セミナー

Minoru Tanaka, Osaka University

Isotope shift as a probe of new physics

Hybrid On-site: Kenkyu Honkan Seminar room 321, 322 Online: Zoom

Isotope shift (IS) in atomic spectra is sensitive to a new interaction between the electron and the neutron. In the standard model (SM) of particle physics, the finite nuclear mass and size varying from one isotope to another cause the IS. Since the theoretical calculation of IS is not easy, even in the SM, we introduce a new method to search for the new interaction. Our method employs a generalization of the King linearity of IS, the generalized IS linearity.
We apply various generalized linearities to recent IS data of Ytterbium (Yb) and illustrate constraints on the new interaction.

References
K. Mikami, MT, Y.Yamamoto, EPJC 77, 896 (2017)
K. Ono, MT et al. PRX 12, 021033 (2022)

高柳匡, 京都大学基礎物理学研究所

[金茶会] 時空は幻想?量子力学とブラックホールの不思議な物語

4号館セミナーホール リモート会場:J-PARC研究棟2階会議室
https://www-conf.kek.jp/kincha/
Recently, a new interpretation of gravitational spacetime in terms of quantum entanglement has been obtained. The idea of holography in string theory provides a simple geometric computation of entanglement entropy. This generalizes the well-known Bekenstein-Hawking formula of black hole entropy and strongly suggests that a gravitational spacetime consists of many qubits with quantum entanglement. Also a new progress on black hole information problem has been made recently by applying this idea. I will explain these developments in this talk.

Laszlo Feher, Szeged University

Bi-Hamiltonian structures of integrable many-body models

Seminar room, Kenkyu Honkan 3F
The evolution equations of several exactly solvable dynamical systems can be written in Hamiltonian form in two distinct manners, using two different Poisson bracket structures and corresponding Hamiltonians. Such bi Hamiltonian structures lead to the existence of conserved quantities associated with the integrability of the pertinent systems. In this talk we review our results on bi-Hamiltonian structures of integrable many-body models of point particles moving along one dimension, which are also coupled to internal `spin’ degrees of freedom. The models of our interest belong to the celebrated family of Calogero–Moser–Sutherland and Toda type systems. They will be viewed as shadows (alias Poisson reductions) of simple higher dimensional bi-Hamiltonian systems having large symmetry groups.

Jorge de Blas, University of Granada

Global SMEFT studies at future colliders

Hybrid On-site: Kenkyu Honkan Seminar room 321, 322 Online: Zoom
At a time when the particle physics community is trying to decide what the next large particle collider experiment may be, it becomes crucial to study and establish the potential for indirect tests of new physics at the different projects that have been proposed, in order to make an informed decision. In the absence of a clear indication of what the new physics beyond the Standard Model may be, a model-independent approach for such studies is preferred, to make sure we cover all possibilities. In this talk, I will discuss some of the studies that were prepared for the 2020 Update of the European Strategy for Particle Physics and later updated during the 2021 Snowmass process using the general formalism of the Standard Model Effective Field Theory, with emphasis on the physics of the electroweak and Higgs sectors.

Enrico Speranza, CERN

[QCD theory seminar] Causal and stable first-order chiral hydrodynamics

Online (Zoom)
In recent years, there has been a growing interest in the study of chiral hydrodynamics, the hydrodynamic theory that incorporates the effect of quantum anomalies. This theory is expected to be a powerful description of various systems in high-energy nuclear physics, cosmology, astrophysics, and condensed matter. However, chiral hydrodynamics derived in previous works have problems related to causality and stability. These issues prevent the full theory from being used to make theoretical predictions using numerical simulations. In this talk, I will present a novel first-order theory of chiral hydrodynamics which is proven to be causal in the nonlinear regime and linearly stable. I will show that causality demands the absence of vorticity-induced heat flux, forcing a departure from the thermodynamic frame. The inequalities for causality and stability define a hypervolume in the space of transport parameters, wherein each point corresponds to a consistent formulation. Notably, causality is determined by just three combinations of transport parameters. The results will be presented in a form amenable to numerical hydrodynamic simulations.

Kaloian Lozanov, Kavli IPMU / U. Tokyo

Induced Gravitational Waves from Inflaton Oscillons

Hybrid On-site: Kenkyu Honkan Seminar room 321, 322 Online: Zoom
We present a new way to study cosmic inflation with gravitational waves. The gravitational signal is generated thanks to nonlinear structures in the inflaton field, called oscillons. This novel probe allows us to test models of inflation which are challenging to test with CMB experiments.

Kohei Fujikura, Univ of Tokyo

Cosmological Phase Transitions in Composite Higgs Models

Hybrid On-site: Kenkyu Honkan Seminar room 321, 322 Online: Zoom
Composite Higgs models consist of four-dimensional asymptotically-free gauge field theories. Each model may lead to a confinement-deconfinement transition and a phase transition associated with the spontaneous breaking of a global symmetry that realizes the standard model Higgs field as a pseudo-Nambu-Goldstone boson. In this talk, I will discuss order of thermal phase transitions in various composite Higgs models based on the argument of universality. In particular, we focus on phase transitions associated with the global symmetry breaking by studying the renormalization group flow using the ϵ-expansion at the one-loop order.
We find that first-order phase transitions are favored in some of composite Higgs models. If I have a time, I would like to discuss the confinement-deconfinement transition in a UV-completed composite Higgs model based on a Sp(2Nc) gauge theory.

Jesse Thaler, MIT

[IPNS Physics and Theory Seminar] Quarks and Gluons through the Lens of Machine Learning

Hybrid On-site: Bldg 4 Seminar Hall Online: Zoom

https://kds.kek.jp/event/48743/

Tomohiro Matsuda, Saitama Institute of Technology

The Exact WKB for particle production: from baryogenesis to Hawking radiation

Hybrid On-site: Kenkyu Honkan Seminar room 321, 322 Online: Zoom
Most particle production can be solved by approximate methods, but some problems cannot be solved without serious consideration of the Stokes phenomenon. One such particle production is baryon number production from rotating fields. Processes such as particle-antiparticle mixing increase the order of the differential equations to be solved, so new knowledge of ExactWKB, including Virtual Turning Point, is required. The other is particle production from a steady state. This problem includes the Schwinger effect, the Unruh effect and Hawking radiation. In particular, the Stokes phenomenon of the Unruh effect has been unsolved for 50 years. This talk shows how the Exact WKB can be used to solve these problems clearly.

Katsuki Aoki, YITP

Towards S-matrix theory of unstable particles

Online (Zoom)
The S-matrix is one of the central objects in quantum field theory and has gained renewed interest recently to better understand the possible structures of low-energy effective field theories, strongly-coupled systems, quantum gravity, etc. However, most of the particles have finite decay widths and thus do not appear in asymptotic states. Therefore, the standard S-matrix arguments may not be directly applied to scatterings of such unstable particles and we need to formulate “the S-matrix theory of unstable particles” to properly understand the availability of the S-matrix arguments in realistic systems. In this talk, I will talk about some progress towards this goal. In particular, I will discuss non-perturbative consequences of unitarity in scattering amplitudes of unstable particles and their analytic properties.

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