Faculty of Physics University of Warsaw > Events > Seminars > "Theory of Particle Physics and Cosmology" Seminar

"Theory of Particle Physics and Cosmology" Seminar

2017/2018 | 2018/2019 | 2019/2020 | 2020/2021 | 2021/2022 | 2022/2023 | 2023/2024 | 2024/2025

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Titas Chanda (IFT UJ)

Lattice gauge theories in the age of quantum technologies: Bosonic Schwinger model out of equilibrium

After the formulation of lattice gauge theories in 1970s, it has gained a renewed interest in recent years due to – (a) recently developing tensor network techniques to efficiently solve lattice problems, and (b) the possibilities of experimental realization / quantum simulation of high-energy physics in table-top experiments using ultra-cold atoms. In this talk, first I will introduce the field of lattice gauge theories from the perspective of ultra-cold atomic physics, and mention some experimental breakthroughs regarding their quantum simulation. Then I will present our results on out-of-equilibrium dynamics of a particular gauge theory with bosonic matter, where we drive the vacuum of a relativistic theory of bosons coupled to a U(1) gauge field in 1+1 dimensions (bosonic Schwinger model) by creating a spatially separated particle-antiparticle pair connected by a string of electric field. During the evolution, we observe a strong confinement of the bosons witnessed by the bending of their light cone. As a consequence, for the time scales we are able to simulate, the system evades thermalization and generates exotic asymptotic states. These states are made of two disjoint regions, an external deconfined region that seems to thermalize, and an inner core that reveals an area-law saturation of the entanglement entropy.
https://us02web.zoom.us/j/86031056161?pwd=aXRLTnpPSk1JUVdOWVZ1N3QrZE5zdz09

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Iñaki Lara (IFT UW)

The gravitino, the muon g-2 and LLP searches at the LHC

The μνSSM is the minimal supersymmetric extension of the standard model capable of solving the mu problem of the MSSM and generating neutrino masses, through an R-parity violating coupling between Higgs superfields and righ-handed neutrino superfields. The smallness of the neutrino Yukawa coupling, necessary for generating correct neutrino physics, dictates the size of the R-parity violating (RPV) interactions. For this reason, the gravitino has a life-time long enough to be a viable dark matter candidate. In addition, the smallness of RPV causes a suppression of the decay amplitude of the lightest supersymmetric particle big enough to make its decay displaced at colliders.Light smuons are possible in the model and could explain the discrepancy between the experimentally measured value of the anomalous magnetic moment of the muon and the SM prediction. Predicting at the same time signatures of long lived particles at the LHC.
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Ayuki Kamada (IFT UW)

Composite asymmetric dark matter and galactic rotation curves

Asymmetric dark matter (ADM) is an attractive framework relating the observed baryon asymmetry of the Universe to the DM density.A composite particle in a new strong dynamics is a promising candidate for ADM as the strong dynamics naturally explains the ADM mass in the GeV range.Its large annihilation cross section due to the strong dynamics leaves the asymmetric component to be dominant over the symmetric component.Its large self-scattering cross section may also explain the diversity of galactic rotation curves that is difficult to understand in the conventional collisionless DM.Such scenarios generically require some entropy transfer mechanism below the composite scale; otherwise, their late-time cosmology is incompatible with observations.We show that a tiny kinetic mixing term between a dark photon and the visible photon is a promising example of the low-energy portal, by introducing a simple dark sector model.We also demonstrate that grand unifications in the dark and the visible sectors explain the origin of the tiny kinetic mixing.
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Janusz Gluza (U. of Silesia)

Theory Needs for FCC-ee: Towards high precision EWPO calculations

The concept of the FCC-ee collider is at the High Energy and Precision Frontier and will provide a set of ground-breaking measurements of a large number of new-physics sensitive observables, with improvement by one to two orders of magnitude in experimental precision. The full exploitation of the significantly increased experimental precision in Z-pole observables, W boson and top quark masses, and a broad array of Higgs observables, necessitates Standard Model (SM) predictions accurate at a level commensurate with this precision. In the talk, I outline the status of electroweak pseudo-observables (EWPO) calculations and the challenges posed for the necessary development of theoretical methods required for the calculation of the higher-order EWPO in the SM.
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(IFT UW)

Canceled

Seminar canceld due to speaker's illness.

