. We derive an explicit form for surface term contribution, employing elementary calculus, and explicitly show that surface terms are related to lower sectors in the decomposition. As an instructive example of the application of our framework, we reconstruct the complete IBP reduction in the simple case of the two-loop sunset diagram.

Speaker: Ray Sameshima

Pheno_2020 (3).pdf

15:45 -

16:00 Coffee Break

Tools

Convener: Jürgen Reuter (DESY Hamburg, Germany)

55 A universal framework for t-channel dark matter models

We present a unique general framework allowing for all simulations relevant for simplified t-channel dark matter models at colliders and for the complementary cosmology calculations. We describe how to match next-to-leading-order QCD fixed-order calculations with parton showers to derive robust bounds and predictions in the context of LHC dark matter searches.

Speaker: Benjamin Fuks (Centre National de la Recherche Scientifique (FR))

fuks_pheno.pdf

56 A Robust Measure of Event Isotropy at Colliders

We introduce a new event shape observable -- event isotropy -- that quantifies how close the radiation pattern of a collider event is to a uniform distribution. This observable is based on a normalized version of the energy mover's distance, which is the minimum "work'' needed to rearrange one radiation pattern into another of equal energy. We investigate the utility of event isotropy both at electron-positron colliders, where events are compared to a perfectly spherical radiation pattern, as well as at proton-proton colliders, where the natural comparison is to either cylindrical or ring-like patterns. Compared to traditional event shape observables like sphericity and thrust, event isotropy exhibits a larger dynamic range for high-multiplicity events. This enables event isotropy to not only distinguish between dijet and multijet processes but also separate uniform N-body phase space configurations for different values of N. As a key application of this new observable, we study its performance to characterize strongly-coupled new physics scenarios with isotropic collider signatures.

Speaker: Cari Cesarotti (Harvard University)

phenoIsotropy.pdf

57 Learning Physics at Future $e^-e^+$ Colliders with Machine

Information deformation and loss in jet clustering are among the major limitations for precisely measuring hadronic events at future $e^-e^+$ colliders. Because of their dominance in data, the measurements of such events are crucial for advancing the precision frontier of Higgs and electroweak physics in the next decades. We show that this difficulty can be well-addressed by synergizing the event-level information into the data analysis, with the techniques of deep neutral network. For this purpose, we introduce a CMB-like observable scheme, where the event-level kinematics is encoded as the Fox-Wolfram (FW) moments at leading order and multi-spectra at higher orders. Then we develop a series of
jet-level (w/ and w/o the FW moments) and event-level classifiers, and analyze their sensitivity performance comparatively. As part of the benchmark study, we analyze the precision of measuring Higgs decay width at $e^-e^+$ colliders with the data of 5ab$^{-1}@$240GeV. The precision obtained is significantly better than the baseline ones presented in documents. We expect this strategy to be applied to many other hadronic-event measurements at future $e^-e^+$ colliders, and to open a new angle for evaluating their physics capability.

Speaker: LINGFENG LI (UC Davis)

EventLevel_Pheno2020.pdf

58 Generalizied Interpretation of single VLQ Searches at the LHC

Significant efforts have been put forward at both ATLAS and CMS experiments in search of Vector-like Quarks (VLQs). The results of these searches are relatable in the context of different VLQ models when they are represented in a general fashion. This talk summarizes challenges associated with such interpretations of singly produced VLQ searches and proposes a generalized, semi-analytical framework that interprets these results in terms of unconstrained, free parameters of the VLQ Lagrangian. A simple parameterization of the correction factor to the single VLQ production cross-section at large decay widths is presented. The proposed framework is used to conveniently represent statistical limits by numerically reinterpreting results from benchmark ATLAS and CMS analyses.

Speaker: Avik Roy (University of Texas at Austin (US))

Avik_Pheno2020.pdf

59 Delaunay Tessellations for Bayesian Wombling on LHC Data

The relevant information from LHC collision events can be represented as spatial point data in a suitable phase space. The observation of sharp discontinuities in the observed event number density would hint at the presence of new physics beyond the Standard Model. We apply and further improve upon some known wombling techniques from other fields. In the process we refine some of the known methods of calculating gradients from point data.

Speaker: Alex Roman (University of Florida)

Optimized_Wombling_for_LHC_data___Pheno.pdf

60 JHU generator framework: new features for Higgs boson studies

The JHU generator framework includes an event generator of anomalous HVV and Hff interactions of the Higgs boson in production and decay and a MELA library for matrix element analysis. This framework allows constraints on dimension-six operators of an effective field theory from a joint analysis of on-shell and off-shell production of the Higgs boson and of triple and quartic gauge boson interactions. Gluon fusion, vector boson fusion, and associated production with a vector boson are considered. Potential contributions from new states are included. Associated production with one or two top quarks and gluon fusion process allow access to the CP structure of Yukawa interactions. Practical applications to the EFT analysis of the current and future LHC datasets are discussed.

Speaker: Heshy Roskes (Johns Hopkins University (US))

JHUGen.pdf

61 A quantum algorithm for model independent searches for new physics

Recently there has been a growing interest in the application of quantum computing in many scientific disciplines, including high energy physics. In this talk, we will look at a novel quantum computing based technique to search for unmodeled deviations from a simulated expectation in high-dimensional collider data.

Speaker: Prasanth Shyamsundar (University of Florida)

Presentation.pdf

18:15 -

Cosmology II

Convener: Keisuke Harigaya (IAS)

62 Hubble Hullabaloo and String Cosmology

The discrepancy in measurements of the Hubble constant $H_0$ indicates new physics in dark energy, dark matter, or both. Drawing inspiration from string theory, where the dilaton interacts with the other moduli fields to accommodate the Agrawal-Obied-Vafa proposal of fading dark matter, we explore possible solutions to overcome the $H_0$ problem.

Speaker: Prof. Luis Anchordoqui (City University of New York)

Anchordoqui_pheno2020.pdf

63 Braneworld Cosmological Effect on Freeze-in Dark Matter Density and Lifetime Frontier

In the 5-dimensional braneworld cosmology, the Friedmann equation of our 4-dimensional universe on a brane is modified at high temperatures while the standard Big Bang cosmology is reproduced at low temperatures. Based on two well-known scenarios, the Randall-Sundrum and Gauss-Bonnet braneworld cosmologies, we investigate the braneworld cosmological effect on the relic density of a non-thermal dark matter particle whose interactions with the Standard Model particles are so weak that its relic density is determined by the freeze-in mechanism. For dark matter production processes in the early universe, we assume a simple scenario with a light vector-boson mediator for the dark matter particle to communicate with the Standard Model particles. We find that the braneworld cosmological effect can dramatically alters the resultant dark matter relic density from the one in the standard Big Bang cosmology. As an application, we consider a right-handed neutrino dark matter in the minimal B−L extended Standard Model with a light B−L gauge boson (Z′) as a mediator. We find an impact of the braneworld cosmological effect on the search for the long-lived Z′ boson at the planned/proposed Lifetime Frontier experiments.

Speaker: Victor Baules (University of Alabama, The)

BCE_Pheno2020_Vbaules_040520_updated_(please use this version).pdf

BCE_Pheno2020_Vbaules.pdf

64 A Reconstruction Conjecture: Deciphering the Structure of the Dark Sector from the Matter Power Spectrum

Non-trivial dynamics within the dark sector can give rise to a complicated, non-thermal dark-matter phase-space distribution, which in turn can affect the shape of the matter power spectrum. In this talk, we examine the extent to which one can address the archaeological "inverse" problem of deciphering the properties of the underlying dark sector from features imprinted in the matter power spectrum. We also posit a simple relation that allows us to reconstruct the salient features of the underlying dark-matter phase-space distribution directly from the matter power spectrum. This conjecture therefore provides a way of gleaning additional information about the particle properties of the dark sector through purely gravitational means.

Speaker: Prof. Brooks Thomas (Lafayette College)

brooks-thomas-pheno-2020.pdf

65 Deciphering the Structure of the Dark Sector from the Matter Power Spectrum: A Concrete Example

Particle-physics processes within the dark sector could leave imprints on the dark-matter phase-space distribution, and therefore influence the way in which structure forms in the early universe. In a recent paper [arXiv:2001.02193], we proposed a procedure for reconstructing the dark-matter phase-space distribution from the shape of the matter power spectrum. In this talk, we demonstrate how this reconstruction procedure works in practice by applying it in the context of an illustrative example model in which a variety of non-trivial and even multi-modal dark-matter phase-space distributions can arise from decays within a non-minimal dark-sector. We examine the relationship between the decay dynamics and the shape of the transfer function and demonstrate that indeed our reconstruction procedure allows us to reconstruct the salient features of the dark-matter phase-space distribution.

Speaker: Fei Huang (ITP CAS and UC Irvine)

pheno 2020.pdf

66 Spontaneous Freeze Out of Dark Matter from an Early Thermal Phase Transition

In this talk I will introduce a new paradigm for the thermal production of dark matter in the early Universe, in which dark-matter particles acquire their mass and freeze out spontaneously from the thermal bath after a dark phase transition takes place. The decoupling arises because the dark-matter particles become suddenly nonrelativistic and not because of any decay channel becoming kinematically close. We propose a minimal scenario in which a scalar and a fermionic dark matter are in thermal equilibrium with the standard-model bath. We compute the finite temperature corrections to the scalar potential and identify a region of the parameter space where the fermionic dark-matter mass spontaneously jumps over the temperature when the dark phase transition happens. We explore the phenomenological implications of such a model in simple cases and show that the annihilation cross section of dark-matter particles has to be larger by more than 1 order of magnitude as compared to the usual constant-mass weakly interacting massive particle scenario in order to accommodate the correct relic abundance. We show that in the spontaneous freeze out regime a TeV-scale fermionic dark matter that annihilates into leptons through s-wave processes can be accessible to detection in the near future.

Speaker: Lucien Heurtier (University of Arizona, Tucson, AZ, USA)

Heurtier_2020_Pheno.pdf

67 Warm Self-Interacting Dark Matter Bounds from Lyman Alpha

Lyman-alpha forest observations require the mass of warm dark matter (DM) particles to be greater than a few keV. We calculate how this bound is modified if the warm dark matter particles are also self-interacting. We use a linear perturbation evolution code, which we wrote ourselves, to determine the growth of the initial perturbations in the early universe for warm self-interacting dark matter. We compare our results to observation of the matter power spectrum at high wave number and determine what regions of the cross section-dark matter mass parameter space is ruled out by current observations. This is currently a work in progress, and I will present the current status and and outlook of the project.

Speaker: Daniel Gift (Stony Brook University)

Probing Self-Interacting Dark Matter via Matter Power Spectrum (6).pdf

68 Post-inflationary Production of Light Dark Sector

Light dark sector particles, especially bosons if coupled to the inflaton can be copiously produced during (p)reheating epoch courtesy to Bose enhancement. In many particle physics scenarios such particles are often invoked to resolve tensions with cosmologicalbounds from Big Bang Nucleosynthesis (BBN), Cosmic Microwave Background (CMB) and Large Scale Structure (LSS). We will discuss two specific cases - one involving bosonic mediators with light sterile neutrinos invoked in context to several neutrino experimental anomalies and one in context to non-thermal production of dark matter. We will discuss the post-inflationary particle production in a large field inflationary model and highlight the region of the parameter space viable with early universe cosmology.

Speaker: Dr Anish Ghoshal

Talk7Ghoshal.pdf

18:15 -

Flavor I

Convener: Simon Eydelman (Budker Institute of Nuclear Physics (RU))

69 Flavor Mini-review

I will give a brief introduction to flavor physics theory, with a focus on recent developments in B, D, and K decays.

Speaker: Joachim Brod (University of Cincinnati)

flavor.pdf

70 A low-scale flavon model with a ZN symmetry

We propose a model that explains the fermion mass hierarchy by the Froggatt-Nielsen mechanism with a discrete $Z_N$ discrete flavor symmetry. As a concrete model, we study a supersymmetric model with a single flavon coupled to the minimal supersymmetric Standard Model. Flavon develops a TeV scale vacuum expectation value for realizing flavor hierarchy, an appropriate $\mu$-term and the electroweak scale, hence the model has a low cutoff scale. We demonstrate how the flavon is successfully stabilized together with the Higgs bosons in the model. The discrete flavor symmetry $Z^F_N$ controls not only the Standard Model fermion masses, but also the Higgs potential and a mass of the Higgsino which is a good candidate for dark matter. The hierarchy in the Higgs-flavon sector is determined in order to make the model anomaly-free and realize a stable electroweak vacuum. We show that this model can explain the fermion mass hierarchy, realistic Higgs-flavon potential and thermally produced dark matter at the same time. We discuss flavor violating processes induced by the light flavon which would be detected in future experiments.

Speaker: Junichiro Kawamura (Keio University)

Pheno_JKawamura.pdf

71 A $\mathcal{T}_{13}$ Family Symmetry Model for Quarks and Leptons

I will propose a phenomenologically successful $SU(5)$ Yukawa texture for both quarks and leptons that explains their GUT-scale mass ratios and mixing angles. Together with a complex-tribimaximal (TBM) seesaw mixing, this texture reproduces the neutrino mixing angles and predicts both Dirac and Majorana leptonic $CP$ violation. I will show that this framework can be accommodated in a family symmetry model based on the Frobenius group $\mathcal{T}_{13}$, a subgroup of $SU(3)$. The most important ingredient of the texture, asymmetry, singles out $\mathcal{T}_{13}$ as the minimal discrete symmetry. I will discuss how to build a unified model of effective interactions that yields the nontrivial features of the asymmetric texture without any fine-tuning.

Speaker: Moinul Hossain Rahat (University of Florida)

Pheno2020_Rahat.pdf

72 Revisiting $X(3872) \to D^0 \bar{D}^0 \pi^0$ in XEFT

The calculation of the decay $X(3872)\to D^0 \bar{D}^0 \pi^0$ in
effective field theory is revisited to include final state $\pi^0 D^0$,
$\pi^0 \bar{D}^0$ and $D^0\bar{D}^0$ rescattering diagrams. These introduce significant
uncertainty into the prediction for the partial width as a function of
the binding energy. The differential distribution in the pion energy is
also studied for the first time. The normalization of the distribution is again quite uncertain due to higher order effects but the shape of
the distribution is unaffected by higher order corrections. Furthermore
the shape of the distribution and the location of the peak are sensitive to the binding energy of $X(3872)$. The shape is strongly impacted by the presence of virtual $D^{*0}$ graphs which highlights the molecular nature of the $X(3872)$.
Measurement of the pion energy distribution in the decay $X(3872)\to D^0 \bar{D}^0 \pi^0$ can reveal interesting information about the binding
nature of the $X(3872)$.

Speaker: Lin Dai (Duke University)

Lin-Dai-pheno20.pdf

73 Charm-meson Triangle Singularity in $e^+e^-$ Annihilation into $D^{∗0}\bar{D}^0+\gamma$

We calculate the cross section for $e^+e^-$ annihilation into $D^{∗0}\bar{D}^0+\gamma$ at center-of-mass energies near the $D^{∗0}\bar{D}^{∗0}$ threshold under the assumption that $X(3872)$ is a weakly bound charm meson molecule. The Dalitz plot has a $\bar{D}^{∗0}$ resonance band in the squared invariant mass $t$ of $\bar{D}^0 \gamma$. In the limit as the decay width of the $D^{∗0}$ goes to 0, the Dalitz plot also has a narrow band from a charm-meson triangle singularity in the squared invariant mass $u$ of $D^{∗0}\bar{D}^0$. At the physical value of the $D^{∗0}$ width, the narrow band reduces to a shoulder. Thus the triangle singularity cannot be observed directly as a peak in a differential cross section as a function of $u$. It may however be observed indirectly as a local minimum in the $t$ distribution for events with $u$ below the triangle singularity. The minimum is produced by the Schmid cancellation between the triangle diagrams and their interference with a tree diagram. The observation of this minimum would support the identification of $X(3872)$ as a weakly bound charm meson molecule.

Speaker: Dr Jun Jiang

CharmSlides.pdf

74 Doubly Heavy Tetraquarks in the Heavy-Diquark Limit with Error Bars

In the heavy-diquark limit, the two heavy quarks in a doubly heavy baryon or a doubly heavy tetraquark are bound by their color-Coulomb potential into a compact core. The doubly heavy hadron is related by an approximate symmetry to the heavy hadron obtained by replacing the diquark core by a heavy antiquark. The masses of heavy hadrons can be expanded in inverse powers of the heavy quark mass. These expansions can be used to predict the masses of doubly heavy tetraquarks using as inputs the masses of heavy mesons and heavy baryons measured in experiments and the masses of doubly heavy baryons calculated using lattice QCD. We present the resulting predictions with error bars for the masses of the ground-state doubly heavy tetraquarks.

