KMI2025 : The 6th KMI International SymposiumConference

5 Mar 2025, 09:00 → 7 Mar 2025, 17:30 Asia/Tokyo

Sakata and Hirata Hall (Nagoya University)

Quest for the Origin of Particles and the Universe

The Kobayashi-Maskawa Institute (KMI), Nagoya University will host the 6th KMI International Symposium on “Quest for the Origin of Particles and the Universe” (KMI2025) from March 5 through 7, 2025. The symposium aims to review the status and prospects of cutting-edge research in relevant fields and to develop interdisciplinary research on particle physics and astrophysics.

 

Date

From March 5 (Wed) through 7 (Fri), 2025

Programs

- Timetable

Conference Venue

Sakata and Hirata Hall, Science South building, Nagoya University

The hall is marked as D2-7 on the map of Higashiyama Campus.

Registration

• The registration is free of charge.
• Please register from the KMI2025 registration page
• (2025-01-14): Closed an application form for visa support
• (2025-01-23): Important Notice: Beware of unauthorized travel agencies (open the page for details)
• (2025-01-31): Closed an application form for travel support

Reception & Banquet

• The reception will be held on the evening of March 5th (1st day).
• The banquet will be held on the evening of March 6th (2nd day).
• Both events are free of charge.
• Both events are held at the same building as Sakata-Hirata Hall

 

 

 

Wednesday 5 March

Opening Remark

1 Opening Remark

Speaker: Prof. Toru Iijima (KMI, Nagoya University)

2 Practical Information

Speaker: Shota Takahashi (KMI)

20250305_kmi2025_practical_information.pdf

3 Introduction of DarMa

Speaker: Yoshitaka Itow

YoshitakaItowDarMa.pdf

Session1

Convener: Junji Hisano (Nagoya University)

4 WIMP dark matter

Weakly Interacting Massive Particle (WIMP) is an attractive candidate for particle dark matter. Typical WIMP models predict the scattering process of dark matter off nuclei, and they can be probed by direct detection experiments such as the XENONnT. There are many direct detection experiments for more than a few decades, and there is no significant scattering signal. This implies that the DM-nucleon scattering cross section is highly suppressed. In this talk, we discuss how to suppress the WIMP-nucleon scattering cross section.

Speaker: Tomohiro Abe (Tokyo University of Science)

TomohiroAbe.pdf

5 The direct search for dark matter with liquid xenon detector: XENONnT and XLZD

The XENONnT is a direct dark matter search experiment using a time projection chamber with 8.5 tons of liquid xenon. The experiment has been conducted at located at Laboratori Nazionali del Gran Sasso (LNGS), Italy, and taking the science data since 2021. In this talk, a summary of recent status/results of the XENONnT experiment, and its future project, the XLZD experiment, will be presented.

Speaker: Masatoshi Kobayashi (KMI, Naogya University)

MasatoshiKobayashi.pdf

6 Dark Matter Search Experiments with High-Resolution Nuclear Emulsion Tracker for Ultra-Short Tracks and Recent Application Developments

The NIT (Nano Imaging Tracker), developed and studied at Nagoya University since 2010, is a promising tool for searching for dark matter signals, which are expected to be observable only with several tens keV of recoiled atoms by it.

We have set up a manufacturing plant of NIT at the National Laboratory of Gran Sasso in Italy and have conducted joint research as a NEWSdm experiment. In recent years, its high-resolution device characteristics have been applied to the QUPLAS experiment, which aims to identify delicate patterns of antimatter interferometry, and the FOOT experiment, which aims to model nuclear fragmentation in hadrontherapy with high precision. This talk will discuss recent progress, including the development of these applications.

Speaker: Takashi Asada (Department of Physics, Faculty of Science, Toho University)

TakashiAsada.pdf

10:40 Coffee

Session2

Convener: Yoshitaka Itow

7 Dark Matter Particle Searches and Prospects with High-Energy Gamma Rays

Since weakly interacting massive particles (WIMPs) are predicted to exist at the electroweak scale, various experiments—including collider searches, satellite observations, and underground detectors—aim to explore the mass range from GeV to TeV in a complementary approach.

In particular, TeV-scale WIMPs can be effectively probed by Imaging Atmospheric Cherenkov Telescopes (IACTs), which offer excellent sensitivity in this energy range. Dark matter searches with IACTs focus on detecting photons produced in the final state of dark matter annihilation, making this approach highly sensitive to measuring the annihilation cross-section. This, in turn, provides valuable insights into the production mechanisms of dark matter in the early universe.

In this talk, I will present an overview of recent progress in WIMP searches using current IACTs and discuss future prospects with the Cherenkov Telescope Array (CTA).

Speaker: Tomohiro Inada (Kyushu University)

TomohiroInada.pdf

8 Dark matter searches in colliders

Dark matter production in high energy accelerators comprises one of the three main pillars of the dark matter detection strategies together with the scattering and the annihilation.

This talk overviews the latest searches in the collider experiments and provides personal vision on what to do next.

Speaker: Shion Chen (Kyoto University)

9 Dark Matter in the Milky Way and its Satellites

The Milky Way and its satellite galaxies provide invaluable laboratories for exploring the nature of dark matter.
Their structural and dynamical properties offer unique opportunities to place constraints on dark matter spatial and velocity distributions on small scales.
These systems are also prime targets for direct and indirect dark matter searches.
Unveiling their dark matter distributions requires detailed kinematic data from plenty of stellar samples and a thorough understanding of the systematics involved in dynamical modeling.
In this talk, I will present current efforts to constrain dark matter in the Milky Way and its dwarf satellites using dynamical analyses of the available data. I will also discuss future prospects for advancing these studies, including improvements in data quality and modeling techniques.

Speaker: Kohei Hayashi (NIT, Sendai college)

KoheiHayashi.pdf

12:40 Lunch

Session3

Convener: Yasuyuki Horii

10 Introduction of FlaP

Speaker: Toru Iijima (KMI, Nagoya University)

11 Status and prospects of the LHC - Physics at the High-Energy Frontier

The talk reviews some of the latest results and prospects of energy-frontier physics at the LHC.

Speaker: Andreas Hoecker (CERN)

AndreasHoecker.pdf

12 Higgs results and prospect at ATLAS

The Higgs sector is a unique part of the Standard Model in particle
physics. Even after the discovery of the Higgs boson in 2012 at the
Large Hadron Collider (LHC), the complete picture of the Higgs sector is
still uncovered. The ATLAS experiment is one of the two experiments that discovered the Higgs boson and can directly see it in proton-proton
collisions. It has measured the nature of the Higgs boson, for example,
its coupling with the gauge bosons and the fermions, during the first
and second operation phases. The self-couplings of the Higgs boson have recently been becoming interesting in understanding the potential of the Higgs fields. High statistics are essential for observing the Higgs
self-couplings, and the phase-II upgrades of the LHC and ATLAS detectors have begun towards the start of operation in 2030. In this talk, I will summarize the recent hot results on the Higgs sector from the ATLAS experiment and the prospects of the current operation and the phase-II upgrade with the KMI activities in ATLAS.

Speaker: Shota Izumiyama (KMI, Nagoya University)

ShotaIzumiyama.pdf

13 Muon g-2 and EDM

The muon’s magnetic anomaly (g-2) and electric dipole moment (EDM) serve as powerful windows into physics beyond the Standard Model. Precise measurements of these fundamental properties can reveal potential contributions from undiscovered particles and interactions. In this talk, I will present the current status the Fermilab Muon g-2 experiment and provide an update on the PSI muEDM experiment.

