Conveners
Beyond Standard Model
- stefania gori (UC Santa Cruz)
- Christopher Rogan (The University of Kansas (US))
- Lawrence Lee Jr (Harvard University (US))
- Verena Ingrid Martinez Outschoorn (University of Massachusetts (US))
Beyond Standard Model
- Verena Ingrid Martinez Outschoorn (University of Massachusetts (US))
- Christopher Rogan (The University of Kansas (US))
- Lawrence Lee Jr (Harvard University (US))
- stefania gori (UC Santa Cruz)
Beyond Standard Model
- Lawrence Lee Jr (Harvard University (US))
- Christopher Rogan (The University of Kansas (US))
- stefania gori (UC Santa Cruz)
- Verena Ingrid Martinez Outschoorn (University of Massachusetts (US))
Beyond Standard Model
- Lawrence Lee Jr (Harvard University (US))
- Verena Ingrid Martinez Outschoorn (University of Massachusetts (US))
- Stefania Gori (UC Santa Cruz)
- Christopher Rogan (The University of Kansas (US))
Beyond Standard Model: BSM & DM Joint Session: Dark Matter at Accelerators
- Lawrence Lee Jr (Harvard University (US))
- Benjamin Safdi
- Rupak Mahapatra (Texas A&M University)
- Lindley Winslow (Massachusetts Institute of Technology)
- Stefania Gori (UC Santa Cruz)
- Verena Ingrid Martinez Outschoorn (University of Massachusetts (US))
- Christopher Rogan (The University of Kansas (US))
Beyond Standard Model
- Lawrence Lee Jr (Harvard University (US))
- Stefania Gori (UC Santa Cruz)
- Verena Ingrid Martinez Outschoorn (University of Massachusetts (US))
- Christopher Rogan (The University of Kansas (US))
Beyond Standard Model
- Verena Ingrid Martinez Outschoorn (University of Massachusetts (US))
- Stefania Gori (UC Santa Cruz)
- Lawrence Lee Jr (Harvard University (US))
- Christopher Rogan (The University of Kansas (US))
Beyond Standard Model
- Verena Ingrid Martinez Outschoorn (University of Massachusetts (US))
- Lawrence Lee Jr (Harvard University (US))
- Christopher Rogan (The University of Kansas (US))
- Stefania Gori (UC Santa Cruz)
Description
parallel sessions
New long-lived particles (LLPs) are a feature of many extensions to the Standard Model and may elude searches for promptly decaying particles. An analysis of data collected in $pp$ collisions at $\sqrt{s}=$ 13 TeV with the ATLAS detector at the Large Hadron Collider is described, focusing on identifying signatures of jets produced by LLPs decaying to Standard Model fermions within the ATLAS...
Searches for long-lived particles using proton-proton collisions expand the discovery possibilities beyond traditional searches for short-lived particles. These searches often require new algorithm and technique development. Recent results and techniques using data from the CMS experiment will be presented.
A search for highly displaced vertices resulting from the decay of neutral long-lived particles produced by proton-proton collisions at $\sqrt{s}=$ 13 TeV using 140 fb$^{-1}$of data collected by the ATLAS experiment is in progress. Such long-lived particles are predicted by several beyond the Standard Model theories. Benchmark models used in the analysis will be discussed. For displaced...
With the great promise of deep learning, discoveries of new particles at the Large Hadron Collider (LHC) may be imminent. Following the discovery of a new particle in an all-hadronic channel, deep learning can also be used to identify the quantum numbers of the new particle. We show that convolutional neural networks (CNNs) using jet images can significantly improve upon existing techniques...
We investigate a class of models where the supergravity model with the standard model gauge group is extended by a hidden sector $U(1)_X$ gauge group and where the lightest supersymmetric particle is the neutralino in the hidden sector. We investigate this possibility in a class of models where the stau is the lightest supersymmetric particle in the MSSM sector and the next-to-lightest...