Speaker: Liping He (Ohio State University)

Tetraquark-pheno-LipingHe.pdf

75 ATLAS results on quarkonia and heavy flavour production (including exotics)

The associated production of vector boson with quarkonia is a key observable for understanding the quarkonium production mechanisms, including the separation of single and double parton scattering components. This talk will present the latest measurements from ATLAS on quarkonium production, including associated production, and recent results from heavy flavour production. In addition, recent searches for exotic states, such as pentaquarks, will be highlighted.

Speaker: Tatiana Lyubushkina (Joint Institute for Nuclear Research (RU))

Lyubushkina_ATLAS_QHfProd.pdf

Higgs I

Convener: William Shepherd (Sam Houston State University)

76 A Light Scalar Explanation of Muon g−2 and the KOTO Anomaly

The KOTO experiment has recently performed a search for neutral Kaons decaying into neutral pions and a pair of neutrinos. Three events were observed in the KOTO signal region, with an expected background of about 0.05. Since no clear signal of systematic errors have been found, the excess of events in the decay $K_{L}\rightarrow\pi^0\nu\bar{\nu}$ is quite intriguing. One possibility to explain this anomaly would be the presence of a scalar $\phi$ with mass of the order of the pion mass and inducing decays $K_L \to \pi^0 \phi$ which mimic the observed signal. A scalar with mass of the order of the pion mass and a coupling to muons of the order of the Standard Model Higgs coupling could also explain the muon anomalous magnetic moment anomaly $(g-2)_{\mu}$. We built on these facts to show that a light singlet scalar with couplings to the leptons and quarks as the ones induced by mixing with Higgs states in two Higgs doublet models may lead to an explanation of both anomalies. More specifically, we show that this is the case in the so-called type-X models in which leptons and quarks couple to two different Higgs doublets, and for scalar masses that are in the range between 40 and 70 MeV. Due to the relatively large coupling to leptons required to fit $(g-2)_{\mu}$, the scalar lifetime accidentally falls into the sub-nanosecond range which is essential to evade the severe proton beam dump experiments and astrophysical constraints, though it becomes sensitive to constraints from electron beam dump experiments. The additional phenomenological properties of this model are discussed.

Speaker: Jia Liu (University of Chicago)

2020-05-04-Pheno2020-JL-6-short.pdf

77 Light Scalars and the KOTO Anomaly

The KOTO experiment recently presented an excess of events in their search for the rare Standard Model (SM) process $K_L \to \pi^0 \nu\bar{\nu}$, well above the combined SM signal and background prediction. In this talk, I will show how an excess of events may be explained by weakly-coupled scalar particles produced in Kaon decays that escape KOTO undetected. I will review two concrete realizations: the minimal Higgs portal and a hadrophilic scalar model. Both have regions of parameter space that can explain the observed events while satisfying bounds from other flavor and beam-dump experiments. Hadronic beam-dump experiments provide particularly interesting constraints on light scalar particles, and I will discuss in detail the often underestimated uncertainties associated with these bounds. The simplicity of the models which can explain the excess, and their possible connections to other well known theories of beyond the Standard Model physics, provides strong theoretical motivation for a new physics interpretation of the KOTO data.

Speaker: Samuel Homiller (YITP, Stony Brook)

homiller_koto.pdf

78 Neutral and Doubly-Charged Scalars at Future Lepton Colliders

Many new physics scenarios beyond the Standard Model (BSM) often necessitate the existence of new neutral and/or charged scalar fields, which might couple to the SM charged leptons and thus give some BSM signals while evading all existing constraints. We show that future lepton colliders provide a clean environment to probe these BSM including some interesting lepton flavor violating (LFV) signals. We study the distributions of the final state leptons to distinguish the BSM contributions from neutral and doublycharged scalars each other, as well as from the irreducible SM background at future lepton colliders, such as ILC and CLIC.

Speaker: Fang Xu

Probing Neutral and Doubly-Charged Scalars at Future Lepton Colliders.pdf

79 Updated constraints on the Georgi-Machacek model

The Georgi-Machacek (GM) model extends the Standard Model Higgs sector with weak isospin triplets in such a way as to preserve the $\rho$ parameter at tree level. We evaluate the experimental constraints on the GM model from direct searches for new Higgs bosons and from measurements of the 125 GeV Higgs. A large number of constraints are implemented by interfacing the public codes HiggsBounds and HiggsSignals with the GM model calculator GMCALC.

We find that large regions of parameter space are allowed by the current data. Furthermore, we evaluate the allowed couplings of the 125 GeV Higgs after applying all experimental constraints, noting that the most stringent constraints arise from direct searches for new Higgs bosons, rather than from 125 GeV Higgs signal strengths. We also identify novel constraints on the model from new Higgs decays $H_3^0 \rightarrow Zh$ and $H \rightarrow hh$. These are promising channels for future searches.

Speaker: Ameen Ismail (Cornell University)

Ameen_Ismail_pheno_2020.pdf

80 Constraints on the Inert(1+2)HDM

We study a three Higgs doublet model where one doublet is inert and the other two doublets are active. Flavor changing neutral currents are avoided at tree-level by imposing a softly broken $𝑍_2$ symmetry and we consider type I and type II Yukawa structures. The lightest inert scalar is a viable Dark Matter (DM) candidate. A numerical scan of the free parameters is performed taking into account theoretical constraints such as positivity of the scalar potential and unitarity of 2 → 2 scattering amplitudes. The model is further constrained by experimental results such as B physics lower limits on charged Higgs masses, Electroweak Precision Observables, LEP II, LHC Higgs measurements, Planck measurement of the DM relic abundance and WIMP direct searches by the LUX and XENON1T experiments. The model predictions for mono-jet, mono Z and mono Higgs final states are studied and tested against current LHC data and we find the model to be allowed. We also discuss the effects of abandoning the “dark democracy” assumption common in studies of inert models. Projected sensitivities of direct detection experiments will leave only a tiny window in the DM mass versus coupling plane that is compliant with relic density bounds

Speaker: Marco Merchand

pheno_pres.pdf

81 Probing Exotic Charged Higgs Decays in the Type-II 2HDM through Top Rich Signal at a Future 100 TeV pp Collider

The exotic decay modes of non-Standard Model (SM) Higgs bosons are efficient in probing the hierarchical Two Higgs Doublet Models (2HDM). In particular, the decay mode $H^\pm\to HW^\pm$ serves as a powerful channel in searching for the charged Higgses. In our study, we analyzed the reach for $H^\pm\to HW^\pm \to t\bar{t}W$ at a 100 TeV $pp$ collider, and showed that it extends the reach of the previously studied $\tau\tau W$ final states. Top tagging technique is used, in combination with the boosted decision tree classifier. Almost the entire hierarchical Type-II 2HDM parameter space can be probed via the combination of all exotic decay channels at low $\tan\beta$ region.

Speaker: Shuailong Li

ShuailongLi_pheno2020.pdf

82 Testing the EWPT of 2HDM at future lepton Colliders

A successful electro-weak baryongenesis calls for a strong first order electro-weak phase transition (SFOEWPT), which is unavailable in the Standard Model (SM). Some degree of modification on Higgs potential at electro-weak temperature is required to develop an energy barrier, and the property of Higgs at zero temperature is also changed accordingly. In this work we study the realization of SFOEWPT in type-I and type-II two Higgs doublet model (2HDM), and changes of Higgs couplings in SFOEWPT satisfied parameter regions. A global fit to various search channels at future electron colliders is performed to obtain the 95% C.L. limits on parameter space. Our results shows that future electron colliders are capable of excluding most SFOEWPT parameter region in type-I and type-II 2HDM.

Speaker: wei su (university of Adelaide)

pheno2020-weisu.pdf

83 Higgs troika for baryon asymmetry

To explain the baryon asymmetry of the Universe, we extend the
Standard Model (SM) with two additional Higgs doublets with small vacuum expectation values. The additional Higgs fields interact with SM fermions through complex Yukawa couplings, leading to new sources of CP violation. We propose a simple flavor model with $\mathcal{O}(1)$ or less Yukawa couplings for quarks and charged leptons, consistent with current flavor constraints. To generate neutrino masses and the baryon asymmetry, right-handed neutrinos in the $\sim 0.1-10$~TeV range couple to the ``Higgs Troika.'' The new Higgs doublet masses are at or above the TeV scale, allowing for asymmetric decays into SM lepton doublets and right-handed neutrinos. The asymmetry in lepton doublets is then processed into a baryon asymmetry, similar to leptogenesis. Since the masses of the new fields could be near the TeV scale, there is potentially a rich high energy collider phenomenology, including observable deviations in the 125~GeV Higgs decay into muons and taus, as well as detectable low energy signals such as the electron EDM or $\mu\rightarrow e\gamma$. Hence, this is in principle a testable model for generation of baryon asymmetry.

Speaker: Matthew Sullivan (University of Kansas)

HiggsTroika.pdf

QCD & EW II

Convener: Dr Bin Yan (Michigan State University)

84 Valence and Connected Sea Partons in Hadronic Tensor and LaMET

We point out the deficiency of the phenomenological definition of the valence partons as the difference between the partons and antipartons in the NNLO evolution equations and show that the classification of the partons of the valence and connected sea from the path-intergral formulations QCD in terms of the hadronic tensor and the quasi-PDF with LaMET resolves this issue.

Speaker: Kehfei Liu (University of Kentucky)

Pheno_2020.pdf

85 Gluon parton distribution function from Lattice QCD

The parton distribution functions (PDFs) are process-indenpendent information of the quark and gluon inside the hadron. Even though gluon PDF could be obtained from the global fit of the experimental data and dominates at the small x region, gluon PDF studies from theoretical side are much fewer then quark PDF. We present the results to access the x-dependence of the gluon unpolarized PDF inside nucleon using lattice QCD. The lattice calculation is carried out for the gluon PDF matrix element with the nucleon momentum up to 2.16 GeV and lattice spacing a=0.12 fm and 0.15 fm. Our results for these matrix elements are compared with the Fourier transform of the global fit CT18 of the gluon PDF.

Speaker: Mr Zhouyou Fan (Michigan State University)

2020-05-04_Zhouyou.pdf

86 Strange parton distribution function (PDF) from lattice QCD

Strange PDF is important for us to understand the nucleon structure and the test of electroweak interactions, but is not significantly constrained by experimental data. We present the first preliminary results of the unpolarized strange PDF from lattice calculation in the large momentum effective theory (LaMET) approach. The calculation is done on a lattice with lattice spacing $a\approx0.12$ fm and $M_\pi\approx310$ MeV. The nucleon is boosted with momentum up to $P_z=2.18$ GeV to obtain the spatial correlations that can be matched to the light-cone PDF with a perturbative kernel. The non-perturbative renormalization factors in the regularization independent momentum subtractions scheme are applied to renormalized the bare matrix elements. It’s difficult to directly match the results to light-cone PDF in this case, thus we compared our results with the matrix elements obtained from matching the CT18NNLO and NNPDF3.1NNLO global fitting PDF. Our data support a symmetric $s-\bar{s}$ distribution, but the distribution in coordinate space from our results are flatter than the global fitting results, indicating a smaller first moment.

Speaker: Mr Rui Zhang (Michigan State University)

Pheno20_Rui.pdf

87 The Electroweak PDFs (I): the general considerations

The collinear factorization of the photon parton distribution function (PDF), such as the Weizsaicker-Williams approximation, i.e., ``equivalent photon approximation (EPA)'', works very well at the low and intermediate energies. However, with energy increasing above the electroweak (EW) scale $(v)$, the photon mixes with $Z$-boson, which makes the photon PDF not well defined, anymore. Therefore, we would expect that the electroweak bosons come in and make a difference.
In this work, we extend the traditional photon PDF to the EW theory $SU(2)_L\times U(1)_Y$, and define the EW PDFs properly, which includes the gauge bosons $W^\pm,Z$ and Higgs scalars as well. Due to the chiral nature of the EW theory, some new phenomena emerge. (a) Due to parity violation of EW interactions, we are not able to factorize the beam or hadronic cross section in an unpolarized way, even for unpolarized beams. Therefore, the polarized PDFs are necessary. (b) In the high energy limit, the conventional PDFs encounter logarithmic violation even at the leading order splitting, which is intrinsically different from QED and QCD. (c) Considering the EW symmetry breaking (EWSB), we need a systematic matching between the high energy asymptotically symmetric phase and the broken phase at low energy.

Speaker: Keping Xie (University of Pittsburgh)

EWPDF4Pheno.pdf

88 The Electroweak PDFs (II): the necessity and applications

The Weizsaicker-Williams approximation, i.e., ''equivalent photon approximation'', is a powerful tool, both in understanding the electromagnetic radiation and in studying the photon interaction processes. Just like the quark and gluon partons in quantum chromodynamics, photon could be treated as a parton constituent in the initial state beam particles and described using a photon parton distribution function (PDF). However, questions arise when people consider physics processes beyond the electroweak (EW) scale characterized by $Z$ boson mass, where the ``photon'' is not well defined anymore. Does the conventional photon PDF remain valid at scales above $m_Z$? Do we need to consider adding in the $Z$ and the $\gamma Z$ mixing PDFs? How much do the EW PDFs affect the theoretical predictions?
Therefore, we take a realistic process, $e^-\mu^+\to e^-W^+\bar{\nu}_\mu$, to explore the relative contribution at leading order from the photon, $Z$ boson, and the interference, which helps answer the necessity of the EW PDFs. It is found that, the EW PDFs affects are strongly polarization dependent, which agrees with the chiral feature of the EW theory. In the initial $e_L^-$ beam case, we obtain a large cancellation between the $Z$ and the $\gamma Z$ interference. But for the $e_R^-$ case, we get a constructive contribution from the $\gamma Z$ interference. The EW PDF contribution from the $Z$ and $\gamma Z$ interference become comparable with the one from photon PDF at energies starting around $\sqrt{s}=1$ TeV. Particularly, for $e_R^-$ beam, the EW PDFs contribute $20\%$ of the total cross section at $500$ GeV, which can be tested at colliders in the near future, such as ILC and FCCee.

Speaker: Yang Ma (University of Pittsburgh)

EWPDF2.pdf

89 Recent observation and measurements of vector-boson fusion and scattering with ATLAS

The scattering of electroweak bosons tests the gauge structure of the Standard Model and is sensitive to anomalous weak boson self interactions. In this talk, we present recent results on weak-boson fusion and weak-boson scattering from the ATLAS experiment using proton-proton collisions at √s=13 TeV. We present the first observation of ZZ production via weak-boson scattering as well as evidence for Z𝛾 production, in final states where the Z boson decays leptonically. If available, measurements of Vjj final states produced via weak-boson fusion will also be presented.

Speaker: Jing Chen (University of Science and Technology of China (CN))

VBF_Jing_Pheno2020.pdf

18:00 -

BSM II

Convener: Gil Paz (Wayne State University)

90 Sensitivity of LNV Meson Decays in Different Experiments

We study the discovery prospect of different three body lepton number violating~(LNV) meson decays $M_{1}^{-}\to\ell_{1}^{-}\ell_{2}^{-}M_{2}^{+}$ in the framework of right handed~(RH) neutrino extended Standard Model~(SM). We consider a number of ongoing experiments, such as, NA62 and LHCb at CERN, Belle II at SuperKEK, as well as at the proposed future experiments, SHiP, MATHUSLA and FCC-ee. The RH Majorana neutrino $N$ mediating these meson decays provides a resonant enhancement of the rates, if the mass of $N$ lies in the range $(100\, \text{MeV}-6\, \text{GeV})$. We consider the effect of parent mesons velocity, as well as, the effect of finite detector size. Using the expected upper limits on the number of events for the LNV decay modes, $M_{1}^{-} \to\ell_1^{-}\ell_2^{-}\pi^{+}$~($M_{1}=B, B_c,D, D_{s}\,\text{and}\,K$), we analyze the sensitivity reach of the mixing angles $|V_{e N}|^{2}$, $|V_{\mu N}|^{2}$, $|V_{\tau N}|^{2}$, $|V_{e N}V_{\mu N}|$, $|V_{e N}V_{\tau N}|$ and $|V_{\mu N}V_{\tau N}|$ as a function of heavy neutrino mass $M_{N}$. We show that, inclusion of parent meson velocity can account to a large difference for active-sterile mixing, specially for $D$, $D_s$ meson decay at SHiP and $K$ meson decay at NA62. Taking into account the velocity of the $D_s$ meson, the future beam dump experiment SHiP can probe $|V_{eN}|^2 \sim 10^{-9}$. For RH neutrino mass in between 2 - 5 GeV, MATHUSLA can provide best sensitivity reach of active-sterile mixings.