Speaker: Kim Siang Khaw (Shanghai Jiao Tong University)

KimSiangKhaw.pdf

15:30 Coffee

Session4

Convener: Toshiyuki Nakano

14 Status and prospect of the J-PARC muon g-2/EDM experiment

The J-PARC muon g-2/EDM experiment aims to measure the muon magnetic moment anomaly (a_μ = (g-2)/2) and to search for the muon electric dipole moment, with sensitivity comparable to the highest in the world. This will be achieved using a small-emittance muon beam, created by cooling muons and accelerating them with a multi-stage linac. The experimental approach significantly differs from the previous measurements conducted in BNL E821 and Fermilab E989. As seen in the recent theoretical advancements in studying a_μ through various approaches, the J-PARC measurement will enhance our experimental understanding of a_μ and its deviation from theoretical predictions. The experiment, planned to begin commissioning in 2030, is currently progressing with the development and implementation of experimental instruments and facility construction. Notably, the first-stage acceleration of cooled muons has been successfully demonstrated at J-PARC. This talk will present the current status and future prospects of the experiment.

Speaker: Kazuhito Suzuki (KMI, Nagoya University)

KazuhitoSuzuki.pdf

15 Long Baseline Neutrino Physics at T2K and Hyper-Kamiokande

The currently operating T2K long baseline neutrino experiment is probing the phenomenon of neutrino oscillations, providing world leading constraints on neutrino mixing parameters while searching for CP violation in neutrinos. The next generation experiment, Hyper-Kamiokande (Hyper-K), is currently under construction and will succeed T2K and Super-Kamiokande with a higher beam intensity and 8x larger detection mass. With unprecedented statistics for neutrino oscillation measurements, control of systematic uncertainties will be critical for Hyper-K. The Hyper-K Intermediate Water Cherenkov Detector (IWCD) is being built to address critical systematic uncertainties on neutrino-nucleus scattering modeling for Hyper-K. In this talk, I will report on the status of the T2K and Hyper-K experiments and efforts to realize the IWCD detector for Hyper-K.

Speaker: Mark Hartz (TRIUMF & KMI, Nagoya University)

MarkHartz.pdf

16 NINJA experiment and novel neutrino activities using nuclear emulsion

We are advancing the NINJA experiment at J-PARC using nuclear emulsion to study low-energy neutrinos in the Sub-Multi GeV range. Currently, we are conducting a physics run aimed at the precise measurement of neutrino-water interactions, which is crucial for reducing systematic uncertainties in long-baseline neutrino oscillation experiments that test CP symmetry violation in the lepton sector. In this presentation, I will report on the status of this experiment. Additionally, we are developing techniques for detecting alpha and beta rays in nuclear emulsion to explore neutrinoless double-beta decay and to study rocks for precise measurement of geoneutrinos. I would also like to introduce these new initiatives.

Speaker: Tsutomu Fukuda (Nagoya University)

TsutomuFukuda.pdf

17 Tau neutrino study in SHiP and DsTau.

Tau neutrinos is one of least studied particles. Measurement of the interaction crossection with a nucleon were reported by DONuT experiment but larger statistical and systematic errors. SHiP experiment is a hybrid experimnt constructing and run in 2030s. The experiment have two main subjevts, one is hidden particle search in a large decay volume and the other is tau neutrino detector with large statistics. With input from DsTau experiment results on tau neutrino flux estimation, a few percent accuracy on tau neutrino cross secrtion would be measured and compared with other neutrino types (electron and muon neutrinos),

Speaker: Osamu Sato (Nagoya University)

OsamuSato.pdf

18 Recent Results from Super-Kamiokande

Super-Kamiokande (SK) has been operational since 1996, revealing neutrino oscillations and precisely measuring oscillation parameters. With the extensive atmospheric neutrino data collected, we have recently been exploring the neutrino mass hierarchy. In 2020, gadolinium was added to the SK tank, and since then, we have been collecting data with neutron tagging information. One of the most intriguing subject of the Gd-loaded Super-K is the search for the diffuse supernova neutrino background. In addition, performance of galactic supernova detection has been improved. This presentation covers the latest physics results from the long-term SK operation and the recently obtained Gd-loaded data.

Speaker: Masayuki Nakahata (Kamioka Observatory, ICRR, University of Tokyo)

MasayukiNakahata.pdf

Poster Session: Reception

19 A Neural Network Approach to Consider Secondary Dependence of Halo Bias

Galaxies form in dark matter haloes. The spatial distribution of dark matter haloes, and the distribution and the number of galaxies within a dark matter halo, depend primarily on the halo mass. However, they are also known to depend on halo properties other than mass, such as halo formation history (Wechsler et al. 2006). This secondary dependence is called assembly bias. Due to dramatic improvements in the statistical accuracy of upcoming galaxy surveys, ignoring the assembly bias would bias cosmological parameter constraints (Miyatake et al. 2022). In this work, to construct a halo statistics emulator that also predicts the assembly bias, we focus on the concentration of haloes as a representative secondary parameter, and measure the cross-correlation function of various halo samples selected according to the mass and concentration using Dark Quest II simulation data. We construct an emulator for these statistics based on a feed-forward neural network. As a result, we find that the halo correlation function can be emulated with a typical accuracy of 1%. In this poster, we will mention that the result emulated in redshift space not only real space, and the outlook relative to the Stage IV survey; LSST, Roman projects.

Speaker: Keitaro Ishikawa (Nagoya University)

20 Algebraic ER=EPR in LLM

The algebraic ER=EPR conjecture claims that the types of von Neumann algebras to which the QFT at the boundary belongs determine the emergent spacetime picture on the bulk side. Following this proposal, we explored the conjecture’s claims using the Lin-Lunin-Maldacena (LLM) system. Specifically, we began by constructing entangled quantum states in the LLM system, switched over types and saw transitions of the spacetime picture. Our results indicate that the thermodynamic properties of spacetime change as the type transitions. In this poster, we will present such changes observed on the bulk side in response to the type change in the QFT.

Speaker: Ryo Nemoto (Nagoya University)

21 Analysis of exotic hadrons by superposition of hadronic molecules and charmonium

Hadrons that are difficult to explain as ordinary hadrons are called exotic hadrons, and since the Belle experiment reported $X(3872)$ in 2003, a large number of exotic hadrons containing charm quarks have been reported. Some of these have the same quantum number as charmonium and are located near the mass threshold of the two hadrons. In this study, we analyze the exotic hadrons associated with $\chi_{cJ}(2P)$ as superpositions of bare $\chi_{cJ}(2P)$ and $D^{(*)}\bar{D}^{(*)}$ hadronic molecules.

Speaker: Kotaro Miyake (Nagoya University)

22 Anisotropic halo bias from vector dark matter/energy and anisotropic inflation

We present the first confirmation of anisotropic halo bias induced by vector dark matter/energy and anisotropic inflation. Vector dark matter/energy and anisotropic inflation models distort cosmological matter distributions. Anisotropy of matter distributions can affect halo distributions. Using cosmological N-body simulations, we show that halo bias becomes anisotropic in the presence of vector dark matter/energy and/or anisotropic inflation.