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Alejo Rossia (DESY)

Anomalous Wilson, or how to relate EFTs with anomalies

Can higher dimensional operators in an EFT generate gauge anomalies if the renormalizable part of the EFT is anomaly free? When are certain Wilson Coefficients dictated by the global anomalies of the UV sector? These 2 questions, which cover both directions in the relationship between anomalies and Wilson Coefficients, can be answered with similar techniques. First, I will discuss whether dimension-6 operators in SMEFT can induce gauge anomalies. We find a negative answer, contrarily to what was claimed by Cata et al in a recent paper (2011.09976) and therefore I'll discuss why the triangle-diagram computations performed in the aforementioned paper lead to apparent anomalies. In the second half of the talk, I'll show how our techniques elucidate the relation between global anomalies and axion couplings to gauge bosons. We find no such relation for massive chiral gauge fields, while we recover the well-know correspondence for the case of axion couplings to photons and gluons. This allows us to understand better the structure of the most general axion EFT and to clarify what a possible measurement of axion couplings would tell us about the UV theory. The icing on the cake is that this analysis provides us a phenomenological tool to easily detect chiral extensions of the SM.
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Marek Karliner (Tel Aviv U.)

The New Heavy Exotics

I will discuss the very recent experimental and theoretical developments regarding new types of hadrons involving heavy quarks: tetraquark and pentaquark hadronic molecules, doubly heavy baryons, stable tetraquarks and others.
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(IFT UW)

Paweł Kozów

Effective Field Theory approach to new physics in Vector Boson Scattering

Vector Boson Scattering (VBS) processes are regarded as the best lab to study the VVVV interactions, where V = W, Z. We take the Effective Field Theory (EFT) approach to parametrize potential effects from New Physics (NP). The approach, although common, undergoes consistency constraints particularly severe when the VV invariant mass is not resolved experimentally. We (i) discuss and present constraints on effective vertices based on LHC run 2 dataset and (ii) study perspectives for discovery reach of NP at HL-LHC.In both aspects the EFT consistency conditions play a crucial role and influence the results significantly. Presented conclusions on EFT validity conditions may also be relevant in processes other than VBS, that feature broad energy spectrum, e.g. di-boson or di-jet production at LHC.
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Neda Darvishi (IFT UW)

Classifying Accidental Symmetries in multi-Higgs Doublet Models

I will discuss classifying accidental symmetries in multi-Higgs DoubletModels (nHDMs). The potentials of nHDMs contain a large number ofSU(2)_L-preserving accidental symmetries as subgroups of the symplecticgroup Sp(2n). To classify these, we introduce prime invariants andirreducible representations in bilinear field space that enable us toexplicitly construct accidentally symmetric nHDM potentials. I willshowcase the classification of the symmetries and present the relationshipbetween the theoretical parameters of the scalar potential for; (i) theTwo Higgs Doublet Model (2HDM) and (ii) the Three Higgs Doublet Model(3HDM). I show the maximum number of 13 accidental symmetries for the 2HDMpotential and present the complete list of 40 accidental symmetries forthe 3HDM potential.Furthermore, I will present the complete set of continuous maximalsymmetries that the potential of an nHDM should satisfy for naturalStandard Model (SM) alignment. As a result, no large mass scales orfine-tuning is required for such alignment, which still persists even ifthese symmetries were broken softly by bilinear mass terms. In particular,the Maximal Symmetric HDM (MS-nHDM) can provide both natural SM alignmentand quartic coupling unification up to the Planck scale. Most remarkably,I show that the MS-2HDM is a very predictive extension of the SM governedby two only additional parameters: (i) the charged Higgs mass and (ii)tanβ, whilst the quartic coupling unification scale μX ispredicted to assume two discrete values. With these two input parameters,the entire Higgs-mass spectrum of the model can be determined.
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Fernando Arias Aragón (Madrid, Autonoma U.)

Production of Thermal Axions across the ElectroWeak Phase Transition

Light axions can potentially leave a cosmic background just like the neutrinos. We complete the study of thermal axion production above the QCD phase transition by providing a smooth and continuous treatment across the electroweak phase transition. Focusing on flavour conserving axion couplings, we quantify axion production due to scattering of thermal bath particles and we include for the first time the contributions from the longitudinal components of the W and Z bosons. We perform a model independent analysis in terms of axion effective coupling to heavy quarks, and we also study the predictions for particular QCD axion scenarios, the so-called Minimal Flavour Violating Axion, as well as the invisible axion KSVZ and DFSZ models. Finally, we explore the possibility of testing with cosmological observations the solar axion interpretation of the XENON1T excess. We study minimal scenarios with a detectable signal in future CMB surveys: axions coupled democratically to all fermions, axion-electron coupling generated radiatively and the DFSZ framework for the QCD axion.
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