Speaker: Dr Sanjoy Mandal (IFIC, University of Valencia)

Pheno2020.pdf

91 Pair-production of dark particles in meson decays

Rare decays of $K,B$ mesons provide a powerful probe of dark sectors with light new particles. We show that the pair production of $O(100\,{\rm MeV})$ dark states can be probed with the decays of $K_L$ mesons, owing to the enhanced two-body kinematics, $K_L\to X_1X_2$. If either or these two particles is unstable, {\em e.g.} $X_2\to X_1\pi^0$ or $X_{1,2}\to \gamma\gamma$, such decays could easily mimic $K_L\to \pi^0 \nu\overline{\nu}$ signatures, while not being ruled out by the decays of charged kaons. We construct explicit models that could account for the KOTO excess events, and pass all other constraints from collider searches and meson decays. The lightest of $X_{1,2}$ particles, in some models, could constitute the entirety of dark matter.

Speaker: Dr Matheus Hostert (University of Minnesota)

m_hostert_slides.pdf

92 Hunting Inflaton at FASER

We explore a possibility that an inflaton, which drives the cosmological inflation in the early universe, can be detected by the recently approved FASER at the High-Luminosity LHC (HL-LHC). We consider nonminimal quartic inflation scenario in the minimal U(1)$_X$ extension of the Standard Model (SM) with the classical conformal invariance, where the inflaton is identified with the U(1)$_X$ Higgs field ($\phi$). By virtue of the classical conformal invariance and the radiative U(1)$_X$ symmetry breaking via the Coleman-Weinberg mechanism, the inflationary predictions (in particular, the tensor-to-scaler ratio ($r$)), the U(1)$_X$ coupling ($g_X$) and the U(1)$_X$ gauge boson mass ($m_{Z^\prime}$), are all determined by only two free parameters, the inflaton mass ($m_\phi$) and its mixing angle ($\theta$) with the SM Higgs field. FASER can search for the inflaton for the parameter ranges of $0.1 \leq m_\phi[{\rm GeV}] \leq 4$ and $10^{-5} \leq \theta \leq 10^{-3}$. Each point in the ($m_\phi$, $\theta$)-plane searched by FASER has a one-to-one correspondence with inflationary predictions ($r$) and $Z^\prime$ boson search parameters ($g_X$ and $m_{Z^\prime}$) at the HL-LHC. Therefore, the cosmological observation, LHC experiment, and long-lived particle search at FASER are complementary to test our scenario.

Speaker: Prof. Nobuchika Okada (University of Alabama)

NobuOkada_Pheno2020.pdf

93 Diagnosing the Hidden Sector with MATHUSLA and CMS

Many BSM scenarios predict the existence of new long-lived particles (LLPs). Several new experiments have been proposed to probe the long-lifetime regime at the LHC. One of these is MATHUSLA, a large-volume surface-level detector designed to detect neutral ultra-long lived particles. In this talk I will describe how information from MATHUSLA can be combined with main-detector events to identify the production topology of detected LLPs in an LLP simplified model framework, as well as to estimate the masses of the LLP as well as any possible parent particles in the production process. Surprisingly, as few as 10-100 detected events are enough to determine the production mode and mass parameters in many cases. This has important implications for using MATHUSLA as a CMS L1 trigger.

Speaker: Jared Barron (University of Toronto)

BarronJared_MATHUSLA_Slides_20200504.pdf

94 Long-lived particle search @ LHC

Long-lived particle is well motivated for the new physics search both for collider phenomenology and dark sector. We make use of new variables related to position to search for long-lived, basing on current CMS detector and the Phase-2 Upgrade of the CMS endcap calorimeter which is a high granularity silicon-based calorimeter (HGCAL). We study the long-lived particle signal induced by long-lived sterile neutrino and long-lived Higgs portal particle. The position related variables have been developed to suppress QCD and fake track backgrounds. The final results depends on trigger performance and are generally promising.

Speaker: Xiaoping Wang

XiaopingWang-Pheno-2020.pdf

95 Supernova limit on a light CP-even scalar and implications for the KOTO anomaly

A light CP-even scalar $S$ can be produced abundantly in the supernova core, via the nucleon bremsstrahlung process $N N \to N N S$ due to its mixing with the standard model (SM) Higgs boson. Taking into account the decay and re-absorption of $S$, we obtain the supernova luminosity constraints on the scalar mass $m_S$ and mixing angle $\sin\theta$ of $S$ with the SM Higgs. $\sin\theta$ is excluded in the range of $3.5 \times 10^{-7}$ to $2.5 \times 10^{-5}$, depending on the scalar mass up to around 270 MeV. Such a light scalar can be used to explain the KOTO anomaly in flavor-changing rare decay $K_L \to \pi^0 \nu \bar\nu$.

Speaker: Yongchao Zhang

supernova_KOTO.pdf

96 Searching for Dark Photon Dark Matter with LIGO

Traditionally, Dark Matter (DM) searches are dominantly focused on GeV – TeV mass window. However, though these experiments have reached unprecedented detection sensitivities, the successes only resulted in a push for stronger limits on parameters. This forces people to keep their minds open on other DM candidates, especially in different mass regime. If DM particle is an ultralight gauge boson, i.e. dark photon, DM should be considered as a background field. With certain assumptions on its coupling to Standard Model particles, this DM background field could exert forces on test masses in gravitational wave detectors, resulting in displacements with a characteristic frequency set by the gauge boson mass. In this talk, I will discuss a novel strategy to hunt for such DM. I will also give more details about DM background simulation, the properties of DPDM signal and analysis method. The O1 results show that LIGO have the capability to make a 5σ discovery in unexplored parameter regimes.

Speaker: Mr Fengwei Yang (The University of Hong Kong)

GW-DPDM Pheno Symposium 2020 v1.pdf

97 Searching for long-lived particles with CMS during Run-3 and at the HL-LHC

This talk discusses new techniques to detect signatures potentially originating from long-lived particles in the CMS detector and present prospects for discovery at Run-3 and at the HL-LHC.

Speaker: Sven Dildick (Rice University (US))

Pheno2020_SD_20200428.pdf

DM II

Convener: Jonathan Cornell (University of Cincinnati)

98 Detecting keV-range super-light dark matter using graphene Josephson junction

We propose a new dark matter detection strategy that will enable the search of super-light dark matter $m_\chi \simeq 0.1$ keV, representing an improvement of the minimum detectable mass by more than three order of magnitude over the ongoing experiments. This is possible by integrating intimately the target material, $\pi$-bond electrons in graphene, into a Josephson junction to achieve a high sensitivity detector that can resolve a small energy exchange from dark matter as low as $\sim 0.1$ meV. We investigate detection prospects with mg-scale and g-scale detectors by calculating the scattering rate between dark matter and the free electrons confined in two-dimensional graphene with Pauli blocking factors included. We find not only that the proposed detector can serve as a complementary probe of super-light dark matter but also achieve higher experimental sensitivities than other proposed experiments, i.e. in having a low detectable threshold provided the same target mass, thanks to the extremely low energy threshold of our Josephson junction sensor.

Speaker: Doojin Kim (Texas A & M University (US))

Presentation_Pheno2020_DoojinKim.pdf

99 The relation between Migdal effect and dark matter-electron scatterings in atoms and semiconductors

A key strategy for the direct detection of sub-GeV dark matter is to search for small ionization signals. These can arise from dark matter-electron scattering or when the dark matter-nucleus scattering process is accompanied by a 'Migdal' electron. In this talk, I will discuss the parametric relationship between dark matter-electron scattering and the 'Migdal' ionization for noble-liquid targets and, for the first time, provide an estimate of the 'Migdal' ionization rate in semiconductors that is based on evaluating a crystal form factor that accounts for the semiconductor band structure. I will also present new dark-matter-nucleus scattering limits down to dark matter masses of 500 KeV using published data from XENON10, XENON100, and a SENSEI prototype Skipper-CCD and also show projections for proposed experiments with xenon and silicon targets.

Speaker: Mukul Sholapurkar (YITP, Stony Brook)

mukul_sholapurkar_pheno2020.pdf

100 Multiphonon excitations from dark matter scattering in crystals

For direct detection of sub-MeV dark matter, a promising strategy is to search for individual phonon excitations in a crystal. We perform an analytic calculation of the rate for light dark matter (keV < mDM < MeV) to produce two acoustic phonons through scattering in cubic crystals such as GaAs, Ge, Si and diamond. The multiphonon rate is always smaller than the rate to produce a single optical phonon, whenever the latter is kinematically accessible. In Si and diamond there is a dark matter mass range for which multiphonon production can be the most promising process, depending on the experimental threshold.

Speaker: Brian Campbell-Deem (University of California, San Diego)

brian_campbell-deem_pheno2020_multiphononDM.pdf

101 Millicharged Dark Sectors at FerMINI, Neutrino Experiments, and Neutrino Observatories

Millicharged particles (MCPs) are linked to the fundamental questions like charge quantization, and can make up a fraction of the DM abundance. The recent surge of interest of MCPs is linked to the EDGES anomaly, the excesses seen in direct-detection experiments, and the study of strongly interacting dark matter (SIDM).

In this talk, I will present the searches of MCP and millicharged SIDM in fixed target facilities and neutrino observatories.
MCPs can be produced from intense proton beams hitting the target, or from cosmic-ray hitting the earth's upper atmosphere. The MCPs produced can be detected by the detectors downstream of the fixed-target facility or by large neutrino observatories located underground. I will discuss the constraints and sensitivity reaches of these probes. Finally, I will introduce a specialized fixed-target scintillation experiment, FerMINI, that could provide the best sensitivity reach of MCP and millicharged SIDM in the MeV to GeV regime.

This talk is mainly based on 
- https://arxiv.org/abs/1812.03998
- https://arxiv.org/abs/1806.03310
- https://arxiv.org/abs/2002.11732
(see https://arxiv.org/a/tsai_y_1.html for more refs.)

Speaker: Dr Yu-Dai Tsai (Fermilab)

Tsai_MCP_FerMINI.pdf

102 Dynamics of millicharged dark matter in supernova remnants

Dark matter could have a small electromagnetic charge, provided the charge-to-mass ratio is much less than that of electrons or protons. This candidate, commonly known as millicharged dark matter (mDM), would form a plasma and interact with the interstellar medium and electromagnetic fields within galaxies. In general, understanding the dynamics of mDM requires consideration of collective plasma effects. It has been proposed that mDM can be accelerated in supernova remnants, forming a dark cosmic ray population that would leave distinct experimental signatures. In this work, we study a microphysical model where mDM is shocked by a supernova remnant and isotropized in the frame of the expanding fluid. We find a range of mass-to-charge ratio that the isotropization length for electromagnetic plasma instabilities is much shorter than the size of the supernova remnant. This is a necessary, though not sufficient, first step for formation of a Fermi-accelerated mDM component, and determining the size of this component requires further study.

Speaker: Mr Jung-Tsung Li (UC San Diego)

Jung-Tsung Li, DM II.pdf

103 FIMP dark matter at the KOTO experiment

The KOTO experiment has reported an excess of $K_L\to\pi^0\bar\nu\nu$ events above standard model expectations. New physics interpretations of an excess in this channel are constrained by the Grossman-Nir bound, but another possibility is that the observed events in fact originate from a different process entirely: a decay of the form $K_L\to\pi^0\phi$, where $\phi$ denotes one or more new invisible species. We introduce a set of fiducial models to study this scenario, and we examine the possibility that $\phi$ may also account for cosmological dark matter. We show that $\phi$ is in fact a natural dark matter candidate, and that it is readily produced non-thermally, particularly with a low reheating scale. We discuss astrophysical and terrestrial signatures that may allow further tests of this paradigm.

Speaker: Benjamin Lehmann (UC Santa Cruz)

lehmann_pheno_2020.pdf

104 "Dark Scalars and Heavy Neutral Leptons at the Fermilab SeaQuest Experiment"

We analyze the sensitivity of the Fermilab SeaQuest experiment to GeV-scale dark scalars and heavy neutral leptons. We consider a variety of production mechanisms, including meson decays, proton bremsstrahlung, and perturbative QCD processes, and study a variety of displaced final states signatures for these light exotic new particles.
We show that SeaQuest has the potential to probe significant new regions of parameter space in these scenarios on a time scale that is competitive with or better than other planned experiments.

Speaker: Mr Mudit Rai (University of Pittsburgh)

Pheno_Presentation_2020_Seaquest (6).pdf

105 Absorption of Fermionic Dark Matter by Nuclear Targets

Absorption of fermionic dark matter leads to a range of distinct and novel signatures at dark matter direct detection and neutrino experiments. We study the possible signals from fermionic absorption by nuclear targets, which we divide into two classes of four Fermi operators: neutral and charged current. In the neutral current signal, dark matter is absorbed by a target nucleus and a neutrino is emitted. This results in a characteristically different nuclear recoil energy spectrum from that of elastic scattering. The charged current channel leads to induced $\beta$ decays in isotopes which are stable in vacuum as well as shifts of the kinematic endpoint of $ \beta$ spectra in unstable isotopes. To confirm the possibility of observing these signals in light of other constraints, we introduce UV completions of example higher dimensional operators that lead to fermionic absorption signals and study their phenomenology. Most prominently, dark matter which exhibits fermionic absorption signals is necessarily unstable leading to stringent bounds from indirect detection searches. Nevertheless, we find a large viable parameter space in which dark matter is sufficiently long lived and detectable in current and future experiments.

Speaker: Robert McGehee (University of California, Berkeley)

slides.pdf

Tuesday 5 May

Plenary: III

Convener: Susanne Westhoff (Heidelberg University)

106 Muon physics at FNAL

Speaker: Jarek Kaspar

kaspar_muon_g-2_pheno_v4.pdf

107 News from neutrino experiments

Speaker: Francesca Di Lodovico (University of London (GB))

Pheno2020_DiLodovico.key

108 Neutrino physics: the theory and phenomenology

Speaker: Pedro Machado

Machado-Pheno-2020-final.pdf

10:30 Coffee Break

Plenary: IV

Convener: Shufang Su (University of Arizona)

109 Physics Highlights from LHCb

Speaker: Katharina Mueller (Universitaet Zuerich (CH))

katharina.mueller.pdf

katharina.mueller_v2.pdf

110 Physics at the Electron-Ion Collider (EIC)

Speaker: Dr Jianwei Qiu (Jefferson Lab)

Qiu-Pheno-EIC.pdf

111 BSM Opportunities at the LHC

Speaker: Zhen Liu (Fermilab)

BSM_Opportunities_Pheno2020_ZL.pdf

12:45 Lunch

BSM III

Convener: Rodolfo Capdevilla (University of Notre Dame)

112 Searches for Diboson Resonances at ATLAS

The unprecedented energy and luminosity of LHC has been used to search for the production of pairs of bosons, as predicted in heavy vector triplet and radion models, amongst others. The searches reported here use the full-run 2 ATLAS data set to look for VV, VH, HH and Hgamma boson pairs. Various boson decay modes including W->lnu and qq, Z->ll, vv and qq, and H->bb and tautau are used, with all analyses featuring at least one hadronic boson decay. The production modes considered are either inclusive, or through vector boson fusion. Novel boosted analysis techniques have been used in both the bb and tautau final states.

Speaker: Alex Emerman (Columbia University (US))

DibosonPheno20_may4.pdf

113 Beyond exclusive leptonic resonances with the ATLAS detector

Exclusive dilepton resonance have been a cornerstone of LHC searches probing the highest energies. However, given that no derivations from the SM have been observed with the full run-2 data. it is necessary to go beyond this simple paradigm. This includes searches for non-resonant dilepton phenomena, such as may be produce by a resonance above the scale of direct detection at the LHC, or in inclusive final states in association with jets, as predicted for example by models such as Quantum Black Holes, heavy neutrinos or leptoquarks. The results of the most recent searches on 13 TeV pp data will be presented.

Speaker: Damiano Vannicola (Sapienza Universita e INFN, Roma I (IT))

DamianoVannicolapheno2020.pdf

114 Search for new phenomena in leptonic final states at CMS

Leptons are a powerful probe of new physics at the LHC. Many models of BSM physics such as extra dimensions, an extended gauge sector, leptoquarks and resonant or non-resonant phenomena, are expected to manifest themselves in final states enriched with leptons. This talk presents searches by CMS for new exotic signals in leptonic final states. I will be focusing on the recent results obtained using the Run-II dataset with up to 137 fb$^{-1}$ collected at the LHC.