Speaker: Shogo Masaki (Chukyo University)

23 Challenges for the top quark mass measurement using J⁄ψ meson in t→W(→lν)b(→J/ψ+X) decay at ATLAS Run 2

Improving the precision of the top quark mass measurement is essential for understanding the properties of the Higgs field at high energy scales and the vacuum stability of the universe. In previous measurements with inclusive top quark decays (such as the lepton + jets final state), the dominant uncertainties arose from the energy reconstruction of QCD jets. We have developed a method to extract the mass from a high-momentum lepton and a J⁄ψ meson in the decay chain of the top quark. By using only lepton momentum, the uncertainties associated with jet reconstruction have been reduced to below 100 MeV. However, uncertainties related to the modeling of top quark production and decay are now dominant and must be controlled. A rigorous estimation has shown that the uncertainties arising from the modeling of tt ̅ events can be suppressed to below 1 GeV, bringing them to the same level as the statistical uncertainty. The method of this measurement using J⁄ψ meson and the estimation of the systematic uncertainties are presented.

Speaker: Haruka Asada (Nagoya University)

24 COSMOS: A numerical relativity code specialized for PBH formation

Primordial black holes (PBHs) are black holes generated in the early universe without experience of the form of a star. It has been pointed out that PBHs may be candidates for black holes and compact objects of various masses in the universe or a major component of dark matter. In particular, PBHs have been attracting much attention in the recent development of gravitational wave observation. In the standard formation process, PBHs are formed from super-horizon primordial fluctuations with non-linearly large initial amplitude. In order to follow the whole non-linear gravitational dynamics, one has to rely on numerical relativity to solve Einstein equations. COSMOS and COSMOS-S are open C++ packages for solving Einstein equations in 3+1 dimensions and spherical symmetry (1+1 dimensions), respectively, specialized for PBH formation.

Speaker: Chulmoon Yoo (Nagoya University)

25 Design of bridge coupler in Disk-and-Washer structure for muon acceleration

A muon linear accelerator is under development at J-PARC for precise measurement of the muon anomalous magnetic moment (g-2) and electric dipole moment (EDM). The disk-and-washer (DAW) structure is employed to accelerate muons from 30% of the speed of light (kinetic energy = 4 MeV) to 70% (40 MeV) at 1296 MHz. The muon DAW consists of tanks accelerating the muons and bridge couplers that couple the tanks and focus the beam using an internal quadrupole doublet. The manufacturing accuracy of bridge couplers affects the accelerating field in tanks, so a detailed design of bridge couplers is important. This paper presents the design of the bridge-coupler prototype based on electromagnetic field calculation.

Speaker: Ayaka Kondo (Nagoya University)

26 Development and validation of the firmware for the new inner-station TGC detector in the ATLAS muon trigger system at the HL-LHC

In the ATLAS experiment at HL-LHC, the first-level muon trigger will be redesigned to suppress the trigger rate in the high pileup environment. In the endcap region, the hit signals from thin gap chamber (TGC) are processed in XCVU13P FPGA and muon track is reconstructed. In order to suppress the trigger for particles not originating from the interaction point, the new algorithm exploits the upgraded TGC detectors in the inner station (TGC EIL4). I present the design and the validation results for the TGC EIL4 firmware.

Speaker: Shogo Manita (Nagoya University)

27 Development of a high-speed automatic nuclear emulsion scanning system, HTS-2

The nuclear emulsion is a charged particle detector with submicron spatial resolution based on the principles of silver halide photography. Nagoya University’s nuclear emulsion film production facility produces 1,500 square meters of film annually, which is used in ongoing experiments such as neutrino interaction measurements and cosmic gamma ray observations. After each experiment, all films must be scanned with an optical microscope system to read out the tracks. The poster will introduce the latest system HTS-2, which is capable of scanning 1000 square meters of film per year.

Speaker: Tsuyoshi Kawahara (Nagoya University)

28 Development of a Trace Hydrogen Measurement Method for Quantitative Evaluation of Tritium Concentration in Gas Xenon

As observed in XENON1T, tritium, which exists as an impurity in liquid xenon, can potentially contribute to background signals in direct dark matter detection experiments using liquid xenon. Therefore, this study aims to measure hydrogen concentrations at the ppt level in gaseous xenon to quantitatively evaluate tritium concentration. This poster presents the current progress in trace hydrogen measurement in argon gas using a residual gas analyzer and a hydrogen separation membrane module.

Speaker: Mitsuki Utoyama (Nagoya University)

29 Development of hermetic xenon detector for XLZD

Direct dark matter search with liquid xenon such as XENONnT experiment has the best sensitivity to dark matter in the form of Weakly Interacting Massive Particles (WIMPs) today. XLZD experiment, the future direct dark matter search with about 50 tons of xenon, aims to improve the sensitivity to 10 times that of previous experiments and we need to decrease the background rate to achieve the goal. The most common background is the beta decay of the daughter nucleus of Rn-222 emanating from detector components. Then, we proposed a method to prevent the radon from entering the sensitive area with a hermetic chamber made of quartz and fluoroplastic (PTFE) and developed a small chamber with a diameter of 5cm. The hermeticity of the chamber was evaluated by measurement of the ratio of radon concentration in gaseous xenon inside and outside the chamber. As a result, the hermeticity was estimated to meet the requirement of XLZD.

Speaker: Ryuta Miyata (Nagoya University)

30 Development of single-phase liquid xenon detector and microstrip electrodes for XLZD

In the R&D for next-generation liquid xenon-based dark matter detectors, not only the conventional dual-phase detectors using both gaseous and liquid xenon but also single-phase detectors, which do not require strict liquid level management, have been gaining attention. This study focuses on developing a single-phase liquid xenon detector and a stable electrode with microstrip-patterned metal on the surface of quartz glass. In this poster, we will report on the electrodes developed in collaboration with Toyota Technological Institute and the measurement results of signals originating from ionization electrons produced by a radiation source in the liquid xenon chamber.

Speaker: Taiki Shimada (ISEE, Nagoya University)

31 Evaluation of FSR photon correction to di-muon invariant mass for search for Higgs decaying into two muons in the ATLAS experiment

The Higgs boson coupling to muons has not yet been observed, making its measurement an important target in studying the Higgs sector. The decay of the Higgs boson into a muon pair is a rare process, predicted by the Standard Model with a branching ratio of approximately 0.02%. The ATLAS experiment aims to improve the sensitivity of this search during Run 3. One of the key factors affecting the sensitivity is the resolution of the di-muon invariant mass. Previous studies have shown that incorporating photons emitted via Final State Radiation (FSR) into the invariant mass reconstruction improves the resolution. In this study, we evaluate the impact of FSR photon correction on the mass resolution using Z -> µµ samples in partial Run 3 data.

Speaker: Arisa Wada (Nagoya University)

32 Evanescent operator contribution to radiative correction to QCD theta parameter at two-loop level in the BMHV scheme

In this paper, we evaluate the QCD $\theta$ angle radiatively induced at the two-loop level using the dimensional regularization with the BMHV scheme in a simplified model. When the Lagrangian is promoted into $d$-dimensional space through the dimensional regularization, evanescent operators are introduced, which break the chiral symmetry. Consequently, a parity-odd fermion loop with the BMHV scheme generates an evanescent contribution that deviates from the original chiral symmetry. We carefully classify the evanescent contribution into two types: one originating from the evanescent operator and the other directly produced by the two-loop calculation. These unphysical contributions can be removed from the renormalization equation for the QCD $\theta$ angle by re-parameterizing the angle.