The high luminosity run of the Large Hadron Collider (HL-LHC) promises a dataset far larger than previously collected in the preceding LHC runs. With this opportunity comes additional challenges. The increasing number of interactions present in each event adds difficulty to particle reconstruction and pileup disambiguation. To address this issue, ATLAS and CMS have been developing new...
We describe a search for the production of a pair of vector-like quarks (VLQ's) with masses greater than 1000 GeV/c$^2$ each decaying into a $b$ quark and a Higgs Boson using data from proton-proton collisions at center-of-mass energy of 13 TeV recorded by the CMS Experiment. Since the predominant decay mode of the Higgs boson is to a $b \bar{b}$ pair, the analysis focuses on a final state...
In traditional searches for physics beyond the standard model, a requirement of high missing transverse momentum (MET) is often used. However, without any signs of significant deviations from the standard model expectations, we decided to relax this requirement for the search reported in this talk. Many new physics models, including versions of supersymmetry (SUSY) characterized by R-parity...
Many models predict new particles with sizeable couplings to quarks and gluons. A search is performed for localized excesses in dijet mass distributions of low-dijet-mass events produced in association with a high transverse energy photon. The search uses up to 79.8 fb$^{-1}$ of LHC proton–proton collisions collected by the ATLAS experiment at a center-of-mass energy of 13 TeV during...
New, massive bosons could be found with the LHC. Theories with warped extra dimensions and supersymmetry predict the existence of such resonances, which for some model parameters, have a significant branching fraction to two Higgs bosons. A search for such particles in the HH->bbWW->bbqq'lnu channel with the CMS detector is presented. The analysis uses data collected during Run 2 of the LHC at...
An approach is presented for the calculation of high-energy hadron-lepton and hadron-hadron interactions at large momentum transfer in the presence of Lorentz-violating background fields affecting quarks. Cross sections for deep inelastic scattering and the Drell-Yan process are calculated at leading order for minimal and nonminimal Lorentz violation using the Standard-Model Extension, an...
A massive U(1)′ gauge boson known as a “dark photon” or A′, has long been proposed as a potential explanation for the discrepancy observed between the experimental measurement and theoretical determination of the anomalous magnetic moment of the muon ($g_μ$ − 2) anomaly. Recently, experimental results have excluded this possibility for a dark photon exhibiting exclusively visible or invisible...
The Muon g-2 Experiment (E989) at Fermilab measures the anomalous magnetic moment of the muon $a_{\mu}$, aiming at resolving the 3.6-$\sigma$ discrepancy between the previous measurement and the Standard Model calculation with a improved precision of 140 part-per-billion (ppb). In E989, the muon beam is stored in a ring magnet. The spin precession frequency $\omega_{a}$ is measured by counting...
It is very likely that similar to the case of visible matter, dark matter too is composed of more than one stable component. In this work we investigate a two-component dark matter with one component from the visible sector and the other from the hidden sector. Specifically we consider a $U(1)_X$ hidden sector extension of MSSM/SUGRA where we allow for kinetic and Stueckelberg mass mixing...
Searches for dark-matter particles at the GeV mass scale have been
receiving much attention in the last several years, partly motivated
by the failure of direct and indirect searches of heavier candidates
to produce a signal. The SpinQuest dimuon experiment in the 120-GeV
Main-Injector proton beam at Fermilab, currently in the commissioning
stage, is uniquely equipped to search for dark...
Extensions of the Standard Model are often highly constrained by cosmology. The presence of new states can dramatically alter observed properties of the universe by the presence of additional matter or entropy. In particular, attempts too solve the hierarchy problem through naturalness invariably predict new particles near the weak scale which come into thermal equilibrium. Without a means to...
We present searches of the top squark production with the data collected by CMS detector, at a center-of-mass energy of 13 TeV and correspond to an integrated luminosity of 137/fb. A variety of final state decays are considered with an emphasis on targeting different kinematic regions. These channels have distinctive signatures and deep learning top taggers are used to further optimizes searches.