Speaker: Angira Rastogi (Indian Institute of Science Education and Research (IN))

CMSEXO_Pheno2020_AngiraRastogi.pdf

115 Collider signature of multicharged vectorlike leptons

Multicharged vectorlike leptons (VLL) appear in BSM models such as TeV-scale see-saw neutrino masses, little Higgs etc. Their decays depend generally on how they couple to the W, Z and Higgs along with SM leptons. Based on that, it is possible to observe the VLL signatures in multilepton final states at LHC. Motivated by the muon (g-2) problem and flavor anomalies, it is possible to construct a model, where the VLL decays to a charged Higgs and then the charged Higgs decays to SM leptons. The collider signature of this model has unique features which is distinguishable from general vector like lepton signatures searched at LHC so far.

Speaker: Dr Nilanjana Kumar (University of Delhi, India)

pheno_nkumar.pdf

116 Analysis of the Scalar sector and prospect of a scalar dark matter candidate in the Electroweak Scale Right handed neutrino-model

Motivated by the no-show of any New Physics signals coming from the BSM searches in the post-Higgs era of the LHC, we study the scalar sector of the original electroweak-scale right-handed neutrino (EWν_R) model, which includes Majorana masses and mirror fermions having masses in the EW scale, within the reach of the current colliders. This scenario successfully links the see-saw mechanism, strong CP and DM sectors and contains distinguished Long-lived particle (LLP) signals with large displaced vertices (mm-cm) in quark and lepton sectors. In this work, we analyze the complete scalar sector spectrum which includes heavier triplets, doublets and singlet higgs states in conjunction with the specific 125-GeV scalar state. We present the obtained heavy scalar particle spectrum in the light of the current LHC constraints and comment on their reach at the current/future colliders. We also specifically investigate the prospect of the light singlet scalar fulfilling the role of the DM candidate in this framework.

Speaker: Shreyashi Chakdar

Chakdar_Pheno2020.pdf

117 Beyond the Standard Model Effective Field Theory: The Singlet Extended Standard Model

One of the assumptions of simplified models is that there are a few new particles and interactions accessible at the LHC and all other new particles are heavy and decoupled. Effective field theory (EFT) methods provide a consistent method to test this assumption. Simplified models can be augmented with higher order operators involving the new particles accessible at the LHC. Any UV
completion of the simplified model will be able to match onto these beyond the Standard Model EFTs (BSM-EFT). In this paper we study the simplest simplified model: the Standard Model extended by a real gauge singlet scalar. In addition to the usual renormalizable interactions, we include dimension-5 interactions of the singlet scalar with Standard Model particles. As we will show, even when the cutoff scale is 3 TeV, these new effective interactions can drastically change
the interpretation of Higgs precision measurements and scalar searches. In addition, we discuss how power counting in a BSM-EFT depends strongly on the processes and parameter space under consideration. Finally, we propose a $\chi^2$ method to consistently combine the limits from new particle searches with measurements of the Standard Model. Unlike imposing a hard cut off on heavy resonance rates, our method allows fluctuations in individual channels that are consistent with global fits.

Speaker: Shekhar Adhikari (The University of Kansas)

pheno_2020.pdf

118 Drell-Yan in the SMEFT Including Coupling Shift Effects

We present the extension of a search for model-independent new physics events in dilepton production at the LHC using the SMEFT toolkit. This search, for the first time, includes the effect both of the set of four-fermion operators that give contributions growing with energy and the operators which alter the would-be SM couplings of the Z boson to fermions, leading to corrections proportional to the SM prediction. Our results give prospective bounds on the now four-dimensional parameter space of SMEFT effects in Drell-Yan, including the effects of treating unknown contributions at higher orders in the EFT expansion as theoretical uncertainties.

Speakers: Ms Alyssa Horne (Sam Houston State University), Mr Marcus Snedeker (Sam Houston State University)

Pheno_pres_2.pdf

15:45 -

DM III

Convener: Yuhsin Tsai (University of Maryland)

119 Ultralight Boson Dark Matter Constraints from Superradiance Leveraging the Event Horizon Telescope Collaboration's Observations of M87*

The initial data from the Event Horizon Telescope (EHT) on M87$^∗$, the supermassive black hole at the center of the M87 galaxy, provide direct observational information on its mass, spin, and accretion disk properties. A combination of the EHT data and other constraints provide evidence that M87$^∗$ has a mass $\sim6.5\times10^9$ $M_\odot$ and dimensionless spin parameter $|a^∗|\ge0.5$. These determinations disfavor ultra light bosons of mass $\mu_b\sim10^{-21}$ eV via the phenomenon of superradiance, within the range considered for fuzzy dark matter, invoked to explain dark matter distribution on $\sim$kpc scales. Future observations of M87$^∗$ could be expected to strengthen our conclusions.

Speaker: Peter Denton (Niels Bohr International Academy)

Denton_Pheno_ULB_2020.pdf

120 Looking for primordial black holes in the spectra of GRBs and FRBs

The massive compact halo objects (MACHOs) such as primordial black holes
or dense mini-halos can gravitational lens the signal of gamma ray bursts (GRB)
and fast radio bursts (FRB). I will discuss that most GRB spectra are
inappropriate for this kind of lensing searches due to their large sizes.
However, FRB lensing, producing a characteristic interference pattern in the
frequency spectrum, can probe the MACHOs in the mass range from 10^−4 to
0.1 solar mass.

Speaker: Wei Xue (CERN)

DiffractiveLensing_Pheno2020.pdf

121 Asteroid-Mass Primordial Black Holes as Dark Matter

Microlensing of stars places significant constraints on sub-planetary mass compact objects, including primordial black holes, as dark matter candidates. However, when the Einstein radius of the lens in the source plane is smaller than the size of the light source, amplification is strongly suppressed, making it difficult to constrain lenses with a mass below ~10^-10 solar masses, i.e. asteroid-mass objects. Previous constraints, using Subaru HSC observations of M31, assume a fixed source size of one solar radius. We correct the HSC constraints by constructing a source size distribution based on the M31 PHAT survey and on a synthetic stellar catalogue, and by correspondingly calculating the finite-size source effects. We find that the actual HSC constraints are weaker by up to almost three orders of magnitude in some cases, broadening the range of masses for which primordial black holes can be the totality of the cosmological dark matter by almost one order of magnitude.

Speaker: Nolan Smyth (University of California, Santa Cruz)

Pheno Smyth 5_5_2020.pdf

122 A testable hidden-sector model for Dark Matter and neutrino masses

We consider a minimal extension of the Standard Model with a hidden sector charged under a dark local U(1)′ gauge group, accounting simultaneously for light neutrino masses and the observed Dark Matter relic abundance. The model contains two copies of right-handed neutrinos which give rise to light neutrino-masses via an extended seesaw mechanism. The presence of a stable Dark-Matter candidate and a massless state naturally arise by requiring the simplest anomaly-free particle content without introducing any extra symmetries. We investigate the phenomenology of the hidden sector considering the U(1)′ breaking scale of the order of the electroweak scale. Confronting the thermal history of this hidden-sector model with existing and future constraints from collider, direct and indirect detection experiments provides various possibilities of probing the model in complementary ways as every particle of the dark sector plays a specific cosmological role. Across the identified viable parameter space, a large region predicts a sizable contribution to the effective relativistic degrees-of-freedom in the early Universe that allows to alleviate the recently reported tension between late and early measurements of the Hubble constant.

Speaker: Julia Gehrlein

pheno2020_jg.pdf

123 Constraining atomic dark matter with white dwarfs

Dark matter, or a subcomponent of dark matter, could be in the form of dark atoms bound together by a dark U(1). Such objects are predicted in well-motivated models, including Mirror Twin Higgs, and are a good benchmark for general dissipative dark matter models. In this talk I will describe a new way of constraining the abundance of atomic dark matter using white dwarf cooling. If atomic dark matter exists, it will accumulate in the cores of stars and radiate energy away from the stellar interior as dark radiation. This can dramatically affect the cooling rate of white dwarfs. We are able to derive constraints across a wide range of masses and probe extremely small values of the kinetic mixing parameter.

Speaker: Dr Jack Setford (University of Toronto)

Constraining atomic dark matter with white dwarfs.pdf

124 UV and IR freeze-in production of fermionic dark matter and its possible X-ray signature

Non-thermal dark matter produced via freeze-in is a well-motivated scenario and it can explain the null results of direct detection experiment because of its feeble interaction with the standard model (SM) particles. In this work, we have considered a minimal extension of SM by adding an SM gauge singlet and $\mathbb{Z}_2$ odd Dirac fermion $\chi$ which is the dark matter candidate, a pseudo scalar $\tilde{\phi}$ which also SM gauge singlet but $\mathbb{Z}_2$ even. $\chi$ interacts with the SM fields via dimension five operator and because of that, the couplings are suppressed by a heavy mass scale $\Lambda$. We have studied the production of the DM candidate via UV, IR and mixed freeze-in in detail and found that for $10^{10}\,{\rm GeV}\,\leq\,\Lambda\leq 10^{15}$ GeV, $\chi$ is dominantly produced via UV and mixed UV-IR freeze-in when reheat temperature $T_{\rm RH} \gt 10^4$ GeV and the production is dominated by IR and mixed freeze-in below $T_{\rm RH} \simeq 10^4$ GeV. We have studied the cascade annihilation $\chi \bar{\chi} \rightarrow \tilde{\phi}\tilde{\phi}\rightarrow 4\gamma$ to address the $\sim 3.5$ keV X-ray line observed from various galaxies taking into account the long lifetime of $\tilde{\phi}$. Finally the allowed parameter space for $\Lambda - g$ plane is obtained by comparing the X-ray flux from the Milky-Way galaxy observed by XMM Newton telescope.

Speaker: Sougata Ganguly (Indian Association for the Cultivation of Science)

SGanguly_Pheno_2020.pdf

125 "Non-Local" Effects from Boosted Dark Matter in Indirect Detection

Indirect dark matter detection methods are capable of shedding light on numerous dark sector properties. One such method is by searching for annihilation or decay products from regions of high dark matter concentration. A key feature in such analyses is the J-factor which encodes astrophysical properties. The J-factor develops different dependencies based on the nature of the dark sector. We consider a two-component dark sector where SM particles are created in "non-local" annihilations arising from boosted dark matter production. A natural consequence of this model is an increased dependence on halo size for the strength of an observed standard model signal. This added dependence can help to alleviate the tension between dwarf galaxy results and the galactic center excess.

Speaker: Steven Clark (Brown University)

Pheno_2020_Steven_Clark.pdf

15:45 -

Neutrinos II

Convener: Dr Manimala Mitra (Institute of Physics)

126 Probing New Physics with Standard Double Beta Decay

The non-zero neutrino masses and the possibility of New Physics discovery drive the hunt for neutrinoless double beta decay. While searching for this hypothetical nuclear process, a significant amount of the two-neutrino double beta decay data has been collected by a number of experiments. While these events are from the particle physics viewpoint regarded and studied mainly, if not merely, as the background of neutrinoless double beta decay, they can be also used to probe physics beyond the Standard Model and that will be the focus of my talk.

Speaker: Lukas Graf (Max-Planck-Institut fuer Kernphysik)

GrafPheno2020.pdf

127 Neutrinoless double beta decay in minimal left-right symmetric model with long range contributions

We include the effects of the so called long-range contributions to the neutrinoless double beta decay rate in the context of the minimal left-right symmetric model. This new contribution can be the dominant one in a considerable portion of the parameter space relevant to phenomenology. Our results show how the inclusion of this long-range effects in the decay rate, must be included in order to give robust estimates for the decay rate in a given particle physics model.

Speaker: Juan Carlos (Universidad Técnica Federico Santa María)

PHENO2020_2.pdf

PHENO2020.pdf

128 TeV-scale Lepton Number Violation: 0νββ−decay, the origin of matter and energy frontier probes

Lepton number violation (LNV) is a very attractive research topic for theoretical and experimental physicists due to its implications beyond the Standard Model. It provides feasible theoretical explanations to several open questions in particle physics (e.g., the origin of neutrino mass) and also has a rich phenomenology at different energy scales. We explore the underlying connections between neutrinoless double $\beta-$decay ($0\nu\beta\beta$) experiments, hadron colliders, and cosmology observations. In the context of simplified models, we show that future collider and $0\nu\beta\beta$ experimental results may complement each other.

Speaker: Mr Sebastian Urrutia-Quirga (UMass Amherst)

Pheno2020_suq_lnv.pdf

129 Searches for Atmospheric Long-Lived Particles

Long-lived particles are predicted in extensions of the Standard Model that involve relatively light but very weakly interacting sectors. In this paper we consider the possibility that some of these particles are produced in atmospheric cosmic ray showers, and their decay intercepted by neutrino detectors such as IceCube or Super-Kamiokande. We present the methodology and evaluate the sensitivity of these searches in various scenarios, including extensions with heavy neutral leptons in models of massive neutrinos, models with an extra U(1) gauge symmetry, and a combination of both in a U(1)_{B−L} model. Our results are shown as a function of the production rate and the lifetime of the corresponding long-lived particles.

Speaker: Carlos Arguelles (MIT)

CADLongLivedParticles2020.pdf

130 Towards Minimal SU(5)

A simple $SU(5)$ model is proposed that connects the neutrino mass generation mechanism to the observed disparity between the masses of charged leptons and down-type quarks. The model is built out of $5$-, $10$-, $15$-, $24$-, and $35$-dimensional representations of $SU(5)$ and comprises two (three) $3 \times 3$ ($3 \times 1$) Yukawa coupling matrices to accommodate all experimentally measured fermion masses and mixing parameters. The gauge coupling unification considerations, coupled with phenomenological constraints inferred from experiments that probe neutrino masses and mixing parameters and/or look for proton decay, fix all relevant mass scales of the model. The proposed scenario places several multiplets at the scales potentially accessible at the LHC and future colliders and correlates this feature with the gauge boson mediated proton decay signatures. It also predicts that one neutrino is massless.

Speaker: shaikh saad (oklahoma state university)

PHENO20-SAAD.pdf

131 Constraining Sterile Neutrino Dark Matter in Left-Right Theories

$SU(2)_L \times SU(2)_R$ gauge symmetry requires three right-handed neutrinos ($ N _i $), one of which, $N_1$, can be sufficiently stable to be dark matter. In the early universe, $ W _R $ exchange with the Standard Model thermal bath keeps the right-handed neutrinos in thermal equilibrium at high temperatures.
$N_1$ can make up all of dark matter if they freeze-out while relativistic and are mildly diluted by subsequent decays of a long-lived and heavier right-handed neutrino, $N_2$. We systematically study this parameter space, constraining the symmetry breaking scale of $SU(2)_R$ and the mass of $N_1$ to a triangle in the $(v_R,M_1)$ plane, with $v_R = (10^6 - 3 \times 10^{12})$ GeV and $M_1 = (2\, {\rm keV} - 1 \, {\rm MeV})$. Much of this triangle can be probed by signals of warm dark matter, especially if leptogenesis from $N_2$ decay yields the observed baryon asymmetry. In addition, there is a component of hot $N_1$ dark matter resulting from the late decay of $N_2 \rightarrow N_1 \ell^+ \ell^-$ that can be probed by future cosmic microwave background observations.

Speaker: David Dunsky (UC Berkeley)

Dunsky_Pheno20.pdf

15:30 -

Higgs II

Convener: Jia Liu (University of Chicago)

132 Composite Higgs Models at the LHC and beyond

Compositeness is an elegant way to address the hierarchy problem. In this talk, under broad assumption of partial compositeness and Higgs doublet as the pseudo-Nambu-Goldstone bosons, I will discuss about phenomenology of the spin-1 resonances and the top partners in CHMs and the relevance of their strong interactions in the searches at the LHC. I will also discuss about the strong multi-pole interaction as the target scenario for the precision measurement in the di-boson processes at the HL-LHC. Finally, I will briefly discuss about the universal relationship between the Higgs couplings predicted by the non-linearity and their phenomenological relevance in the future lepton colliders.

Speaker: Dr Da Liu (UC, Davis)

What symmetry can tell us about the composite Higgs models_v2.pdf

133 A Natural Composite Higgs via Universal Boundary Conditions

In this talk, I will present a novel realization of a composite Higgs, which can naturally produce top partners above the current LHC bounds without increasing the tuning above 10%. This is achieved by combining softened breaking of the Higgs shift symmetry with an enhanced ('maximal') symmetry of the composite sector, which turn out to perfectly complement each other. I will finally provide a simple 5D realization of the model, featuring universal UV and IR boundary conditions for the bulk fermions that contain the SM fields and leading to a complete viable setup for a naturally light Higgs without much tuning.

