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The 30th International Conference on Supersymmetry and Unification of Fundamental Interactions
The aim of the SUSY conference is to review and discuss recent research related to supersymmetric theories and all other approaches to physics beyond the Standard Model in all aspects, including formal theory, phenomenology, astrophysics, experiment, etc.
The University of Southampton is responsible for organising the 30th International Conference on Supersymmetry and Unification of Fundamental Interactions (SUSY 2023).
Registration and Abstract submission will open on 20th April and close on 16th June for both the SUSY 2023 conference and the pre-SUSY school.
Supergravity and string based models typically contain hidden sectors. We discuss the physics of hidden sectors and how they affect analyses of phenomena related to particles and cosmology
It is known that there is huge hierarchy among the masses of quarks and leptons, and the lepton mixing is drastically different from quark mixing. The origin of fermion masses and flavor mixing is a longstanding puzzle of SM. Modular symmetry is a promising approach to address the flavor puzzle. This approach can overcome the drawbacks of traditional flavor symmetry, and it allows to explain the observed fermion masses and mixing parameters with a small number of free parameters. In this talk, I shall present some developments of the modular flavor symmetry, the possible connection to the top-down approach will be mentioned.
Common lore suggests that effects of quantum gravity are difficult to unravel. The Planck scale is in fact about 14 orders of magnitude above the highest energy reached on Earth, namely at the Large Hadron Collider. In this talk, I will show that the quantum gravity cut-off can decrease in certain situations thus making quantum gravity effects accessible at energies lower than the Planck scale. Based on the results of recent and ongoing work, I will show that quantum gravity can constrain a variety of aspects of cosmic acceleration and give a prediction of supersymmetry signatures at energies of order TeV.
The latest SUSY/BSM related searches and hints/anomalies in CMS
An overview of anomalies identified in ATLAS searches for new physics phenomena will be presented.
The LHCb experiment conducts a wide programme of measurements which indirectly probe physics beyond the standard model. Rare decays of beauty and charm quarks which proceed via flavour-changing neutral currents are particularly sensitive to new physics at the TeV scale and above. This talk will describe recent LHCb analyses of rare B and D meson decays to muons that have particular sensitivity to supersymmetric particles.
In this talk, we focus on the TeV scale B−L extension of the Minimal Supersymmetric Standard Model (BLSSM), which naturally incorporates a seesaw mechanism for generating light neutrino masses. Our emphasis will be on exploring the various phenomenological implications of this class of models.
I present a brief overview of SUSY phenomenology: where theory
intersects with experiment. Three areas are addressed: 1. indirect effects
including g-2, B-decays, EDMs; 2. dark matter signatures featuring
thermally produced WIMPs and non-thermal SUSY dark matter including
axions and light moduli; and 3. collider signatures featuring standard
LHC searches which then confront the naturalness issue.
I explain how older conventional measures overestimated SUSY finetuning
and show that plenty of natural parameter space is left to explore.
The advent of the string landscape percolated slowly into
SUSY phenomenology, but now rather general arguments suggest a landscape
draw to large soft terms modulated by requiring a derived weak scale
in each viable pocket universe be not too far from our measured value so that
atoms and complexity can arise. This stringy naturalness then predicts
m(h)~125 GeV with sparticles largely beyond present LHC reach.
The anomalous magnetic moment of the muon is one of the most sensitive probes of physics at the weak scale. Its current measurement presents a 4.2 sigma deviations from the Standard Model prediction, what is an exciting hint of physics beyond the Standard Model. However, such a prediction is subject to theoretical and experimental uncertainties, coming mainly from the hadronic vacuum polarization contributions. I will discuss the current status of this anomaly, the possibility of explaining it within low energy Supersymmetry, as well as an attempt to reconcile the hadronic vacuum polarization contributions obtained from dispersion relations of the hadronic cross section as well as their first principle lattice determination.
While the third run of the Large Hadron Collider (LHC) is ongoing, the
model that extends the Standard Model remains so far unknown. Left-Right Models
(LRMs) introduce a new gauge sector, and can restore parity symmetry at high enough
energies. If LRMs are indeed realized in nature, the mediators of the new weak force can
be searched for in colliders via their direct production. We recast existing experimental
bounds from LHC Run 2 on the heavy LRM gauge boson masses. As a novelty, we
discuss the effect of the LRM scalar content on the total width of the new gauge bosons,
obtaining model-independent bounds within the specific realizations of the LRM scalar
sectors analysed here. These bounds avoid the need to detail the spectrum of the scalar
sector, and apply in the general case where no discrete symmetry is enforced. Moreover,
we emphasize the effect of the structure of the quark right-handed mixing matrix on the
charged LRM gauge boson production at LHC.
Left-Right (LR) theories are one of the successful beyond Standard Model (SM) frameworks that explain the origin of small neutrino masses and low-energy weak parity violation. However, the conventional LR theory faces a challenge due to the presence of flavor changing neutral currents (FCNCs). To address this, we have studied an Alternative LR model (ALRM), which avoids FCNC constraints. Our study shows that ALRM has distinct new physics signatures compared to conventional LR symmetric models in $0 \nu \beta \beta$ decay and leptogenesis. Specifically, we show that the vector-scalar mediated diagrams contribute significantly in $0 \nu \beta \beta$ while the small Dirac CP-phase in the right handed neutrino sector can saturate the current BAU bound. Additionally, our model predicts dark matter candidates stabilised by an R-parity, similar to supersymmetry.
Many different theories beyond the Standard Model (SM) predict that new physics will manifest itself by decaying into final states involving leptons. Leptoquarks are predicted by many new physics theories to describe the similarities between the lepton and quark sectors of the SM. Right-handed Ws and heavy-neutrinos are also predicted by many extensions of the SM in the gauge sector, and lepton flavour violation could manifest itself by decays of new gauge bosons into leptons of different flavours. This talk will present the most recent 13 TeV results on the searches for leptoquarks with the ATLAS detector, covering flavour-diagonal and cross-generational final states, as well as the latest searches for lepton-flavour violating Z' and heavy neutrinos arising from left-right symmetric models.
In the first part of this talk I will describe a Left-Right symmetric model that provides an explanation for the mass hierarchy of the charged fermions within the framework of the Standard Model. This explanation is achieved through the utilization of both tree-level and radiative seesaw mechanisms. In this model, the tiny masses of the light active neutrinos are generated via a three-loop radiative inverse seesaw mechanism, with Dirac and Majorana submatrices arising at one-loop level. To the best of my knowledge, this is the first example of the inverse seesaw mechanism being implemented with both submatrices generated at one-loop level. The model contains a global U(1)X symmetry which, after its spontaneous breaking, allows for the stabilization of the Dark Matter (DM) candidates. The model is consistent with electroweak precision observables, the electron and muon anomalous magnetic moments as well as with the constraints arising from charged lepton flavor violation and the 95 GeV diphoton excess. In the second part of the talk, I will describe a minimal model where a dark sector seeds neutrino mass generation radiatively within the linear seesaw mechanism and I will discuss its implications in charged lepton flavor violation, dark matter and colliders.
The large top quark samples collected with the ATLAS experiment at the LHC have yielded measurements of the production cross section of unprecedented precision and in new kinematic regimes. They have also enabled new measurements of top quark properties that were previously inaccessible, enabled the observation of many rare top quark production processes predicted by the Standard Model and boosted searches for flavour- changing-neutral-current interactions of the top quark, that are heavily suppressed in the SM. In this contribution the highlights of the ATLAS top quark physics program are presented. ATLAS presents in particular new measurements of the production cross section and production asymmetries in different tt+X final states as well as new measurements of top quark properties. The recent observation of associated production of a single top quark with a photon completes the list of processes and adds sensitivity to the electroweak couplings of the top quark. A first look into top production in Run 3 data is also given. ATLAS furthermore reports strong evidence for the four-top-production process. Strict bounds are also presented of searches for flavour-changing-neutral-current processes involving top quarks.
This talk covers recent measurements on top-pair production, and top-pair in association with additional boson or quarks, using the data collected by the CMS detector. Differential measurements of tt+X processes under the EFT framework are also presented.
The top-quark pair production in association with a W boson is an important background to processes like t¯tH or 4-top production. Due to higher order electroweak corrections, the process is difficult to model. In consequence, a difference between the measured and the predicted value for σ(t¯tW) has been observed in previous analyses. To improve our understanding of this process, a new inclusive and differential measurement of this process in events with 2 or 3 leptons was performed. Also the ratio of ttW events with a positively and a negatively charged W-boson will be shown. Another challenging final state is the 4-top process. While a previous result in the 2 and 3 lepton channel already allowed to see evidence of this process, a re-analysis of this dataset with several modifications for the event selection, data-driven background estimate and the final discriminant allow for improvement on the significance. In addition to the measurement of the cross-section itself, limits are set on the production of three tops as well as on the CP properties of the top Yukawa coupling and on EFT operator coefficients affecting the 4-top production.
Higgs pair production is a one-loop process, which is potentially sensitive to BSM physics, which can also enter at one loop. We look at the case of light stops in the MSSM and NMSSM. We developed a method, where factorise the cross section to a part depending only on the couplings and a part with all mass dependences and we can efficiently produce kinematical distributions for varying configurations. We can show how the di-Higgs signal arises from individual diagrams and their interferences. The methodology also allows one to revert the problem, i.e. starting from final state distributions one may extract estimates of the couplings involved.
Neutrinos having a non-zero mass is our first laboratory evidence for New Physics. Yet the absolute mass scale remains unknown. Cosmology plays a fundamental role, as it sets the world-leading constraint and, in the near future, it should measure the exact value.
However, any cosmology inference is indirect. So, what are we really measuring with current cosmological data?
In this talk, I will review the impact of neutrino masses on our most precise cosmological observables. I will show that simple long-ranged interactions among neutrinos fully invalidate the present cosmological mass bound, which could lead to contradictions between next-generation measurements and the laboratory. I will discuss the key role that kinematic measurements, such as that at KATRIN, play in unraveling the properties of non-relativistic neutrinos.
We investigate the doublet variant left-right symmetric model (LRSM) using the cosmic microwave background (CMB). The masses of neutrinos and other fermions are determined solely by their interactions with the Higgs bidoublet in this model. Light neutrinos, as Dirac particles, introduce additional relativistic degrees of freedom that interact in the early universe, particularly in the right sector through gauge interactions. By applying Planck 2018 constraints and considering future CMB Stage IV experiments, we conclude that a $W_R$ boson mass below 4.06 TeV is ruled out with 2σ C.L., consistent with constraints from LHC dijet resonance searches. Moreover, even when accounting for additional relativistic degrees of freedom in the TeV range, the Planck 2018 limit at a 1σ confidence level excludes a significantly larger parameter space beyond the reach of current direct search experiments. We also analyze the implications of these constraints on dark matter in this framework, where a dominant dark matter component is represented by a right-handed real fermion quintuplet in the universe.
Axion-like particles (ALPs) decaying before the time of recombination can have strong implications in a range of cosmological and astrophysical observations. In this talk I present a global analysis of a model of decaying ALP, focusing specifically on their coupling to photons. Exploiting the multidisciplinary nature of the GAMBIT framework, we combine state-of-the-art calculations of the irreducible ALP freeze-in abundance, primordial element abundances (including photodisintegration through ALP decays), CMB spectral distortions and temperature anisotropies, and astrophysical constraints from supernovae and stellar cooling. Most notable among the interesting results that I will present are a definite lower bound on the ALP mass, and a surprising improvement of the fit to the primordial abundances compared to vanilla ΛCDM.
A cosmological network of axion strings in our Universe today may leave its imprint on the polarization pattern of the cosmic microwave background radiation through the phenomenon of axion-string-induced birefringence. I will explain how this signal arises, discuss how it depends on the properties of the string network and the axion-photon coupling, describe how existing measurements of anisotropic birefringence place constraints on axion strings, and discuss how the non-Gaussian nature of this signal could be leveraged in searches with future data.
I will present the most minimal realistic SU(5) unification model to date. The minimality of the field content of the model dictates that the neutrinos are purely Majorana fermions while one of the three neutrinos is a massless particle. The model also connects the neutrino mass generation mechanism with the experimentally observed mass disparity between the down-type quarks and charged leptons. This, in turn, implies normal ordering of the neutrino mass spectrum.
What is the minimal viable renormalizable SU(5) GUT with representations no higher than adjoints? In this talk I discuss an SU(5) model in which vectorlike fermions $5_F+\overline 5_F$ as well as two copies of $15_H$ Higgs fields are introduced in order to accommodate for correct charged fermion and neutrino masses and to reproduce the matter-antimatter asymmetry of the universe. The presented model is highly predictive and will be fully tested by a combination of upcoming proton decay experiments as well as low energy experiments in search of flavor violations.
In this work, we present a comprehensive study of the phase diagram of supersymmetric QCD with $N_{f}=N_{c}+1$ flavors perturbed by Anomaly Mediated Supersymmetry Breaking (AMSB). We extend the analysis done before for the s-confining ASQCD theories in three different directions. Previously it was assumed that it is possible to ignore terms proportional to $m_{3/2}^{2}$ when $m_{3/2}$ is small. We show that this approximation is not valid for the baryon preserving direction since is possible to rescale the potential in such a way as to remove the dependence of $m_{3/2}$. We further expand the analysis of these models by including two and three-loop contributions in order to investigate the robustness of the results. Finally, we include the leading effect of higher order Kähler to investigate the stability of the phase diagram as we approach the confining energy scale.
We generalise the Missing Partner Mechanism to split the electron-like states from the coloured ones of vector-like $SU(5)$ 10-plets. Together with the extra light weak doublets from the Double Missing Partner Mechanism (DMPM), this realises gauge coupling unification in the presence of a light weak triplet and colour octet - the characteristic light relics from the adjoint in $SU(5)$ GUT inflation models - without fine-tuning. Additionally, we show how the vector-like 10-plets may generate realistic fermion masses while the DMPM ensures that dimension five nucleon decay is suppressed. A discovery of the light relic states at future colliders would provide a ``smoking gun'' signal of the scenario.
If the strongly-interacting squarks and gluinos are light enough to be produced at the LHC, they would produce striking events with energetic objects. This talk covers recent searches for ???strong SUSY.??? Emphasis is placed on 3rd generation stops and sbottoms, which are required to be light by Higgs mass naturalness considerations. Additionally, novel searches in final states with charm jets are presented.