Speaker: Naohiro Osamura (Nagoya University)

33 Excited bound states & their role in Dark Matter Production

[arXiv: 2308.01336 and 2411.08737] We explore the impact of highly excited bound states on the evolution of number densities of new physics particles, specifically dark matter, in the early Universe. Focusing on dipole transitions within perturbative, unbroken gauge theories, we develop an efficient method for including around a million bound state formation and bound-to-bound transition processes. This enables us to examine partial-wave unitarity and accurately describe the freeze-out dynamics down to very low temperatures. We find that unitarity is systematically violated in perturbative leading order calculations below a critical velocity, even for arbitrarily small couplings given sufficiently highly excited states are regarded and initial states are less attractive than the captured bound states. In the non-Abelian case, we find that highly excited states can prevent the particles from freezing out, supporting a continuous depletion in the regime consistent with perturbativity and unitarity. We apply our formalism to a simplified dark matter model featuring a colored and electrically charged t-channel mediator. Our focus is on the regime of superWIMP production which is commonly characterized by a mediator freeze-out followed by its late decay into dark matter. In contrast, we find that excited states render mediator depletion efficient all the way until its decay, introducing a dependence of the dark matter density on the mediator lifetime as a novel feature. The impact of bound states on the viable dark matter mass can amount to an order of magnitude, relaxing constraints from Lyman-α observations.

Speaker: Stefan Lederer (Tokyo University of Science)

34 Exploration of Confinement in Supersymmetric Gauge Theories

It remains a big challenge to provide a theoretical explanation for confinement. The principal obstacle lies in the behavior of the QCD coupling constant. It is no longer small and thus perturbation theory becomes unusable in the low energy regime. As a promising approach to the problem, we turn to supersymmetric gauge theories, which provide analytical control. We defined a new type of confining supersymmetric gauge theories, truly-confining theories. Moreover, we successfully classified all truly-confining theories and identified condensation of some operators in each case, which must be related to confinement.

Speaker: Riku Ishikawa (The University of Tokyo)

35 First star information from hydrogen 21cm global signal

After the dark ages of the Universe, the first generation of stars formed without any heavy elements. These metal-free stars, known as Population III (Pop III) stars, are thought to have influenced cosmic reionization, although the extent of their contribution remains uncertain. Therefore, understanding their properties is crucial for cosmology. However, direct observations remain challenging. One promising approach is to observe the neutral hydrogen 21cm line, which provides valuable information about the effects of Pop III stars on the surrounding neutral hydrogen. In our research, we forecast how precisely future observations of the 21cm global signal will constrain the typical mass and star formation efficiency of Pop III stars, using semi-numerical simulations.

Speaker: Sho Ukai (Nagoya University)

36 Heavy quark symmetry behind b → c semileptonic sum rule

Lepton flavor universality violations in semileptonic b→c transitions have garnered attention over a decade. For RH_c=BR(H_b→H_cτν)/BR(H_b→H_cℓν) with ℓ being e, μ, a sum rule among RD, RD∗ and RΛc was proposed to check consistency in the experimental results independently of new physics models. We revisit this relation from the perspective of the heavy quark symmetry. We derive a sum rule holding exactly in the heavy quark limit and clarify how model-dependent corrections are introduced in a realistic situation.

Speaker: Syuhei Iguro (KEK/IAR/KMI)

37 Impact of the Electroweak Weinberg Operator on the Electric Dipole Moment of Electron

Recent progress in the electric dipole moment (EDM) measurements of the electron using the paramagnetic atom or molecule is remarkable. In this paper, we calculate a contribution to the electron EDM at three-loop level, introducing the CP-violating Yukawa couplings of new SU(2)$_L$ multiplets. At two-loop level, the Yukawa interactions generate a CP-violating dimension-six operator, composed of three SU(2)$_L$ field strengths, called the electroweak-Weinberg operator. Another one-loop diagram with this operator inserted induces the electron EDM. We derive the matching condition and find that even if new SU(2)$_L$ particles have masses around the TeV scale, the electron EDM may be larger than the Standard Model (SM) contribution to the paramagnetic atom or molecule EDMs. We also discuss the relation between the Barr-Zee diagram contribution at two-loop level and three-loop one, assuming that the SM Higgs has new Yukawa interactions with the SU(2)$_L$ multiplets.

Speaker: Kiyoto Ogawa (Nagoya University)

38 Measurement of neutron whispering gallery states induced by non-inertial Schrödinger dynamics

A neutron whispering gallery state is a quantum state localized on the surface of a material bound by centrifugal force and material potential. Precise measurement of this quantum state makes it possible to verify quantum mechanics in non-inertial systems, determine the shape of the material surface potential, and search for hypothetical short-range interactions on the nm scale. We observed neutron whispering gallery states using the J-PARC pulsed cold neutron source. Comparing the results of the measurements with theoretical calculations, there were some differences larger than the systematic error, but the agreement was within 2% for the centrifugal acceleration of 7 × 10^7 m/s^2. In addition, by comparing the interference fringes appearing in the wavelength distribution with the theoretical curve, it was shown that the sensitivity could be improved by two orders of magnitude.

Speaker: Go Ichikawa (KEK)

39 Millicharged dark matter detection with Mach-Zehnder interferometer

If the dark sector exists and communicates with Standard Model through the U (1) mixing, it is possible that electromagnetism would have influence on matter fields in dark sector, so-called millicharge particles (mCPs). Furthermore, the highest mCPs could be dark matter particles. Recently it has been shown that the mCPs would be slowed down and captured by the earth. As a result, the number density of accumulated mCPs underground is enhanced by several orders of magnitude as compared to that of dark matter in our solar system. In this study, we propose to use the Mach-Zehnder (MZ) laser interferometer to detect earth bound mCPs through the detection of phase shifts of photons. We show that, for mass of mCPs lager than 1 GeV, the sensitivity of probing the mixing parameter ? could reach as low as 10^{−11} if number density is larger than 1 cm^{−3}.

Speaker: Chrisna Setyo Nugroho (National Taiwan Normal University)

40 Neutron Interferometer with multilayer netron mirrors at J-PARC

We report about novel neutron interferometer using pulsed neutrons. In the case of conventional interferometer, crystal diffraction is used for splitting and superposition of neutron wave. The sensitivity of the interferometer has limitation in applicable wavelength. In addition, we must scan the phase shifter plate to get interferogram. This scanning creates the systematic uncertainty for long time measurement. We developed the neutron interferometer with multilayer mirrors which can use long wavelengths neutrons. It can be applied pulse neutron beam by using Time-Of-Flight method. Using pulsed neutrons, we can get interferogram along wavelength simultaneously without the phase shifter and suppress the environmental disturbance depending on time. I will report on the current activities of NI at J-PARC.

Speaker: Taro Nambu (Nagoya University)

41 Non-perturbative overlaps in JT gravity

The interplay between black hole interior dynamics and quantum chaos provides a crucial framework for probing quantum effects in quantum gravity. In this work, we investigate non-perturbative overlaps in Jackiw-Teitelboim (JT) gravity to uncover universal signatures of quantum chaos and quantum complexity. Taking advantage of universal spectral correlators from random matrix theory, we compute the overlaps between the thermofield double (TFD) state and two distinct classes of states: fixed-length states, which encode maximal volume slices, and time-shifted TFD states. The squared overlaps naturally define probability distributions that quantify the expectation values of gravitational observables. Central to our results is the introduction of generating functions for quantum complexity measures, such as $\langle e^{-\alpha \ell} \rangle$. The time evolution of these generating functions exhibits the universal slope-ramp-plateau structure, mirroring the behavior of the spectral form factor (SFF). Using generating functions, we further demonstrate that the universal time evolution of complexity for chaotic systems, which is characterized by a linear growth followed by a late-time plateau, arises from the disappearance of the linear ramp as the regularization parameter $\alpha$ decreases. With regard to the time-shifted TFD state, we derive a surprising result: the expectation value of the time shift, which classically grows linearly, vanishes when non-perturbative quantum corrections are incorporated. This cancellation highlights a fundamental distinction between semiclassical and quantum gravitational descriptions of the black hole interior. All our findings establish generating functions as powerful probes of quantum complexity and chaos in gravitational and quantum systems.