Speaker: Dr Florian Goertz (Max-Planck-Gesellschaft (DE))

Pheno20_FG.pdf

134 Doubly Charged Higgs Boson Production at Hadron Colliders

The production of doubly charged Higgs bosons $\Delta^{\pm\pm}$ in high-$p_T$ proton collisions is a key prediction of several new physics scenarios, particularly the Type II Seesaw model for neutrino masses. We present a state-of-the-art and systematic comparison of $\Delta^{\pm\pm}$ production mechanisms, emphasizing the importance of higher-order corrections and subdominant channels. For Drell-Yan processes, we present the impact of a static jet veto at NLO+NNLL(veto). For the photon fusion channel, the dependence on photon PDF modeling is definitively assessed. Finally, an updated outlook for the discovery potential at HL-LHC and beyond are summarized. [arXiv:1912.08975]

Speaker: Richard Ruiz (Universite Catholique de Louvain)

rruiz_Pheno2020_DblyChargedHiggs.pdf

135 The Higgs and Leptophobic Force at the LHC

The Higgs boson could provide the key to discover new physics at the Large Hadron Collider. We investigate novel decays of the Standard Model (SM) Higgs boson into leptophobic gauge bosons which can be light in agreement with all experimental constraints. We study the associated production of the SM Higgs and the leptophobic gauge boson that could be crucial to test the existence of a leptophobic force. Our results demonstrate that it is possible to have a simple gauge extension of the SM at the low scale, without assuming very small couplings and in agreement with all the experimental bounds that can be probed at the LHC (ArXiv: 2003.09426).

Speaker: Elliot Golias (Case Western Reserve University)

PHENO20.pdf

136 Flavor Changing Neutral Higgs Boson Meets the Top and the Tau at Hadron Colliders

We investigate the prospects for discovering a top quark decaying into
one light Higgs boson ($h^0$) along with a charm quark
in top quark pair production at the CERN Large Hadron Collider (LHC)
and future hadron colliders.
A general two Higgs doublet model is adopted to study the signature
of flavor changing neutral Higgs (FCNH) interactions with $t \to c h^0$,
followed by $h^0 \to \tau^+ \tau^-$.
We study the discovery potential for the FCNH signal and physics background
from dominant processes with realistic acceptance cuts
and tagging efficiencies.
Promising results are found for the LHC running at 13 or 14 TeV
collision energy as well as a future pp collider at 27 TeV.

Speaker: Mr Rishabh Jain (University Of Oklahoma)

Rishabh_Pheno_2020.pdf

137 A New Precision Process at FCC-hh: the diphoton leptonic Wh channel

The increase in luminosity and center of mass energy at the FCC-hh will open up new clean channels where BSM contributions are enhanced at high energy. In this paper, we study one such channel, $Wh \to \ell\nu\gamma\gamma$. We estimate the sensitivity to the $\mathcal{O}_{\varphi q}^{(3)}, \, \mathcal{O}_{\varphi\text{W}}$, and $\mathcal{O}_{\varphi\widetilde{\text{W}}}$ SMEFT operators. We find that this channel will be competitive with fully leptonic $WZ$ production in setting bounds on $\mathcal{O}_{\varphi q}^{(3)}$. We also find that the double differential distribution in the $p_T^h$ and the leptonic azimuthal angle can be exploited to enhance the sensitivity to $\mathcal{O}_{\varphi\widetilde{\text{W}}}$.
However, the bounds on $\mathcal{O}_{\varphi\text{W}}$ and $\mathcal{O}_{\varphi\widetilde{\text{W}}}$ we obtain in our analysis, though complementary and more direct, are not competitive with those coming from other measurements such as EDMs and inclusive Higgs measurements.

Speaker: Alejo Rossia (Deutsches Elektronen-Synchrotron DESY)

Rossia_Wh_PHENO2020.pdf

138 EFT Perspective on Precision Higgs Couplings in Neutral Naturalness Models

The naturalness problem motivates new physics beyond the Standard Model (SM). The Higgs sector in neutral naturalness models provides a portal to the hidden QCD sector, and thus Higgs coupling measurements play a central role in exploring the model parameter space. We investigate several classes of neutral naturalness models, in which the Higgs boson is a pseudo-Goldstone boson with the radial mode at the TeV scale. Integrating out the radial mode, we obtain various dimensional-six operators in the SM effective field theory, and calculate the low energy effective Higgs potential with radiative corrections. With Higgs precision measurements at a future Higgs factory, we explore the implication on the model parameter spaces.

Speaker: Huayang Song (University of Arizona)

EFT_Precision_Higgs_Couplings_NN.pdf

139 Probing Extended Scalar Sector Through $e^+e^-\rightarrow Zh$ Process at NLO

Speaker: Jia Zhou (INFN Sezione di Pavia)

pheno20_zh.pdf

Flavor II

Convener: Lin Dai

140 Recent results on bottomonium from Belle

We present recent results on hadronic transitions between
bottomonium states obtained by the Belle Collaboration.
They include decays of the Upsilon(4S) into lower bottomonia
with pi+pi-, eta and eta' transitions. Also discussed is the
first observation of the Upsilon(10753) state using a large
data sample collected near the Upsilon(10860) resonance.
We also briefly describe plans of bottomonium studies at BelleII.

Speaker: Dr Simon Eidelman (Lebedev Physical Institute and Budker Institute)

phen20.pdf

141 Search for rare B decays with the LHCb experiment

Decays that are very rare in the Standard Model are excellent probes for New Physics contributions,
as the Standard Model background is low and contributions from New Physics can be sizeable.
Recent measurements of decays with $b\to sll$ transitions show a pattern of anomalies, including some that hint at lepton flavour non-universal couplings.
This talk focuses on measurements that are motivated by the flavour anomalies described above, performed with the LHCb experiment. A recent search for very rare B decays with leptons in the final state will be presented.

Speaker: Titus Mombächer (Technische Universitaet Dortmund (DE))

Pheno2020_TMombaecher.pdf

142 First measurements of isospin amplitudes in Lambda_b and Xi_b decays

Ratios of isospin amplitudes in hadron decays are a useful probe of the interplay between weak and strong interactions, and allow searches for physics beyond the Standard Model. We present the first results on isospin amplitudes in b-baryon decays, using data corresponding to an integrated luminosity of 8.5 fb^−1, collected with the LHCb detector in pp collisions at center of mass energies of 7, 8 and 13 TeV. The isospin amplitude ratio |A1(Λb→J/ψ Σ^0)/A0(Λb→J/ψ Λ)|, where the subscript on A indicates the final-state isospin, is measured to be less than 1/21.8 at 95\% confidence level. The Cabibbo suppressed Ξb^0→J/ψΛ decay is observed for the first time, allowing for the measurement |A0(Ξb^0→J/ψ Λ)/A1/2(Ξb^0→J/ψ Ξ^0)|=0.37±0.06±0.02, where the uncertainties are statistical and systematic, respectively.

Speaker: Aravindhan Venkateswaran (Syracuse University (US))

PHENO2020_AV_v2.pdf

143 ATLAS Measurements of CP Violation and Rare Decays Processes with Beauty Mesons

The ATLAS experiment has a rich $B$ physics program including measurements of CP violation in $B$ meson decays and studies of rare FCNC decays of $B$ mesons as sensitive probes of physics beyond the SM.
In this talk, recent studies of the CP violating phase $\phi_s$ in $B^0_s \to J/\Psi \phi$ and of the rare decay of $B^0$ and $B^0_s$ to muon pairs are highlighted.

Speaker: Ann-Kathrin Perrevoort (Nikhef National institute for subatomic physics (NL))

Pheno2020_Perrevoort.pdf

144 Latest measurement of $K^+ \rightarrow \pi^+ \nu \bar{\nu}$ with the NA62 experiment at CERN

The decay $K^+ \rightarrow \pi^+ \nu \bar{\nu}$, with a very precisely predicted branching ratio of less than $10^{-10}$,is one of the best candidates to reveal indirect effects of new physics at the highest mass scales.The NA62 experiment at the CERN SPS is designed to measure the branching ratio of the $K^+ \rightarrow \pi^+ \nu \bar{\nu}$ with a decay-in-flight technique. NA62 took data so far in 2016-2018. Statistics collected in 2016 allowed NA62 to reach the Standard Model sensitivity for $K^+ \rightarrow \pi^+ \nu \bar{\nu}$, entering the domain of $10^{-10}$ single event sensitivity and showing the proof of principle of the experiment. Thanks to the statistics collected in 2017, NA62 surpasses the present best sensitivity. The analysis strategy is reviewed and the preliminary result from the 2017 data set is presented.
The NA62 hermetic photon-veto system, needed to reject the $K^+ \rightarrow \pi^+ \pi^0$ background in the $K^+ \rightarrow \pi^+ \nu \bar{\nu}$ analysis, allows for a high-sensitivity search for $\pi^0$, or a new particle with mass around the $\pi^0$ one, decaying to invisible particles. A preliminary result on this search, obtained with the 2017 data sample, is presented. The signature with only a charged pion in the final state is exploited also to search for a new feebly interacting particle $X$ in the decay $K^+ \rightarrow \pi^+ X$, with $X$ not decaying to $SM$ particles within the experimental apparatus. A preliminary result is presented on the reinterpretation of the $K^+ \rightarrow \pi^+ \nu \bar{\nu}$ analysis in a bump hunting in the variable $m_{miss}^{2} = ({\bf p}_{K^{+}}-{\bf p}_{\pi^{+}})^2$ corresponding to searching for a new particle with mass in $\sim [0,100]$ MeV$/c^2$ or $\sim[160,260]$ MeV$/c^2$.

Speaker: Dr Roberta Volpe (Comenius University, Bratislava)

volpeNA62.pdf

145 Searches for exotics decays with NA62

The NA62 experiment at the CERN SPS is designed to measure the branching ratio of the K+→π+vv ̅decay, one of the best candidates to reveal indirect effects of new physics at the highest mass scales. NA62 took data in 2016-2018. High-intensity setup and detector performance make NA62 particularly suited for searching new-physics effects from different scenarios involving feebly interacting particles in the MeV—GeV mass range: heavy-neutral leptons, axion-like particles, and others. The results from the analysis of data taken with dedicated setup and triggers developed to this purpose will be highlighted.

Speaker: Stefan Alexandru Ghinescu (Horia Hulubei National Institute of Physics and Nuclear Enginee)

Search_for_exotics_NA62.pdf

146 Searches for lepton flavour and lepton number violation in K+ decays

The NA62 experiment at CERN collected a large sample of charged kaon decays into final states with multiple charged particles in 2016-2018. The sensitivity to a range of lepton flavour and lepton number violating kaon decays provided by this data set improves over the previously reported measurements. Results from the searches for these processes with a partial NA62 data sample are presented.

Speaker: Prof. Paolo Massarotti (Università degli studi di Napoli Federico II e INFN Napoli)

Pheno2020PM.pdf

147 [More] Treasures from Kaons

Kaons have had a great history. Many fundamental discoveries. We add to this classic list. This took ~37 + years and overcoming numerous obstacles… May be a dozen PhD’s. These new ones will deeply further our understanding of the SM and our concept of naturalness. It will provide powerful constraints on BSMs

Speaker: AMARJIT Soni (BNL)

final 4 pheno2020v.pdf

Top

Convener: Dr LINGFENG LI (UC Davis)

148 Pheno at a distance: A global search for new physics with top quarks

Heavy new physics above LHC energies is best searched for through indirect effects in precise observables. In this talk I discuss our global analysis of top-quark observables in the framework of Standard Model Effective Field Theory. I show how to penetrate untrodden directions in the Wilson coefficient space by exploiting kinematic distributions and by measuring new observables in collected LHC data.

Speaker: Susanne Westhoff (Heidelberg University)

pheno-westhoff.pdf

149 Single-top-quark production at NNLO

We present a new calculation of single-top-quark production at NNLO. Our calculation is fully differential in the five-flavor scheme and includes the full leptonic top-quark decay. Our results settle the issue of previous calculations that found disagreement at the level of the NNLO corrections. We discuss the relevance of the process and the higher-order corrections for Standard Model precision phenomenology at the LHC.

Speaker: Tobias Neumann (Fermi National Accelerator Laboratory)

out.pdf

150 Probing $Zt\bar{t}$ couplings using $Z$ boson polarization in $ZZ$ production at hadron colliders

We propose to utilize the polarization information of the $Z$ bosons in $ZZ$ production, via the gluon-gluon fusion process $gg\to ZZ$, to probe the $Zt\bar{t}$ gauge coupling. The contribution of longitudinally polarized $Z$ bosons is sensitive to the axial-vector component ($a_t$) of the $Zt\bar{t}$ coupling. We demonstrate that the angular distribution of the charged lepton from $Z$ boson decays serves well for measuring the polarization of $Z$ bosons and the determination of $a_t$. We show that $ZZ$ production via the $gg\to ZZ$ process complement to $Zt\bar{t}$ and $tZj$ productions in measuring the $Zt\bar{t}$ coupling at hadron colliders.

Speaker: Dr Bin Yan (Michigan State University)

pheno20_BY.pdf

151 Measurement of top-quark properties with the ATLAS detector at the LHC

Due to its high mass top quarks decay before top-flavoured hadrons are formed. This feature leads to interesting phenomenological consequences, among them is the access to spin polarisation effects in top-quark production. While top-quarks are produced unpolarized in top-quark-antiquark pair production, there exists a correlation between the spins of the top-quark and the top-antiquark. In the presentation, last year's measurement of spin correlation in top-quark-antiquark pair events is reviewed, including recent changes which were implemented for the resubmission to the journal. Besides the measurement of the standard model effect, the observed data are also interpreted as search for supersymmetric top-quark partners.
In addition, the talk covers a measurement of the charge asymmetry in top-quark-antiquark pair production. The asymmetry is due to a subtle interference effect of quark-antiquark-annihilation amplitudes in quantum chromodynamics. Based on the full Run 2 data set the effect is established at a level of more than four standard deviations. The analysis is performed in the lepton-plus-jets channel.
The third analysis presented measures the top-quark width in the di-lepton channel.

Speaker: Jacob Julian Kempster (University of Birmingham (GB))

JKempster_Pheno2020.pdf

152 Measurement of rare top-quark production processes with the ATLAS detector

The top quark is the heaviest elementary particle in Standard Model. Measurements involving top quarks in their final states provide precision tests of the Standard Model and are also sensitive to new physics at the high-energy frontier. The latest cross-section measurements of rare processes with top quarks (tZq, ttX, 4top production) are presented here using 13 TeV proton-proton collisions recorded by the ATLAS detectors at the Large Hadron Collider at CERN. The measured values are compared to the most accurate theoretical calculations.

Speaker: Zhi Zheng (University of Michigan (US))

zzheng_raretop_pheno2020.pdf

153 Rare top quark production in CMS: ttZ, ttW, ttgamma, tZ, tgamma, and tttt production

A comprehensive set of measurements of top quark pair and single top quark production in association with EWK bosons (W, Z or ɣ) is presented. The results are compared to theory predictions and re-interpreted as searches for new physics inducing deviations from the standard model predictions using an effective field theory approach. The status of the search for four top quark production, to which the LHC experiments are starting to be sensitive, and that has important BSM re-interpretations, is also reported.

Speaker: Clara Ramon Alvarez (Universidad de Oviedo (ES))

Pheno2020_ClaraRamon.pdf

154 Recent top quark properties in CMS

Measurements of top quark properties using data collected by the CMS experiment are presented. Among them, the latest results on top mass and its running, top Yukawa coupling, the top sector of the CKM matrix, ttbar forward backward asymmetry, as well as other new results will be discussed.

Speaker: Agostino De Iorio (Universita e sezione INFN di Napoli (IT))

DeIorio_TopProperties_Pheno2020.pdf

155 Recent ttbar and single top inclusive and differential cross sections results in CMS

Latest results on inclusive and differential top quark pair and single top quark production cross sections are presented using collision data collected by CMS. In different kinematic regimes, the differential cross sections are measured as a function of various observables of the top quarks and the jets and leptons of the event final state. The results are confronted with precise theory calculations. The single top quark analyses investigate separately the production of top quarks via t-channel exchange, via associated production with a W boson (tW), and via the s-channel.