In this talk, we will discuss the consequences of models where dark sector quarks could be produced at the LHC, which subsequently undergo a dark parton shower, generating jets of dark hadrons that ultimately decay back to Standard Model hadrons. This yields collider objects that can be nearly indistinguishable from Standard Model jets, motivating the reliance on substructure observables to tease out the signal. However, substructure predictions are sensitive to the details of the incalculable dark hadronization. We will show how the Lund jet plane can be an effective tool for designing observables that are resilient against the unknown impact of dark hadronization on the substructure properties of dark sector jets.
Experimental uncertainties related to hadronic object reconstruction can limit the precision of physics analyses at the LHC, and so improvements in performance have the potential to broadly increase the impact of results. Recent refinements to reconstruction and calibration procedures for ATLAS jets and MET result in reduced uncertainties, improved pileup stability and other performance gains. In this contribution, selected highlights of these developments will be presented.
Hadronic object reconstruction is one of the most promising settings for cutting-edge machine learning and artificial intelligence algorithms at the LHC. In this contribution, selected highlights of ML/AI applications by ATLAS to particle and boosted-object identification, MET reconstruction and other tasks will be presented.
Model building based on string compactifications faces difficult challenges: moduli can be tricky to stabilize, scales to separate, dark energies to uplift and supersymmetry to break in a controlled fashion. String theories where the latter is broken at the string scale can offer different corners of the landscape to explore, with different pros and cons. I will describe how the instabilities of these models leave room for potentially realistic braneworld cosmologies, focusing on the simplest known examples.
I will discuss some theoretical and phenomenological implications of a string theory-inspired, cosmological phase of kination, dominated by the kinetic energy of a rapidly rolling scalar. In the first part of the talk, I will argue how such a kination epoch can naturally arise in string compactifications after inflation, focusing on the case where it is driven by the volume modulus. I will also show how a phase of volume kination for approximately no-scale vacua can be uplifted to a classical Kasner solution in 10d where the non-compact dimensions collapse towards a Big Crunch, in contrast with the standard picture of decompactification limits. This is suggestive of the existence of a "dynamical" Swampland, placing restrictions on the cosmological solutions allowed within String Theory. In the second part of the talk, I will describe how kination, together with other effects such as reheating from moduli decays, paints a very distinctive picture for a string-inspired, early universe cosmology. In particular, such a modified cosmological history leads to a different evolution of density perturbations and may be tested through small-scale structure observations.
In our study, we explore the influence of catalysis on the vacuum decay within the framework of type IIB string theory. This decay process involves the creation of a bubble that combines with an impurity, effectively acting as a catalyst. Although we show the 1-loop analysis at first, to calculate the life-time more accurately, we take use of variational perturbation method and go beyond the approximation. Our investigation also addresses the Trans-Planckian Censorship Conjecture.
We present the full Lagrangian and local supersymmetry transformation rules for the gauged D=4, N=4 (half-maximal) supergravity coupled to an arbitrary number of vector multiplets. Using the embedding tensor formulation, the final results are universal and valid in an arbitrary symplectic frame. We also derive the conditions satisfied by the critical points of the scalar potential and we specify the mass matrices of all the fields in the theory for Minkowski vacua that completely break N=4 supersymmetry. Furthermore, we show that the supertrace of the squared mass eigenvalues vanishes for all such vacua of any gauged D=4, N=4 supergravity irrespective of the number of vector multiplets and the choice of the gauge group, which implies the absence of quadratic divergences in the 1-loop effective potential for this class of vacua. We also provide some interesting byproducts of our analysis, such as the field equations and the quadratic constraints satisfied by the fermion shifts characterizing the gauging (also known as T-tensor identities).
Many theories beyond the Standard Model predict new phenomena, such as heavy vectors or scalar, vector-like quarks, and leptoquarks in final states containing bottom or top quarks. Such final states offer great potential to reduce the Standard Model background, although with significant challenges in reconstructing and identifying the decay products and modelling the remaining background. The recent 13 TeV pp results, along with the associated improvements in identification techniques, will be reported.
The absence of new particles in the LHC direct searches starts challenging the idea of Naturalness. In this talk, we present a solution to the hierarchy problem, where the new particles are third-generation-philic. Due to this feature, the mass bounds from the direct searches are much weaker and the required fine-tuning can be reduced drastically. The idea is realized with a concrete model based on a $SU(6)/Sp(6)$ fundamental composite Higgs model.
I will discuss an Effective Field Theory which extends the SM by an Axion-Like Particle (ALP) and particularly focus on the coupling of a light ALP to top quarks.
We use high-energy LHC probes, and examine both the direct probe to this coupling in associated production of a top-pair with an ALP, and the indirect probe through loop-induced gluon fusion to an ALP leading to top pairs. Using the latest LHC Run II data, we provide the best limit on this coupling and furthermore compare these limits with those
obtained from loop-induced couplings in diboson final states.
I will present theoretical calculations of total cross sections and top-quark transverse-momentum and rapidity distributions in the associated production of a top-antitop pair with a photon (t t~ γ production) in the SM and SMEFT.
The theory predictions include complete QCD and electroweak corrections at NLO as well as soft-gluon corrections at approximate NNLO. Implications for SM predictions and bounds on top-quark electroweak anomalous couplings will be presented.
In this talk, within the bottom-up approach to holography, I will consider a class of six-dimensional gravity models and solutions that can be interpreted in terms of dual five-dimensional conformal field theories deformed by a single scalar operator. The scaling dimension of this operator is treated as a free parameter. One dimension in the geometry is compactified on a shrinking circle, mimicking confinement in the dual four-dimensional theories.
I will discuss the mass spectrum of bosonic states, and along confining branch of solutions, appearance of a tachyonic instability in part of the parameter space. In a region of parameter space nearby the tachyonic one, the lightest scalar particle can be interpreted as an approximate dilaton and its mass is parametrically suppressed. The dilatonic and tachyonic regions will be hidden behind a first-order phase transition, and the (approximate) dilaton will appear in metastable solutions. If time permits, I will consider the generalisation of the method to composite Higgs models.
A vector boson $W_{1}$ with the quantum numbers $\left(3,1\right)$ under the electroweak group $SU\left(2\right)_{L}\times U(1)_{Y}$ could in principle couple
with the Higgs field via the renormalizable term $W_{1}^{\mu*}H D_{\mu}H$. This interaction is known to affect the $T$ parameter and, in so doing, it could potentially explain the 2022 CDF measurement of the W-boson mass.
As it is often the case with vectors, building a viable model with a $W_{1}$ gauge boson is non-trivial. In this talk I will describe two variations of a minimal setup containing this field; they are based on an extended $SO(5)\times SU\left(2\right)\times U(1)$ electroweak group. I will nevertheless show that interactions such as $W_{1}^{\mu*}H\partial_{\mu}H$ are not generated in a Yang-Mills theory. A coupling between $W_{1}$, $H$ and another Higgs doublet $H^{\prime}$ is possible though.
In this talk, I delve into the potential of multi-scalar interactions within the $\kappa$-framework as effective discriminators of BSM physics at current and upcoming colliders. By analysing the existing and projected collider constraints on these coupling modifiers, we can identify deviations from the Standard Model expectations, which serve as signposts for BSM discoveries. Building upon these findings, we can navigate the diverse BSM landscape within the $\kappa_{2V}-\kappa_V$ plane, showcasing carefully chosen examples that highlight the influence of geometry, Higgs-mixing, renormalisability considerations, and their interplay.
Using the $\kappa$ framework, the constraints on the quartic interactions of Higgs with gauge bosons give a qualitative picture of consistency with the SM when the statistical yield is low. However, increasing statistics demand a more theoretically consistent framework to limit such couplings. Adopting the Higgs Effective Field Theory (HEFT) framework, we calculate the radiative corrections to Higgs decays and obtain the current and future sensitivity to quartic Higgs gauge couplings using the single Higgs data. We further discuss the improvements in the sensitivity of these couplings by employing the approach of Graph Neural Networks to Higgs pair production via weak boson fusion.
In this talk, I will discuss the latest efforts to constrain the mass of the ultra-light dark matter models, focusing on the current bounds of the fuzzy dark matter (FDM) model. I will show how we can use the different predictions of this model and different astrophysical systems to put the strongest bounds to date on the mass of this ultra-light axion, showing also the incompatibilities that are currently present in these bounds. I will also discuss the current developments in using interference patterns and vortices as a way to probe the FDM model and give the example of strong lensing as a powerful probe to measure this wave behavior.
Dark matter may exist as an ultralight bosonic particle, leading to the formation of an ever-present field that could interact with us via a new long-range fifth force. Recently, quantum sensing techniques have been shown to be promising avenues with which to detect such a dark matter candidate. However, these studies did not entirely capture the stochastic nature of the field, which is important to construct realistic exclusion limits and discovery regions. In this talk, I will show how an experiment employing an array of optomechanical sensors can be used to place leading bounds on ultralight dark photon dark matter via an improved statistical treatment. I will highlight the different statistical regimes required depending on how long the dark matter field is observed. In particular, I will show how, in the low-observation time regime, projected limits can suffer by an order of magnitude compared to previous estimates. Our results demonstrate that an array of optomechanical sensors would form a powerful probe of ultralight dark matter, with our study highlighting the experimental considerations necessary to optimise its sensitivity.
We revisit the Affleck-Dine leptogenesis via the $L H_u$ flat direction with a light slepton field. Although the light slepton field is favored in low-energy SUSY phenomenologies, such as the muon $g-2$ anomaly and bino-slepton coannihilation, it may cause a problem in the Affleck-Dine leptogenesis: it may create an unwanted charge-breaking vacuum in the Affleck-Dine field potential so that the Affleck-Dine field is trapped during the course of leptogenesis. We investigate the conditions under which such an unwanted vacuum exists and clarify that both thermal and quantum corrections are important for the (temporal) disappearance of the charge-breaking minimum. We also confirm that if the charge-breaking vacuum disappears due to the thermal or quantum correction, the correct baryon asymmetry can be produced while avoiding the cosmological gravitino problem.
A Strong First-Order Electroweak Phase Transition (SFOEWPT) is a necessary ingredient for Electroweak Baryogenesis (EWBG) to explain the observed Baryon asymmetry of the Universe. Supersymmetric models with singlet extensions can easily accommodate single or multi-step first-order phase transitions (FOPT). In this work, we examine the dynamics of an SFOEWPT and the possibility of EWBG by extending the Z3-invariant Next-to Minimal Supersymmetric Standard Model (NMSSM) with a right-handed neutrino superfield, consistent with the collider, neutrino, and flavour physics constraints. We examine the role of additional parameters on phase transition dynamics in comparison to NMSSM, and we observed that the occurrence of a FOPT prefers a light right-handed sneutrino state below 125 GeV. We further analyze the chances of detecting stochastic gravitational waves (GW) that can occur from such phase transitions by comparing the results to the sensitivity curves of the future space-based GW interferometers. We find promising GWs spectrum that can be detected within the sensitivity ranges of DECIGO-corr, U-DECIGO, U-DECIGO-corr, etc. In addition to collider searches, our study provides a complementary probe for Physics beyond the Standard Model at the GW detector fronts.
References:
[1] P. Borah, P. Ghosh, S. Roy, and A. K. Saha, Electroweak Phase Transition in a Right-Handed Neutrino Superfield Extended NMSSM [2301.05061][hep-ph]
The "minimal" potentially realistic non-supersymmetric $\mathrm{SO}(10)$ GUT model has a scalar sector consisting of representations $45+126+10$. The $45+126$ part breaks $\mathrm{SO}(10)$ to the Standard Model symmetry, while $126+10$ should enable a realistic Yukawa sector. This model is expected to facilitate an unusually robust proton decay prediction, but its analysis is impeded by tachyonic instabilities in the tree-level scalar potential. We shall present the latest developments in the model's analysis: the one-loop effective potential requires in the perturbative regime a breaking pattern through an intermediate $\mathrm{SU}(4)\times\mathrm{SU}(2)\times\mathrm{U}(1)$ stage, but this region of parameter space does not allow for suitable fine-tuning to accommodate a realistic EW-scale Higgs doublet. The model is thus by all indications perturbatively unviable.
In this work, we construct promising model building routes towards SO(10) GUT inflation. We consider a supersymmetric framework within which the so-called doublet-triplet splitting problem is solved without introducing fine-tuning. Additionally, realistic fermion masses and mixings, gauge coupling unification, and cosmic inflation are incorporated by utilizing superfields with representations no higher than the adjoint representation. Among the three possible scenarios, two of these cases require a single adjoint Higgs field. In contrast, the third scenario consisting of two adjoints, can lead to observable gravitational waves from cosmic strings that are within reach of several ongoing and upcoming gravitational observatories.
There have been a lot of developments on identification of heavy objects decaying hadronically though large-size jets based machine learning. These techniques have revolutionized searches for Supersymmetry at the LHC. In this talk, recent searches for Supersymmetry using heavy object tagging will be presented. The results are obtained from the proton-proton collision data at the center of mass energy of 13 TeV collected during the LHC Run 2.
Coloured sparticles are expected to be produced copiously at the LHC. As no squarks or gluinos have been found so far, their lower mass limits are in the TeV range, and they would therefore always be produced close to their production threshold. In this kinematical limit, potentially dangerous large logarithms can be summed systematically to all orders by means of threshold resummation techniques, restoring the predictive power of perturbation theory.
In my talk, I will present updated results on precision calculations for squark and gluino production at the LHC Run 3 with a centre-of-mass energy of $\sqrt{S} = 13.6$ TeV, using the latest available PDF4LHC21 sets. The theoretical predictions consist of total cross sections and theoretical uncertainty estimates, calculated at an approximated NNLO and including the resummation of soft and Coulomb gluons up to NNLL accuracy in the Mellin-moment space approach. The additional contributions lead to an enhancement of the production cross sections, and generally reduce the theoretical uncertainty, improving the theoretical accuracy for experimental SUSY searches. The results are implemented in the publicly available package NNLL-fast 2.0.
This talk presents combinations of orthogonal search channels, which improve the sensitivity to supersymmetric models by considering multiple final states simultaneously.
