The International Conference on Beyond Standard Model: From Theory To Experiment (BSM-2021)

Searching for a Dark Photon Signal with PADME

F. Oliva 1

1 Universita` del Salento and INFN Lecce, Via per Arnesano, 73100 Lecce, Italy

PADME (Positron Annihilation into Dark Matter Experiment) is a fixed target experiment located at the Beam Test Facility (BTF) at the Laboratori Nazionali di Frascati (LNF) that searches for a massive dark photon A′ in the process e+e− → γA′, using a positron beam of energy up to 550 MeV. The experiment uses the missing mass technique, which allows to search for the dark photon in a model independent way. A sensitivity on the mixing constant ε > 10−3 for a dark photon mass in the range 1 ≤ mA′ ≤ 23.7 MeV/c2 can be achieved by collecting an integrated luminosity of 4 × 1013 positrons on target.

Revisiting Freeze-in Dark Matter from Renormalizble Operators

Simone Biondini 1

1 Department of Physics, University of Basel, Klingelbergstr. 82, CH-4056 Basel, Switzerland

In this conference paper we summarize the findings of a recent study [1], where the impact of the ultra- relativistic regime on the production of a feebly interacting dark matter particle is considered. As its pop- ulation accumulates over the thermal history, we inspected thoroughly the temperature window T ≫ M, which has been previously neglected in the context of dark matter models with renormalizable operators. At high temperatures, and for the model considered in our work, the production rate of the feebly in- teracting particle is driven by multiple soft scatterings, as well as 2 → 2 processes, that can give a large contribution to the dark matter energy density.

Gravitino Thermal Production

Helmut Eberl 1, Ioannis D. Gialamas 2, Vassilis C. Spanos 2

1 Institut fu¨ r Hochenergiephysik der O¨ sterreichischen Akademie der Wissenschaften, A–1050 Vienna, Austria
2 National and Kapodistrian University of Athens, Department of Physics, Section of Nuclear & Particle Physics, GR–157 84 Athens, Greece

In this talk1 we present a new calculation of the gravitino production rate, using its full one-loop corrected thermal self-energy, beyond the hard thermal loop approximation. Gravitino production 2 → 2 processes, that are not related to its self-energy have been taken properly into account. Our result, compared to the latest estimation, differs by almost 10%. In addition, we present a handy parametrization of our finding, that can be used to calculate the gravitino thermal abundance, as a function of the reheating temperature.

Searching for Dark Matter through Vector Boson Fusion Topology at the LHC

Santiago Duque-Escobar 1, Daniel Ocampo-Henao 1, Jose ́ David Ruiz-Alvarez 1

1 Instituto de F ́ısica, Universidad de Antioquia, A.A. 1226 Medell ́ın, Colombia

We describe different searches that have been conducted in the LHC using the vector boson fusion topol- ogy, specially in the regard of beyond standard model physics and dark matter. We finalize proposing a first glimpse into what could be a proposal for new searches of dark matter using the vector boson fusion topology with simplified dark matter models.

Weak Gravity Conjecture in an Accelerating Universe

Ignatios Antoniadis 1, 2, Karim Benakli 1

1 1Laboratoire de Physique Th´eorique et Hautes Energies (LPTHE), UMR 7589 Sorbonne Universit´e and CNRS, 4 place Jussieu, 75252 Paris Cedex 05, France
2 Institute for Theoretical Physics, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium

The study of de Sitter Reissner-Nordstrøm black holes allows us to uncover a Weak Gravity Conjecture in de Sitter space. It states that for a given mass m there should be a state with a charge q bigger than a minimal value qmin(m, l), depending on the mass and the de Sitter radius l, in Planck units. This reproduces the well known flat space-time result q > m/ p 2 in the large radius limit (large l). In the highly curved de Sitter space (small l) qmin behaves as p ml. Finally, we discuss the case of backgrounds from gauged R-symmetry in N = 1 supergravity. This talk is based on 2006.12512 [1].

Spinor-Vector Duality and BSM Phenomenology

Alon E. Faraggi 1

1 Department of Mathematical Sciences, University of Liverpool, Liverpool L69 7ZL, United Kingdom

Spinor–Vector Duality (SVD) has been observed in worldsheet constructions of heterotic–string compacti- fications. Recently, its realisation in the effective field theory limit of string vacua in six and five dimensions has been investigated. The SVD has been used to construct a string model that allows for an extra family universal U(1), with the standard E6 embedding of its charges, to remain unbroken down to low scales. Anomaly cancellation of the extra U(1) charges mandates the existence of additional matter states at the extra U(1) breaking scale, which affects precision measurements of Standard Model parameters. I discuss the construction of non-supersymmetric sting vacua and “modular maps” akin to the spacetime supersym- metry map. Such “modular maps” provide a glimpse into the enormous symmetry structure underlying the entire space of perturbative string vacua that is yet to be uncovered.