Speaker: Shono Shibuya (Nagoya University)

42 Optimisation of the voltage ratio to extend the lifetime of MCP-PMT for the TOP counter in the Belle Ⅱ experiment

The Belle II detector TOP counter is a particle identification device consisting of a quartz radiator and a Micro-Channel-Plate Photomultiplier tube (MCP-PMT). The identification performance depends on the quantum efficiency (QE) of the MCP-PMT, which decreases as the integrated output charge increases, but the QE measured from the physics run data decreased faster than expected. As a possible cause, we consider degradation of the photocathode due to ions inside the MCP. In this study, we aim to suppress the generation of ions while maintaining the performance of the MCP-PMT by optimizing the voltage application ratio inside the MCP-PMT.

Speaker: Tadaki Ichikawa (Nagoya university)

43 Parity-violating scalar trispectrum from helical primordial magnetic fields

Recent detections of parity violation in cosmological observations, such as galaxy clustering and cosmic microwave background anisotropies, suggest the existence of parity-violating sources in the universe. To properly extract these signals from future cosmological experiments, a thorough analysis of parity-violating signatures and exploration of relevant models are essential. In this talk, we focus on galaxy clustering, which offers a window into parity violation through the analysis of the four-point correlation function, or its Fourier counterpart, the trispectrum. Specifically, we consider primordial magnetic fields (PMFs) generated during inflation as a source of parity violation. PMFs have attracted much attention in recent years as a potential origin of the observed large-scale magnetic fields. It is known that the anisotropic stress of PMFs can act as a source of curvature perturbations on superhorizon scales, called the passive scalar mode. Consequently, the helical components of the PMFs, which represent the parity-violating part, can be probed via the galaxy four-point correlation function. To investigate cosmological parity violation from PMFs, we first derive the trispectrum of galaxy density fields induced by the anisotropic stress of PMFs by employing a pole approximation. Our results confirm that the crosstalk between non-helical and helical PMFs is essential to produce a non-zero imaginary component in the trispectrum, which is a probe of the parity violation signal. We will present some discussion on what configurations in Fourier space of the parity-odd signals are enhanced. With our analytical and numerical results, we will provide a better constraint on the amplitude of helical PMFs from the future cosmological observations such as the galaxy trispectrum.

Speaker: Kaito Yura (Nagoya University)

44 Performance evaluation of the new inner-station TGC detector and the power distribution board at the HL-LHC ATLAS experiment

In the HL-LHC ATLAS experiment, the TGC detector inside the magnetic field region will be changed from two layers to three layers in order to improve the detector redundancy and positional accuracy. Performance evaluation was conducted to install three of the new detectors during the EYETS2024, and the occupancy rate of electrical noise above 100 mV is less than 10^{-4}. In addition, quality check of the detector's new electronics, the power distribution board, was performed, and it was shown to operate properly in an environment similar to the actual operation.

Speaker: Kotaro Chiba (Nagoya University)

45 Polarization Measurement of 6.6 MeV Gamma-ray Beam with Nuclear Emulsion

Observations of cosmic gamma rays contribute greatly to cosmic ray physics by elucidating a mechanism of cosmic ray acceleration and identifying gamma-ray sources, but due to the technical difficulties of the measurement method, many parts of this field are less developed than other wavelength. In particular, the polarization of cosmic gamma rays is a physical quantity that can reveal the magnetic field structure of astronomical objects, and is expected to provide a new approach to the radiation mechanism but there are few examples of its observation. The Gamma-Ray Astro-Imager with Nuclear Emulsion (GRAINE) experiment aims to precisely observe cosmic gamma rays with a balloon-borne telescope using nuclear emulsions with excellent spatial resolution. GRAINE can observe cosmic gamma rays with the worlds’ highest resolution by measuring electron pair production originating from cosmic gamma rays in the sub-GeV/GeV energy band and is sensitive to polarization. Polarization measurement requires grain-by-grain analysis in track images at the vicinity of pair-production conversion point, and we are currently developing a precision measurement system using an optical microscope. In this study, we observed Compton-scattered electron tracks due to 6.6 MeV gamma ray beam using nuclear emulsion films and the precision measurement system to verify the ability to measure low-energy electrons, and also to measure the polarization of gamma rays.

Speaker: Ibuki Yasuda (Nagoya University)

46 Recent $B^{+} ⁣ \rightarrow K^{+} \nu \nu$ Excess and Muon g-2 illuminating Light Dark Sector with Higgs Portal

The Belle II collaboration recently announced that they observed the B→Kνν decay process for the first time. This dineutrino mode of B→Kνν has been theoretically identified as a very clean channel. However, their result encounters a 2.7σ deviation from the Standard Model (SM) calculation. On the other hand, last year, Fermilab released new data on muon g−2 away from the SM expectation with 5σ. In this presentation, we study the simplest UV-complete U(1)Lμ−Lτ -charged complex scalar Dark Matter (DM) model. Thanks to the existence of light dark Higgs boson and light dark photon, we can explain the observed relic density of DM and resolve the results reported by both Belle II and Fermilab experiments simultaneously. As a byproduct, the Hubble tension is alleviated by taking ΔNeff≃0.3 induced by the light dark photon.

Speaker: Jongkuk Kim (Chung-Ang University)

47 Resolving Individual Signal in the Presence of Stochastic Background in Future Pulsar Timing Arrays

Recent pulsar timing arrays (PTA) observations indicate evidence of a gravitational wave background (GWB) has been detected. If supermassive black holes (SMBHs) are indeed the primary source of this signal, future PTA observations, such as those from the Square Kilometer Array (SKA), are expected to simultaneously capture multiple continuous gravitational waves (CGWs) emitted by bright individual SMBH binaries alongside a gravitational wave background (GWB). To deal with this anticipated scenario in the SKA era, we revisit F-statistic, a detection method for single source signals in PTA datasets, and introduce a new modeling that accounts for unresolved GWs as a stochastic GWB. Here, we applied this improved F-statistic to the mock datasets that include both CGW and GWB and evaluated how accurately F-statistic can identify the parameters of CGW. As a result, we show our approach can successfully resolve the sky position and the amplitude of CGW when GWB is dominant compared to white noise. Considering the prospect of the precision for SKA and the future improvement of our approach, we discuss the possibility of establishing the realistic algorithm based on F-statistic toward future PTA measurements.

Speaker: Kazuya Furusawa (Nagoya University)

48 Scalar leptoquark based on the B meson anomaly

In the decay process of B mesons, discrepancies between the predictions of the Standard Model and experimental results have been reported. These can be clues to physics beyond the Standard Model. Here, based on the R(D) anomaly, we will reveal the predictions and correlations of R2 leptoquark that could contribute to other interesting B meson decay processes.