Early Dark Energy (EDE) is a promising model to resolve the Hubble Tension, that, informed by Cosmic Microwave Background data, features a generalization of the potential energy usually associated with axion-like particles. We develop realizations of EDE in type IIB string theory with the EDE field identified as either a $C_4$ or $C_2$ axion and
with full closed string moduli stabilization within the framework of either KKLT or the Large Volume Scenario. We explain how to achieve a natural hierarchy between the EDE energy scale and that of the other fields within a controlled effective field theory. We argue that the data-driven EDE energy scale and decay constant can be achieved without any tuning of the microscopic parameters for EDE fields that violate the weak gravity conjecture, while for states that respect the conjecture it is necessary to introduce a fine-tuning. This singles out as the most promising EDE candidates, amongst several working models, the $C_2$ axions in LVS with 3 non-perturbative corrections to the superpotential generated by gaugino condensation on D$7$-branes with non-zero world-volume fluxes.
RG-induced moduli stabilisation was recently proposed as a new mechanism that adapts to string theory a perturbative method for stabilising moduli without leaving the domain of perturbative control and without the inclusion of non-perturbative effects. In this talk, we briefly revise the necessary ingredients in the construction of this mechanism. In addition, we examine the cosmological implications of the corresponding scalar potential in the framework of brane-antibrane inflation and show that inflationary observables can be reproduced within the regime of parametric control of the four-dimensional effective field theory.
We study the inflection point inflation generated by polynomial superpotential and canonical K\"ahler potential under the supergravity framework, where only one chiral superfield is needed. We find the special form of the scalar potential limits the possible Hubble value up to $\mathcal{O}(10^{10}) \, \textrm{GeV}$ and the inflaton mass to $\mathcal{O}(10^{11}) \, \textrm{GeV}$. We obtained analytic results for samll field cases and present numerical results for large field ones. We find the tensor to scalar ratio $r$ is always suppressed in these models while the running of spectral index $\alpha$ will be testable in next generation CMB experiments. We also discuss the possible effects of SUSY breaking polonyi term presenting in the super potential. We find a general upper bound for SUSY breaking scale for a given Hubble value.
We investigate the formation of composite states of the goldstino in theories with non-linearly realized supersymmetry and show that the Volkov-Akulov model has an instability towards goldstino condensation. We discuss the implications of our findings for string models involving anti-brane uplifts.
For those interested in connecting string theory to observational physics, the asymptotic limits of string theory moduli space represent one of the most interesting regions. This talk explores these limits from two distinct directions: first, surprising results concerning (integer) conformal dimensions in scenarios with moduli stabilised in these asymptotic regimes and second, the cosmology of moduli evolution towards stabilised vacua in the extremities of moduli space.
A brief review of model building in F-theory will be presented. Next, some recent insights into the flux induced superpotentials of the moduli fields will be discussed.
In this talk I will consider the string theory axiverse in type IIB Calabi-Yau orientifold compactifications, and focus on the computation of axion photon couplings and hierarchies that arise in the many axion limit — i.e. at large values of $h^{1,1}$. In particular, I will discuss two distinct phenomena that hierarchically suppress axion photon interactions when the QED divisor is small: the former is a suppression in ratios of mass scales that decouples all axions lighter than the QED axion. The latter is geometric in origin: at most a handful of mass eigenstates have internal wavefunctions that significantly overlap with QED.
Equipped with these insights I will present preliminary data on cosmic birefringence, and astrophysical constraints on the axiverse.
I will attempt to review some recent directions in theoretical studies of dark matter candidates, underlying models, production mechanisms, etc., focusing primarily on WIMPs and axions. Next, I will discuss sensitivity of the ensuing properties of dark matter candidates on underlying assumptions and illustrate this with the case of axions produced in nonstandard cosmologies of the Big Bang.
Supersymmetry (with R-parity conservation) provides a natural dark matter candidate. In models with gravity mediated supersymmetry breaking, the discovery of the Higgs boson with mass 125 GeV and the lack of discovery of supersymmetric particles at the LHC heavily constrains this framework for dark matter. The current status will be reviewed. Supergravity may also play an important role in formulating models of inflation. For example, experimentally favored models such as Starobinsky inflation arise very easily in no-scale models of supergravity. The present status of these models will also be reviewed.
The nature of dark matter is one of the most important questions in fundamental physics. The talk will cover potential explanations, related experiments together with their latest results and potential for the future.
Cosmological relaxation of the electroweak scale via Higgs-axion interplay, named as relaxion mechanism, provides a dynamical solution to the Higgs mass hierarchy. I will review the status of the proposal and
will show that the relaxion can naturally explain the observed dark matter density in the universe.
In addition to the supersymmetric vacua in 10 dimensions, heterotic-string theory gives rise to non-supersymmetric vacua that are in general contain physical tachyons in compactifications to 4 dimensions, which can be projected out by the GSO projections, and produce string amplitudes that are finite at one—loop. Over the past few years, in collaboration with Viktor Matyas and Ben Percival, we developed systematic methodology to analyse the spectrum of the tachyon free non-supersymmetric heterotic-string vacua and study their phenomenological properties. In collaboration with Alonzo Diaz Avalos, Viktor Matyas and Benjamin Percival, we analysed the would be Fayet-Iliopoulos term in non-supersymmetric heterotic string vacua and a D-term uplift of the vacuum energy from negative to positive energy. Examples of positive uplift are found for models with explicitly broken supersymmetry as well as models with Scherk-Schwarz breaking. The moduli space of the string compactifications will be discussed and vacua in which all geometrical moduli are fixed will be presented, with the eventual aim being to produce a string model with stable moduli and positive vacuum energy.
Modular transformations of string theory are shown to play a crucial role as discrete flavor symmetries of the Standard Model. They include CP transformations and provide a unification of CP and traditional flavor symmetries within the framework of the eclectic flavor scheme. The unified flavor group is non-universal in moduli space and exhibits the phenomenon of "Local Flavor Unification" with enhanced flavor symmetries at the fixed points and the boundary of the fundamental domain of the modular group.
I will argue that coloured gravitational instantons compromise the standard axion solution to the strong CP problem and propose a companion axion model as the solution, that necessarily contains two axions. I will discuss some phenomenological and cosmological consequences of this model.
Based on - 2108.05549, 2109.12920, 2110.11014
Dimensionless fundamental constants can vary as a function of time if an ultralight field couples to the standard model. Using data on strontium, ytterbium and caesium atomic-clock transitions collected by the National Physical Laboratory in the UK, fine-structure constant and electron-to-proton mass ratio variations have been measured for about two weeks. These data enable the extraction of model-independent constraints on leading scalar-SM couplings. Analysing the amplitude spectrum as a function of oscillation frequency leads to new constraints on models of scalar and axion-like dark matter.
We study the contributions of an axion-like particle to the electroweak precision observables. The particle is assumed to couple with the standard model electroweak gauge bosons. It is found that the effects arise not only via the oblique $S$ and $U$ parameters but also via radiative corrections to the gauge couplings. Besides, the decay of $Z\to a\gamma$ affects the total width of the $Z$ boson. All of those contributions are considered simultaneously in the global fit analysis of the electroweak precision observables. Also, we discuss the recent CDF result of the W-boson mass measurement. It is found that the discrepancy from the standard model prediction is solved if the axion-like particle is heavier than 500 GeV and its coupling to the di-photon is suppressed.
The positivity of the scattering amplitude is a necessary condition for a low-energy effective field theory (EFT) to be UV complete. The gravitational positivity bound provides quantitative "swampland" constraints for low-energy EFTs to be UV complete within quantum gravity. The condition can give significant constraint on a feebly interacting particle model and its UV completion. In this talk I will discuss the outlines of the gravitational positivity bound and its phenomenological application to a dark gauge sector.
An attractive explanation for the flavor puzzle of the Standard Model is the multi-scale origin of the flavor hierarchies, where the size of the Standard Model Yukawas of the different families is associated to different scales. This allows to circumvent the tight flavor bounds for New Physics, and opens the possibility of interesting UV completions of the SM at the TeV scale. I will explore this approach to BSM physics and discuss different realizations.
In the pursuit of physics beyond the Standard Model, a promising path is the study of exclusive B-meson decays caused by the transition b→sℓ+ℓ−. A key observable in such decays is the ratio $R_K$, which measures electron-muon universality in B→Kμ+μ−/e+e-. At first sight, the recent LHCb measurement of RK ~ 1 may seem to largely constrain deviations from universality in these decays. However, this is actually not the case: new sources of CP violation allow for universality violation consistent with $R_K = 1$ [2303.08764]. Another central observable is the branching ratio of the semileptonic decay B→Kμ+μ−, which shows a ~4σ tension between experiment and theory. New physics causing this tension is customarily encoded in the Wilson coefficients $C_9$ and $C_{10}$. We discuss a new way to extract CP-violating phases in these coefficients [2212.09575]. We also discuss CP violation in the leptonic decay Bs→μ+μ−, which complements semileptonic decays through its outstanding sensitivity to scalar and pseudoscalar physics. These studies provide exciting new opportunities to search for new physics in rare B-meson decays.
Precise determination of the magnitudes and phases of the elements, in particular, $V_{ub}$ and $V_{cb}$, of the Cabibbo-Kobayashi-Maskawa (CKM) matrix is crucial for testing the unitarity of the CKM matrix, hence testing the Standard Model. The magnitudes of these elements are best measured by using $B$-meson semileptonic decays. Moreover, semileptonic $B$-meson decays provide a great testing ground for lepton universality of charged-current weak interaction processes. In this talk, we report recent unique and/or competitive results of inclusive and exclusive $B$-meson semileptonic decays, which have been measured by analyzing high-statistics data sample of $B\bar{B}$ pairs from the Belle and Belle II experiments. Some of these analyses utilize tag-side reconstruction of a companion $B$-meson decaying into hadronic final states, providing direct access to the signal $B$ rest-frame and the relevant decay characteristics. The subjects we present in this talk are all relevant for either testing lepton universality or precision measurement of the CKM elements $|V_{cb}|$ and $|V_{ub}|$.
We investigate the right handed sneutrino effect, in the framework of the $B−L$ extension of Minimal Supersymmetric Standard Model with Inverse Seesaw, on $b \to c l \bar\nu_l$ decays anomalies which has been recently measured in the lepton-universality ratios $\mathcal{R(D^{(*)})}=\mathcal{BR(B \to D^{(*)}\tau \bar\nu_{\tau})/BR(B \to D^{(*)}l \bar\nu_l)}$ ($l=e$ or $\mu$). Taking into account various constraints, we show that a right-handed sneutrino with light chargino and neutralino running in the lepton penguin is able to explain within 1σ the (averaged) measured values of $\mathcal{R(D^{(*)})}$.
This talk reviews recent measurements of multiboson production using CMS data. Inclusive and differential cross sections are measured using several kinematic observables.
CP-violating contributions to Higgs--fermion couplings are absent in the standard model of particle physics (SM) but are motivated by models of electroweak baryogenesis. In this talk, I will present results of a study of the constraints on these couplings from a combination of LHC data and experimental bounds on the electron, neutron, and mercury electric dipole moments (EDMs). While previous studies have focused on scenarios with CP-violation in the interaction of the Higgs with a single fermion species, we have undertaken global fits that allow for the presence of CP-violating contributions from several fermion species simultaneously. I will show that allowing for these multiple CP-violating interactions can substantially relax previously presented constraints from EDMs. However, particularly for the case where there is only CP violation in the couplings with the third-generation fermions, non-trivial correlations between EDM and LHC results can persist even in this more complicated parameter space.
At the proposed future Large Hadron-Electron Collider (LHeC), the coupling between the Higgs boson (H) and the massive gauge bosons (V = W, Z) of weak interaction can be investigated through the single Higgs boson production. In this presentation, I will focus on the potential of the collider to determine constraints on the new physics parameters associated with the most general structure of the HVV couplings. Our study involves exploring various angular observables that are sensitive to these couplings at an electron-proton collider with 60 GeV electron and 7 TeV proton energies. I will present a statistical analysis that leads to exclusion limits on individual new physics parameters as a function of luminosity. To improve the theoretical precision, we incorporate Next-to-Leading (NLO) order QCD correction in the Standard Model calculation. Additionally, I will discuss the impact of NLO QCD corrections on angular observables and how they ultimately influence the constraints on the new physics parameters of the HVV couplings.
Determination of the nature of dark matter is one of the most fundamental problems of particle physics and cosmology. This talk presents recent searches for dark matter particles from the CMS experiment at the Large Hadron Collider. The results are obtained from the proton-proton collision data at the center of mass energy of 13 TeV collected during the LHC Run 2.
I will discuss about the halo-independent bounds on the WIMP-nucleon couplings of the non-relativistic effective Hamiltonian that drives the scattering off nuclei of a WIMP of spin 1/2. We will see that for most of the couplings the degree of relaxation of the halo-independent bounds compared to those obtained assuming the Standard Halo Model is with few exceptions relatively moderate in the low and high WIMP mass regimes, while in the intermediate mass range it can be larger. An exception to this general pattern, with more moderate values of the bound relaxation, is observed in the case of the spin-dependent type WIMP-proton couplings, for which WIMP capture in the Sun is strongly enhanced due to the WIMP scatterings off Hydrogen, the most abundant element in the Sun. Within this class of operators the bound relaxation is particularly small for interactions that are driven by only the velocity-dependent term, for which the solar capture signal is enhanced because of the high speed of scattering WIMPs in the strong gravitational field of the Sun.
FIMP dark matter is produced via the freeze-in mechanism that generally implies tiny coupling between the DM and the standard model particles, making DM direct detection and collider searches almost hopeless. This is not the case for a DM at low reheating temperatures, where direct detection plays a fundamental role in constraining the parameter space. We show the viability of a scalar and a spin 3/2 model and discuss the details of the production mechanism and future experiments that can test it.