Flavor and CP from String Theory

Hans Peter Nilles 1, Sau ́l Ramos-Sa ́nchez 3, Patrick K. S. Vaudrevange 2

1 Bethe Zentrum fu ̈r Theoretische Physik, Universita ̈t Bonn, Nussallee 12, 53115 Bonn, Germany
2 Physik Department T75, Technische Universita ̈t Mu ̈nchen, James-Franck-Straße 1, 85748 Garching, Germany
3 Instituto de F ́ısica, Universidad Nacional Auto ́noma de Me ́xico, POB 20-364, Cd.Mx. 01000, Me ́xico

Modular transformations of string theory are shown to play a crucial role in the discussion of discrete flavor symmetries in the Standard Model. They include CP transformations and provide a unification of CP with 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”, where different sectors of the theory (like quarks and leptons) can be subject to different flavor structures.

Jet Energy Scale and Resolution in the High-Granularity Timing Detector in ATLAS Upgrades at HL-LHC

Asmaa Aboulhorma 1, Farida Fassi 1

1 Mohammed V University in Rabat, Morocco

The large increase of pileup is one of the main experimental challenges for the High Luminosity-Large Hadron Collider (HL-LHC) physics program. HL-LHC is expected to start in 2027 and to provide an in- tegrated luminosity of 3000fb1 in ten years, a factor 10 more than what will be collected by 2023. A pow- erful new way to address this challenge is to exploit the time spread of the interactions to distinguish between collisions occurring very close in space but well separated in time. A High-Granularity Timing Detector (HGTD), based on low gain avalanche detector technology, is proposed for the ATLAS Phase-II upgrade. Covering the pseudo rapidity region between 2.4 and 4.0, with a timing resolution of 30 ps for minimum-ionizing particles, this device will significantly improve the performance in the forward region. The improvement of the jet energy scale and resolution in the forward region by reducing the pileup track contamination in hard scatter jets from nearby pileup interactions is presented. The impact of HGTD in reducing pileup track contamination in the jets reconstruction in the forward region is investigated. The performance is evaluated in terms of jet energy response and resolution as a function of pseudo rapidity η, transverse momentum pT .

Explaining the Cabibbo Angle Anomaly and Lepton Flavour Universality Violation in Tau Decays with a Singly-Charged Scalar Singlet

Fiona Kirk 1, 2

1 Physik-Institut, Universita ̈t Zu ̈rich, Winterthurerstrasse 190, CH–8057 Zu ̈rich, Switzerland
2 Paul Scherrer Institut, CH–5232 Villigen PSI, Switzerland

The singly charged SU(2)L singlet scalar, with its necessarily flavour violating couplings to leptons, lends itself particularly well for an explanation of the Cabibbo Angle Anomaly and of hints for lepton flavour universality violation in tau decays.

Search for Higgs boson Decays to Beyond-the-Standard-Model Light Bosons in Four-Lepton Final States with the ATLAS Detector at the LHC

Zainab Soumaimi 3, Diallo Boye 1, Farida Fassi 3, Ketevi Assamagan 2, Simon Connell 1, Christian Weber 2

1 University of Johannesburg, South Africa
2 Brookhaven National laboratory, USA
3 Mohammed V University in Rabat, Morocco

Hidden sector or dark sector states appear in many extensions to the Standard Model (SM), to provide particle mediators for dark matter in the universe. A new probe of this hypothetical hidden or dark sector may have become available at the energy frontier opened up by the LHC with the Higgs boson and its distinct couplings to SM particles. A search is conducted for a beyond-the-Standard-Model vector boson using events where a Higgs boson with mass 125 GeV decays to four leptons. This decay is presumed to occur via an intermediate state which contains one or two decaying light exotic bosons, H → Z(Zd)Zd → 4l(l = e, μ), where Zd is a new vector boson with mass between 1 and 60 GeV. The search uses pp collision data collected with the ATLAS detector at the LHC with an integrated luminosity of 36 f b−1 at the center- of-mass energy of 13 TeV. No significant excess of events above SM background predictions is observed; therefore, upper bounds on the branching ratios BR(H → ZdZd → 4l) are set as a function of the mass of the dark vector boson at 95% confidence level.

Search for New Resonances Decaying into Top-Quark Pairs Using Lepton-Plus-Jets Events in Proton-Proton Collisions at √s = 13 TeV with the ATLAS Detec

Badr-eddine Ngair 1, Farida Fassi 1

1 Mohammed V University in Rabat, Morocco

A search for new resonances that decay into top-quark pairs is performed using data collected from protonproton collisions at a centre-of-mass energy of 13 TeV by the ATLAS detector at the Large Hadron Collider. The integrated luminosity of the data sample is 36.1 f b􀀀1. Events consistent with top-quark pair production are selected by requiring a single isolated charged lepton, missing transverse momentum and jet activity compatible with a hadronic top-quark decay. The invariant mass spectrum of the candidate topquark pairs is examined for excesses above the background expectation. No significant deviations from the Standard Model predictions are found.

