セミナー 2023年

Yui Hayashi, YITP

[QCD theory Seminar] Higgs-confinement continuity in light of particle-vortex statistics

Online (Zoom)
Certain gauge theories with superfluidity, such as dense QCD, exhibit nontrivial Aharonov-Bohm (AB) phases around vortices, or anyonic particle-vortex statistics, in the Higgs regime. There has been a debate on whether this nontrivial AB phase implies a Higgs-confinement transition even with fundamental matters. In this seminar, we address this question in favor of Higgs-confinement continuity. By performing explicit calculations in relevant lattice models, we demonstrate how the AB phase realizes the continuity between the confining and Higgs regimes. In particular, this result supports the possibility of the quark-hadron continuity scenario.
This talk is based on arXiv:2303.02129 [hep-th].

Toshiki Kurita, IPMU

Constraints on anisotropic primordial non-Gaussianity from intrinsic alignments of SDSS-III BOSS galaxies

Hybrid On-site: Seminar room 321, 322 Online:(Zoom)
The current standard cosmological model, LambdaCDM model, predicts that the present-day cosmic large-scale structure (LSS) has formed as a result of a gravitational amplification of seed primordial fluctuations that were generated in the early universe such as inflationary scenario. The standard method to analyze LSS is based on the three-dimensional distribution of galaxies, inferred from their positions on the sky and redshifts. Here we show that “shapes” of galaxies, inferred from light (star) distribution in each galaxy, similarly originate from the primordial fluctuations in LSS formation — this phenomenon is called intrinsic alignments (IAs) of galaxy shapes. In this talk I will describe what the IA effect is, and show the actual measurement results from the SDSS-III BOSS datasets and the constraints on the anisotropic (quadrupolar) local primordial non-Gaussianity.

Yoshiki Kanazawa, University of Tokyo

Solution to Axion Quality Problem by Non-Minimal Gravitational Coupling

Hybrid On-site: Seminar room 321, 322 Online: Zoom
It is expected that any global symmetry is explicitly violated by gravity. In QCD axion models, the effective axion potential obtains other terms than QCD contributions due to gravitational violation of the global U(1) Peccei-Quinn (PQ) symmetry, and the minimum of the potential is deviated from the CP-conserving points. In general, the deviation is large enough to invalidate the PQ solution to the strong CP problem. This is called “quality problem“. In this talk, assuming that axionic wormhole is the only source of gravitational violation of U(1) PQ symmetry, we give a novel solution to the quality problem in which a non-minimal gravitational coupling is introduced to suppress the gravitational violation. We discuss our solution for two formulations of the gravity; the metric and the Palatini formulations. We will show that the condition to avoid the quality problem is different between the two formulations.

Elisa Ferreira, IPMU

Narrowing the mass range of ultra-light dark matter

Hybrid On-site: Seminar room 321, 322 Online:(Zoom)
In this talk, I will discuss the latest efforts to constraint the mass of the ultra-light dark matter models, focusing on the current bounds on 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 behaviour. If time permits, I will also introduce the superfluid DM model, where DM forms a superfluid in galaxies leading to an effective dynamics representing that of MOdified Newtonian Dynamics (MOND) on galactic scales.

Albert Escriva, Nagoya University

Simulations of PBH formation: from the collapse of adiabatic fluctuations to the formation of vacuum bubbles

Hybrid On-site: Seminar room 321, 322 Online: Zoom
Primordial Black Holes are black holes that could have been formed in the very early Universe and are arguably the most economical candidates for Dark Matter. But to make precise estimations of their abundance, it is essential to accurately know the initial conditions that could lead to their production. In this seminar, I will describe the current standard formalism and methods to accurately predict the necessary initial conditions for black hole formation, including the consequent numerical results from simulations of the collapse of adiabatic fluctuations generated during inflation. Moreover, I will present new results on the simulation of the formation of false vacuum bubbles, which can be produced if the inflaton becomes trapped during inflation. These localized bubbles will eventually end up forming black holes, also called baby Universes.