Numerous studies have led to upper limits on the dark matter annihilation cross-section assuming only single exclusive annihilation channels. We consider a more realistic situation and present a study taking into account the complete annihilation pattern within a given particle physics model. This allows us to study the impact on the derived upper limits on the dark matter annihilation cross-section from a full annihilation pattern compared to the case of a single annihilation channel. We use mockdata for the Cherenkov Telescope Array simulating the observations of the promising dwarf spheroidal galaxy Sculptor. We show the impact of considering the full annihilation pattern within a simple framework where the Standard Model of particle physics is extended by a singlet scalar. Such a model shows new features in the shape of the predicted upper limit which reaches a value of ⟨σv⟩=3.8×10−24 cm−3s−1 for a dark matter mass of 1 TeV at 95% confidence level. Based on our study, we recommend to consider the complete particle physics information in order to derive more realistic limits.
The difficulty in realizing the metastable de Sitter vacuum in the string model has been considered in light of the distance conjecture. In this talk, we investigate the Type IIB compactifications containing the warped throat and point out that the uplift potential produced by anti-D3 branes satisfies the scaling behavior with respect to the tower mass scale, hence can be directly connected to the distance conjecture. Unless the throat length is extremely close to zero, the tower mass scale corresponds to the Kaluza-Klein mass, the lowest tower mass scale.
A concrete possibility for String Phenomenology consists in the study of vacua in which supersymmetry is broken at the string scale. Unfortunately such scenarios are often plagued by instabilities coming from tadpoles and perturbative corrections that modifies the background geometry. Although the fate of these vacua is not known in general, they rely on absence of tachyons in the tree level spectrum, thus being classically stable. However the situation could be much worse and indeed in literature vacua giving rise to tachyons from SUSY breaking are well known, for which any further perturbative analysis is meaningless.
In this talk I will show how the sector averaged sum, a quantity encoding the global behaviour of the spectrum at large mass defined by Dienes and refined by Cribiori, Tonioni, Parameswaran and Wrase, is well suited to distinguish the two situations for closed string vacua, although not being able to describe cases in which both open and closed tachyon is projected out through an orientifold realization. A model independent proof of the previous statements along with explicit 10d and 9d examples will be provided.
The volume-preserving diffeomorphism is a key feature that characterizes the large constant R-R ($p-1$)-form field background in a D$p$-brane theory. It represents a symmetry of the theory that preserves the volume of space. To describe this symmetry, we introduce the concept of the ($p-1$)-bracket, which generates the volume-preserving diffeomorphism. The ($p-1$)-bracket is a mathematical operation that acts on ($p-1$)-forms and encodes the transformation of the background field under the symmetry. To generalize the ($p-1$)-bracket, we can apply it to the non-Abelian one-form gauge field, which is relevant in gauge theories with non-Abelian gauge groups. This allows us to extend the concept of volume-preserving diffeomorphism and its associated symmetry to non-Abelian gauge theories. When considering D-branes and T-duality, we introduce the transverse coordinates of the branes. T-duality is a symmetry transformation that relates String Theory compactified on different backgrounds. It exchanges the momentum and winding modes of strings and leads to an equivalence between theories with different numbers of dimensions. By incorporating T-duality and the generalized bracket, a general expression for the action in D$p$-branes can be derived when $p\le 6$. This result connects the existing construction of D$p$-branes with our generalized bracket, illustrating the relationship between the symmetry and its associated transformations and the dynamics of the branes. In addition, we can discuss the non-Abelianization of the ($p-2$)-form gauge potential. This process involves generalizing the concept of non-Abelian gauge fields to higher-form gauge potentials. By extending the Lagrangian description of a single D-brane to multiple D-branes, a similar Lagrangian description can be established for both cases, highlighting the common underlying structure and symmetry properties. Our developments demonstrate the interplay between symmetries, gauge fields, and D-brane dynamics, providing a deeper understanding of the underlying principles within D-branes.
Abstract: The primary ingredient for studying the phases of a quantum field theory is the effective action. Though obtaining an exact form is beyond the scope of the existing techniques, approximate expressions using perturbative methods which to the leading order involve computation of one-loop determinants are available. In this talk which is based on our papers [1] and [2], I will describe a method for computing one-loop partition functions for scalars and fermions on $AdS_{d+1}$ for zero and finite temperature for arbitrary $d$ that reproduces results known in the literature. The derivation is based on the method of images and uses the generalized eigenfunctions of the Laplacian and Dirac operator on Euclidean $AdS$ which under thermal identification satisfy the desired periodicities. Employing these results, I will then discuss the phases of scalar and fermionic field theories in thermal $AdS_{d+1}$ spaces for $d=1,2,3$. We will first analyze scalar field theories with global $O(N)$ symmetry for finite as well as large $N$. The symmetry-preserving and symmetry-breaking phases will be identified as a function of the mass-squared of the scalar field ($m_s^2$) and temperature ($T=1/ \beta$) in the $\beta$-$m_s^2$ parameter space. It will also be seen that the sign of the regularized volume of thermal $AdS_{d+1}$ plays a crucial role in the qualitative nature of the phase diagrams. We will confirm that for a finite temperature theory in $AdS$ there occurs a symmetry breaking phase in two dimensions in contrast to flat space where the Coleman-Mermin-Wagner theorem prohibits continuous symmetry breaking. We will also see that unlike flat space, there exists a region in $AdS$ space where both the symmetry breaking and symmetry preserving phases coexist.
I will next discuss the zero temperature phases of fermionic field theories (Yukawa theories and Gross-Neveu models) as regions in the corresponding parameter spaces. For the Yukawa theories the phases and corresponding phase boundaries will then be identified as a function of the mass-squared of the scalar field ($m_s^2$) and temperature ($T=1/ \beta$) in the $\beta$-$m_s^2$ parameter space. I, next, will discuss the changes in the phases of the Gross-Neveu models for $d=1,2$ as a function of the fermionic mass ($m_f$) and the coupling constant ($g$) at finite temperature. In the large $N$ limit we will see that, unlike flat space where the discrete chiral symmetry is restored beyond a certain temperature, the discrete chiral symmetry appearing in the $m_f=0$ limit remains broken at all temperatures for $d=1,2$ in $AdS$ space. For the theory to be renormalizable in $d=3$, I will discuss the Gross-Neveu Yukawa model.
References:
[1] A. Kakkar and S. Sarkar, "On partition functions and phases of scalars in AdS," JHEP 07 (2022), 089 doi:10.1007/JHEP07(2022)089 [arXiv:2201.09043 [hep-th]].
[2] A. Kakkar and S. Sarkar, "Phases of theories with fermions in AdS," JHEP 06 (2023), 009 doi:10.1007/JHEP06(2023)009 [arXiv:2303.02711 [hep-th]].
The latest results from searches for electroweak production of SUSY particles with the CMS experiment will be presented. The analyses are based on the full dataset of pp collisions recorded at sqrt(s) = 13 TeV during the LHC Run 2. Searches are performed in multiple final states and the combination of those searches will be also discussed.
We consider the application of machine learning techniques to searches at the Large Hadron Collider (LHC) for pair-produced lepton partners which decay to leptons and invisible particles. This scenario can arise in the Minimal Supersymmetric Standard Model (MSSM), but can be realized in many other models. We focus on the case of intermediate bino-slepton mass splitting (~ 30 GeV), for which, due to large electroweak backgrounds, the LHC has made little improvement over LEP. As a benchmark, we find that the use of machine learning techniques can push the LHC well past discovery sensitivity for a right-handed muon partner with mass of ~110 GeV, for an integrated luminosity of 300 fb^{-1}, with a signal-to-background ratio of ~0.5. We identify several machine learning techniques which can be useful in other LHC searches involving large and complex backgrounds.
Accommodating differing signs of the supersymmetric contributions to $g-2$ values of muon and electron can be difficult in the Minimal Supersymmetric Standard Model (MSSM) in the context of Fermilab muon ${(g-2)}_\mu$ data and electron ${(g-2)}_e$ result as obtained from the fine structure constant ($\alpha$) measurement through ${}^{133}{\rm Cs}$ matter-wave nterferometry. The latter would mean a negative SUSY contribution to ${(g-2)}_e$.
The issue of simultaneously satisfying the two leptonic magnetic moments does not arise for the positive ${(g-2)}_e$ case coming from a ${}^{87}{\rm Rb}$ based experiment to
measure $\alpha$. The results of the two $\alpha$ experiments disagree among themselves. A future measurement may resolve the anomaly. We focus on the case of negative ${(g-2)}_e$ to explore MSSM models with non-holomorphic (NH) soft terms. A large and negative non-standard trilinear coupling $A_e^\prime$ value accommodates ${(g-2)}_e$ via bino-selectron loop contributions. On the other hand, large values of $A_e^\prime$ is allowed via the highly accommodative charge-breaking constraint corresponding to a four-vev scenario where one adds the contributions from the soft terms with $A_e^\prime$ on the top of the terms of charge breaking potential of MSSM. Additionally, there is also radiative enhancement of electron Yukawa coupling due to $A_e^\prime$. Apart from the two leptonic magnetic moments, we consider dark matter constraints via a higgsino type of lightest supersymmetric particle while having a large Wino mass and take the left and right slepton mass parameters for the first two generations to be the same.
We identify the available parameter space while also satisfying the ATLAS data from slepton pair production as well as the same from compressed higgsino searches.
(Ref: Eur.Phys.J.C 83 (2023) 1, 60 • e-Print: 2112.09867 [hep-ph])
The lack of positive signals from supersymmetry searches at the LHC has pushed most of supersymmetric particles to very heavy masses. The notable exception is the electroweak sector of the MSSM which, due to their mixings and complex parameter structure, could still survive at fairly low masses. In this talk I will present a global study of the electroweak minimal supersymmetry extension of the Standard Model in
the presence of a light gravitino. The results show that the combination of recent supersymmetry searches at the LHC and Standard Model inclusive cross section measurements strongly constrains the model at low masses, except for a light Higgsino scenario that can simultaneosly fit various minor excesses in LHC searches.
Searches for new physics (NP) at particle colliders typically involve multi-variate analysis of kinematic distributions of final state particles produced in a decay o fa hypothetical NP resonance. Since the pair-production cross-sections mediated by such resonances are strongly suppressed by the NP scale, this analysis becomes less relevant for
NP searches for masses of the BSM resonance above 1 TeV. On the other hand, t-channel processes are less sensitive to the mass of the virtual mediator and therefore larger phase-space can be potentially probed as well as the couplings between the NP particles and the Standard Model fields. The fact that mixings between different generations of quarks
and leptons may exist, the potential of the search presented in this paper can be used, as a reference guide, to enlarge significantly the scope of searches performed at the LHC to flavour off-diagonal channels, in a theoretical consistent approach. In this work, we study non-resonant production of scalar leptoquarks which have been proposed in the literature to provide a potential avenue for radiative generation of neutrino masses, accommodating as well existing flavour mixings and anomalies. Final states involving just two muons a the LHC (μ+μ−), are used as a case study
Muon reconstruction performance plays a crucial role in the precision and sensitivity of the Large Hadron Collider (LHC) data analysis of the ATLAS experiment. Using di-muon Resonances we are able to calibrate to per-mil accuracy the detector response for muons. Innovative techniques developed throughout the Run-2 period and during the LHC shut-down significantly improve the measurement of muon reconstruction, identification and calibration performance with these preliminary data. New analysis techniques are exploited which involve multivariate analyses for rejecting background hadrons from prompt leptons from the hard interactions as well as innovative in-situ corrections on data that reduce biases in muon momenta induced from residual detector displacements. We measure the reconstruction efficiencies and momentum performance measured with these methods. The results achieved are fundamental for improving the reach of measurements and searches involving leptons, such as Higgs decays to dimuons and ZZ or the first low mass and high mass searches in the beyond-the-standard model sector. This talk will present the recently released results on the muon reconstruction performance using the Run-3 data collected in 2022 by the ATLAS detector.
The event rates and kinematics of Higgs boson production and decay processes at the LHC are sensitive probes of possible new phenomena beyond the Standard Model (BSM). This talk presents precise measurements of Higgs boson production and decay rates, obtained using the full Run 2 and partial Run 3 pp collision dataset collected by the ATLAS experiment at 13 TeV and 13.6 TeV. These include total and fiducial cross-sections for the main Higgs boson processes as well as branching ratios into final states with bosons and fermions. Differential cross-sections in a variety of observables are also reported, as well as a fine-grained description of the Higgs boson production kinematics within the Simplified Template Cross-section (STXS) framework. Combinations of such measurements are also presented, as well as their interpretation in terms of Higgs boson couplings and in the context of Effective Field Theory (EFT) frameworks and specific BSM models.
This talk presents precise measurement of the properties of the Higgs boson, including its mass, total width, spin, and CP quantum number. The measurements are performed in various Higgs boson production and decay modes, as well as their combinations. Observation of deviations between these measurements and Standard Model (SM) predictions would be a sign of possible new phenomena beyond the SM
In this talk we discuss recent results from the CMS experiment on Higgs boson coupling and cross section measurements. A variety of different production modes and final states are discussed. We also present differential cross section measurements and constraints on anomalous Higgs boson couplings.
We introduce a methodology and investigate the feasibility of measuring quantum properties of tau lepton pairs in the $𝐻 \to \tau^+ \tau^−$ decay at future lepton colliders. In particular, observation of entanglement and violation of Bell inequalities are examined for the ILC and FCC-ee. As a by-product, we show that a novel model-independent test of CP violation can be performed and the CP-phase of $H \tau \tau$ interaction can be constrained with an accuracy comparable to dedicated analyses.
We study the production of Dark Matter (DM) in a minimal freeze-in model during inflationary reheating. We analyze the case where a heavier parent particle decays into DM and a Standard Model fermion in two reheating scenarios: bosonic reheating (BR) and fermionic reheating (FR). Firstly, we show that for low reheating temperatures, BR and FR scenarios predict different lifetimes and masses for the parent particle when considering reheating potentials with power-law behavior. Additionally, we highlight how different treatments of the reheating phase and definitions of the reheating temperature in the literature can lead to conflicting conclusions about the relevance of long-lived particle (LLP) searches in testing the freeze-in model. Moreover, we investigate the interplay between LLP searches and cosmological constraints on SUGRA-motivated inflationary models, specifically $\alpha$-attractor E- and T-models. In essence, we find that the inflaton potential and the reheating temperature significantly affect the relic density of DM and could have crucial implications for interpreting collider signatures and understanding the dynamics of inflationary reheating.