Enhancing Jet Taggers with Mass Unspecific Supervised Tagging (MUST)

J. F. Seabra 1

1 Departamento de F´ıisica and CFTP, Instituto Superior T´ecnico, Universidade de Lisboa, Av. Rovisco Pais, 1, 1049-001 Lisboa, Portugal

We introduce a new approach for training jet taggers based on multivariate methods, where the mass and transverse momentum are input variables, along with jet substructure observables, varying over wide ranges. Known as Mass Unspecific Supervised Tagging (MUST), this strategy allows the development of taggers that are sensitive to different types of signal and efficient across large kinematical regions. Additionally, it provides an optimal solution to the mass correlation problem that affects other supervised taggers. We build MUST-inspired generic taggers using neural networks which, when tested with various multi-pronged signals, perform much better than variables commonly used in experiments to discriminate signal from background. These taggers can also spot signals not used in training with a good efficiency. Taggers built upon MUST can be designed to identify the prongness of a jet, which could be extremely useful in a scenario where a new phisics signal is discovered.

Search for Invisible Higgs Bosons Produced via Vector Boson Fusion at the LHC Using ATLAS Detector

Mohamed Zaazoua 2, Farida Fassi 2, K´et´evi Adikl`e Assamagan 1, Loan Truong 1

1 Brookhaven National Laboratory, USA
2 Mohammed V University in Rabat, Morocco

A variety of astrophysical observations showed direct evidence for the existence of dark matter which accounts for about 85% of matter in the universe and does not interact with ordinary matter, except through gravity. Despite its abundance, dark matter particles are very elusive and hard to spot and no experiment confirmed their existence. In this work the invisible Higgs sector was investigated where Higgs bosons are produced via the vector boson fusion (VBF) process and subsequently decay into invisible particles. The expectation for the branching fraction of invisible decays from the standard model is O(0.1)% but several scenarios beyond the standard model allow larger values of O(10)%. The hypothesis under consideration is that the Higgs boson might decay into a pair of weakly interacting massive particles (WIMPs) which are candidates to explain the existence of dark matter. The experimental signature in the detector is a pair of energetic jets and large missing energy. The analysis uses data samples of an integrated luminosity of 139 fb􀀀1 of proton proton collisions at p s = 13 TeV recorded by ATLAS detector at the LHC. The observed number of events are found to be in agreement with the background expectation from standard model processes. Assuming a 125 GeV Higgs boson with a standard model production cross section, the observed and expected upper limits on the branching fraction of its decay into invisible particles are found to be 0.13 at 95% confidence level.

Distinguishing Different BSM Signatures at Present and Future Colliders

Saunak Dutta 1, Priyotosh Bandyopadhyay 1, Anirban Karan 1

1 Indian Institute of Technology Hyderabad, Telangana 502285, India

We show how angular distributions can distinguish different scenarios beyond the standard model by characterising particles of different spins at the LHC. We illustrate the idea with scalar and vector leptoquarks along with the heavy fermions in Type-III seesaw as spin zero, spin one and spin half examples respectively. On the other hand, zeros of single photon tree level amplitude can separate different particles according their electromagnetic charges. This phenomenon can be used to distinguish leptoquarks of different gauge representations, even different excitations of same SU(2)L gauge group, within the same spin frame work. We explore electron-photon and electron-hadron colliders to discern such scenarios in the context of the leptoquark models by means of zeros in scattering amplitudes. We found that the discerning effect in these two colliders are complementary to each other and both of them are required for an exhaustive analysis of leptoquark models. The analyses are carried out for different leptoquark masses and centre of mass energies of the collisions which involve a PYTHIA based simulation.

Highlights of Results by CMS

Milos Dordevic on behalf of the CMS Collaboration 1

1 Vinca Institute of Nuclear Sciences, National Institute of the Republic of Serbia, University of Belgrade, Belgrade, Serbia

A selection of the most recent results from the CMS Collaboration at CERN is presented in this overview. The CMS detector status and performance in the LHC Run 2 are outlined. The results of Standard Model physics studies, the studies of the Higgs boson production and properties, as well as a selection of the results of beyond Standard Model searches and an observation of a new excited beauty baryon are presented and discussed. All the results outlined in this overview are found to be in a good agreement with the Standard Model of particle physics. The activities of the CMS Collaboration during the Long Shutdown 2, status and plans for the incoming LHC Run 3, as well as preparation for the HL-LHC are also presented.

Gauge Fixing and Field Redefinitions of the Hartle-Hawking Wavefunction Path Integral

Herve Partouche 2, Nicolaos Toumbas 1, Balthazar de Vaulchier 2

1 Department of Physics, University of Cyprus, Nicosia 1678, Cyprus
2 1CPHT, CNRS, Ecole Polytechnique, IP Paris, F-91128 Palaiseau, France

We review some recent results concerning the Hartle-Hawking wavefunction of the universe.We focus on pure Einstein theory of gravity in the presence of a positive cosmological constant.We carefully implement the gauge-fixing procedure for the minisuperspace path integral, by identifying the single modulus and by using diffeomorphism-invariant measures for the ghosts and the scale factor. Field redefinitions of the scale factor yield different prescriptions for computing the no-boundary ground-state wavefunction. They give rise to an infinite set of ground-state wavefunctions, each satisfying a different Wheeler-DeWitt equation, at the semi-classical level. The differences in the form of the Wheeler-DeWitt equations can be traced to ordering ambiguities in constructing the Hamiltonian upon canonical quantization. However, the inner products of the corresponding Hilbert spaces turn out to be equivalent, at least semi-classically. Thus, the model yields universal quantum predictions.