Supersymmetry, which extends the Standard Model (SM) by introducing supersymmetric partners for the SM particles, can provide an elegant solution to the hierarchy problem. One of the most important parameters in supersymmetry is the mass of the supersymmetric partner to the top quark, referred to as stop. In the absence of the stop signature in the previous searches at the LHC, compressed stop...
We examine new aspects of leptoquark (LQ) phenomenology using effective field theory (EFT). We construct a complete set of leading effective operators involving SU(2) singlets scalar LQ and the SM fields up to dimension six. We show that, while the renormalizable LQ-lepton-quark interaction Lagrangian can address the persistent hints for physics beyond the Standard Model in the B-decays $\bar...
Leptoquarks are hypothetical bosons with fractional electric charge which present a new symmetry between quarks and leptons. They are predicted in multiple models of physics beyond the standard model, including as a potential explanation of the current tension with the standard model seen in the decays of B mesons. An overview of the theoretical motivation and present searches for leptoquarks...
One of the most pressing issues in particle physics is the hierarchy problem: how is the Higgs boson so light? A common feature in many of the theories proposed to solve the hierarchy problem is the prediction of TeV-scale vector like quarks. This talk will give an overview of the recent searches for vector like quarks performed by the ATLAS experiment and the combination of vector like...
We describe a search for the production of a pair of vector-like quarks (VLQ's) with masses greater than 1000 GeV/c$^2$in a di-lepton final state using data from proton-proton collisions at a center-of-mass energy of 13 TeV recorded by the CMS Experiment. The analysis is based on detection of a di-lepton pair from the decay of a $Z$ boson and is sensitive to events in which one VLQ decays to a...
The Standard Model Effective Theory (SMEFT) is a powerful tool to constrain physics beyond the Standard Model through data, without making restricting assumptions about the nature of the UV theory.
Even though there has been a lot of work put into constraining many of the dimension 6 operators, the large subset of four-Fermi operators has been wildly neglected in NLO analysis, due to SMEFT...
The total decay width of the Higgs has not yet been constrained precisely, which allows for up to 30% of the branching fraction to be from beyond the standard model decays. If sufficiently light, dark matter motivates a decay of the Higgs to invisible final states. This talk will discuss searches for invisible decays of the Higgs produced in all production modes in $pp$ collisions at...
Current searches for dark matter at the LHC focus on mono-X signatures where the production of dark matter in association with a Standard Model (SM) particle is considered. The simplest benchmark model involves a massive spin-1 mediator, the Z′ boson, between the dark matter χ and the SM. Limits derived from mono-X channels are most effective when the mediator can decay into two on-shell dark...
The ATLAS experiment at the Large Hadron Collider (LHC) has a broad and systematic search program for dark matter. Many models of dark matter predict a new particle that mediates the interaction between Standard Model particles and dark matter. If this mediator can be produced by colliding protons at the LHC, then it should also decay to components of the proton, producing a dijet resonance...
Here we continue predictions for detection of new neutral and charged particles in a model which contains both supersymmetry and new non-supersymmetric particles from an extended Higgs sector [1-3]. The lowest energy of the new particles, which also have an R-parity of -1 [1], is an ideal dark matter WIMP with a mass $\leq$ 125 GeV/c$^2$ [2]. All the new non-susy particles couple to standard...
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 its signature. The ATLAS detector has developed a broad and systematic search program for dark...
MoEDAL is an LHC experiment designed to search for anomalously ionizing messengers of new physics such as magnetic monopoles or massive (pseudo-)stable charged particles, which are predicted to exist in many models beyond the Standard Model. It started data taking at the LHC at a centre-of-mass energy of 13 TeV in 2015. Its physics program yields insights into such foundational questions as:...
The status of the milliQan experiment is discussed. milliQan is a proposed search for milli-charged particles produced at the LHC with expected sensitivity to charges of between 0.1e and 0.001e for masses in 0.1 - 100 GeV range. The proposed detector is an array of 4 stacks of 60 cm long plastic scintillator arrays read out by PMTs. It will be installed in an existing tunnel 33 m from the CMS...