Primordial Black Holes (PBHs) may form in the early universe, from the gravitational collapse of large density perturbations, generated by large quantum fluctuations during inflation. Since PBHs form from rare over-densities, their abundance is sensitive to the tail of the primordial probability distribution function (PDF) of the perturbations. It is therefore important to calculate the full PDF of the perturbations, which can be carried out non-perturbatively using the 'stochastic inflation' framework. In single field inflationary models, generating large enough perturbations to produce an interesting abundance of PBHs requires violation of slow roll. It is therefore necessary to extend the stochastic inflation formalism beyond slow roll, and consequently there has been a surge in the research interest in this direction in the recent years. A crucial ingredient for this is the stochastic noise matrix corresponding to the small wavelength fluctuations. In this talk, after providing a brief introduction to PBHs and ultra slow-roll inflation, the speaker will discuss analytical and numerical calculations of these matrix elements for an inflaton potential with a feature which violates slow roll and produces large, potentially PBH generating, perturbations. The talk will be based on the following work carried out at the Particle Cosmology Group, University of Nottingham [arXiv: 2303.17375].
We have shown that the process of non-instantaneous reheating during the post-inflationary period can have a sizeable impact on the charged lepton equilibration temperature in the early Universe. This suggests a relooking into the flavor effects of leptogenesis where the production and decay of right-handed neutrinos take place within this extended era of reheating. We observe that the decay of the lightest RHN in the set-up not only provides a platform to study flavor leptogenesis during reheating, but also an interesting paradigm of quasi-thermal leptogenesis emerges.
After a brief introduction to phase transitions and explain why they are worth studying, I will examine those in the minimal extension of the SM using a real singlet scalar field. The uniqueness of our study lies in the identification and detailed analysis of a parameter space region where a first-order phase transition with relativistic expanding bubbles can occur. This particular region is intriguing because it may give rise to newly discussed mechanisms for baryogenesis and Dark Matter production. My main focus will be on an EW baryogenesis model that we have investigated, as well as the potential for its discovery in current and future experiments.
We revisit the minimal Nambu-Goldstone(NG)-Higgs supersymmetric (SUSY) SU(5) grand unified model and study its phenomenological implications. The Higgs sector of the model possesses a global SU (6) symmetry, which is spontaneously broken and results in the Higgs doublets of the minimal SUSY Standard Model (MSSM) as NG chiral superfields. Therefore, the model naturally leads to light Higgs doublets and solves the doublet-triplet splitting problem. Because of the SU(6) symmetry, the couplings of the Higgs sector are tightly restricted, and thus the model is more predictive than the minimal SUSY SU(5). We determine all the grand unified theory parameters via the matching conditions of the gauge coupling constants at the unification scale and calculate proton lifetime, confronting this with current experimental bounds. We discuss that this model is incompatible with the constrained MSSM, whilst it has a large viable parameter space in the high-scale SUSY scenario. The perturbativity condition on the trilinear coupling of the adjoint Higgs field imposes an upper (lower) limit on the wino (gluino) mass, implying a hierarchical mass pattern for these gauginos. Future proton-decay searches can probe a large part of the parameter space, especially if the SUSY-breaking scale is ≲100 TeV.
The lack of evidence for new physics in the LHC data puts stringent constraints on supersymmetric theories. However, searches for supersymmetric particles at the LHC are made channel-by-channel in specific final states, and the results are typically presented in the context of simplified models. It is therefore important to reinterpret the results of these searches by confronting them to full theories. So far, such reinterpretation has also mostly been done in a channel-by-channel approach, considering the constraints from each experimental search separately. In this presentation, we go a step further and discuss how combining LHC search results into a global likelihood can give better and statistically more robust constraints on the tested models. Concretely, our analysis focuses on the electroweakino sector of the MSSM, for which we derive global constraints based on the ~10 publicly available and reusable ATLAS and CMS searches for signals in this sector through the SModelS package.
FlexibleSUSY provides automated calculations of the mass spectrum of BSM particles and other observables such as muon g-2 precision predictions of the W and Higgs mass, and electric dipole moments in user defined extensions of the standard model. I will summarise capabilities and uses of the code with a focus on recent developments. These include recent improvements to muon g-2, MW, and the Higgs mass, the introduction of new flavour violating observables, and recent steps towards allowing new observables and amplitudes to be added by the user.
The majority of searches for supersymmetry assume conservation of R-parity, in which the lightest supersymmetric particle is a stable dark matter candidate that escapes detection and produces large missing transverse energy. This talk covers searches for R-parity violating supersymmetry, in which the lightest supersymmetric particle is unstable and can decay to standard model particles. These scenarios would be missed by traditional searches focusing on large missing transverse energy and can produce a wide variety of interesting signatures including possible resonances.
Grand Unified Theories (GUTs) aim to unify all three fundamental interactions including electromagnetic, strong and weak interactions. A well-known phenomenological prediction of GUTs is proton decay, which sets a strong constraint to GUTs due to its null observation. On the other hand, masses and mixing of quarks and leptons are correlated since all fermions are arranged in the same representation of SO(10). As the era of neutrino precision measurement is coming, experimental data in the fermion sector will become more and more important in the future study of GUTs. On the cosmological side, the breaking of SO(10) to the Standard Model gauge groups generates cosmic strings, which radiates gravitational waves via string oscillation. In this talk, I will discuss all these phenomenological constraints, and show a GUT model consistent with all known experimental data. I will further mention how enough matter-antimatter asymmetry can be generated in the GUT model.
Modified (the higher-derivative) supergravity models of cosmological inflation are introduced by extending the Starobinsky model of inflation to supergravity and including production of primordial black holes, in agreement with current precision measurements of the cosmic microwave background radiation. It leads to multi-field inflation, dark matter genesis as primordial black holes, and detectable (induced) stochastic gravitational waves. Adding the nilpotent superfield describing Akulov-Volkov goldstino with a no-scale Kaehler potential and a polynomial superpotential leads to spontaneous SUSY breaking near the inflationary scale and super-heavy gravitino particles.
Particles that interact with the standard-model very weakly, or only gravitationally, may be created merely by the expansion of the universe. This mechanism may produce dark matter and be used to limit the properties of particles beyond the standard model.
High energy cosmic neutrinos are generated by the interactions of cosmic rays with matter & radiation, so their spectrum extends up to ZeV energies. The detection of cosmic neutrinos up to multi-PeV energies by the IceCube Neutrino Observatory at the South Pole has thus provided a novel laboratory for fundamental interactions, complementary to collider experiments. The measured cross-section & inelasticity distribution of high energy neutrino interactions are consistent with pQCD, but at higher energies there may be signals of physics beyond the SM. Measurements of the flavour ratio also provide a sensitive probe of new physics that can affect neutrino oscillations over astronomical baselines.
Motivated by the expected future progress in long-lived particle searches there has been a lot of activity recently from theorists studying models for LLPs. This talk concentrates on LLPs motivated by the observed smallness of neutrino masses. Examples are simple heavy neutral lepton models, motivated by different variants of the seesaw, or also supersymmetric models with R-parity violation. Since no new physics has been found so far at the LHC, effective field theory is the appropriate tool to search for BSM physics. NRSMEFT, ie. SMEFT extended by light right-handed neutrinos, is discussed and forecasts for LLP experiments are presented for NRSMEFT.
In 2005 I gave a talk at SUSY provocatively titled Neutr - the only Observed Ino (So Far). So far it still is. I will give a brief survey the progress made since 2005 and the prospects for further progress by future projects.
SModelS is a public tool for the fast reinterpretation of LHC searches for new physics on the basis of (mostly SUSY) simplified-model results. The latest version is v2.3, released in May 2023. In this talk, I will present some major novelties of the SModelS v2 series, in particular the database update with a large number of full-luminosity Run2 results, the treatment of signatures with long-lived particles (simultaneously with prompt signatures), the statistical evaluation using different backends (from simplified likelihoods to full Histfactory models), and the ability of combining likelihoods in global analyses. Moreover, I will discuss subtleties that are important for the optimal usage of the tool, and demonstrate the physics capabilities by means of a case study.
Flavor has been traditionally seen as a problem for supersymmetric theories, "the flavor problem". Still, the Standard Model is not immune to this problem, also Yukawa couplings should be naturally O(1).
Flavor symmetries are used to explain the structure of Yukawa couplings and, simultaneously, of soft-breaking couplings in supersymmetric theories. In this scenario, SUSY can help to determine the flavor symmetry at work: the measure of the supersymmetric spectrum can give us very valuable information on the mechanism responsible for flavor.
However, no SUSY has been found so far. Even if SUSY is not present at low energies, supersymmetry is usually required in flavor theories to obtain a correct alignment of the flavon fields from a general scalar potential. We will see that, even if supersymmetry is broken at low energies, it is still possible to maintain this, much simpler, supersymmetric flavon alignment.
In summary: SUSY needs flavor and flavor needs SUSY.
The neutrino oscillation studies of the last decades have brought neutrinos to the center of particle physics, leaving an important legacy for new physics. I will briefly review the status of precision neutrino results and comment on the insights they bring into the basic drawbacks of the Standard Model such as the origin of neutrino mass, the flavour problem and dark matter.
I present a general formalism for multiple moduli and their associated modular symmetries, then apply it to examples based on finite modular symmetries, leading to viable and predictive modular flavour models.
We present the first complete model of the Littlest Modular Seesaw, based on two right-handed neutrinos, within the framework of multiple modular symmetries, justifying the use of multiple moduli fields which take their values at 3 specific stabilizers of $\Gamma_4 \simeq S_4$, including a new phenomenological possibility. Using a semi-analytical approach, we perform a $\chi^2$ analysis of each case and show that good agreement with neutrino oscillation data is obtained, including predictive relations between the leptonic mixing angles and the ratio of light neutrino masses, which non-trivially agree with the experimental values. It is noteworthy that in this very predictive setup, the models fit the global fits of the experimental data remarkably well, both with and without the Super-Kamiokande atmospheric data, for both models presented here. By extending the model to include a weighton and the double cover group $\Gamma'_4 \simeq S'_4$, we are able to also account for the hierarchy of the charged leptons using modular symmetries, without altering the neutrino predictions.
In this work, we revisit the constraints on neutrinos flavour models given by discrete symmetries. We study the solar and atmospheric sum rules and test them against the up-to-date fit of the neutrino oscillation data. We show that some models, such as a version of the Golden Ratio (GR1), are already excluded at $3\sigma$ and discuss which are the most favored models by the data. We also test Littlest Seesaw models, which can be considered a subset of one class of tri-maximal mixing models (TM1), we show their high predictivity and present their constraints.
The aim of this presentation is to introduce a dark extension of the SM that communicates to it through three portals: neutrino, vector and scalar mixing, by which it could be possible to explain the Low Energy Excess (LEE) at MiniBooNE. In the model, Heavy Neutral leptons are produced by upscattering via a dark photon, with masses around 10 MeV – 2 GeV, and subsequently decay into an electron-positron pair and neutrinos. If sufficiently collimated or asymmetric in energy, these events can be detected as a single shower and explain the MiniBooNE LEE. We show how the model can well reconstruct the energy spectrum. We consider two cases: 3 ν + 1 HNL and 3 ν + 2 HNLs.
Neutrino non-standard interactions (NSI) have been extensively explored in the context of dedicated neutrino experiments. However, the next generation of direct detection experiments is on course to observe a significant number of solar neutrino events, and the sensitivities of these experiments within the NSI landscape are yet to be determined. Due to their sensitivity to neutrino-nucleus and neutrino-electron scattering, as well as to tau neutrinos, direct detection provides a complementary view of the NSI parameter space to that of spallation source and neutrino oscillation experiments. To study their potential in the NSI landscape, we develop a re-parametrisation or the NSI framework that explicitly includes a variable electron contribution and allows for a clear visualisation of the complementarity of the different experimental sources. For the first time, we compute the NSI sensitivity limits from the first results of the XENONnT and LZ experiments, and we obtain future xenon-based projections. Our results demonstrate indicate that next-generation direct detection experiments will form powerful probes of neutrino NSI.
More than twenty years ago a paradigm emerged according to which supersymmetric theories with compact extra dimensions and Scherk-Schwarz SUSY breaking could naturally provide a UV-insensitive Higgs mass $m_H$, and more generally a UV-insensitive Higgs potential $V_{1l}(\phi)$. Some warnings were originally raised on the validity of such an outcome, but the community soon came to an agreement in its favor. Since then, this idea and the related result have been frequently used in models of phenomenological interest, including recent applications to the dark energy problem. The UV-insensitiveness is typically understood as a result of the non-local nature of the Scherk-Schwarz SUSY breaking, and the latter is usually thought to be operative only at distances larger than the compactification radius. In this talk, I intend to present a novel and thorough analysis of the framework on which the paradigm is based. I will show that a source of strong UV-sensitivity, intimately connected to the non-trivial boundary conditions that trigger the Scherk-Schwarz mechanism, so in turn to the non-trivial topology of these models' spacetime, was missed at the time. These findings call for a reconsideration of the usual picture of the Scherk-Schwarz mechanism and of its physical consequences.
Searches are being carried out at the Large Hadron Collider (LHC) for the decay of the CP-odd scalar $(A^{0})$ in Two-Higgs-Doublet Models (2HDMs) with Natural Flavour Conservation (NFC) in the channel $A^{0}\rightarrow h^{0}Z^{*}$ (with $m_{h^{0}}=125 GeV$ and Z on-shell). In the absence of any signal, limits on the parameter space of $[tan\beta , cos(\beta -\alpha ), m_{A^{0}}]$in each 2HDM are derived form $m_{A^{0}}> 225 GeV$. In this work we consider the scenario of inverted hierarchy with $m _{h^{0}}< 125 GeV$ and $m _{H^{0}}=125 GeV$ in which the decay $A^{0}\rightarrow h^{0}Z^{*}$ (i.e. including the case of an off-shell Z) can have a large branching ratio in the 2HDM (Type I) for $m_{A^{0}}< 225 GeV$. We calculate the signal cross section $\sigma (gg\to A^{0})\times BR(A^{0}\to h^{0}Z^{()*)})\times BR(h^{0}\to b \bar{b} )$ in the 2HDM (Type I) with NFC and compare its magnitude with the cross section for the case of normal hierarchy ($m _{h^{0}}=125 GeV$) that is currently being searched for at the LHC. For the experimentally unexplored region $m_{A^{0}}< 225 GeV$ it is shown that the above cross section for signal events in the scenario of inverted hierarchy can be of the order of a few picobarns. Such sizeable cross sections are several orders of magnitude larger than the cross sections for the case of normal hierarchy, thus motivating an extension of the ongoing searches for $A^{0}\rightarrow h^{0}Z^{*}$ to probe the scenario of inverted hierarchy.