Does Antimatter Fall Like Matter?: Simulation of the GBAR Experiment

Olivier Rousselle 1, Pierre Clad´ 1, Sa¨ıda Guellati 1, Romain Gu´erout 1, Serge Reynaud 1

1 Laboratoire Kastler Brossel, Sorbonne Universit´e, ENS-PSL, Coll`ege de France, CNRS, 75005 Paris, France

One of the main questions of fundamental physics is the action of gravity on antimatter. We present here the simulation of the last part of the experiment GBAR at CERN, i.e. the measurement of the free fall acceleration ¯ g of antihydrogen atoms in the gravitational field of the Earth. It includes the Monte-Carlo generation of trajectories and the analysis leading to the estimation of ¯ g. A precision of the measurement beyond the % level is confirmed when taking into account the experimental design.

Correction to Black Hole Entropy Variation under Hawking Radiation

Shad Ali 1, 3, Misbah Ullah 4, Johar Zeb 2

1 Department of Physics, University of Okara, 56300, Punjab, Pakistan
2 Department of Physics, Beijing Normal University, Beijing, 100875, China
3 2Department of Astronomy, Xiamen University, Xiamen, Fujian 361005, China
4 Department of Center for Nanosciences,University of Okara, 56300, Punjab Pakistan

We discussed some feature and facts associated to black hole and investigated the process of black hole evaporation by using the concept of interior volume and entropy. For this purpose, the maximal interior volume and quantum modes entropy of Kerr Newman Black Hole (KNBH) is found to be linearly growing with Eddington time t. Which means that the thermodynamical quantities in the interior of black hole are changing with time and information can be restored in its interior. Considering two modified assumptions, an evolution relation is obtained between the entropy of KNBH with Bekenstein Hawking entropy. It gives a good insight for understanding the black hole evaporation process under Hawking radiation. In addition, these analysis also generalizes the characteristic features of black hole evaporation.

Speculation about the Black Hole Final State: Resolving Singularity by Quantum Gravity

Dong-han Yeom 1, 2

1 Department of Physics Education, Pusan National University, Busan 46241, Republic of Korea
2 Research Center for Dielectric and Advanced Matter Physics, Pusan National University, Busan 46241, Republic of Korea

The interior of the black hole can be described by anisotropic cosmology. By quantizing the metric function, we can obtain the Wheeler-DeWitt equation for inside the horizon. In order to interpret the wave function consistently, one needs to impose a boundary condition. In this paper, we introduce a prescription for the Euclidean analytic continuation inside the horizon and the corresponding wave function solution.

Flavor and Lepton Universality Violation Phenomena in F-Theory Inspired GUTs

Athanasios Karozas 1, George K. Leontaris 1, Ilias Tavellaris 1, Nicholas D. Vlachos 2

1 Physics Department, University of Ioannina 45110, Ioannina, Greece
2 Department of Nuclear and Elementary Particle Physics, Aristotle University of Thessaloniki 54124, Thessaloniki, Greece

We discuss low energy implications of F-theory GUTs based on SU(5) extended by a U(1)’ symmetry which couples non-universally to the three chiral families. Several classes of anomaly free models are obtained, distinguished with respect to the U(1)’ charges of the representations, and possible extra zero modes com- ing in vector-like pairs. We considered the case where the spontaneous breaking of the U(1)’ symmetry occurs at a few TeV scale and we compute the observables of several flavor violation exotic processes in the effective theory. Particular cases interpreting the B-meson anomalies observed in LHCb experiments are also discussed.

Are Neutral Minima Stable against Charge Breaking in the Higgs Triplet Model?

P. M. Ferreira 1, 2, B. L. Gonc ̧ alves 1, 2, 3

1 Instituto Superior de Engenharia de Lisboa, Instituto Polite ́cnico de Lisboa 1959-007 Lisboa, Portugal
2 Centro de F ́ısica Teo ́rica e Computacional, Faculdade de Cieˆncias, Universidade de Lisboa, Campo Grande, Edif ́ıcio C8 1749-016 Lisboa, Portugal
3 Departamento de F ́ısica and CFTP, Instituto Superior Te ́cnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal

In the Higgs triplet model, it is a priori possible to have charge breaking minima developing. We analyse the possibility of such minima to be deeper than neutral ones. Analytical expressions relating the depth of minima of different types are obtained. A global symmetry of the model leads to increased stability for charge-preserving vacua. However, when a soft-breaking term is present, deeper charge-breaking minima may occur more easily. We realise that vacuum configurations with a vevless doublet can be possible, with such vev configurations changing the stability picture. We scan the model’s parameter space and realise what vev configurations are most likely to produce charge breaking minima. We also obtain a necessary and sufficient condition for stability against charge-breaking vacua for the model with an intact globalsymmetry.