Speaker: Takeru Uchiyama (Nagoya University)

49 STOLAS: STOchastic LAttice Simulation of cosmic inflation

We develop a C++ package of the STOchastic LAttice Simulation (STOLAS) of cosmic inflation. It performs the numerical lattice simulation in the application of the stochastic-δN formalism. STOLAS can directly compute the three-dimensional map of the observable curvature perturbation without estimating its statistical properties. In its application to two toy models of inflation, chaotic inflation and Starobinsky’s linear-potential inflation, we confirm that STOLAS is well-consistent with the standard perturbation theory. Furthermore, by introducing the importance sampling technique, we have success in numerically sampling the current abundance of primordial black holes in a non-perturbative way.

Speaker: Yurino Mizuguchi (Nagoya University)

50 Testing General Relativity with weak lensing and galaxy clustering from HSC-Y3 and SDSS BOSS: Toward implementing MGCAMB into COCOA

The ΛCDM model, the current standard cosmological model, is capable of describing the geometric and structural evolution of the universe and has been supported by measurements of various cosmological observables, including the large-scale structure (LSS). However, the ΛCDM model requires the assumption of the existence of unknown matter (dark matter), which is the source of the gravitational force of celestial body formation, and unknown energy (cosmological constant, or more generally, dark energy), which is the source of accelerated expansion. In the ΛCDM model, gravitational interaction is described by General Relativity (GR). One possible solution to the above problem is an attempt to explain the universe's accelerated expansion without introducing dark energy by modifying the theory of gravity from GR on cosmological scales. This is called “the modified gravity theory”. Recent observations have improved the accuracy of LSS measurements, and some results suggest internal inconsistency of the ΛCDM model. Future surveys such as the Nancy Grace Roman Space Telescope (hereafter, Roman) are planned, and are expected to make it possible to test the modified gravity theory on cosmological scales. In particular, we will implement the Boltzmann code MGCAMB, which enables the calculation of the power spectrum with modified gravity models, in the cosmological analysis pipeline COCOA, which is being developed for Roman. Then we’ll analyze the final data from the Subaru HSC to test gravity first. MGCAMB can perform theoretical calculations dealing with phenomenological parameters (μ-Σ parameters) that modify the gravity felt by non-relativistic and relativistic matter, without using a specific modified gravity theory. In this presentation, we discuss the cosmological constraints predicted by COCOA with MGCAMB implemented.

Speaker: Kohki Tanida (Nagoya University)

51 The Impact on the 21 cm Absorption Signals of Minihalos by the Radiation Background

One of the important cosmological studies is verifying the accuracy of the standard model, and investigations of small-scale structure formation are needed. However, observations so far for scales smaller than around 100 kpc have not been conducted adequately yet. For these scales, the structures at the epoch of pre-reionization called minihalos are good targets to investigate, and it is estimated to be detected through 21 cm absorption lines. On the other hand, the relationships among the mass of minihalos, the physical process such as radiation, and the 21 cm optical depth are still uncertain. In our study, we investigate the impact of the radiation background on the 21 cm optical depth when minihalos form and estimate the absorption line abundance, etc. We study by combining data from the simulation reflecting the halo’s feature on a large scale with data from the simulation for the physical process on a small scale.

Speaker: Genki Naruse (Nagoya University)

52 The power management of the Sector Logic board for the ATLAS muon trigger at HL-LHC

The upgrade of the ATLAS detector for HL-LHC will start in 2026 towards physics run from 2030. The Sector Logic (SL) board is a part of the first stage muon trigger system. It is equipped with 20 FireFly modules for optical communication and a large-scale FPGA for trigger processing, requiring an advanced power management. The final prototype was manufactured taking into account the feedback from the first prototype. The power-up and down sequencing was established and demonstrated. Only temperature surveys remain for the mass production.

Speaker: Shota Koji (Nagoya University)

53 Toponium at the LHC

We discuss the toponium formation signals at the LHC.

Speaker: Ya-juan Zheng (Iwate University)

Thursday 6 March

Session5

Convener: Syuhei Iguro

54 The Flavour of New Physics

Flavour physics represents one of the most fascinating puzzles of
particle physics. I will discuss some recent developments in this
field, both from a theoretical perspective and from a more
phenomenological point of view. I will focus in particular on the idea
of flavour non-universal gauge interactions as a way to address the
origin of the flavour hierarchies, while enabling new physics at the
TeV scale that can stabilise the electroweak sector. The implications
of this class of models for various short- and medium-term flavour
physics experiments, as well as for new-physics searches at high
energies, will also be discussed.

Speaker: Gino Isidori (University of Zurich)

GinoIsidori.pdf

55 Current status and prospects of B physics

The Belle II experiment at the SuperKEKB collider is building on the achievements of its predecessor, Belle, to explore new frontiers in B physics. With its vastly increased dataset, Belle II enables detailed studies of rare B meson decays and CP violation, offering unique sensitivity to phenomena beyond the Standard Model. These efforts are complemented by results from the LHC, which provide additional insight into rare decays and heavy flavor processes. This presentation highlights recent results from Belle II and selected findings from the LHC, focusing on the search for new physics and its implications for the future of flavor physics.

Speaker: Keisuke Yoshihara (University of Hawaii)

KeisukeYoshihara.pdf

56 Tau Physics at Belle II

Talk highlighting recent tau physics results and future prospects for the Belle II experiment.

Speaker: Petar Rados (KMI, Nagoya University)

PeterRados.pdf

57 Particle Physics with Slow Neutrons: Status and Prospects

The current status of ongoing and planned experiments using low energy (roughly eV and below) neutrons to search for beyond standard model (BSM) physics will be presented. These experiments take place at many different facilities and cover a wide range of physics, including measurements of the static electric dipole moment of the neutron, sensitive searches for time-reversal violation in neutron-nuclear interactions, probes for short-ranged interactions including axions and gravity-like forces, high precision beta decay and more. In this presentation, the motivation and recent progress will be presented for several of these projects and placed in context with other activity in the field of high precision tests of the standard model.

Speaker: Albert Young (North Carolina State University and the Triangle Universities Nuclear Laboratory)

10:50 Coffee

Session6

Convener: Masaaki Kitaguchi

58 An improved result of neutron lifetime measurement with cold neutron beam at J-PARC

The "neutron lifetime puzzle" arises from the discrepancy between neutron lifetime measurements obtained using the beam method, which measures decay products, and the bottle method, which measures the disappearance of neutrons. To resolve this puzzle, we conducted an experiment using a pulsed cold neutron beam at J-PARC.

In this experiment, the neutron lifetime is determined from the ratio of neutron decay counts to $^3$He(n,p)$^3$H reactions in a gas detector. This experiment belongs to the beam method but differs from previous experiments that measured protons, as it instead detects electrons, enabling measurements with distinct systematic uncertainties. By enlarging the beam transport system and reducing systematic uncertainties, we achieved a fivefold improvement in precision.

The average of all acquired data yielded a neutron lifetime of $\tau_{\rm n}=877.2~\pm~1.7_{\rm(stat.)}~^{+4.0}_{-3.6}{}_{\rm (sys.)}$~s. We will present about the new results.