The discovery of the Higgs boson with the mass of about 125 GeV 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 of the Standard Model addressing such shortcomings, including several SUSY benchmark models, introduce additional Higgs-like bosons which can be either neutral or charged. The current status of searches for additional low- and high-mass Higgs bosons based on the full LHC Run 2 dataset of the ATLAS experiment at 13 TeV are presented.
We present searches for additional Higgs bosons with data collected by the CMS experiment. Searches for additional Higgs bosons at high mass, such as those that can constrain the parameter space of the minimal supersymmetric standard model, will be discussed. We also cover searches for the 125 GeV Higgs boson decaying to a pair of light scalars.
We consider Dark Matter (DM) production via the freeze-in mechanism with finite temperature corrections. Freeze-in is mostly sensitive to temperatures corresponding to the highest energy scale involved in the production reactions, contrary to the freeze-out paradigm, which occurs well within a non-relativistic regime. As a result, quantum and finite temperature corrections can significantly alter the predictions for the DM production rate and hence for its relic abundance. However, the conventional Boltzmann approach widely employed in the freeze-in literature is not suited to capture the relevant effects that contribute to the evolution of particle number densities throughout all temperature regimes; for instance, the use of thermal masses to regulate infrared divergences in scattering amplitude comes as an artificial ad-hoc expedient.
Here, I discuss some recent advancements of an ongoing effort to consistently calculate the DM production rate from first principles, combining the real-time approach of thermal quantum field theory with Schwinger–Dyson equations derived from a two-particle irreducible (2PI) effective action. We compare our results with the Boltzmann approach, both in vacuum and with using thermal masses. Moreover, we discuss the applicability and accuracy of these various approaches for phenomenological studies.
We delve deeper into the potential composition of dark matter as stable scalar glueballs from a confining dark $SU(N)$ gauge theory, focusing on $N=\{3,4,5\}$. To predict the relic abundance of glueballs for the various gauge groups and scenarios of thermalization of the dark gluon gas, we employ a thermal effective theory that accounts for the strong-coupling dynamics in agreement with lattice simulations. We compare our methodology with previous works and find that our approach is more comprehensive and reliable. The results are encouraging and show that glueballs can account for the totality of dark matter in many unconstrained scenarios with a phase transition scale $20~MeV < \Lambda < 10^{10}~GeV$, thus opening the possibility of exciting future studies.
Many extensions of the standard model predict new particles with long lifetimes or other properties that give rise to non-conventional signatures in the detector. This talk discusses new techniques to detect such signatures in the CMS detector, and presents recent results from such searches in CMS using the full Run 2 data set of the LHC.
Various theories beyond the Standard Model predict new, long-lived particles with unique signatures which are difficult to reconstruct and for which estimating the background rates is also a challenge. Signatures from displaced and/or delayed decays anywhere from the inner detector to the muon spectrometer, as well as those of new particles with fractional or multiple values of the charge of the electron or high mass stable charged particles are all examples of experimentally demanding signatures. The talk will focus on the most recent results using 13 TeV pp collision data collected by the ATLAS detector.
The neutralinos are well-motivated dark matter candidates and have been studied extensively. If the mass difference between the neutralino and chargino is relatively small, then they can be detected as, for example, disappearing charged tracks in collider experiments. The constraint on the chargino mass by those experiments strongly depends on the chargino lifetime, and hence, it is important to evaluate the decay rate precisely for a given mass difference.
In this talk, we will discuss the up-to-date estimation of the decay branching and decay rate of the chargino including electroweak radiative corrections and expected errors. We will also talk about the experimental implications provided by our results.
A new fundamental theory [1] unavoidably predicts supersymmetry, SO(N) grand unification, and a new description of all fundamental scalar bosons. As discussed in our previous papers [2-5] and many recent talks, this last feature in turn unavoidably predicts a dark matter WIMP which is consistent with all experimental and observational constraints, and which should be observable via direct detection (within the next few years), collider detection (within about 15 years), and indirect detection (for which there is already evidence). Here we point out another important consequence: It is not possible to form the usual sfermions described by the 16 of SO(10), and instead it is necessary to form real scalar boson fields with the same basic character as the higgsons of our earlier papers, having no interactions other than (1) second-order gauge couplings and (2) the usual Higgs coupling. This means that the scalar boson partners of fermions will be harder to produce and observe than is currently expected, with new experimental signatures, and the same will be true of gauginos and Higgsinos via processes which also involve scalar boson superpartners. One then has a different version of natural supersymmetry, with superpartners at ~ a few hundred GeV which are more difficult to observe and which have modified experimental signatures.
[1] Roland E. Allen "Some unresolved problems from a fresh perspective", arXiv:2302.10241.
[2] Reagan Thornberry et al., EPL [European Physics Letters] 134, 49001 (2021), arXiv: 2104.11715 [hep-ph], and references therein.
[3] Caden LaFontaine et al., Universe 7, 270 (2021), arXiv: 2107.14390 [hep-ph].
[4] Bailey Tallman et al., ICHEP-2022 proceedings, arXiv: 2210.05380 [hep-ph].
[5] Bailey Tallman et al., Letters in High Energy Physics LHEP-342 (2023), doi.org/10.31526/hep.2023, arXiv:2210.15019 hep-ph.
Cosmologically plausible compactification scenarios typically require parametric separation between the cosmological and the compactification length scales.
When the higher-dimensional solution is in the semi-classical regime, the full quantum-corrected equations of motion are naturally expanded in the local values of various fields. In this talk, we will present constraints on AdS scale-separation arising from requiring local control of the expansion in the warp-factor and other local fields for classes of warped AdS compactifications in 10- or 11-dimensional supergravity with quantum corrections. Through this approach, we will derive constraints on the ingredients that can produce scale-separation, reproduce certain no-go results, and comment on the compatibility of existing explicit constructions with these constraints, with emphasis on the role of quantum corrections and localized sources. We will also briefly comment on the application of this approach to de Sitter compactifications.
Obtaining genuine lower-dimensional theories from string theory remains a real challenge.
This can be done if the Kaluza-Klein energy scale can be made much larger than the cosmological constant.
In this talk, I review the situation for minimally supersymmetric models in type IIA string theory. There the separation of scales is achieved due to unbounded flux quanta that can be send to infinity. In this talk, I explain how a novel scalar field in the open-string sector allows us to interpolate between such IIA vacua that differ in flux quanta and find that the limit of large fluxes is nicely consistent with the swampland distance conjecture. Furthermore, I discuss that the tower of states that becomes light, does not necessarily invalidate the effective field theory, suggesting the scale-separated vacua might not be in the Swampland.
Finally, I comment on how this can be extended to other flux vacua.
The existence of AdS vacua in string theory with a parametric separation between the Hubble
scale and the Kaluza-Klein scale of the extra dimensions is an open question, and holography is a
promising tool to tackle this. I will discuss some remarkable holographic features
of the DGKT vacua, which are candidate AdS vacua with parametric scale separation.
The absence of supersymmetry in string theory usually leads to runaways, arising from nonvanishing dilaton tadpoles. The spacetime manifestation is a scalar potential, which might be a blessing in disguise for flux compactifications, even though it typically brings along singularities or instabilities.
In this talk, I will discuss a first-order formalism, already known in its most basic form as fake supersymmetry, that can replace supersymmetry as a vacuum-generating technique for non-supersymmetric ten-dimensional strings. This strategy suggests interesting conclusions on vacuum stability, employing a definition of energy inspired by the Witten-Nester approach.
Heavy Neutral Leptons (HNLs), also known as heavy or right-handed neutrinos, are among the best motivated new particles to extend the SM and, when their masses are between the few GeV and few TeV, high-energy colliders are one of our best tools to probe their existence. Nevertheless, most of the experimental searches performed so far only consider simplified scenarios, whose connection to realistic and and well-motivated models might not be clear. In this talk, we will review the current LHC and LEP status in searching for HNLs and discuss what are we actually learning from them, including their flavor structure or their nature.
We present an updated and improved global fit analysis of current flavor and electroweak precision observables to derive bounds on unitarity deviations of the PMNS mixing matrix and the mixing of heavy neutrinos with the active flavours.
This new analysis is motivated by new and updated experimental results on key observables such as $V_{ud}$, the invisible decay width of the $Z$ boson and the $W$ boson mass. It also improves upon previous studies by considering the full correlations among the different observables and explicitly calibrating the test statistic, which may present significant deviations from a $\chi^2$ distribution.
The results are provided for three different scenarios: the minimal scenario with only two additional right-handed neutrinos, the next to minimal one with three extra neutrinos, and the most general one with an arbitrary number of heavy neutrinos that we parametrize via a generic deviation from a unitary lepton mixing matrix. Additionally, we also analyze the case of generic deviations from unitarity of the PMNS matrix, not necessarily induced by the presence of additional neutrinos. This last case relaxes some correlations among the parameters and is able to provide a better fit to the data. Nevertheless, inducing only PMNS unitarity deviations avoiding both the correlations implied by the right-handed neutrino extension as well as more strongly constrained operators is challenging and would imply significantly more complex UV completions.
Collider-testable low scale type I seesaw models for neutrino mass generation generically feature pseudo-Dirac heavy neutrinos, composed of two Majorana states with nearly degenerate masses. These pseudo-Dirac heavy neutral leptons (HNLs) can oscillate between interaction eigenstates that couple to leptons and antileptons, and thus generate oscillations between lepton number conserving (LNC) and lepton number violating (LNV) processes. While it has been argued that for prompt processes LNV is strongly suppressed by the smallness of the light neutrino masses and practically unobservable, taking the oscillations into account can induce observable rates of LNV at the HL-LHC and future colliders. For long-lived heavy neutrinos, the oscillating pattern between LNC and LNV processes as a function of heavy neutrino lifetime may even be resolvable, which would allow for a deep insight into the neutrino mass generation mechanism. Only since recently, a public MadGraph patch exists that allows to include the oscillations in simulations of HNLs at colliders.
We study charged lepton flavor violating processes $\mu^+\mu^+\to\ell^+\ell'^+$ at a future same-sign muon collider. Working in an effective field theory framework, we compare the potential discovery reach with existing limits from rare $\mu$ and $\tau$ decays, finding that muon colliders are the most sensitive probe of charged lepton flavor violation for a range of parameters. As a model example, we then consider the type-ii seesaw model, and show how a muon collider could be used to constrain the CP-violating phases of the corresponding PMNS matrix.
The ATLAS collaboration has recently reported the results of a low-mass Higgs-boson search in the di-photon final state based on the full Run 2 data set. The largest "excess" is observed at 95.4 GeV with a significance of 1.7 $\sigma$. At exactly the same mass in the same channel CMS reported earlier an excess of 2.9 $\sigma$. Other excesses at about the same mass have been published by LEP in the $b \bar b$ channel at 2 $\sigma$ and by CMS in the $\tau\tau$ decay channel at 2.4 $\sigma$. We demonstrate that these excesses can be accomodated in the Two Higgs doublet model with an additional complex singlet (S2HDM). We discuss the prospects to analyze this scenario at the HL-LHC and future $e^+e^-$ colliders.
In the Standard Model, the ground state of the Higgs field is not found at zero but instead corresponds to one of the degenerate solutions minimising the Higgs potential. In turn, this spontaneous electroweak symmetry breaking provides a mechanism for the mass generation of nearly all fundamental particles. While the Standard Model makes a definite prediction for the Higgs boson self-coupling and thereby the shape of the Higgs potential, enhanced rates and modified kinematic properties of Higgs boson pair (HH) production are a smoking-gun signature for new physics. In the case of SUSY, this may appear as new loop contributions in non-resonant HH production or via new scalar resonances decaying to two Higgs bosons. In this talk, the latest searches for Higgs boson pairs by the ATLAS experiment are reported, with emphasis on the results obtained with the full LHC Run 2 dataset at 13 TeV. In the case of non-resonant HH searches, results are interpreted both in terms of sensitivity to the Standard Model and as limits on the Higgs boson self-coupling. Extrapolations of recent HH results towards the High Luminosity LHC upgrade are also discussed. Search results on new resonances decaying into pairs of Higgs bosons are also reported.
In supersymmetric theories the Higgs boson masses are derived quantities where higher-order corrections have to be included in order to match the measured Higgs mass value at the precision of current experiments. Closely related through the Higgs potential are the Higgs self-interactions. In addition, the measurement of the trilinear Higgs self-coupling provides the first step towards the reconstruction of the Higgs potential and the experimental verification of the Higgs mechanism sui generis.
In this talk, I will present the $\mathcal O(\alpha_t^2)$ corrections to the trilinear Higgs self-couplings in the CP-violating Next-to-Minimal Supersymmetric extension of the SM (NMSSM), calculated in the gaugeless limit at vanishing external momenta. The higher-order corrections turn out to be larger than the corresponding mass corrections, but show the expected perturbative convergence. The inclusion of the loop-corrected effective trilinear Higgs self-coupling in gluon fusion into Higgs pairs and the estimate of the theoretical uncertainty due to missing higher-order corrections indicate that the missing electroweak higher-order corrections may be significant.
Vector boson scattering is a key production process to probe the electroweak symmetry breaking of the standard model, since it involves both self-couplings of vector bosons and coupling with the Higgs boson. If the Higgs mechanism is not the sole source of electroweak symmetry breaking, the scattering amplitude deviates from the standard model prediction at high scattering energy. Moreover, deviations may be detectable even if a new physics scale is higher than the reach of direct searches. Latest measurements of production cross sections of vector boson pairs in association with two jets in proton-proton collisions at sqrt(s) = 13 TeV at the LHC are reported using a data set recorded by the CMS detector. Differential fiducial cross sections as functions of several quantities are also measured.