Rare Lepton-Number-Violating W Decays at the LHC: CP Violation

David London 1

1 Physique des Particules, Universite ́ de Montre ́al, 1375 Avenue The ́re`se-Lavoie-Roux, Montre ́al, QC, Canada H2V 0B3

Some models of leptogenesis involve a nearly-degenerate pair of heavy Majorana neutrinos N1,2 whose masses can be small, O(GeV). There can be heavy-light neutrino mixing parametrized by |BlN|2 = 10−5, ±±±′∓ which leads to the rare lepton-number-violating decay W → l1 l2 (q q ̄) . With contributions to this decay from both N1 and N2, a CP-violating rate difference between the decay and its CP-conjugate can be generated. In this talk, I describe the prospects for measuring such a CP asymmetry ACP at the LHC. I consider three versions of the LHC – HL-LHC, HE-LHC, FCC-hh – and show that, for 5 GeV ≤ MN ≤ 80 GeV, small values of the CP asymmetry can be measured at 3σ, in the range 1% <∼ ACP <∼ 15%.

SMEFT Constraints on New Physics beyond the Standard Model

John Ellis 2, 3, 1

1 Theoretical Physics Department, CERN, CH-1211 Geneva 23, Switzerland
2 Department of Physics, King’s College London, London WC2R 2LS, United Kingdom
3 National Institute of Chemical Physics & Biophysics, Ra ̈vala 10, 10143 Tallinn, Estonia

The Fermi effective theory of the weak interaction helped identify the structure of the electroweak sector of the Standard Model, and the chiral effective Lagrangian pointed towards QCD as the theory of the strong interactions. The Standard Model Effective Field Theory (SMEFT) is a systematic and model-independent framework for characterizing experimental deviations from the predictions of the Standard Model and pointing towards the structures of its possible extensions that is complementary to direct searches for new physics beyond the Standard Model. This talk summarizes results from the first global fit to data from LHC Run 2 and earlier experiments including dimension-6 SMEFT operators, and gives examples how it can be used to constrain scenarios for new physics beyond the Standard Model. In addition, some windows for probing dimension-8 SMEFT operators are also mentioned.

Study of a Light NMSSM CP-Odd Higgs Produced via Bottom-Quark Annihilation in the Di-Photon Channel at the LHC

M. M. Almarashi 1

1 Physics Department, Faculty of Science, Taibah University, P. O. Box 344, Medina, KSA

We study the production of a low mass CP-odd Higgs through bottom-quark annihilation in the γ γ final state at the LHC inatnhenfirhamilaewtioorknofinthethNeMSdSiM-p. Thios tporonducthioan nchnanenlelaist stihgneificLaHntCly enhanced at large values of tanβ. We provide some results about the inclusive cross section of this production mode, which may help for extracting the1a1 signal at the LHC.

Baryogenesis from a CP-Violating Inflation

Venus Keus 1

1 Department of Physics, University of Helsinki, P.O.Box 64, FI-00014 Helsinki, Finland Helsinki, Finland

We introduce the novel phenomena of CP-violating inflation in the frameworks of a 3-Higgs doublet model where the inflaton doublets have a non-minimal coupling to gravity. We allow for this coupling to be complex, thereby introducing CP-violation - a necessary source of the baryon asymmetry - in the inflaton couplings. We investigate the inflationary dynamics of such a framework and the inflaton decay in the reheating phase. We discuss how the CP-violation of the model is imprinted on the particle asymmetries.

Flavour Non-Universal UMSSM with Minimal Number of Exotics

Yas ̧ar Hic ̧yılmaz 1, 2, Stefano Moretti 2, Levent Solmaz 1

1 Department of Physics, Balıkesir University, TR10145, Balıkesir, Turkey
2 School of Physics & Astronomy, University of Southampton, Highfield, Southampton SO17 1BJ, UK

We report the phenomenological implications of several family non-universal U(1)′ sub-models in the U(1)′-extended Minimal Supersysmmetric Standard Model (UMSSM) possesing an extra down quark type exotic field. In doing this, we have started by enforcing anomaly cancellation criteria to generate a num- ber of solutions in which the extra U(1)′ charges of the particles are treated as free parameters. We have then imposed existing bounds coming from colliders and astrophysical observations on the assumed sub- models and observed that current limits dictate certain charge orientations.