Speaker: Kenji Mishima (KMI, Nagoya University)

KenjiMishima.pdf

59 Search for T-violation using polarized neutron beam and polarized target : NOPTREX (J-PARC E99)

The violation of discrete symmetries can be significantly enhanced in neutron absorption reactions by nuclei. The NOPTREX collaboration aims to search for an unknown T-violating interaction in nucleon-nucleon interactions using a polarized neutron beam and a polarized nuclear target at J-PARC. The development of a neutron polarizer and a polarized target is currently ongoing. Experiments using a polarized neutron beam and a 139La target are also being conducted at J-PARC. Recent results will be presented

Speaker: Takuya Okudaira (Nagoya University)

TakuyaOkudaira.pdf

60 Hadron Spectroscopy — Past, Present (and Future) —

Speaker: Atsushi Hosaka

AtsushiHosaka.pdf

61 Exotic hadrons as heavy hadronic molecules and their partners

Recent accelerator experiments have reported unexpected states known as exotic hadrons, whose properties cannot be explained by the conventional picture, mesons and baryons. In the heavy quark sector, $XYZ$, $T_{cc}$, $P_c$ etc. have been reported since the discovery of $X(3872)$. There have been many exotic hadrons located near the hadron threshold, and thus loosely hadron bound states called hadronic molecules have been considered. In the heavy hadron sector, the heavy quark symmetry is important, which induces channel coupling effects and also predicts spin partner states. In this talk, we study hadronic molecules of heavy hadrons such as $T_{cc}$. We study bound state properties of hadronic molecules and also discuss partner states of these exotics, predicted by symmetries.

Speaker: Yasuhiro Yamaguchi (Nagoya University)

YasuhiroYamaguchi.pdf

62 FASER experiment at the LHC and its connection to the cosmic-ray muon puzzle

Ultra-high energy cosmic rays are the highest energy particles arriving at the Earth and measured using an extensive air shower induced by them. In 2015, the Pierre Auger Observatory reported an excess of the number of muons in an extensive air shower than that expected in simulations. This indicates a puzzle, a muon puzzle, suggesting the interactions in an extensive air shower are not reproduced well. Forward hadron productions are key parts of extensive air showers and the FASER experiment is sensitive to neutrinos decayed from these forward hadrons. In this talk, I review the recent results from the FASER experiment and discuss their implication for forward hadron productions.

Speaker: Ken Ohashi (LHEP, University of Bern)

KenOhashi.pdf

13:10 Group Photo

13:20 Lunch

IAB Meeting 1

63 Greetings

Speaker: Toru Iijima (KMI, Nagoya University)

KMI_annual_report_2023.pdf

KMI_annual_report_2024_preIAB.pdf

64 Report on recent activities and future plan

Speaker: Toru Iijima (KMI, Nagoya University)

20250305_KMI2025_overview.pdf

65 Division of Theoretical Studies

Speaker: Tetsuya Shiromizu (KMI, Nagoya University)

DivisionTheory2025.pdf

66 Division of Experimental Studies

Speaker: Toru Iijima (KMI, Nagoya University)

CE_Report_250306(Iijima).pdf

67 Flavor Physics International Reserach Center

Speaker: Toru Iijima (KMI, Nagoya University)

20250305_KMI2025_Flap.pdf

68 Dark Matter Physics International Reserach Center

Speaker: Hiroyasu Tajima

DarMa20250205KMIsympo.pdf

DarMa20250206_HTYI.pdf

16:00 Coffee

IAB Meeting 2

69 Discussion

Everyone

70 Closed Session

only for IAB members

71 Comments by IAB

Everyone

72 Discussion

Everyone

73 Conclusion

Speaker: Toru Iijima (KMI, Nagoya University)

Banquet

Friday 7 March

Session7

Convener: Kiyotomo Ichiki

74 The Status of Cosmology and the Euclid Dark Energy Mission

I will present a brief overview of the current status of cosmology, and highlight what we can expect from the Euclid Dark Energy Mission which launched mid-2023.

Speaker: Andy Taylor (Institute for Astronomy, University of Edinburgh)

AndyTaylor.pdf

75 Subaru PFS Cosmology Program

The Subaru Prime Focus Spectrograph (PFS) cosmology program will deliver redshifts for four million [OII] emission-line galaxies over 1200 deg² across 𝑧 = 0.6 to 𝑧 = 2.4, based on approximately 100 nights of observations. The program has two primary goals: (1) to rule out the inverted neutrino mass hierarchy by measuring Σ𝑚𝜈 < 0.1 eV at 95% CL, or to determine the total neutrino mass if Σ𝑚𝜈 > 0.1 eV, and (2) to test the standard ΛCDM paradigm by identifying time evolution in dark energy density or deviations from General Relativity (GR) on cosmological scales, or to confirm ΛCDM with unprecedented precision.

These goals will be achieved by measuring cosmological distances, the expansion rate, and the growth rate of matter density fluctuations with a few percent uncertainty across seven redshift bins. The program's wide redshift coverage enables robust internal consistency checks, while the high galaxy sample density allows extraction of small-scale clustering information. Additionally, synergy with Subaru Hyper Suprime-Cam (HSC) imaging data will enhance constraints on neutrino mass, dark energy, and modified gravity. Cross-correlations between 3D galaxy positions from PFS and weak lensing shear from HSC will improve parameter constraints and provide critical cross-checks, ensuring robust and transformative insights into the Universe.

Speaker: Tomomi Sunayama (ASIAA)

76 Stochastic gravitational wave background as a probe of the early universe

The stochastic gravitational wave background (SGWB) provides a unique window into the early universe, offering insights into high-energy physics beyond the reach of conventional cosmological observations. Unlike the cosmic microwave background, which probes the universe after recombination, gravitational waves can propagate freely from the earliest moments after the Big Bang, carrying imprints of inflation, reheating, phase transitions, and other new physics scenarios. In this talk, I will discuss how SGWB measurements can be used to constrain early universe models, with a particular focus on the ongoing LIGO-Virgo-KAGRA observation runs. I will also address the challenges posed by astrophysical foregrounds and the prospects for disentangling primordial signals from astrophysical contributions.

Speaker: Sachiko Kuroyanagi (IFT UAM-CSIC)

SachikoKuroyanagi.pdf

10:10 Coffee

Session8

Convener: Shuichiro Yokoyama

77 Vlasov-Poisson dynamics of cold dark matters around collapse

Cold dark matter (CDM) is microscopically modelled as a self-gravitating collisionless fluid obeying the Vlasov-Poisson equations. The cold nature suggests that the CDM phase-space structure is described as a three-dimensional super-sheet evolving in six-dimensional phase space. At the initial stage, the phase-space sheet represents a single-stream flow, but as a consequence of the non-linear evolution under self-gravity, the phase-space sheet self-interacts, and subsequently the phase-space sheet becomes a multi-stream flow. I will present how the multi-stream appears, and show the importance of considering the effects of multi-stream regions in analysing the dynamics of CDM.

Speaker: Shohei Saga (KMI, Nagoya University)

ShoheiSaga.pdf

78 Akihiro Ishibashi

Speaker: Akihiro Ishibashi (Department of Physics, Kindai University)

79 Holography for de Sitter gravity

Holography suggests that gravitational theory can be described by a quantum field theory in one lower dimension. This idea provides an invaluable framework to explore the nature of quantum gravity. In this talk, I will review the basic concepts of holography and highlight recent progress in understanding quantum gravity on anti-de Sitter spacetimes, including the roles of quantum entanglement in shaping spacetime. Then, I will introduce my work which proposes a holographic duality between three-dimensional de Sitter spaces and two-dimensional conformal field theories.