Speaker: Silvano Tosi (INFN e Universita Genova (IT))

TalkPhenoTosi.pdf

Theoretical Developments & Extra Dimensions

Convener: Keith Dienes (University of Arizona)

156 Naturalness versus Stringy Naturalness

The notion of stringy naturalness-- that an observable $O_2$ is more natural than $O_1$ if more (phenomenologically acceptable) vacua solutions lead to
$O_2$ rather than $O_1$-- is examined within the context of the Standard Model (SM) and various SUSY extensions: CMSSM/mSUGRA, high-scale SUSY and radiatively-driven natural SUSY (RNS). Rather general arguments from string theory suggest a (possibly mild) statistical draw towards vacua with large soft SUSY breaking terms. These vacua must be tempered by an anthropic veto of non-standard vacua or vacua with too large a value of the weak scale $m(weak)$. We argue that the SM, the CMSSM and the various high-scale SUSY models are all expected to be relatively rare occurrences within the string theory landscape of vacua. In contrast, models with TeV-scale soft terms but with $m(weak)$ ~ $100$ GeV and consequent light higgsinos (SUSY with radiatively-driven naturalness) should be much more common on the landscape. These latter models have a statistical preference for $m_h$ ~ $125$ GeV and strongly interacting sparticles beyond current LHC reach. Thus, while conventional naturalness favors sparticles close to the weak scale, stringy naturalness favors sparticles so heavy that electroweak symmetry is barely broken and one is living dangerously close to vacua with charge-or-color breaking minima, no electroweak breaking or pocket universe weak scale values too far from our measured value. Expectations for how landscape SUSY would manifest itself at collider and dark matter search experiments are then modified compared to usual notions.

Speaker: Shadman Salam

Pheno_2020_latest.pdf

157 Towards predictivity in asymptotically safe quantum gravity with matter

In this talk, I will briefly introduce the scenario of asymptotically safe quantum gravity as a UV complete description of nature. In particular, I will focus on the enhanced predictive power coming along with the existence of an interacting UV fixed point of quantum gravity and matter. This allows to predict the IR values of some standard-model couplings, and might even give rise to a preferred dimensionality of our universe. In parts based on Phys.Lett.B 793 (2019) 383-389.

Speaker: Marc Schiffer (Heidelberg University)

Pheno2020.pdf

158 States of Low Energy and the Initial State(s) of the Inflaton

In this talk we make a case for considering alternatives to the Bunch-Davies vacuum state for quantizing inflaton perturbations. The choice of vacuum state of a (free) quantum field theory in a generic (spatially flat) Friedmann-Robertson-Walker spacetime is unavoidably ambiguous, with two physically viable vacua potentially behaving drastically differently at small momentum. We consider a specific class of vacuum states, known as States of Low Energy (SLE), and show that the associated mode functions will always have a universal small momentum expansion in all Friedmann-Robertson-Walker spacetimes. This expansion also entails that the SLE two-point function for a massless theory will be infrared finite. Finally, we present the primordial power spectrum corresponding to the SLE, and find that it matches the Bunch-Davies power spectrum at high momentum, while showing relative power suppression of low momentum modes.

Speaker: Rudrajit Banerjee (University of Pittsburgh)

159 The on-shell viewpoint of effective field theory

We propose an on-shell viewpoint of the effective field theories (EFT), which treats effective operators as local on-shell amplitudes. As building blocks of an effective theory, both the operator basis and the amplitude basis should contain the same amount of information. In this talk, I will briefly introduce two benefits this viewpoint bring to us. First, we can translate some obvious constraints, like angular momentum conservation, on scattering amplitudes into constraints on operators, by which we find novel selection rules for the operator renormalizations and loop contributions. Second, inspired by studies of local on-shell amplitudes, we are able not only to count, but also to write down a complete basis of Lorentz structures of a given type of operators, which help us develop a method to systematically derive the complete non-redundant operator basis of any model at any dimensions.

Speaker: Minglei Xiao

on-shell EFT.pdf

160 A Tale of Two U(1)s: Kinetic Mixing from Lattice WGC States

We point out that the states required by the Lattice Weak Gravity Conjecture, along with certain genericity conditions, imply the existence of non-vanishing kinetic mixing between massless Abelian gauge groups in the low-energy effective theory. We begin with an estimate using a lattice of states satisfying the WGC up to some coefficients of order unity. We refine our estimate by considering a KK compactification of a 5D U(1) gauge theory on $S^{1}$ and estimate the magnitude of kinetic mixing between the gauge and KK U(1)s. We end with a brief discussion of potential phenomenological implications and possible loopholes to evade the bounds set by our estimates.

Speaker: Aditya Parikh (Harvard University)

KineticMixing_Pheno_AdityaParikh.pdf

161 Signals of KK graviton from extended warped extra dimensions at the LHC (I)

We analyze signals arising from production and subsequent decay of Kaluza-Klein (KK) gravitons in the extended warped extra dimensional models at the LHC. In these models, the extra dimensional bulk is divided into two regions: (i) from the Planck/UV brane to an O(10 TeV) middle brane, and (ii) from the middle brane to an O(TeV) IR brane. The standard model (SM) fermions and Higgs only propagate in region (i), while standard model gauge bosons and gravity propagate through all the bulk. This structure suppresses flavor violation, while keeping gravitons and KK gauge bosons light enough to be accessible at the LHC. We find that the signals from KK graviton are significantly different than in the standard warped model (with only the UV and IR branes). This is because the usually dominant decay modes of KK gravitons are suppressed, allowing other decay channels to shine. In particular, we analyze the following two channels for decays of KK graviton: (1) KK graviton decaying into a pair of radions and each radion decaying subsequently into a pair of jets, giving an overall 4-jet signal with “antler” topology (2) KK graviton decaying into a KK gluon and a (SM gluon) jet followed by the KK gluon decaying into a radion and a gluon jet, and finally the radion decaying into a pair of jets. This again results in a 4-jet signal, but this time with a different, “double-cascade” topology.

Speaker: Majid Ekhterachian (University of Maryland College Park)

KKgravitonLHC pheno 20.pdf

162 Signals of KK graviton from extended warped extra dimensions at the LHC (II)

The extended warped model predicts two 4-jet signals produced by KK graviton decay: (1) KK graviton decay to two radions, which each dominantly decay to two (SM gluon) jets, and (2) KK graviton decay to KK gluon and (SM gluon) jet, followed by KK gluon to radion and (SM gluon) jet, followed by radion to two jets. We analyze two parts of the model's parameter space at 14 TeV HL-LHC specifications. First, when the KK gluon is heavy, the decay of KK graviton to KK gluon and SM gluon is negligible. Analysis cuts focus on the "antler" topology of channel (1), imposing two dijet resonances and the 4-jet resonance on the final state jets. Second, when the KK gluon is lighter, the analysis cuts focus on the "double cascade" topology of channel (2), imposing a dijet resonance nested in a trijet resonance and the 4-jet resonance. For the second part of the analysis, we find the contribution from channel (1) can be important. Multiple benchmark points for each signal are shown with at least $3\sigma$ significance with an integrated luminosity 3000 fb$^{-1}$.

Speaker: Deepak Sathyan (University of Maryland College Park)

Pheno2020Talk.pdf

16:00 Coffee Break

BSM IV

Convener: Dr Da Liu (ITP, CAS/EPFL)

163 Searches for resonances in hadronic final states with the ATLAS detector

Many theories beyond the Standard Model predict new phenomena which decay to quarks.  Light-quarks are of particular interest at the LHC since new phenomena produced in parton collisions are likely to produce final states with (at least) two partons.  On the other hand, b- and top-quarks offer great potential to reduce the Standard Model background and improve sensitivity to new physics models which favour the 3rd generation, although with significant challenges in reconstructing and identifying the decay products and modelling the remaining background.  The most recent searches in various hadronic final states performed with the ATLAS experiment at the LHC on the 13 TeV data will be presented

Speaker: Binbin Dong (Shanghai Jiao Tong University (CN))

Pheno2020.pdf

164 New Limits on Coloured Three Jet Resonances

Collider searches for the top partner mainly focuses on its decay to the SM weak gauge bosons, top quark, and the Higgs boson. However, it is possible that the top partner decay into other particles resulting in new decay topologies. To this end, we consider top partner that decays via non-standard decay modes in light of the current experimental searches conducted at the LHC. In particular, we investigate top parter that decays to three jets and we find that searches for pair production of di-jet and tri-jet resonances are complementary, covering different regions of parameter space.

Speaker: Hassan Easa

Pheno2020_HassanEasa.pdf

165 Search for unconventional signatures at CMS

A selection of new results on searches new physics with unconventional signatures with the CMS experiment will be presented. The analyses are performed using proton-proton collision data recorded with the CMS detector at a center-of-mass energy of 13 TeV using a part or a whole set of Run 2 dataset.

Speaker: Malgorzata Kazana (NCBJ Warsaw (PL))

CMS_LLP_20200505_pheno.pdf

166 Search for dark sector in CMS

Several theories predict dark matter to be a part of a larger dark sector of particles and forces. These dark sector particles, such as dark photons, may interact very weakly with standard model particles resulting in several distinct signatures in the high energy pp collision events at the LHC. This talk presents recent results from CMS on dark sector searches using full Run II data collected during 2016-2018. For low-mass dark photon search in dimuon channel, CMS has used novel data scouting technique. Scouting data is useful to perform searches in regions where nominal triggers have reduced or zero sensitivity. This special triggering technique, based on event-size reduction rather than event filtering, will be discussed in this talk.

Speaker: Ms Swagata Mukherjee (Rheinisch Westfaelische Tech. Hoch. (DE))

Pheno2020_Swagata.pdf

167 Prospects for searches for Leptoquarks with large coupling with the top quark

The LHC search strategies for leptoquarks (LQs) that couple dominantly to a top quark are different than for the ones that couple mostly to the light quarks. In this talk, I will discuss the LHC phenomenology of the LQs that can decay to a top quark and a charged lepton giving rise to a resonance system of a boosted top quark and a high-pT lepton. I will consider all possible LQ models within the Buchmuller-Ruckl-Wyler classifications with the desired decay and present some simple phenomenological Lagrangians that are suitable for bottom-up/experimental studies but, at the same time, can cover the relevant parameter spaces. We shall see that the single production of top-philic LQs in association with a charged lepton could be significant for order one LQ-t-l coupling(s) in certain scenarios. I will also discuss a strategy of selecting events with at least one hadronic-top and two high-pT leptons. This can significantly enhance their discovery prospects at the LHC, especially in the high-mass region where the single productions become more prominent.

Speaker: Subhadip Mitra

Pheno2020.pdf

168 Signatures of the $\tilde{R}_2$ class of leptoquarks at the upcoming $e p$ colliders

LQs are hypothetical particles which can emerge from the unification of quarks and leptons in the Pati-Salam model. LQs also exist in grand unified theories and extended technicolor models. Under the Standard Model (SM) representation, there are twelve types of LQs, six of them are scalar, while the other six are vector type of LQs. We consider the scalar LQ $\tilde{R}_2$ charged as (3,2,1/6) under SM gauge group. The advantage with $\tilde{R}_2$ type of scalar LQ is that in addition to the coupling with the lepton and jet, the model also has right handed (RH) neutrinos coupled to the LQ. Hence, this model provides unique signatures, that can be tested in different collider and non-collider experiments. We explore the signatures of the $\tilde{R}_2$ at the proposed $e p$ colliders, LHeC and FCC-eh.

Speaker: Ms ROJALIN PADHAN (Institute of Physics, Bhubaneswar)

Pheno20_Rojalin_Padhan.pdf

169 Searches for heavy BSM particles coupling to third generation quarks at CMS

We present results from searches for resonances with enhanced couplings to third generation quarks, based on proton-proton collision data at a centre-of-mass energy of 13 TeV recorded by CMS. The signatures include single and pair production of vector-like quarks and heavy resonances decaying to third generation quarks. A wide range of final states, from multi-leptonic to entirely hadronic is covered. Jet substructure techniques are employed to identify highly-boosted heavy SM particles in their hadronic decay modes.

Speaker: James William Dolen (Purdue University Northwest (US))

PHENO 2020 - 2020 May - Dolen.pdf

PHENO 2020 - 2020 May - Dolen - v2.pdf

170 Full Run 2 Results for Disappearing Tracks at CMS

CMS has recently submitted results for a search for disappearing tracks, updated to include the full Run 2 LHC data set. The disappearing track signature would be produced by long-lived charged particles that decay within the volume of the silicon tracker, and is identified as an isolated track with no associated hits in the muon detectors, little energy deposited in the calorimeters, and missing hits in the outermost tracker layers. The addition of a fourth inner layer in the Phase 1 pixel tracker upgrade enables this search to accept shorter tracks, increasing the sensitivity to shorter lifetime particles. The observed events are consistent with estimated backgrounds, and upper limits are set on chargino production in the context of anomaly-mediated supersymmetry breaking using the complete Run 2 LHC data set. These constraints are the most stringent to date.

Speaker: Brian Francis (Ohio State University (US))

bfrancis_pheno2020_v2.pdf

DM IV

Convener: Robert McGehee (University of California, Berkeley)

171 Dark Matter from a secluded Dark SU(N) Theory with a Single Quark Flavor

In this talk, we analyze the viability of dark matter candidates arising from a secluded, confining, large-N SU(N) gauge theory with a single quark flavor. In a SU(N) gauge theory with a single quark flavor, the low-energy bound states consist of a delta-like baryon and an eta-prime meson. By solving coupled Boltzmann equations, we demonstrate that there are ample regions of parameter space in which either delta (via freeze-in) or eta-prime (via freeze-out) dark matter is possible. Limits on dark matter self-interaction and delta-N-effective are applied to constrain the available parameter space of the theory. We find that eta-prime dark matter is generically allowed, while delta dark matter is firmly ruled out by self-interaction constraints.

Speaker: Logan Morrison (University of California, Santa Cruz)

DarkSUNShortSeminar_05_05_20.pdf

172 Exotic Compact Objects in a Dissipative Dark Sector

We study the complete history of structure formation of a simple dark sector and show how to form exotic compact objects that vary in size from a few to millions of solar masses. These exotic compact objects may be detected and their properties measured at new high-precision astronomical observatories, giving insight into the particle nature of the dark sector without the requirement of non-gravitational interactions with the visible sector.

Speaker: Jae Hyeok Chang (YITP, Stony Brook)

Slides_Chang.pdf

173 Light Z′ and Dark Matter from U(1)_X Gauge Symmetry

We consider a U(1)_X gauge symmetry extension of the Standard Model (SM) with a Z′-portal Majorana fermion dark matter that allows for a relatively light gauge boson Z′ with mass of 10 MeV− a few GeV and a much heavier dark matter through the freeze-in mechanism. In a second scenario the roles are reversed, and the dark matter mass, in the keV range or so, lies well below the Z′ mass, say, ∼1 GeV. We outline the parameter space that can be explored for these two scenarios at the future Lifetime Frontier experiments including Belle-II, FASER, LDMX and SHiP.

Speaker: Dr Satomi Okada (University of Alabama)

Pheno2020_SatomiOkada.pdf

174 Freez-In dark matter from secret neutrino interactions

We study a simplified freeze-in dark matter model with a dark matter $\chi$ and a light scalar mediator $\phi$ which couples only to neutrinos in the Standard Model. We point out two possible UV origins generating extremely small scalar and pseudo-scalar couplings between $\phi$ and neutrinos. We find benchmarks to realize the correct relic density with and without re-annihilation scheme by solving the coupled differential equations for number and energy densities of $\phi$ and $\chi$. We investigate the temperature evolution in the dark sector and the effect of decay and inverse decay of $\phi$ on BBN. We find tension in our simplified model between satisfying the cosmological constraint (relic abundance and BBN) and explaining the small scale structure problem with self-interacting dark matter argument.

Speaker: Dr Li Haolin (Institute of Theoretical Phyiscs, Chinese Academey of science)

FIMP.pdf

175 Neutrino Portal to FIMP Dark Matter with an Early Matter era

The freeze-in production of FIMP dark matter candidate through neutrino portal is discussed. The hidden sector is comprised of a fermion and a scalar, while a heavy right handed neutrino is responsible for mediating the interaction between SM and hidden sectors. In addition, we assume that an early matter-dominated era took place for some period between inflation and BBN, making the Universe to expand faster than in the standard radiation-dominated era. In this case, the hidden and SM sectors are easily decoupled, while larger couplings is needed to achieve observed DM relic density. In this scenario, we show that in some case, the model becomes testable through indirect detection searches.

Speaker: Dr Yongcheng Wu (Carleton University)

FIDM_pheno2020_ycwu.pdf

176 Co-SIMP Miracle

I will present a new mechanism for thermally produced dark matter, based on a semi-annihilation-like process, χ + χ + SM → χ + SM, with intriguing consequences for the properties of dark matter. First, its mass is low, 􏰁 1 GeV (but 􏰀 5 keV to avoid structure-formation constraints). Second, it is strongly interacting, leading to kinetic equilibrium between the dark and visible sectors, avoiding the structure-formation problems of χ + χ + χ → χ + χ models. Third, in the 3 → 2 process, one dark matter particle is consumed, giving the standard-model particle a monoenergetic recoil. We show that this new scenario is presently allowed, which is surprising (perhaps a “minor miracle”). However, it can be systematically tested by novel analyses in present and near-term experiments.