Csaba Csaki, Cornell University

Exploring the dynamics of gauge theories via AMSB

Hybrid On-site: Seminar room 321, 322 Online:(Zoom) https://kds.kek.jp/event/46187/
Finding the vacuum structure and the low energy effective Lagrangian of strongly coupled gauge theories is one of the important unsolved questions in particle physics. Within supersymmetric (SUSY) theories many of these questions have been largely resolved in the 1990’s following the work of Seiberg and others, however so far we have not been able to convincingly connect these results to their non-supersymmetric counterparts. Recently Murayama proposed to use anomaly mediated supersymmetry breaking (AMSB) to introduce the SUSY breaking terms which allows finding results consistent with the qualitative expectations for the structure of the non-SUSY theories. In this talk I first show how what the resulting phase structure of the QCD-like theories obtained from perturbing SUSY QCD via AMSB is, and that the expected vauca with chiral symmetry breaking are present for any number of flavors F< 3N at least as local minima. I then discuss the resulting chiral Lagrangian for the light Goldstone bosons in these models, and examine the large N limit of the eta' mass generation mechanism. We confirm Witten's picture of several branches of vacua as a function of the theta parameters for fixed number of flavors. However, for F~N we find that in some situations the vacuum energy as a function of theta might be smooth without any phase transitions, corresponding to an instanton generated potential. If time allows I will also comment on applying AMSB to find novel vacua of chiral gauge theories as well as monopole condensation as the origin of confinement for the SO(N) series.

Tilo Wettig, University of Regensburg

Induced QCD

Hybrid On-site: Seminar room 321, 322 Online:(Zoom)
We explore an alternative discretization of continuum SU($N_c$) Yang-Mills theory on a Euclidean spacetime lattice, originally introduced by Budzcies and Zirnbauer. In this discretization the self-interactions of the gauge field are induced by a path integral over $N_b$ auxiliary boson fields, which are coupled linearly to the gauge field. The main progress compared to earlier approaches is that $N_b$ can be as small as $N_c$. We show analytically and numerically that the continuum limit of the new discretization reproduces Yang-Mills theory
and perform a perturbative calculation to match the bare parameter of the induced gauge theory to the standard lattice coupling. We also explore the possibility to integrate out the gauge fields to arrive at a dual formulation of lattice QCD.

Michael E. Peskin, SLAC

Thinking about Particle Physics at 10 TeV and above

Hybrid On-site: Seminar room 321,322 Online: (Zoom) https://kds.kek.jp/event/46186/
Particle physicists have become interested in accelerators much more powerful than the LHC, probing energy scales 10 times higher or more. This idea stimulates many questions for which we do not yet know the answers. These questions cover all areas of particle physics from accelerators to theory: (1) What is the motivation for experiments at the 10 TeV scale? Do we really expect to find something beyond the Standard Model? What are the important targets for experiment? (2) How will we do experiments at 10 TeV? Can we simply evolve current experimental concepts? (3) What accelerator technologies will take us to 10 TeV? At this moment, different groups propose proton colliders such as SPPC, muon colliders, and electron and photon colliders. All of these approaches have significant challenges. How close are we to solving them? I do not have good answers to any of these questions, but I will give my perspective.

Rafał Masełek, Warsaw University

Prospects for detecting long-lived particles at the Large Hadron Collider

Hybrid On-site: Seminar room 321, 322 Online:(Zoom)
The detection of the Higgs boson in 2012 raised hopes for rapid discovery of Physics Beyond the Standard Model at the LHC, however, the search for New Physics turned out to be much more difficult than anticipated. The lack of a positive result led to a growing interest in previously unexplored exotic signatures, e.g. long-lived particles. In the talk, I will discuss different search strategies for long-lived particles at the LHC. Special emphasis will be put on the prospects for the detection of long-lived particles in the MoEDAL experiment, which had been primarily designed to search for magnetic monopoles, but can also be utilised to detect semi-stable charged particles. Prospects for the detection of long-lived particles at the end of Run 3 and HL-LHC phases will be presented, and a comparison between different search strategies in MoEDAL, ATLAS and CMS experiments will be made.

Shi Chen, Univ. of Tokyo

[QCD theory Seminar] Solitonic symmetry beyond homotopy groups

Solitonic symmetry is believed to be classified by homotopy groups, but I will point out a more sophisticated algebraic structure. I shall focus on a concrete QFT, the 4d CP^1 model, and demonstrate that π_3 (CP^1) = Z does not lead to a U(1) 0-form solitonic symmetry. Actually, the invertible 0-form solitonic symmetry is a Z_2 which comes from Ω^spin_3 (CP^1) = Z_2. The complete 0-form solitonic symmetry is a non-invertible symmetry generated by 3d spin TQFTs.

1 2 3 4