Global non-topological solitons (Q-balls) exist when the potential of a charged scalar field grows slower than quadratically. At zero temperature, this requires attractive interactions. We first show that finite temperature effects can generate the necessary terms even in the absence of attractive interactions at zero temperature. As a result, non-topological solitons exist at finite temperature in a variety of models which do not have non-topological solitons at zero temperature.
The necessary finite temperature terms are generated by bosons whose mass depends on the scalar VEV, which makes the Standard Model Higgs sector a natural place to look for them. We show that gauge interactions between Higgs quanta prevent their existence in the Standard Model, but they can exist in extensions of the Standard Model, particularly those with additional scalars.
Based on the recent article [2023.02399], we discuss the LISA potential for finding evidence of New Physics from measurements of the Stochastic GW Background (SGWB). As a benchmark scenario, we study a version of the low-scale Majoron model equipped with lepton number symmetry and an inverse seesaw mechanism for neutrino mass generation. In particular, we discuss under which circumstances the model can be probed at LISA and which implications result for collider physics observables, such as the Higgs trilinear coupling, the scalar mixing angle and the mass of a new CP-even Higgs boson. If time allows, we will also report on a scenario of symmetry restoration at zero temperature based on a model with two scalar leptoquarks.
Cosmological phase transitions that are strongly first order are well motivated in physics beyond the standard model, for example as part of an electroweak baryogenesis solution to the matter anti-matter asymmetry, and could give rise to an observable gravitational wave spectra. Based on https://arxiv.org/abs/2305.02357 and https://arxiv.org/abs/2212.07559 I discuss various subtle issues in the prediction of gravitational wave spectra from first order phase transitions that can significantly impact the predictions and review the current status of predictions for gravitational waves from first order phase transitions. In particular I will discuss criteria for determining if a phase transition completes, the dependence of gravitational wave spectra on the choice of a reference temperature and other thermal parameters, the use of fit formulae from simulations and analytical calculations of gravitational wave spectra, and recent developments that affect these.
We discuss a dark photon model with successive symmetry breaking $\mathrm{SU(2)_D}$ $\to$ $\mathrm{U(1)_D}$ $\to$ $\mathbb{Z}_2$ in the dark sector. Various dark topological defects appear, such as monopoles, dyons, strings and beads. They are shown to induce QED electromagnetic fields through kinetic and magnetic mixing between $\mathrm{U(1)_{QED}}$ and $\mathrm{U(1)_D}$. In particular, dark beads appear from a distance to be particles with magnetic and electric charge, which we call pseudo-monopoles (dyons).
The presence of a non-baryonic Dark Matter (DM) component in the Universe is inferred from the observation of its gravitational interaction. If Dark Matter interacts weakly with the Standard Model (SM) it could be produced at the LHC. The ATLAS Collaboration has developed a broad search program for DM candidates in final states with large missing transverse momentum produced in association with other SM particles (light and heavy quarks, photons, Z and H bosons, as well as additional heavy scalar particles) and searches where the Higgs boson provides a portal to Dark Matter, leading to invisible Higgs decays. The results of recent searches on 13 TeV pp data from the LHC, their interplay and interpretation will be presented.
We discuss Dark Matter (DM) in combination of $(g-2)_\mu$ in the MSSM. Six different scenarios according to the nature of the Next-to-lightest SUSY particle are identified. All relevant bounds from LHC searches, DM relic abundance and direct detection (DD) are taken into account. We show how collider searches and direct detection experiments can fully test these scenarios.
We revisit the model where bino coannihilates with slepton and higgsino is also at electroweak scale.
We update the LHC constraints and the dark matter direct detection constraints. Also, we consider the new physics contributions to muon g-2 and we find that there remains unexplored regions.
Higher-order corrections involving (external) charginos and/or neutralinos require a renormalization of this sector. External particles should be renormalized on-shell (OS). Since the six chargino/neutralino masses are controlled by three mass parameters, many different OS renormalization schemes (RS) are possible. A given RS can be well suited to yield "stable" and "well behaved" higher-order corrections in one part of the MSSM parameter space, but can fail completely in other parts. We present a method how to choose a well behaved RS before the higher-order correction is carried out. We demonstrate the effectiveness of our method for the one-loop calculation of chargino decay widths. This new method for the RS choice now allows the full automation of higher-order corrections in the chargino/neutralino sector.
Using interaction rates computed to second order in string perturbation theory, we pose a system of Boltzmann equations describing an ensemble of long open and closed strings in different regimes (which include high and low density of D-branes), for an arbitrary number of "effectively non-compact" directions, along which strings cannot wind. We find equilibrium distributions for all these systems and study their behaviour under fluctuations, which we use to estimate thermalization rates. We comment on the relevance of this scenario in early Universe cosmology.
No-Scale SUGRA has attracted considerable interest as a framework for inflation as it provides a natural realisation of Starobinsky-like inflation models. Recently, it was shown that suitable modifications of the Kahler potential produce a kink on the inflaton scalar potential that generates an enhancement in the power spectrum, leading to the production of Gravitational Waves. In this talk, we revisit a No-Scale inflationary model that breaks SUSY at the end of inflation due to the presence of a Polonyi term, and we study how the proposed Kahler potential modifications can lead to the production of Gravitational Waves. To find suitable points in the parameter space, we employ an Artificial Intelligence scan based on an Evolutionary Strategy algorithm, and study the phenomenological implications of the Gravitational Waves spectrum and the gravitino mass.
"Shi-Fuller mechanism" is known as one of the scenarios which can explain all dark matter by sterile neutrinos not conflicting with any other current observational constraints. We revisit the numerical calculation of final energy spectrum of sterile neutrinos for given initial lepton asymmetry in Shi-Fuller mechanism by properly incorporating the effects of neutrino oscillation in active sector and effects of time evolution of lepton asymmetry during the production of sterile neutrinos. Then we comprehensively discuss the constraint on this scenario from current X-ray observations. Also, Shi-Fuller mechanism needs significant lepton asymmetry in the early universe compared to observed baryon asymmetry. We discuss the generation of such lepton asymmetry by Affleck-Dine mechanism.
The aim of this paper is to highlight the challenges and potential gains surrounding a coherent description of physics from the high-energy scales of inflation down to the lower energy scales probed in particle-physics experiments. As an example, we revisit the way inflation can be realised within an effective Minimal Supersymmetric Standard Model (eMSSM), in which the LLe and udd flat directions are lifted by the combined effect of soft-supersymmetric-breaking masses already present in the MSSM, together with the addition of effective non-renormalizable operators. We clarify some features of the model and address the question of the one-loop Renormalization Group improvement of the inflationary potential, discussing its impact on the fine-tuning of the model. We also compare the parameter space that is compatible with current observations (in particular the amplitude, $A_s$, and the spectral index, $n_s$, of the primordial cosmological fluctuations) at tree level and at one loop, and discuss the role of reheating. Finally we perform combined fits of particle and cosmological observables (mainly $A_s$, $n_s$, the Higgs mass, and the cold-dark-matter energy density) with the one-loop inflationary potential applied to some examples of dark-matter annihilation channels (Higgs-funnel, Higgsinos and A-funnel), and discuss the status of the ensuing MSSM spectra with respect to the LHC searches. [arXiv:2304.04534, Phys.Rev.D 108, 023511 (2023)]
Higher symmetries in quantum field theory are novel concepts of symmetry that involve extended operators such as Wilson lines in gauge theory. We briefly review this formalism and then discuss recent applications to particle physics, including an organizing principle for unification models and instanton effects. Finally, we discuss how higher symmetry violation can lead to simple models of Dirac neutrinos with natural masses that are exponentially small.
String theory provides a powerful framework for generating and studying strongly coupled quantum field theories, including so-called “non-Lagrangian” theories that have no weak coupling limit. In this talk, I will summarize recent developments regarding dual descriptions of a class of strongly interacting 4d N=2 superconformal field theories that arise from string theory. I will highlight how the interplay of geometric engineering, holography, and Lagrangian gauge theory leads to new insights into these SCFTs’ novel features.
I will argue on the possibility that the smallness of some physical parameters signals a universe at a large distance corner in the string landscape of vacua. Such parameters can be the scales of dark energy and supersymmetry breaking, which should then be tied to a large `dark' dimension at the micron scale. I will discuss the theoretical framework and some of its main physical implications.
Dark Matter constitutes more that 80% of the total amount of matter in the Universe, yet almost nothing is known about its nature. A powerful investigation technique is that of searching for the products of annihilations of Dark Matter particles in the galactic halo (and beyond), on top of the ordinary cosmic rays.
If a few anomalies still exist (notably the GeV GC gamma-ray excess), most recent experiments have reported constraints. What is the current status? What is in store for the near future in this field?
The Next-to-Minimal Supersymmetric Extension of the Standard Model (NMSSM) is a well motivated supersymmetric extension beyond the minimal version, the MSSM. It solves the mu-problem and relaxes somewhat the tension in achieving the measured value of the Standard Model (SM)-like Higgs boson mass value. In this talk, I will address precision predictions for the NMSSM Higgs sector as well as the prospects of the NMSSM to solve open problems of the SM: I review recent developments of precision predictions in the Higgs sector, namely for the masses and the trilinear couplings of the NMSSM Higgs bosons. I will discuss prospects of Higgs pair production at the LHC and for a strong first order electroweak phase transition. I will furthermore discuss the possibility to explain the deviation of the measured muon anomalous magnetic moment from the SM value.
The Weak Gravity Conjecture proposes that in any effective theory that can be consistently coupled to gravity, gravity must be the weakest force. I will review recent work on understanding this idea in anti-de Sitter space using holography. In particular, I will show that a certain formulation of the Weak Gravity Conjecture can be mapped to convexity properties of operators which are charged under global symmetries in conformal field theories . This convexity can then, in turn, be mapped to physical consistency constraints on Goldstone boson excitations about the charged states in the conformal field theory (which are dual to the charged operators by the state-operator correspondence).
In the context of string compactification, classifying possible gauge theories coupled to supergravity is intrinsically linked to classification problems in geometry. In this talk I will briefly review known bounds on the topology of CY manifolds and gauge fields over then. The field theory implications of these contraints can play an important role in characterizing both 4-dimensional N=2 and N=1 string vacua. I will also present new results on the geometry of Calabi-Yau conifold transitions as they arise in heterotic string compactifications. In particular, I will present particular classes of branes/bundles which can traverse the CY geometric transition in a controllable way.
By studying M-theory on singular non-compact special holonomy spaces X we demonstrate, via a process of cutting and gluing of singularities that extend to the boundary of X, the appearance of 0-form, 1-form and 2-group symmetries in the resulting supersymmetric quantum field theory. We study the fate of these symmetries when these spaces become compact by employing sophisticated gluing techniques. We focus on prototype examples with spaces X being elliptically fibered Calabi-Yau manifolds, which describe constructions dual to (non-) compact F-theory, including Standard Model constructions. We can compare obtained results to previous ones, encoded in the arithmetic structure of elliptic curves.
Genetic Algorithms (GAs) are some of the most simple and effective search methods. In this talk I will demonstrate and review their effectiveness in various applications in BSM physics, including string searches, cosmology and phenomenological searches. For the latter I will emphasize the untapped potential for combining GAs with other search methods.
I will discuss the possibility of non-minimal flavour violation the supersymmetric theories. Focussing on the sector of squarks, after a general introduction, I will review recent results covering both the implementation within grand unified theories and TeV-scale phenomenology.
Ten years of LHC Higgs data indicate that the properties of the observed Higgs boson are consistent (within the precision of the experimental data) with the predictions of the Standard Model (SM). Thus, any viable supersymmetric extension of the SM must incorporate a SM-like Higgs boson. This can be achieved either via the decoupling limit (where all additional Higgs scalars have masses above, say, 500 GeV) or in the so-called Higgs alignment limit without decoupling. Plausible scenarios in the frameworks of the MSSM and the NMSSM are described and discussed.
I discuss computer tools for SUSY collider phenomenology, recent developments and applications.
We review models of partial compositeness based on underlying four dimensional gauge theories with fermionic matter.
The matter content is chosen in such a way as to give rise to a Higgs boson as a pseudo-Nambu--Goldstone boson as well as a Dirac-like partner to the top quark. We discuss recent lattice results (by other groups) and their relevance to these constructions.
We conclude by presenting one universal aspect of the phenomenology of these models, namely the presence of axion-like particles at relative low mass, and discuss their experimental signatures.
Two major ingredients of a composite Higgs model are vacuum misalignment and partial compositeness. The former is essential to trigger the electroweak symmetry breaking, while the latter can explain the mass hierarchy of the quarks. The partial compositeness mechansim employes a mixing between the SM quarks and vector-like quarks, arising from a new confining sector, via four-Fermi operators. We demonstrate the necessity of these four-Fermi interactions to misalign the vacuum of the strong sector leading to electroweak symmetry breaking and connect our observations with recent results from lattice gauge theory calculations. We also discuss the current status and future prospects for searching vector-like quarks via their non-standard decay channels at the LHC.
In this talk I will present some models of weakly coupled scalar fields which are massless at the tree level, despite the fact that the scalar potential includes all renormalizable operators compatible with the symmetries, and that it exhibits no accidentally enhanced symmetries associated with pseudo-Nambu-Goldstone bosons (pNGBs). These accidentally light fields are close cousins of both pNGBs and of pseudomoduli in spontaneously broken supersymmetry. They could have applications in solving the little hierarchy problem, or in particle cosmology.
The proposed LUXE experiment (LASER Und XFEL Experiment) at DESY, Hamburg, using the electron beam from the European XFEL, aims to probe QED in the non-perturbative regime created in collisions between high-intensity laser pulses and high-energy electron or photon beams. This setup also provides a unique opportunity to probe physics beyond the standard model. In this talk we show that by leveraging the large photon flux generated at LUXE, one can probe axion-like-particles (ALPs) up to a mass of 350 MeV and with photon coupling of 3×10−6 GeV−1. This reach is comparable to the background-free projection from NA62. In addition, we will discuss the ongoing optimisation of the experimental setup for the ALP search.