New physics has traditionally been expected in the high-pT region at high-energy collider experiments. If new particles are light and weakly-coupled, however, this focus may be completely misguided: light particles are typically highly collimated around the beam line, allowing sensitive searches with small detectors, and even extremely weakly-coupled particles may be produced in large numbers...
The features of the NA62 experiment at the CERN SPS – high-intensity setup, trigger-system flexibility, high-frequency tracking of beam particles, redundant particle identification, and high-efficiency photon vetoes – make NA62 particularly suitable to search for long-lived, weakly-coupled particles within Beyond the Standard Model (BSM) physics, using kaon and pion decays as well as operating...
A search for long-lived particles decaying to an oppositely-charged lepton pair, $\mu\mu$, $ee$, or $e\mu$?, is presented
using 32.8 fb$^{-1}$ of $pp$ collision data collected at $\sqrt{s}$ = 13 TeV by the ATLAS detector at the LHC.
Candidate leptons are required to form a vertex, within the inner tracking volume of ATLAS, displaced
from the primary pp interaction region. No lepton pairs with...
Lorentz violation has been a popular field in recent years in the search for new physics beyond the Standard Model. We present a general method to build all Lorentz-violating terms in gauge field theories, including ones involving operators of arbitrary mass dimension. Applying these results to two types of experiments in high-energy colliders, light-by-light scattering and deep-inelastic...
Among many minimal and phenomenologically motivated Supersymmetry (SUSY) scenarios, the "compressed mass spectra scenario" is the one of the most appealing. This is favored by the observed dark matter relic abundance and the naturalness argument and so on, where the electroweak gaugino (EWKino) states typically have O(1) GeV - 100 GeV mass splitting between them. While these EWKino states can...
A search for supersymmetry through the pair production of electroweakinos is presented in a three-lepton final state. The analyzed proton-proton collision data taken at a centre-of-mass energy of $\sqrt{s}$ = 13 TeV was collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139 $\mbox{fb\(^{-1}\)}$. The search...
Due to their small production cross sections, electroweakinos are difficult to directly search for at colliders. However, the LHC has reached sufficiently high integrated luminosity that the existence of electroweakinos at masses of hundreds of GeV can now be probed. In this talk I will present the results of a likelihood analysis of the electroweakino sector using the GAMBIT global fitting...
We present the results of searches for supersymmetry in final states with tau leptons using data collected by the CMS experiment corresponding to integrated luminosities of up to 137 /fb. A variety of supersymmetric scenarios in which tau sleptons may be produced are considered, targeting scenarios in which tau sleptons could be amongst the lightest supersymmetric particles. These searches are...
A search is presented for chargino pair-production and chargino-neutralino production, where the almost mass-degenerate chargino and neutralino each decay via $R$-Parity-violating couplings to a boson ($W/Z/H$) and a charged lepton or neutrino. This analysis searches for a trilepton invariant mass resonance in data corresponding to an integrated luminosity of 139 fb$^{-1}$ recorded in...
The decay K+→π+vv, with a very precisely predicted branching ratio of less than 10exp[-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+→π+vv with a decay-in-flight technique. NA62 took data so far in 2016-2018. Statistics collected in 2016 allowed...
Neutral mesons provide a unique opportunity to study indirect CPT violation arising from Lorentz-violating backgrounds coupled to quark fields. The existing formalism is extended using an effective scalar field theory, and the theoretical description of indirect CPT violation is generalized to include operators of arbitrarily large mass dimension. Estimates of the attainable sensitivities of...
Observation of neutrinoless muon-to-electron conversion in the presence of a nucleus would be unambiguous evidence of physics Beyond the Standard Model. Two experiments, COMET at J-PARC and Mu2e at Fermilab, will search for this process in the next few years. These experiments will provide upper-limits on this branching ratio up to 10,000 times better than previously published. To successfully...
The $\eta$ and $\eta'$ mesons are almost unique in the particle universe since they are Goldstone boson and the dynamics of their decay are strongly constrained.