Speaker: Tatsuma Nishioka (Osaka University)

12:00 Lunch

Session9

Convener: Hironao Miyatake

80 Universality of cosmic reionization: a data driven discovery

TBD

Speaker: Yin Li

YinLi.pdf

81 ML on FPGA developments in ATLAS

The use of machine learning (ML) in high energy physics has exploded in the past decade. While it has provide impressive improvements across a broad range of use cases, it has typically been limited to uses with data already collected by experiments. I will discuss the challenges involved with the use of ML on FPGAs in trigger and data acquisition systems in general as well as specific applications of ML on FPGAs in the ATLAS experiment.

Speaker: Dylan Rankin (University of Pennsylvania, Department of Physics and Astronomy)

DylanRankin.pdf

82 Toward Scientific Foundations Models for HEP and AI Research Ecosystem

There has been a significant progress in development of large language models in the industries. These models use self-supervised learning methods through which a big AI model can learn how to effectively capture a greater scope of contexts and result in so-called Foundation Models (FMs). Thanks to their strong encoding capability that extracts a comprehensive set of key features in data, once trained with a big data, FMs can be applied on a spectrum of tasks with high quality output, often competitive against traditional deep learning models trained with a supervised learning method. There has been an active research to develop a Scientific FMs, the big models trailed with self-supervision on scientific datasets. While progress is made, there are unique challenges and potential AI/ML research opportunities identified for scientific datasets. In this talk, I will give a brief example of FMs and applications in High Energy Physics. I will also discuss FMs research as an opportunity to develop a greater AI/ML research ecosystem that can be benefited across multiple domains of science.

Speaker: Kazuhiro Terao (SLAC National Accelerator Laboratory)

83 "Machine Learning Physics" --- an emergent new arena of research unifying AI and physics

Machine learning and physics have long been deeply intertwined, and there have been eras when their relationship came to the forefront. Even in today’s revolutionary AI development, physics has played a significant role—for example, in diffusion models. From a physics standpoint as well, an integrative perspective across various specialized domains is provided by innovative new mathematical frameworks, and machine learning serves as one such framework. Launched in fiscal year 2022, the Scientific Transformation Area Research (A) initiative “Creation of Machine Learning Physics” was established to forge a new interdisciplinary field merging machine learning and physics. Now in its third year, it has produced a wide range of research outcomes and functions as a central hub where many researchers gather. In this talk, I will introduce the goals of this initiative, illustrating them with specific research examples, and discuss the future relationship between machine learning and physics.

Speaker: Koji Hashimoto (Kyoto University)

14:45 Coffee

Session10

Convener: Hiroyasu Tajima

84 GRAINE: sub-GeV/GeV gamma-ray observation using a balloon-borne telescope equipped with nuclear emulsion films

The observation of cosmic gamma rays is crucial for understanding high-energy astrophysical phenomena and the mechanism of cosmic-ray acceleration. We have been running the GRAINE project, a cosmic gamma-ray observation project in an energy range of 10MeV – 100GeV, using balloon-borne telescope equipped with nuclear emulsion, characterized with a high-angular resolution and polarization sensitivity, with a large aperture area (10 m2). The observation in the immediate vicinity of the Galactic center with the high angular resolution may bring new insights into the dark matter density profile among other exciting discoveries. So far, we have repeated balloon experiments for the demonstration. Then, the brightest known gamma- ray source, the Vela pulsar, was clearly detected in 2018 balloon experiment, and the emulsion gamma-ray telescope with the highest angular resolution in this energy region was established in sub-GeV energy region. The latest balloon experiment is GRAINE2023, performed in Australia with an aperture area of 2.5 m2, which is the first step of scientific observation, and we will start to observe not only the pulsar but also the Galactic center region. We will show the overview of GRAINE2023 and the performance evaluation of the flight data.

Speaker: Yuya Nakamura (KMI, Nagoya University)

YuyaNakamura.pdf

85 Analyzing the MWA data for understanding the Epoch of Reionization and Cosmic Dawn

The 21 cm line emitted by neutral hydrogen (HI) atoms is a valuable observable for investigating the high redshift universe. In particular, before cosmic reionization, the universe was filled with neutral hydrogen gas. Due to cosmic expansion, the redshifted 21 cm line before the reionization is observed at frequencies below 200 MHz. Therefore, low-frequency radio observations can map HI signals across multiple epochs. The physical state of HI gas strongly depends on radiation from the first stars and galaxies. The 21 cm signal reveals the history of gas heating, sources of reionization, birth of first stars, and fundamental cosmology. However, despite significant efforts of multiple observatory, the 21 cm fluctuations from the Epoch of Reionization (EoR) have not yet been detected, though several radio instruments have provided upper limits on the signal. The Murchison Widefield Array (MWA), a low-frequency radio interferometer located in Western Australia, has been conducting 21 cm line observations for the past 10 years. In this talk, I review recent and ongoing EoR 21cm line analyses, with a particular focus on the MWA.

Speaker: Shintaro Yoshiura (NAOJ)

86 Observations of X-ray and Gamma-ray Line Emissions with XRISM and COSI

The XRISM satellite, launched in 2023, provides an X-ray spectroscopy with > 1000 resolving power around 6 keV Fe-K lines. The mission is providing numerous new insights with the high resolution spectra. On 2027, the MeV all-sky mission COSI will be launched. The mission will provide >~ 100 resolving power at 511-2 MeV. We will give the latest review of the early science results and project status of these missions.

Speaker: Kazuhiro Nakazawa (Nagoya University)

87 Overview of gravitational-wave observations and detector improvements

The LIGO-Virgo-KAGRA collaboration is currently in its fourth observing run, having detected approximately 200 gravitational wave (GW) events. This presentation will provide an overview of GW observations since the first detection in 2015, discuss future prospects, and highlight our research on GW detector science at Nagoya University.

Speaker: Keiko Kokeyama (Nagoya University / Cardiff University)

KeikoKokeyama.pdf

88 Gamma Ray Busters: the search of the lost PeVatrons

Gamma-ray astronomy plays a fundamental role in the understanding of very high energy tricky and outstanding sources in our own Galaxy and their role in particle acceleration.

In this context, despite the enormous efforts done in very recent years, both theoretically and experimentally, Cosmic Ray (CR) origin remain without clear answers. Two are the hints of CR acceleration that are sought in the gmma-ray band: the "pion bump" at about 68 MeV and an emission at energy above 100 TeV.

Their commonly accepted galactic sources, Supernova Remnants, can accelerate low-energy CRs (below 1 TeV) but theoretical models show that only very young SNRs (<100yrs) accelerate CRs at PeV energies.

In the meantime, current VHE instruments added other candidate sources for CR acceleration; massive star clusters, novae and microquasars jets that were been recently detected at VHE, adding themselves to the fascinating world of Galactic accelerators. Moreover, the last results published by the LHAASO collaboration, then confirmed by other instruments, revealed the existence of several PeV sources likely related to PWNae, well known leptonic factories (e.g. the Crab Nebula for all). And finally also some known SNRs, older than 100 yrs, were detected t E>100 TeV.

Parameters understanding, multi-wavelength comparison, lower spectral errors are fundamental ingredients to distingush hadronic and leptonic accelerators and to do another step forward the understanding of CR origin. In this context, the future Cherenkov telescopes, as ASTRI Mini-Array and CTA, and a possible gamma-ray satellite focused on the "pion bump" energies, will have a great role.

Speaker: Martina Cardillo (IAPS-INAF)

MartinaCardillo.pdf

Final remark