We suggest a new class of models "a Fermionic Portal Vector Dark Matter" (FPVDM) which extends the Standard Model (SM) with a minimal non-Abelian $SU(2)_D$ dark gauge sector. Since the mixing between the SM and dark scalars is negligibly small, the main connection between two sectors is established on the mixing between a Vector-Like (VL) fermionic doublet of $SU(2)_D$ dark group and their SM partners through the Yukawa interaction related the dark scalar. The stability of the Vector Dark Matter (VDM) from $SU(2)_D$ dark group is ensured by the conservation of the dark charge. Multiple realisations are allowed depending on the VL partner and scalar potential. In this talk, we discuss an example of minimal FPVDM realisations with merely a VL-top partner. The kinetic mixing between Z and V bosons and the multipole moment from fermionic triangle diagrams at one loop play a vital role in the direct detection constraint which excludes a large region in parameter space. However, they only have a mild effect on the DM relic abundance, indirect detection and collider constraints. We present the multiple projections of viable parameter space that survive from the DM direct and indirect detection, relic density and collider searches.
In the first part of the talk I will describe a Majoron-like extension of the Standard Model with an extra global U(1)X symmetry where neutrino masses are generated through an inverse seesaw mechanism at the 1-loop level. In contrast to the tree-level inverse seesaw, the framework contains dark matter candidates stabilized by a residual Z2 symmetry surviving spontaneous breaking of the U(1)X group. I will discuss the implications of the model in dark matter and charged lepton flavor violation. In the second part of the talk I will describe a minimally extended inert doublet model where the tiny neutrino masses are generated through a three-loop seesaw. The model leads to a rich phenomenology while satisfying all the current constraints imposed by neutrinoless double-beta decay, charged-lepton flavor violation, and electroweak precision observables. The model could also successfully explain the W mass anomaly and provides viable fermionic or scalar dark matter candidates.
I will discuss flavour non-universal gauge interactions as a generic,
and well-motivated, possibility for new physics at the TeV scale. Such
dynamics could explain the hierarchical structure of fermion masses and
mixing angles - the so-called 'flavour puzzle' - by delivering
approximate flavour symmetries as accidental. The extended gauge
interactions imply heavy gauge bosons that couple directly to the Higgs,
which give unavoidable 1-loop contributions to the Higgs mass.
I will hence use naturalness as a guide in this space of low-scale
flavour models, and discuss general phenomenological consequences in
natural regions of parameter space. This includes measurable effects in
precision flavour (and electroweak) observables, and high energy
searches at the LHC with third family final states.
I will discuss a tri-hypercharge (TH) extension of the Standard Model (SM) in which a separate gauged weak hypercharge is associated with each fermion family, avoiding the family repetition of the SM. If the SM Higgs doublet only carries third family hypercharge, then only third family renormalisable Yukawa couplings are allowed, explaining the hierarchical heaviness of their masses. I will motivate the addition of a second Higgs doublet as a natural explanation for the hierarchies between the fermion masses in the different charged sectors. Yukawa couplings for light fermion families are induced in the form of non-renormalisable operators provided by the high scale Higgs fields (hyperons) which break the TH group down to SM hypercharge, explaining fermion mass hierarchies and the smallness of CKM quark mixing. I will show that due to the TH gauge symmetry, the implementation of a seesaw mechanism naturally leads to a low scale seesaw, where the right-handed neutrinos may be as light as the TeV scale. Finally, I will motivate that the breaking of the TH group could be as low as the TeV scale, with implications for flavour-violating observables, LHC physics and electroweak precision observables related to low scale Z' bosons.
The Froggatt-Nielsen Mechanism is a powerful way to explain the hierarchical structure found in the masses and mixing angles of quarks and leptons.
In this mechanism, the above structure is realized by imposing different U(1) charges on each generation of fermions under a new U(1) flavor symmetry.
In this talk, I will present the results of a reconsideration of the phenomenologically valid choice of U(1) charges by a Bayesian statistical approach.
I will also talk about the effect of flavor symmetry on proton decay.
We consider a minimal non-supersymmetric SO(10) Grand Unified Theory (GUT) model that can reproduce the observed fermionic masses and mixing parameters of the Standard Model. We calculate the scales of spontaneous symmetry breaking from the GUT to the Standard Model gauge group using two-loop renormalisation group equations. This procedure determines the proton decay rate and the scale of U(1)B−L breaking, which generates cosmic strings and the right-handed neutrino mass scales. Consequently, the regions of parameter space where thermal leptogenesis is viable are identified and correlated with the fermion masses and mixing, the neutrinoless double beta decay rate and the proton decay rate. We demonstrate that this framework, which can explain the Standard Model fermion masses and mixing and the observed baryon asymmetry, will be highly constrained by the next generation of gravitational wave detectors and neutrino oscillation experiments which will also constrain the proton lifetime.
In the SO(10) GUTs with or without supersymmetry, the third-generation fermions' Yukawa couplings can be unified by employing renormalization group (RG) analysis, similar to the gauge couplings. In the considered models, Yukawa unification implies that different Yukawa couplings are generated from a single coupling in the UV through the decomposition of scalar and fermion representations of the GUT group. Thus, the Yukawa hierarchy emerges from the CG coefficient of decomposition of the GUT group and vacuum expectation values (vevs) of different scalars. Previous research has examined the realization of Yukawa unification in supersymmetric SO(10) models. In this talk, we will present a non-supersymmetric SO(10) model with an intermediate Pati-Salam symmetry scale, where both gauge and Yukawa unification can be achieved simultaneously. Then, as an example, we show that the Yukawa unification in the SO(10) model can be obtained from an $E_6$ model where the two SO(10) scalar multiples belong to a single $E_6$ multiple. By considering phenomenological constraints such as the proton decay and the absence of flavor-changing neutral currents at tree-level, we can obtain a phenomenologically acceptable model. By RG flows to the IR scale, we show that Yukawa unification implies a constraint on the parameter space of the low-energy 2HDM, specifically, to the ratio of the vevs of the two Higgs doublets at the electroweak scale, referred to as $\tan \beta$.
The modular symmetry provides us with an intriguing solution to the flavor mixing puzzle. In the bottom-up approach to the modular-invariant flavor models, the modulus parameter $\tau$ is usually treated as a free parameter. Interestingly, there exist some special values of $\tau$ called stabilizers at which residual symmetries can be preserved after the spontaneous breaking of the global modular symmetry. In this talk, I will discuss the application of modulus stabilizers on the modular invariant neutrino mass models. I will also briefly explore how to fix the value of $\tau$ via modulus stabilization.
Here, we investigate the parameter space of the Georgi-Machacek
(GM) model in both cases where the extra CP-even scalar could be lighter or heavier than the Higgs. W consider many theoretical and experimental constraints, in addition to the constraints from doubly charged
Higgs bosons and Drell-Yan di-photon production and the indirect constraint from the $b\to s$ transition processes. We found that some unwanted wrong minima that may violate the CP and/or the electric charge symmetries; are possible. This excludes about 75 \% of the parameter space. In addition, negative heavy resonance searches exclude a significant part of the viable parameter space.
Phenomenological implications of the simplest multi-Higgs extensions of the Standard Model constrained by additional global horizontal flavour symmetries will be overviewed. A particular focus would be given to their basic implications for Higgs and flavour physics as well as for possible detection of primordial gravitational waves.
MicroBooNE is an 85-tonne active mass liquid argon time projection chamber (LArTPC) at Fermilab. With an excellent calorimetric, spatial and energy resolution, the detector was exposed to two neutrino beams between 2015 and 2020. These characteristics make MicroBooNE a powerful detector not just to explore neutrino physics, but also for Beyond the Standard Model (BSM) physics. Recently, MicroBooNE has published a search for heavy neutral leptons and Higgs portal scalars from kaon decays. In addition, MicroBooNE has developed tools for a neutron-antineutron oscillation search for the upcoming Deep Underground Neutrino Experiment (DUNE). This talk will explore MicroBooNE’s capabilities for BSM physics and highlight its most recent results.
Observation of Multiple Parton Scattering at High Energy Proton-Proton Collisions
M. Y. Hussein
Search Center
Shaikh Ebrahim Bin Mohammed Al-Khalifa Center for Culture and Research
Muharraq, P.O Box 13725
Kingdom of Bahrain
Multiple parton scattering “MPS” occurs when two or more independent identified hard particle from each proton takes place in the same proton-proton collision. Multiparton scattering mechanism got a new interest at the large hadron collider ‘LHC’, where much higher collision energies available. The field has received a new impulse and several experimental and theoretical studies address the problem of pinning down MPS effects. We perform an investigation of double and triple parton scattering.
A generic expression to compute double and triple parton scattering in high energy proton- proton (pp) collisions is presented as a function of the corresponding single parton cross sections and the transverse parton distribution in the proton and effective cross-section parameter in double and triple parton scattering.
The framework to compute the cross sections for the production of particles “Associate Higgs boson with bottom quarks, like charge W production ….” with high mass and/or large transverse momentum in double DPS, triple TPS; and in general n-parton scatterings from the corresponding single parton scattering cross section value in high energy proton- proton collisions are reviewed.
We discuss triple Higgs couplings (THCs) in the 2 Higgs Doublet Model (2HDM). We show how the SM-like THC, but also BSM THCs involving BSM Higgs bosons can be tested in di-Higgs production at the HL-LHC. We emphasize the role of experimental uncertainties in the measurement of these processes.
We discuss the interplay of First Order Electroweak Phase Transitions (FOEWPT), Triple Higgs Couplings (THCs) and Gravitational Waves (GWs) in the 2 Higgs Doublet Model (2HDM). We identify six thermal histories in the 2HDM, out of which one leads to a FOEWPT. We discuss the implications for GWs and the measurement of THCs at the HL-LHC and future $e^+e^-$ colliders, such as the ILC.
The recent observation of $^4$He favors a large lepton asymmetry at the big bang nucleosynthesis. If Q-balls with a lepton charge decay after the electroweak phase transition, such a large lepton asymmetry can be generated without producing too large baryon asymmetry. In this scenario, Q-balls dominate the universe before the decay and induce the sharp transition from the early matter-dominated era to the radiation-dominated era, which enhances the gravitational waves produced through a second-order effect of the scalar perturbations. We evaluate the density of the produced GWs and show that pulsar timing array observations can probe this scenario.
I will talk about how to distinguish the nature of neutrino masses, Dirac vs Majorana, from the spectrum of gravitational waves generated. I will discuss two simple models of Majorana and Dirac mass genesis motivated by generating small neutrino masses without assuming tiny Yukawa couplings. For Majorana neutrinos, spontaneous breaking of the gauged $U(1)_{B−L}$ symmetry gives a cosmic string induced gravitational wave signal flat over a large range of frequencies, whereas for Dirac neutrinos, spontaneous and soft-breaking of a $Z_2$ symmetry generate a peaked gravitational wave spectrum from annihilation of domain walls. The striking difference between the shape of the spectra in the two cases can help differentiate between Dirac vs Majorana neutrino masses in the two class of models considered, complementing results of neutrinoless double beta decay experiments.
The sound shell source from a cosmic phase transition is a compelling explanation for the stochastic gravitational wave background recently seen by various PTA collaborations. I discuss motivations for such a phase transition as well as comparing the sound shell model using the full velocity profile, as opposed to the broken power law that results from using the rms fluid velocity. Finally I give some theoretical improvements that can be made on this analysis.
I will review different ideas to probe leptogenesis with gravitational waves caused by first-order phase transitions or cosmic strings. In particular, I will focus on local cosmic strings produced after the breaking of a U(1)_(B-L) gauge symmetry that gives masses to right-handed neutrinos. Cosmic strings are expected to produce a stochastic gravitational background that could be probed experimentally in the very near future by e.g. LISA. In our work, we investigate what impact an observation of stochastic gravitational waves originating from U(1)_B-L cosmic strings could have on our understanding of mechanisms that are relevant for leptogenesis. In particular, we scrutinize whether particle production from local cosmic strings in the early universe could have affected leptogenesis via non-thermal production of right-handed neutrinos.
Monopoles are inevitable predictions of GUT theories. They are produced during phase transitions in the early universe, but also mechanisms like Schwinger effect in strong magnetic fields could give relevant contributions to the monopole number density. I will show that from the detection of intergalactic magnetic fields of primordial origin we can infer additional bounds on the magnetic monopole flux. I will also discuss the implications of these bounds for minicharged monopoles, for magnetic black holes and for monopole pair production in primordial magnetic fields.
In gaguge-mediated supersymmetry breaking (GMSB) scenarios, the lightest SUSY particles is a nearly massless gravitino. Searches for GMSB SUSY are presented in which the next-to-lighest SUSY particles are the higgsinos, which decay to a Higgs or Z boson and the gravitino, leading to final states with missing transverse energy and ZZ, Zh, or hh boson pairs.
Results from the CMS experiment are presented for supersymmetry searches targeting so-called compressed spectra, with small mass splittings between the different supersymmetric partners. Such a spectrum presents unique experimental challenges. This talk describes the new techniques utilized by CMS to address such difficult scenarios. The searches use proton-proton collision data at the center of mass energy of 13 TeV collected during the LHC Run 2.
Under supersymmetry (SUSY) models with low electroweak naturalness (natSUSY), which have been suggested to be the most likely version of SUSY to emerge from the string landscape, we examine the viabilities of future search for the heavy SUSY Higgs bosons H, A, H^\pm through various their decay signatures in LHC. The traditional H, A -> tautau, as well as H^\pm -> tau+nu, t+b, with a spectator top-jet channels are considered. In particular, we also examine H/A/H^\pm -> W/Z/h + MET. These decay channels only come from natSUSY, in which the higgsinos are expected at the few hundred GeV scales whilst electroweak gauginos inhabit the TeV scale, such that for TeV-scale heavy SUSY Higgs bosons as the current LHC limits required, their decays modes into gauggino plus higgsino are kinematically open. We evaluate these signals against several Standard Model backgrounds to get both the 95% CL exclusion and 5σ discovery reach in the mA vs. tan β plane for the future high luminosity LHC (HL-LHC) with 3000 fb^-1 of integrated luminosity.
If the strongly-interacting squarks and gluinos are too heavy to be produced at the LHC with observable rates, searches for the weakly-interacting charginos, neutralinos, and sleptons could offer the best path to discovering supersymmetry. These particles can lead to challenging signatures with lower production rates and less energetic final state objects.
I will discuss perspectives on the future of supersymmetry.
I will announce the next SUSY conference at the IFT in Madrid (Spain).