Vector-Like Leptons in Light of the Cabibbo-Angle Anomaly

Claudio Andrea Manzari 1, 2

1 Physik-Institut, Universita ̈t Zu ̈rich, Winterthurerstrasse 190, CH–8057 Zu ̈rich, Switzerland
2 Paul Scherrer Institut, CH–5232 Villigen PSI, Switzerland

The first row of the Cabibbo-Cobayashi-Maskawa (CKM) matrix shows a discrepancy of ∼3 σ with uni- tarity, known as the ”Cabibbo Angle Anomaly” (CAA). This tension can be explained via modified W couplings to leptons, but in order to consistently assess the validity, a global fit including the electroweak (EW) precision constraints and the low energy tests of lepton flavour universality (LFU) is necessary. Per- forming such a fit for gauge-invariant dimension-6 operators, we find that even when assuming LFU, including the CKM elements Vus and Vud into the electroweak fit has a relevant impact, shifting the best fit point significantly. Vector-like leptons (VLLs) are prime candidates for a corresponding UV completion since they can affect the W and Z couplings to leptons already at tree-level. Studing each pattern of new physics (NP) given by the six possible representations of VLLs (under the SM gauge group) we find that any single representation describes experimental data at most slighlty better than the SM hypothesis. How- ever, allowing for several representations of VLLs at the same time, we find a simple scenario consisting of a singlet, N, coupling to electrons and a triplet, Σ1, coupling to muons which not only explains the CAA but also improves the electroweak fit in such a way that its best fit point is preferred by more than 4 σ with respect to the SM.

Search for Heavy Neutral Higgs Bosons at the LHC

M. Ashry 2, 1, K. Ezzat 1, 3, S. Khalil 1

1 Center for Fundamental Physics, Zewail City of Science and Technology, 6th of October City, Giza 12578, Egypt
2 Department of Mathematics, Faculty of Science, Cairo University, Giza 12613, Egypt
3 Department of Mathematics, Faculty of Science, Ain Shams University, Cairo 11566, Egypt

A search for a CP-even heavy Higgs boson at the LHC is analysed in a Left-Right model with minimal Higgs sector. We report our results for potential signatures for heavy neutral Higgs decay into two SM-like Higgs bosons, namely h → hh → bbγγ for a center-of-mass energy s = 14 TeV and integrated luminosity Lint = 300, 3000 fb−1.

Phenomenology of Ultralight Scalars in Leptonic Observables

Pablo Escribano 1

1 Instituto de F ́ısica Corpuscular, CSIC-Universitat de Vale`ncia, 46980 Paterna, Spain

Ultralight scalars, which are states that are either exactly massless or much lighter than any other mas- sive particle in the model, appear in many new physics scenarios. Axions and majorons constitute well- motivated examples of this type of particle. In this work, we explore the phenomenology of these states in low-energy leptonic observables adopting a model independent approach that includes both scalar and pseudoscalar interactions. Then, we consider processes in which the ultralight scalar φ is directly produced, such as μ → e φ, or acts as a mediator, as in τ → μμμ. Finally, contributions to the charged leptons mag- netic and electric moments are studied as well. In particular, it is shown that the muon g − 2 anomaly can be explained provided a mechanism for suppressing the experimental bounds on the coupling between the ultralight scalar and a pair of muons is introduced.

Light Scalar and Lepton Anomalous Magnetic Moments

Sudip Jana 1, Vishnu P.K. 2, Shaikh Saad 2

1 Max-Planck-Institut fu ̈r Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
2 Department of Physics, Oklahoma State University, Stillwater, OK, 74078, USA

Recent precise determination of the electron anomalous magnetic moment (AMM) adds to the longstand- ing tension of the muon AMM and together strongly point towards physics beyond the Standard Model (BSM). Here we present a solution to both anomalies via a light scalar that emerges from a second Higgs doublet and resides in the O(10)-MeV to O(1)-GeV mass range. A scalar of this type is subject to a number of various experimental constraints, however, as we show, it can remain sufficiently light by evading all ex- perimental bounds and has the great potential to be discovered in the near-future low-energy experiments. In addition to the light scalar, our theory predicts the existence of a nearly degenerate charged scalar and a pseudoscalar, which have masses of the order of the electroweak scale. This scenario can be tested at the LHC by looking at the novel process pp → H±H±jj → l±l±jj + /ET via same-sign pair production of charged Higgs bosons.

LFV, Dark Matter and LHC Data in Different GUTs

Mario E. Go ́mez 2, Smaragda Lola 1

1 Department of Physics, University of Patras, 26500 Patras, Greece
2 Departamento de Ciencias Integradas y Centro de Estudios Avanzados en F ́ısica Matema ́ticas y Computacio ́n, Campus El Carmen, Universidad de Huelva, 21071 Huelva, Spain

We perform an analysis of the predictions of several supersymmetric Grand Unified Theories (GUTs) for Dark Matter and the LHC and compare the results with a possible Lepton Flavour Violating (LFV) signal, when the models are extended with a see-saw mechanism to explain neutrino data. We study unified theo- riesbasedonSU(5),flippedSU(5)andSU(4)cSU(2)LSU(2)R,enhancedwithaType-1see-sawmechanism. Each GUT predicts different Dark Matter (DM) scenarios, which can be used to classify the resulting SUSY predictions and confront them with experimental searches. Our results indicate that LFV is a powerful tool that complements LHC and DM searches, providing significant insight into the sparticle spectra and neutrino mass parameters in different models.