Because the eta has no charge, decays that violate conservation laws can occur
without interfering with a corresponding current. The integrated eta meson
samples collected in earlier experiments have been about ~$10^9$ events,...
The Mu3e experiment searches for the charged lepton flavour violating 𝜇+ → 𝘦+ 𝘦+ 𝘦- decay and it aims at reaching an ultimate sensitivity of 10^-16 on the branching fraction of the 𝜇+ → 𝘦+ 𝘦+ 𝘦- decay, four orders of magnitude better than the current limit B(𝜇+ → 𝘦+ 𝘦+ 𝘦-)<10^-12 set by the SINDRUM experiment. The experiment will be hosted at the Paul Scherrer Institute (Villigen, Switzerland)...
We study theories of extended Higgs sectors with large couplings to light quarks. We show that these theories arise naturally from simple UV completions with spontaneously broken flavor symmetries, which ensure strong suppression of FCNCs. In these theories, extra Higgses are copiously produced at the LHC, and if they mix with the 125 GeV Higgs they lead to dramatic enhancements of its Yukawa...
We propose a supersymmetric extension of the anomaly-free and three families
nonuniversal U(1) model, with the inclusion of four Higgs doublets and four Higgs
singlets. The quark sector is extended by adding three exotic quark singlets, while the
lepton sector includes two exotic charged lepton singlets, three right-handed neutrinos
and three sterile Majorana neutrinos to obtain the fermionic...
We build a model beyond the Standard Model with three generations of fermions. We study the mass hierarchy of the fermions and their mixing angles using a U(1)X gauge symmetry anomaly free. The model contains additionally exotic up-
like quark, two bottom-like quarks, two charged leptons and three right handed neutrino. Three right-handed sterile neutrinos are aklso introduced to implement the...
The “mass-shell equation” E2 I3 = RE2 I3 + KE2 I3 = (RE I3 + i KE I3) x (RE I3 - i KE I3), where
KE I3 = [a12=a21=1= -a33, elsewhere 0, call Matrix X] x [b12=b21= cℏk = -b33, elsewhere 0], implies E = RE +/- i pc = RE + KE, where i p I3 = ℏk I3 = the 3 possible angular momenta, with k converting the (linear) meter into (circular) radians, i rotating the 3 possible planes, and a sign reversal...
A search is presented for chargino pair-production and chargino-neutralino production, where the almost mass-degenerate chargino and neutralino each decay via 𝑅-Parity-violating couplings to a boson (𝑊/𝑍/𝐻) and a charged lepton or neutrino. This analysis searches for a trilepton invariant mass resonance in data corresponding to an integrated luminosity of 139 fb−1 recorded in proton-proton...
While the Standard Model (SM) of particle physics is a very successful theory, it is not a complete theory. Extensions of the SM proposed to address issues in the theory often predict the existence of high-mass resonances that decay to final states with top quarks and $W$ bosons. This talk describes the searches for such new phenomena in $pp$ collisions at $\sqrt{s}=$ 13 TeV with the ATLAS...
The observation of neutral long-lived particles at the LHC would reveal physics beyond the Standard Model and could account for the many open issues in our understanding of our universe. Long-lived particle signatures are well motivated and can appear in many theoretical constructs that address the Hierarchy Problem, Dark Matter, Neutrino Masses and the Baryon Asymmetry of the...
The existence of pseudoscalars weakly coupled to particles from the Standard Model of particle physics, known as axion-like particles (ALP), would induce anomalous scattering of light-by-light. Searching for these particles relying only on their coupling to the electromagnetic field is challenging. This process can be probed at the Large Hadron Collider (LHC) in production of photon pairs in...
Author:
John Brandenburg
The GEMS ( GEM Super) Unification Theory is based on simple physical models yet appears to validate the well-known mathematical path of beginning with the Hilbert Action principle and then expanding it to include first 1 hidden dimension after KK ( Kaluza-Klein), going from 4 dimensional Minkowski space where the Hidden 5th dimension is assumed to “deploy” to some...
