Kotaro Murakami, Tokyo Institute of Technology
Investigation of baryon resonances from meson-baryon scatterings in lattice QCD
Hybrid On-site: Tokai 1st building (KEK Tokai campus), 2F, Room 227, Online : zoom
Studying hadron resonances in lattice QCD plays an important role in understanding exotic hadrons. We investigate baryon resonances from meson-baryon scatterings in the HAL QCD method, where we derive scattering amplitudes in lattice QCD via the interaction potentials. In this talk, I present the analysis of Δ and Ω baryons, both of which belong to the baryon decuplet. In our analysis, we use heavy quark masses so that Δ is a stable particle as well as Ω. If time permits, I also show our preliminary results of the study on Λ(1405) in flavor SU(3) limit.
Alexander Broll, Humboldt University of Berlin
Estimating the B Pi Excited States Contamination of B Meson Correlators with Heavy Meson Chiral Perturbation Theory
Online (Zoom)
CKM matrix elements are free parameters of the Standard Model which are determined by combining experimental and theoretical input. On the theory side, this requires the computation of hadronic matrix elements (ME) in lattice simulations. The lattice correlators can suffer from excited states contamination, i.e. additional contributions from multi-particle states with the same quantum numbers as the initial and/or final state of the matrix element. This can lead to an over- or underestimation of the ME and thus to a systematic error in the results of CKM matrix elements. In this talk, I present how Heavy Meson Chiral Perturbation Theory can be used to estimate the excited states contamination of B meson correlation functions relevant for flavour physics.
Masamichi Miyaji, Nagoya University
Fluctuations in the Entropy of Hawking Radiation
Hybrid On-site: Seminar room, Kenkyu honkan 3F Online: Zoom
Recent study revealed that the inclusion of Euclidean wormhole into the gravitational path integral renders the entropy of Hawking radiation consistent with unitarity, deriving the Page curve of the Hawking radiation. On the other hand, since the gravitational path integral with Euclidean wormhole computes quantities of ensemble average of theories, it is possible that the entropy of Hawking radiation of each gravity theory fluctuate wildly around the ensemble average. In this talk we show that such fluctuation is as small as the dimension of the system, ensuring the answer from the ensemble average is typical. We use the gravitational path integral to compute the fluctuations of the Hawking radiation entropy around the Page curve, in a two-dimensional model introduced by Penington \emph{et al}. Before the Page time, we find that $\delta S = e^{-S}/\sqrt{2}$, where $S$ is the black hole entropy. This result agrees with the Haar-averaged entropy fluctuations of a bipartite system, which we also compute at leading order. After the Page time, we find that $\delta S = \sqrt{2}e^{-S}/\pi$. This is not symmetric under exchange of subsystem sizes and so does not agree with the Haar average for a subsystem of fixed Hilbert space dimension. We show that the discrepancy can be attributed to an additive $\sqrt{2}/\pi$ fluctuation in the number of black hole states in a given energy band. As a by- product, our result gives a refinement on the known upper bound on the subsystem entropy fluctuation in Haar random pure state.
Owe Philipsen, Frankfurt University
[QCD theory Seminar] Surprises on the way toward the QCD phase diagram
Online (Zoom)
A strong fermion sign problem prohibits direct lattice simulations of QCD at finite baryon density, so that knowledge of the phase diagram is limited to small chemical potentials. On the other hand, the phase diagram is severely constrained by information on the chiral limit. I discuss recent lattice results at vanishing density, which show the chiral phase transition for Nf=2-7 degenerate chiral quarks to be of second order, contrary to the expectations based on the seminal paper by Pisarski and Wilczek from 1984. Together with growing information on fluctuations, this implies phenomenologically relevant bounds on a possible critical endpoint. In another development at zero density, a dynamically emergent chiral spin symmetry was discovered in correlator multiplet stuctures in a temperature window above the chiral crossover. I discuss two additional variables, screening masses and the pion spectral functions, which also show this window and suggest its effective degrees of freedom to be hadron-like, rather than partonic.
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.
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, Kenkyu honkan 3F 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, Kenkyu honkan 3F 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, Kenkyu honkan 3F 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, Kenkyu honkan 3F 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, Kenkyu honkan 3F Online:(Zoom) https://kds.kek.jp/event/46187/