Trimaximal Mixing with One Texture Zero from Type II Seesaw and ∆(54) Family Symmetry

M. A. Loualidi 1

1 LPHE-Modeling and Simulations, Faculty of Science, Mohammed V University in Rabat, 10090, Morocco

We propose a neutrino model based on a ∆(54) flavor symmetry suitable for explaining the current neu- trino oscillation data. Neutrino masses arise from the type II seesaw mechanism where the ∆(54) field assignments has led to a simple neutrino mass matrix with one texture zero and which satisfies the magic symmetry consistent with the well-known trimaximal mixing matrix. We found interesting predictions concerning neutrino masses and mixing. In particular, only the normal neutrino mass hierarchy and the lower octant of the atmospheric angles are allowed in this model. The model predicts as well that the CP conserving values for the Dirac CP phase δCP are not allowed and thus, CP is always violated in the neutrino sector. We have also investigated the sum of absolute neutrino masses from cosmological observa- tions, the effective Majorana mass mββ from neutrinoless double beta decay experiments, and the electron neutrino mass mβ from beta decays where we found that the obtained range of mββ can be tested by several experiments in the near future.

Exploring Scalar NSI Effects in Long Baseline Neutrino Experiments

Abinash Medhi 2, Debajyoti Dutta 1, Moon Moon Devi 2

1 Assam Don Bosco University, Kamarkuchi, Sonapur, Assam-782 402, India
2 Tezpur University, Napaam, Sonitpur, Assam-784 028, India

Neutrino oscillations provide an excellent opportunity to look for new physics beyond the Standard Model or popularly known as BSM. The unknown couplings involving neutrinos, termed as Non Standard Inter- actions (NSIs) [1, 2], may appear as a ’new physics’ in different neutrino experiments. The neutrino NSIs offer significant effects in neutrino oscillations and CP sensitivity, which can be probed in various neutrino experiments. The idea of scalar coupling term has evolved recently [3, 4] and looks promising. The effect of scalar NSI can appear as a perturbation that is added to the neutrino mass matrix in the neutrino Hamilto- nian. As it modifies the neutrino mass matrix, it may provide a direct possibility of probing neutrino mass models. As the scalar NSI affects the neutrino mass matrix in the Hamiltonian, its effect is energy inde- pendent. Moreover, the matter effect due to scalar NSI scales linearly with matter density. In this work, we have performed a model independent study of the effects of scalar NSI at long baseline experiments (using DUNE [5]). Various neutrino parameters may get affected due to the inclusion of scalar NSI as it modifies the effective mass matrix of neutrinos. We explored the impact of scalar NSI in neutrino oscillations and its impact on measurement of various mixing parameters. We have studied different oscillation channels and explored the impact of various possible elements in the scalar NSI term.

S3 Symmetric Scotogenic Model for Realistic Neutrino Mixing

Soumita Pramanick 1

1 National Centre for Nuclear Research, Pasteura 7, 02-093 Warsaw, Poland

In a S3 × Z2 framework, realistic neutrino mixing was obtained radiatively at one-loop level. When max- imal mixing occurs between the two right-handed neutrinos present in the model, one can get the form of the left-handed Majorana neutrino mass matrix for θ13 = 0, θ23 = π/4 and solar mixing of any values corresponding to the Tribimaximal (TBM), Bimaximal (BM) and Golden Ratio (GR) mixing scenarios in this set-up. Once we tweak the maximal mixing between the two right-handed neutrinos, we get non-zero θ13, deviation of θ23 from π/4 and small corrections to solar mixing. This scotogenic model also has two inert SU(2)L doublet scalars odd under Z2 the lightest of which can be dark matter.

Neutrino Non-Standard Interactions: Complementarity between LHC and Oscillation Experiments

K. S. Babu 3, Dorival Gonc ̧ alves 3, Sudip Jana 1, Pedro A. N. Machado 2

1 Max-Planck-Institut fu ̈r Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
2 Fermi National Accelerator Laboratory, Batavia, IL, 60510, USA
3 Department of Physics, Oklahoma State University, Stillwater, OK, 74078, USA

We investigate the complementarity between LHC searches and neutrino experiments in probing neutrino non-standard interactions. Our study spans the theoretical frameworks of effective field theory, simplified model and an illustrative UV completion, highlighting the synergies and distinctive features in all cases. We show that besides constraining the allowed NSI parameter space, the LHC data can break important degeneracies present in oscillation experiments such as DUNE, while the latter play an important role in probing light and weakly coupled physics undetectable at the LHC. This talk is based on results presented in hep-ph 2003.03383 [1].