Speaker: Juri Smirnov (Ohio State University, CCAPP)

Co-SIMP-Miracle.pdf

177 KINDER Dark Matter

In the conventional weakly-interacting massive particle (WIMP) paradigm the late-time density of dark matter (DM) is set by the rate of two-body annihilations, but there has been considerable recent interest in exploring alternative DM scenarios where other interactions control the final abundance. I will show that by fully exploring the parameter space of a simple, weakly-coupled dark sector, we can find a range of different mechanisms for obtaining the correct relic density. In particular, we can identify and characterize a general class of mechanisms in which the DM relic abundance is determined by processes controlling the thermal coupling of the DM and Standard Model (dubbed the KINetically DEcoupling Relic -- KINDER), generalizing previously-studied special cases of this behavior.

Speaker: Patrick Fitzpatrick (Massachusetts Institute of Technology)

KINDER_talk_pheno2020_2.pdf

178 Cooking Pasta with Dark Matter

Neutron stars serve as excellent next-generation thermal detectors of dark matter, heated by the scattering and annihilation of dark matter accelerated to relativistic speeds in their deep gravitational wells. However, the dynamics of neutron star cores are uncertain, making it difficult at present to unequivocally compute dark matter scattering in this region. On the other hand, the physics of an outer layer of the neutron star, the crust, is more robustly understood. I will show that dark matter scattering solely with the low-density crust still kinetically heats neutron stars to infrared temperatures detectable by forthcoming telescopes. I will discuss the strong sensitivities obtained for both spin-independent and spin-dependent dark-matter scattering on nucleons, with the leading sensitivity arising from dark matter scattering with a crust constituent called nuclear pasta (including gnocchi, spaghetti, and lasagna phases).

Speaker: Rebecca Leane (Massachusetts Institute of Technology)

RKLeane_pheno20.pdf

Neutrinos III

Convener: Ahmed Ismail

179 Gravitational Origin for Neutrino Masses

We present a scenario where the smallness of neutrino masses is related to a global symmetry violation by quantum gravitational effects. We propose a setup that leads to axion particles which decay into neutrinos. This setup could be probed via cosmological measurements and may help explain the Hubble parameter tension. Depending on the details, the scenario could provide axion dark matter candidates.

Speaker: Hooman Davoudiasl (BNL)

Pheno2020-Talk.pdf

180 Dodelson-Widrow Mechanism in the Presence of Self-Interacting Neutrinos

keV-scale gauge-singlet fermions, when allowed to mix with the active neutrinos, are elegant dark matter (DM) candidates. They are produced in the early Universe via the Dodelson-Widrow mechanism and can be detected as they decay very slowly, emitting x-rays. In the absence of new physics, this hypothesis is virtually ruled out by astrophysical observations. Here, we show that new interactions among the active neutrinos allow these sterile neutrinos to make up all the DM while safely evading all current experimental bounds. The existence of these new neutrino interactions may manifest itself in next-generation experiments, including DUNE.

Speaker: Walter Tangarife (Loyola University Chicago)

Tangarife_SterileNeutrino_PHENO_2020.pdf

181 A renormalizable model of gauged neutrino self-interactions and the Hubble tension

I will introduce arguably the simplest extension of the Standard Model which leads to renormalizable long-range vector-mediated neutrino self-interactions. This gives rise to four-neutrino intractions with a strength similar to what has been discussed to resolve the cosmological hubble tension, whithout conflicting with other data. The extended gauge and scalar sector leads to signatures in invisible Higgs and Z decays, unequivocally relating the Hubble tension to precision measurements at the LHC and future colliders. Furthermore, there are hidden neutrinos which can be in the correct mass and mixing range to resolve short baseline neutrino oscillation anomalies.

Speaker: Andreas Trautner (BCTP, Bonn University)

Trautner_PHENO_20.pdf

182 Neutrino-dark matter connections in gauge theories

We discuss the connection between the origin of neutrino masses and the properties of dark matter candidates in the context of gauge extensions of the Standard Model. We investigate minimal gauge theories for neutrino masses where the neutrinos are predicted to be Dirac or Majorana fermions. We find that the upper bound on the effective number of relativistic species provides the strongest constraint in the scenarios with Dirac neutrinos. Our results imply that we could test simple gauge theories for neutrino masses at current or future experiments.

Speaker: Alexis Plascencia (Case Western Reserve University)

Plascencia_PHENO2020.pdf

183 Dark Matter annihilation to neutrinos: New limits and future prospects

Neutrinos can escape dense environments, otherwise opaque to photons, and travel cosmic distances unscathed by background radiation or magnetic fields. While ideal cosmic messengers, they present a unique opportunity to test physics beyond the Standard Model, especially dark matter. There is a distinct possibility that the principal portal through which the dark matter interacts with the Standard Model is via the neutrino sector. In this talk, we will discuss new opportunities offered by high-energy neutrinos and provide new model-independent limits on dark matter annihilation into neutrinos based on measurements of neutrinos in a wide energy range. We present the most up-to-date and comprehensive results on dark matter annihilation into neutrinos using the most recently available data from neutrino telescopes. Finally, we will present the projections for next-generation neutrino experiments.

Speaker: Ali Kheirandish (Pennsylvania State University)

pheno2020_kheirandish.pdf

184 GZK neutrinos through Earth

IceCube has measured an astrophysical flux of neutrinos extending to 10 PeV. However, a guaranteed yet undetected flux of cosmogenic neutrinos caused by interactions of ultra-high energy cosmic rays with the cosmic microwave background remains elusive. Using the regeneration effect, we show that EeV tau neutrinos traversing the Earth cascade down in energy and emerge at O(PeV), a region where current cubic-kilometer detectors such as IceCube are sensitive. We show that the rate of upgoing cosmogenic neutrinos is twice that of earth-skimming neutrinos, with a unique zenith and spectral distribution. We discuss possible searches with the currently available ten years of IceCube data.

Speaker: IBRAHIM SAFA (University of Wisconsin - Madison)

Safa_pheno_2020.pdf

185 On the general characteristics of neutrino-driven outflows

Neutrino signal from the next galactic supernova may carry in it imprints of the matter profile features that fall in the density range of ∼$10^3$ g/cm$^3$. The features in question include discontinuities and small-scale fluctuations, which are caused by shocks and turbulent mixing. A well-discussed example is the shockwave expanding through the envelope of the star, which reaches the relevant densities a few seconds after the onset of the explosion. Here, however, we focus on the shocks and turbulent mixing occurring in the post-shock region, in the hot bubble created by neutrino-driven outflows from the surface of the proto-neutron star. Extending the traditional treatment of supersonic neutrino winds, we establish physical criteria for the formation of the termination shock, which depend on the parameters of the explosions, such as the neutrino luminosity, proton-neutron star radius and mass, and the postshock density. For realistic physical conditions, the system is found to be on the edge of shock formation, thus reconciling seemingly disparate numerical results in the literature and providing a sensitive probe of the inner workings of the supernova.

Speaker: Payel Mukhopadhyay (Stanford University)

Payel-pheno-2020-talk.mp4

Pheno 2020-Payel.pdf

18:15 -

Higgs III

Convener: Ian Lewis (The University of Kansas)

186 Constraining the Higgs boson self-coupling in a combined measurement of single and double Higgs boson channels at the ATLAS experiment

The most precise measurements of Higgs boson single and double Higgs production cross sections are obtained from a combination of measurements performed in different Higgs boson production and decay channels. While double Higgs production can be used to directly constrain the Higgs boson self-coupling, the latter can be also constrained by exploiting higher-order electroweak corrections to single Higgs boson production. A combined measurement of both results yields the overall highest precision, and reduces model dependence by allowing for the simultaneous determination of the single Higgs boson couplings. Results for this combined measurement are presented based on pp collision data collected at a center-of-mass energy of 13 TeV with the ATLAS detector.

Speaker: Eleonora Rossi (Universita e INFN Roma Tre (IT))

ER_Pheno2020.pdf

187 Combined Higgs boson measurements at the ATLAS experiment

The most precise measurements of Higgs boson cross sections, using the framework of simplified template cross sections, are obtained from a combination of the measurements performed in the different Higgs boson decay channels. This talk presents the combined measurements, as well as their interpretation.

Speaker: Kunlin Ran (Chinese Academy of Sciences (CN))

kunlinRan_comb_20200505.pdf

188 Studies of Higgs boson properties in decays to two b-quarks at the ATLAS experiment

The Higgs boson decay into two b quarks was observed in summer 2018 and is now used to study Higgs boson production with a focus on Higgs boson production with high transverse momentum. This talk will present measurements based on 13 TeV data.

Speaker: Weitao Wang (University of Science and Technology of China (CN))

Weitao_Pheno2020_Hbb_ATLAS.pdf

189 Studies of rare production and decay processes of the Higgs boson at the ATLAS experiment

The study of and search for rare and forbidden production and decay processes is an important aspect of the Higgs physics program at the LHC. Production in association with top-quark pairs can already be used for property studies of the Higgs boson, and several rare and forbidden decays are still being searched for. The status of these searches and measurements based on 13 TeV proton-proton collision data recorded by the ATLAS detector will be presented and discussed.

Speaker: Nadezda Proklova (National Research Nuclear University MEPhI (RU))

Proklova_pheno.pdf

190 Searches for BSM Higgs at ATLAS

The discovery of the Higgs boson with the mass of about 125GeV completed the particle content predicted by the Standard Model. Even though this model is well established and consistent with many measurements, it is not capable to solely explain some observations. Many extensions addressing this fact introduce additional Higgs-like bosons which can be either neutral, singly-charged or even doubly-charged. Other theories suggest that the Higgs may couple to hidden-sector states that do not interact under the Standard Model gauge transformations. Models predicting exotic Higgs decays to pseudoscalars can explain the galactic center gamma-ray excess, if the additional pseudoscalar acts as the dark matter mediator. This talk presents recent ATLAS searches for decays of the 125 GeV Higgs boson to a pair of new light bosons, and searches for additional Higgs bosons The current status of searches based on full Run2 data of the ATLAS experiment at the LHC are presented.

Speaker: Josefina Alconada (Tel Aviv University (IL))

ATLASBSMsearches_Josefina_5MayoPheno2020.pdf

191 Measurements of Higgs boson properties in the final state with four leptons at the ATLAS experiment

The Higgs boson decay into the four-lepton final state can be fully reconstructed with very small backgrounds, and, despite the small $H\to 4\ell$ branching ratio, allows for detailed property measurements. This talk presents measurements sensitive to the Higgs boson production processes, kinematics, and mass based on pp collision data recorded at $13$ TeV.

Speaker: Verena Maria Walbrecht (Max-Planck-Institut fur Physik (DE))

Pheno2020_Walbrecht.pdf

192 Searches for scalar sector extensions of the standard model via H→ZA→llbb process at CMS

We report on a search for an extension to the scalar sector of the standard model, where a new CP-even (odd) boson decays to a Z boson and a lighter CP-odd (even) boson. The Z boson further decays to a b quark pair while as lighter boson is reconstructed via its decays to electron or muon pairs. The analysed data were recorded by the CMS experiment in proton-proton collisions at the LHC during the year 2016 and corresponds to an integrated luminosity of 35.9 fb^−1. Predictions from the standard model are in agreement with data within the uncertainties. Upper limits at 95% confidence level are set on the production crosssection times branching fraction, with masses of the new bosons up to 1000 GeV. The results are interpreted in the context of the two-Higgs-doublet model.

Speaker: Aashaq Shah (University of Delhi (IN))

CMS_Pheno2020.pdf

193 Recent Higgs boson measurements in the WW final state using CMS data

The latest CMS results on the Higgs boson decays to a W boson pair are presented. The focus of the talk are the inclusive and differential cross section measurements performed using the full Run2 data collected by the CMS detector at LHC, as well as the constraints on the Higgs boson couplings to fermions and vector bosons arising from the simultaneous measurement of different production mechanisms. Recent constraints on BSM models arising from high mass resonance searches in the WW channel are also presented.

Speaker: Mr Siewyan Hoh (University of Padova)

SYH_HWW_measurement_Pheno_2020.pdf

QCD & EW III

Convener: Tobias Neumann (Fermi National Accelerator Laboratory)

194 On the Validity of SMEFT Studies: VH and VV Production

WH, ZH, W+W−, and W±Z pair production probes the significance of non-Standard Model interactions of quarks, gauge bosons, and the Higgs boson. These new effects can be quantified in terms of effective field theory (EFT) coefficients. We examine the importance of including next-to-leading order QCD corrections in fits to the EFT coefficients. We explore different approaches to enforcing the validity of the EFT and the resulting implications on the fits.

Speaker: Samuel Lane (University of Kansas and Brookhaven National Lab (US))

NLO_SMEFT_VV+VH.pdf

195 Removing Flat Directions in SMEFT Fits: Complementing the LHC with polarized EIC Data

We study the potential of future Electron-Ion Collider (EIC) data to probe four-fermion operators in the Standard Model Effective Field Theory (SMEFT). The ability to perform measurements with both polarized electron and proton beams at the EIC provides a powerful tool that can disentangle the effects from different SMEFT operators. We compare the potential constraints from an EIC with those obtained from Drell-Yan data at the Large Hadron Collider. We show that EIC data plays an important complementary role since it probes combinations of Wilson coefficients not accessible through available Drell-Yan measurements.

Speaker: Daniel Wiegand (Northwestern University/Argonne National Lab)

DanielWiegand_SMEFT.pdf

196 Simulating Multi-Jet Events at Hadron Colliders using Forward Branching Phase Space Generators

In this talk I will present results obtained using the previously developed projective phase space generator for the calculation of the vector boson plus one jet at next-to-leading order in QCD. I will comment on the scalability of the projective phase space generator and further directions of the research.

Speaker: Terrance Figy (Wichita State University)

Pheno2020_TMFigy.pdf

197 Measurements of inclusive multi-boson production at ATLAS

The production of multiple weak vector bosons at the LHC constitutes a stringent test of the electroweak sector and provide a model-independent means to search for new physics at the TeV scale. In this talk, we present the latest results from the ATLAS experiment for multi-boson production in proton-proton collisions at √s=13 TeV. The measurements exploit both the leptonic and hadronic decays of the weak vector bosons. Differential cross sections are measured that probe the topology of each final state. The data are corrected for detector inefficiency and resolution and are compared to theoretical predictions at NLO (and NNLO) in perturbative QCD. The measurements are sensitive to anomalous triple gauge couplings and are reinterpreted in terms of an effective field theory to constrain new physics beyond the Standard Model.

Speaker: Louie Dartmoor Corpe (University of London (GB))

LCorpe_MultiBosonIncMeasurements_Pheno20_May2020.pdf

198 Precision measurements of W and Z boson production at ATLAS

Precision measurements of the production cross-sections of W/Z boson at LHC provide important tests of perturbative QCD and information about the parton distribution functions for quarks within the proton. In this talk, we present a variety of measurements that probe the production of weak bosons in proton-proton collisions at a variety of collision energies. For inclusive production of W and Z bosons, we present, W+, W− and Z boson cross sections at 2.76 TeV as well as precision measurements of the kinematic properties of Drell-Yan lepton pairs produced at a centre-of-mass energy of 13 TeV. In addition, we present recent measurements of Z production in association with hadronic jets at 8TeV as well as the production of Z bosons in association with heavy flavour jets at 13TeV. All of the measurements are corrected for detector inefficiency and resolution and compared with state-of-the-art theoretical calculations.

Speaker: Victor Solovyev (NRC Kurchatov Institute PNPI (RU))

Pheno2020_W_and_Z_prod_meas.pdf

199 Jet and Photon Measurements using the ATLAS detector

The production of jets and prompt isolated photons at hadron colliders provides stringent tests of perturbative QCD and can be used to evaluate the probability density functions of partons in the proton. In this talk we discuss a variety of measurements in this section done using proton-proton collision data collected by the ATLAS experiment at √s=13 TeV .  For final states containing photons, we present measurements of inclusive isolated photons and isolated photons produced in association with jets. If available, a measurement of photon pair production will also be presented. For multijet production, we present a measurement of event shape variables calculated using hadronic jets. We also present measurements of the internal properties of jets. First, a comprehensive suite of substructure observables are measured for jets reconstructed with the soft-drop algorithm applied. In addition, a measurement of the Lund Plane performed using charged particles will be presented. Finally, if available, a measurement of the fragmentation properties of jets containing B-hadrons will also be presented. All measurements are corrected for detector effects and are compared to the predictions of state-of-the-art Monte Carlo event generators.

Speaker: Manuel Alvarez Estevez (Universidad Autonoma de Madrid (ES))

Pheno2020_MAlvarez_JetPhotonATLAS.pdf

200 Precision Predictions at N3LO

Progress in our ability to compute scattering cross sections has allowed us to obtain prediction for key collider processes at Next-to-next-to-next-to leading order (N3LO) in QCD perturbation theory. I discuss the implications of this progress on our understanding of the Drell-Yan cross section, on differential predictions for Higgs boson observables and on the precision phenomenology program at the LHC in general.

Speaker: Bernhard Mistlberger (Massachusetts Inst. of Technology (US))

Mistlberger_Pheno2020.pdf

18:15 -

SUSY II

Convener: Adam Martin

201 Flavored Gauge Mediation with Discrete Non-Abelian Symmetries

The aim of this talk is to report progress in the exploration of a class of models of the supersymmetry breaking parameters of the MSSM known as flavored gauge mediation models, in which the Higgs and doublet messengers exhibit mixing that is controlled by a discrete non-Abelian symmetry. The discrete non-Abelian symmetry (here chosen to be S_3 for concreteness) may also play a role as part of the family symmetry that governs the SM fermion masses and mixings. Possible scenarios within this framework and their phenomenological implications are presented.

Speaker: Prof. Lisa Everett (University of Wisconsin-Madison)

lle_pheno_2020.pdf

202 Generating the Cabibbo Angle in Models of Discrete, Non-Abelian Flavored Gauge Mediation

Towards a further exploration of a class of flavored gauge mediation models of supersymmetry breaking in which the mixing of the Higgs and messenger doublets are connected by a discrete non-Abelian symmetry, we investigate the generation of nontrivial mass hierarchies and mixing angles for the Standard Model matter fields. We consider here the case in which the Higgs-messenger symmetry, given by $S_3$, also provides a partial family symmetry. Within this specific implementation of $S_3$, we show that couplings at the renormalizable level can result in hierarchical quark masses, but do not lead to phenomenologically viable quark mixing parameters, thus requiring the inclusion of higher-dimensional operators. As a concrete exploration of this idea, we show that the Cabibbo angle can be generated within this framework via such nonrenormalizable couplings and explore the phenomenological implications of this scenario.

Speaker: Ariel Rock (University of Wisconsin-Madison)

Pheno20Slides.pdf

203 A landscape solution to the SUSY flavor and CP problems

In a fertile patch of the string landscape which includes the Minimal Supersymmetric Standard Model (MSSM) as the low energy effective theory, rather general arguments from Douglas suggest a power-law statistical selection of soft breaking terms ($m_{soft}^n$ where $n=2n_F+n_D-1$ with $n_F$ the number of hidden sector $F$-SUSY breaking fields and $n_D$ the number of $D$-term SUSY breaking fields). The statistical draw towards large soft terms must be tempered by requiring an appropriate breakdown of electroweak (EW) symmetry with no contributions to the weak scale larger than a factor 2-5 of its measured value, lest one violates the (anthropic) atomic principle. Such a simple picture generates a light Higgs boson with mass $m_h\simeq 125$ GeV with sparticles (other than higgsinos) typically beyond LHC reach. Then we expect first and second generation matter scalars to be drawn independently to the multi-TeV regime where the upper cutoff arises from two-loop RGE terms which drive third generation soft masses towards tachyonic values. Since the upper bounds on $m_0(1,2)$ are the same for each generation, and flavor independent,
then these will be drawn toward quasi-degenerate values. This mechanism leads to a mixed decoupling/quasi-degeneracy solution to the SUSY flavor problem and a decoupling solution to the SUSY CP problem.

Speaker: Dibyashree Sengupta (University of Oklahoma)

pheno_2020_sengupta.pdf

204 Probing Lepton Flavor Violating decays in MSSM with Non-Holomorphic Soft Terms

The Minimal Supersymmetric Standard Model (MSSM) can be extended to include non-holomorphic trilinear soft supersymmetry (SUSY) breaking interactions that may have distinct signatures. We consider non-vanishing off-diagonal entries of the coupling matrices associated with holomorphic (of MSSM) and non-holomorphic trilinear terms corresponding to sleptons with elements $A^l_{ij}$ and $A^{\prime l}_{ij}$. We first improve the MSSM charge breaking minima condition of the vacuum to include the off-diagonal entries $A^l_{ij}$ (with $i \neq j$). We further extend this analysis for non-holomorphic trilinear interactions. No other sources of lepton flavor violation like that from charged slepton matrices are considered. We constrain the interaction terms via the experimental limits of processes like charged leptons decaying with lepton flavor violation (LFV) and Higgs boson decaying to charged leptons with LFV. Apart from the leptonic decays we compute all the three neutral LFV Higgs boson decays of MSSM. We find that an analysis with non-vanishing $A^\prime_{e\mu}$ involving the first two generations of sleptons receives the dominant constraint from $\mu \to e \gamma$. On the other hand, $A^\prime_{e\tau}$ or $A^\prime_{\mu\tau}$ can be constrained from the LHC 13 TeV analysis giving limits to the respective Yukawa couplings via considering SM Higgs boson decaying into $e\tau$ or $\mu\tau$ final states. Contributions from $A^l_{ij}$ is too little to have any significance compared to the large effect from $A^{\prime l}_{ij}$.

Speaker: Ms Samadrita Mukherjee (Indian Association for the Cultivation of Science)

Samadrita_Mukherjee_Pheno2020.pdf

205 Mixed gluinos and sgluons from a new SU(3) x SU(3) gauge group

I study supersymmetric models in which the QCD gauge group is the remnant diagonal subgroup from the spontaneous breaking of an SU(3)×SU(3) gauge group at a multi-TeV scale. In renormalizable models with soft supersymmetry breaking, the scalar potential is shown to have global minima with the required gauge symmetry breaking pattern. In addition to a massive color octet vector boson, this framework predicts 3 color octet spin-0 sgluons, and 4 color octet gluinos with both Dirac and Majorana mass terms. One of the gluino mass eigenstates typically has a coupling to quark-squark pairs that is at least as large as the prediction of minimal supersymmetry, but it need not be the lightest one.

Speaker: Stephen Martin (Northern Illinois University)

spmartin.pdf

206 One Model Fits All: A Minimal R-parity Violating Supersymmetric Model for the Flavor Anomalies, Muon g-2 and ANITA

We show that both 𝑅𝐷(∗) and 𝑅𝐾(∗) flavor anomalies can be addressed in a minimal 𝑅-parity violating supersymmetric scenario, motivated by Higgs naturalness that requires relatively light third-generation sfermions. Interestingly, this scenario may also be able to accommodate two other seemingly disparate anomalies, namely, muon (𝑔−2) and anomalous upgoing ultra-high energy cosmic ray air showers at ANITA. We find it remarkable that there exists overlap regions in the minimal model parameter space where all (or some) of these anomalies can be simultaneously explained, while satisfying a plethora of precision low-energy and high-energy experimental constraints. We will discuss some testable predictions of the model.

Speaker: Bhupal Dev (Washington University in St. Louis)

dev_pheno20.pdf

207 A multicomponent dark matter scenario consistent with experiment

We review a dark matter scenario which is ideal in many respects [1-4], and which appears to be supported by recent analyses of observations from major satellite experiments, which can provide indirect detection of dark matter particles resulting from their annihilation in space. In this scenario, with both supersymmetry and an extended Higgs sector, there is a doubly rich plethora of new particles and new physics to be discovered in the near or foreseeable future. The mass of the dominant dark matter WIMP (weakly interacting massive particle) is ≤ 125 GeV, its gauge couplings are precisely defined, and its Higgs-mediated couplings should be comparable to those of the neutralino of supersymmetry. Recent (and earlier) analyses of the data from Planck, Fermi-LAT, AMS-02, and other
experiments indicate that (i) the positron excess at ~ 800 GeV or above is not evidence of high-mass dark matter particles (which would have disconfirmed the present theory with a rigorous upper limit of 125 GeV), (ii) the Galactic center excess of gamma rays observed by Fermi is evidence for dark matter particles with a mass below or near 100 GeV, (iii) the gamma-ray excess from Omega Centauri is similar evidence of annihilation of such relatively low-mass particles, and (iv) the antiproton excess observed by AMS is again evidence of roughly 100 GeV dark matter particles. The present scenario, with two stable spin 1/2 WIMPs (a high-mass neutralino and a more abundant “Higgson” with a mass of ≤ 125 GeV) is consistent with these results (as well as all others which have been verified), and it also suggests that detection should be near in a variety of experiments for direct, indirect, and collider detection.
[1] Roland E. Allen and Aritra Saha, Mod. Phys. Lett. A 32, 1730022 (2017).
[2] Roland E. Allen, Phys. Scr. 94, 014010 (2019), arXiv:1811.00670 [hep-ph].
[3] Maxwell Throm, Reagan Thornberry, John Killough, Brian Sun, Gentill Abdulla, and Roland E. Allen. Mod. Phys. Lett. A 34, 1930001 (2019).
[4] Reagan Thornberry, Maxwell Throm, John Killough, Dylan Blend, Michael Erickson,
Brian Sun, Brett Bays, Gabe Frohaug, and Roland E. Allen, “A natural multicomponent
dark matter scenario with two coexisting stable WIMPs”, submitted.

Speaker: Roland Allen (Texas A&M University)

3MB-Allen-PHENO-2020.pdf

18:15 -

Axions & ALPs II

Convener: Brooks Thomas (Lafayette College)

208 The High Quality QCD Axion and the LHC

The QCD axion provides an elegant solution to the Strong CP Problem. While the minimal realization is vulnerable to the so-called “Axion Quality Problem”, I will consider a more robust realization in the presence of a mirror sector related to the Standard Model by a (softly broken) $Z_2$ symmetry. Interestingly, the resulting “heavy” axion has a large and uncharted parameter space where it behaves as a Long-Lived Particle (LLP). By considering the defining axionic coupling to gluons, I will argue that the long-lived nature of the signal can be used to veto background, and evaluate the prospect of discovery of GeV scale axions at the HL-LHC.

Speaker: Soubhik Kumar (University of Maryland)

axion-lhc-pheno20-soubhik.pdf

209 QCD axion DM and inflation scale

I show that the upper bound of the classical QCD axion window can be significantly relaxed with low-scale inflation. If the Gibbons-Hawking temperature during inflation is lower than the QCD scale and the inflation lasts long enough, the initial QCD axion misalignment angle follows an equilibrium distribution. The distribution is peaked at the strong CP conserving minimum and the variance is much smaller than O(1) if the inflation scale is smaller than $10^8\,$GeV. As a result, the axion can be the dark matter even for an axion decay constant much larger than $10^{12}$ GeV.

Speaker: Wen Yin (KAIST)

Pheno2020_3.pdf

210 Gravitational Production of Ultra light Dark(est) Matter

I will present the results of our study of the non-adiabatic cosmological production of ultra light dark matter (ULDM) under a minimal set of assumptions: a free ultra light real scalar as a spectator field in its Bunch-Davies vacuum state during inflation and instantaneous reheating into a radiation dominated era. For (ULDM) fields minimally coupled to gravity, non-adiabatic particle production yields a distribution function peaked at low comoving momentum. The infrared behavior is a remnant of the infrared enhancement of light minimally coupled fields during inflation. We obtain the full energy momentum tensor, show explicitly its equivalence with the fluid-kinetic one in the adiabatic regime, and extract the abundance, equation of state and free streaming length (cutoff in the matter power spectrum). Taking the upper bound on the scale of inflation from Planck, the (UDLM) saturates the dark matter abundance for particles with mass ~10^-5 eV. Thus this cosmologically produced (ULDM) yields a cold dark matter particle without any coupling to Standard Model species and with solely gravitational interactions. We argue that the abundance from non-adiabatic production yields a lower bound on generic (ULDM) and axion-like particles (ALP) that must be included in any assessment of (ULDM)/(ALP) as a dark matter candidate.

Speaker: Nathan Herring (University of Pittsburgh)

Particle Production (Pheno2020).pdf

211 Axion Coupling Quantization in the Presence of Mixing

Many axion models in the literature strive to generate phenomenologically advantageous features, such as hierarchies between axion couplings to different gauge fields and/or large effective field ranges. Because these features are strongly constrained by periodicity of the axion coupling to gauge fields for models with only a single axion, many models use mixing of multiple axion fields to try to evade constraints. In this talk, I will discuss how these models mixing multiple axions continue to be constrained by coupling quantization despite appearances (and some claims in the literature) to the contrary, and how coupling quantization can serve as a useful consistency check on the many models with multiple axions.

Speaker: Katherine Fraser (Harvard University)

Axions_Talk_Pheno_2020.pdf

212 Dynamical axion misalignment with small instantons

We present a new mechanism to relax the initial misalignment angle of the QCD axion and raise the cosmological bound on the axion decay constant. The QCD axion receives a contribution from small UV instantons during inflation, which raises its mass to the inflationary Hubble scale. This makes the axion start rolling down its potential early on. In the scenario, the standard model Yukawa couplings of quarks are dynamical, being of order one during the inflationary era and reducing to their standard model values once it ends. This means that after inflation the contribution of the small instantons is suppressed, and the axion potential reduces to the standard one from the usual IR instantons. As a result, when the axion starts to oscillate again after inflation, the initial misalignment angle is suppressed due to the dynamics during inflation. While the general idea of dynamical axion misalignment has been discussed in the literature before, we present in detail the major bottleneck on the mismatching between the minima of the axion potentials during and after inflation, and how it is circumvented in our scenario via the Froggatt-Nielsen mechanism. Taking into account of all the constraints, we find that the axion decay constant could be raised to the GUT scale, $10^{15}$ GeV, in our scenario.

Speaker: Manuel Buen-Abad (Brown University)

Pheno2020 -- Dyn. Axion Mis. -- M. Buen-Abad.pdf

213 SMART U(1)$_X$ - Standard Model with Axion, Right handed neutrinos, Two Higgs doublets and U(1)$_X$ gauge symmetry

To address five fundamental shortcomings of the Standard Model (SM) of particle physics and cosmology, we propose a SMART U(1)$_X$ model which is a $U(1)_X \times U(1)_{PQ}$ extension of the SM, where the $U(1)_X$ gauge symmetry is a generalization of the well-known $U(1)_{B-L}$ symmetry and $U(1)_{PQ}$ is the global Peccie-Quinn (PQ) symmetry. Three right handed neutrinos required to cancel $U(1)_X$ related anomalies play a crucial role in understanding the observed neutrino oscillations and explain the observed baryon asymmetry in the universe via leptogenesis. The PQ symmetry helps resolve the strong CP problem and also provides axion as a compelling dark matter candidate. The $U(1)_X$ gauge symmetry enables us to implement the inflection-point inflation scenario to realize Hubble parameter during inflation smaller than $2 \times 10^{7}$ GeV. This allows us to overcome a potential axion domain wall problem as well as the axion isocurvature problem. As an example, we show that SMART U(1)$_X$ model can be merged with $SU(5)$.

Speaker: Dr Digesh Raut (University of Alabama)

Pheno20_raut_SMARTU1.pdf

214 QCD Axion Dark Matter from a Late Time Phase Transition

I will discuss a production scenario for QCD axion dark matter where the Peccei-Quinn phase transition occurs at a temperature far below the symmetry breaking scale. Both early cosmic string network dynamics and parametric resonance contribute to the axion population. The observed dark matter abundance is reproduced even if the decay constant is much lower than 10^11 GeV. I will also discuss the rich phenomenology of this scenario as it pertains to future observations of 21 cm lines and rare Kaon decays.

Speaker: Jacob Leedom (University of California, Berkeley)

JML_Pheno.pdf

18:15 -

18:45 Virtual Cocktail Hour

Wednesday 6 May

Plenary: V

Convener: Christopher Kolda (University of Notre Dame)

215 New Physics at the TeV Scale

Speaker: Matthew Reece (Harvard University)

Reece_Pheno_2020.pdf

216 What is the Dark Matter?

Speaker: Stefano Profumo (University of California, Santa Cruz)

Profumo_Pheno_200506.pdf

217 Axion physics

Speaker: Andreas Ringwald (Deutsches Elektronen-Synchrotron DESY)

pheno_axion_physics.pdf

10:30 Coffee Break

Plenary: VI

Convener: Raman Sundrum (University of Maryland)

218 Quantum computing

Speaker: Martin Savage (Institute for Nuclear Theory)

Savage_Pheno2020_May2020_v1p1_pdf.pdf

219 Some new thoughts on the hierarchy problem

Speaker: Nima Arkani-Hamed (IAS)

pheno2020.pdf

220 Strategy in pursuing high energy physics

Speaker: Christophe Grojean (DESY (Hamburg) and Humboldt University (Berlin))

Grojean.pdf