Lepton Family Numbers and Non-Relativistic Majorana Neutrinos

Apriadi Salim Adam 4, Nicholas J. Benoit 1, Yuta Kawamura 1, Yamato Mastuo 1, Takuya Morozumi 3, Yusuke Shimizu 3, Yuya Tokunaga 2, Naoya Toyota 1

1 Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
2 Hakozaki, Higashi-Ku, Fukuoka, 812-0053, Japan
3 Physics Program, Graduate School of Advanced Science and Engineering and Core of Research for the Energetic Universe, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
4 Research Center for Physics, Indonesian Institute of Sciences (LIPI), Serpong PUSPIPTEK Area, Tangerang Selatan 15314, Indonesia

In this talk, we have reviewed the recent development on the time evolution of lepton family number carried by Majorana neutrinos [1]. This article focuses on the subtle points of the derivation of the lepton family numbers and their time evolution. We also show how the time evolution is sensitive to mee and meμ components of the effective Majorana mass matrix by applying the formula to the two family case. The dependence on the Majorana phase is clarified and the implication on CNB (cosmic neutrino background) is also discussed.

Searching for New Physics through Neutrino Non-Standard Interactions

Yong Du 1

1 CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190, P. R. China

Due to the absence of any definite signals of new physics at colliders and from precision measurements, it has gradually become more and more popular in the community to utilize the effective field theory (EFT) framework in searching for new physics in a model-independent manner. In this letter, working in the EFT framework and focusing on neutrino non-standard interactions (NSIs), we report our most recent results on these NSIs from considering terrestrial neutrino oscillation experiments Daya Bay, Double Chooz, RENO, T2K and NOνA, and precision measurements of Neff from Planck and CMB-S4.

Probing Light New Mediators on Coherent Elastic Neutrino-Nucleus Scattering

M. Demirci 1, M. F. Mustamin 1

1 Department of Physics, Karadeniz Technical University, Trabzon, TR61080, Turkey

We study the occurrence of light mediators on coherent elastic neutrino-nucleus scattering in the frame- work of a simplified model. The model includes light mediators in accordance with all possible interactions such as scalar, pseudoscalar, vectorial, axial-vector, and tensorial, and commonly used in explaining solar neutrino phenomena. We show the event rate spectrum using flux from reactor and accelerator neutrino experiment for keV, MeV, and GeV mass scale of the new mediators. We then present the 90% C.L. con- straint on parameter of the considered model with the first COHERENT data.

Neutrino Masses from Z8 Scoto-Seesaw Model with Spontaneous CP Violation

D. M. Barreiros 1, F. R. Joaquim 1, R. Srivastava 3, J. W. F. Valle 2

1 Departamento de F ́ısica and CFTP, Instituto Superior Te ́cnico, Universidade de Lisboa, Av. Rovisco Pais, 1, 1049-001 Lisboa, Portugal
2 AHEP Group, Institut de F ́ısica Corpuscular – C.S.I.C./Universitat de Vale`ncia, Parc Cient ́ıfic de Paterna. C/ Catedra ́tico Jose ́ Beltra ́n, 2 E-46980 Paterna (Valencia), Spain
3 Deparment of Physics, Indian Institute of Science Education and Research - Bhopal, Bhopal Bypass Road, Bhauri, Bhopal, India

We consider a scoto-seesaw model where dark matter, neutrino masses and spontaneous CP violation are accommodated using a single horizontal Z8 symmetry. This symmetry is broken down to a dark Z2 by the complex vacuum expectation value of a scalar singlet, stabilizing dark matter and providing a sponta- neous origin for leptonic CP violation. We conclude that the imposed Z8 symmetry constrains the lightest neutrino mass and the Dirac phase to intervals currently probed by experiments. For a normally-ordered neutrino mass spectrum, the allowed compatibility regions will soon be fully scrutinized by neutrinoless double beta decay experiments and cosmological observations.

Phenomenology of the Minimal Inverse-Seesaw with Abelian Flavour Symmetries

H. B. Caˆmara 2, R. G. Felipe 2, 1, F. R. Joaquim 2, 1

1 ISEL - Instituto Superior de Engenharia de Lisboa, Instituto Polite ́cnico de Lisboa, Rua Conselheiro Em ́ıdio Navarro, 1959-007 Lisboa, Portugal
2 Departamento de F ́ısica and CFTP, Instituto Superior Te ́cnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal

We study the phenomenology of the minimal inverse-seesaw model composed of two “right-handed neu- trinos” and two sterile singlet fermions, besides the Standard Model (SM) particle content. The model is supplemented with Abelian flavour symmetries to ensure maximal predictability and establish the most restrictive flavour patterns which can be realised by those symmetries. This setup requires the addition of a second scalar doublet and two complex scalar singlets to the SM enabling us to implement spontaneous CP violation. Such CP-violating effects can be successfully communicated to the lepton sector by means of the scalar singlets couplings with the new sterile fermions. The Majorana and Dirac CP phases are correlated, and the active-sterile neutrino mixing is fully determined by the active neutrino masses, mixing angles and CP phases. We investigate the constraints imposed on the model by the current experimental limits as well as future projected sensitivities on charged lepton flavour-violating decays and searches sensitive to the presence of heavy sterile neutrinos.