＜＜＜「@」を「__AT__」に置き換えています＞＞＞

Date: Fri, 9 May 2025 16:53:28 +0900
To: sg-l__AT__ml.yukawa.kyoto-u.ac.jp
Subject: [Sg-l:9370] RIKEN FBSP Seminar May 15 by Tomona Kinugawa - Internal structure of near-threshold states using compositeness
From: yuki kamiya (Sg-l 経由) 

皆様、

理研少数多体系物理研究室のセミナーのお知らせです。
今回は、本研究室の衣川友那さんに講演していただきます（講演は英語です）。
詳細については以下をご覧ください。


Tomona Kinugawa (RIKEN) will give the following seminar at the RIKEN 
FBSP laboratory. The seminar will be held at RIKEN Main Research 
Building, Room 213 and online via Zoom. If you are a subscriber of FBSP 
seminars you will receive the Zoom ID and password by e-mail on the day 
of the seminar. If not, you can get this information at any time 
following this link:
http://snp.riken.jp/seminars.php#2025-05-15 


_____________

Date and time: *Thursday, May 15, 2025 - 14:00 Japan time*
Place: RIKEN Main Research Building, Room 213
Speaker: *Tomona Kinugawa* (RIKEN)
Title: *Internal structure of near-threshold states using compositeness*

Abstract:

Motivated by recent observations of exotic hadrons in the near-threshold 
energy region, the internal structure of near-threshold states has been 
intensively studied. In various works, a qualitative measure, called the 
compositeness, has been used to characterize the structure of 
near-threshold states. The compositeness represents the fraction of the 
hadronic molecular component in the wavefunction [1]. It is shown that 
in the limit where the binding energy goes to zero, the compositeness 
becomes unity as a consequence of the low-energy universality [2]. This 
indicates that the states exactly at the threshold commonly have a 
purely molecular structure, independently of the details of the system. 
Based on this fact, near-threshold states with small but finite 
eigenenergies are naively expected to be molecular dominant states whose 
compositeness is close to unity (the threshold energy rule) [3]. 
However, this rule is empirical, and its theoretical foundation has not 
yet been established. To understand the nature of near-threshold exotic 
hadrons, we aim to provide the theoretical foundation of the threshold 
rule by analyzing the structure of near-threshold states in light of the 
low-energy universality.

We first focus on near-threshold bound states slightly below the 
threshold with small and negative eigenenergies. Using an effective 
field theory model, the model dependence of the compositeness of bound 
states is examined. We show that the shallow bound states are usually 
composite dominant without significant fine tuning, which is explained 
by the emergence of the low-energy universality [4]. This provides the 
theoretical foundation of the threshold energy rule for bound states. We 
then consider the structure of the near-threshold resonances, which 
exist above the threshold with small and positive excitation energy. 
Using the effective range expansion, we calculate the compositeness of 
near-threshold resonances, and find that the near-threshold resonances 
are non-composite dominant [5]. This shows that the structure of 
near-threshold resonances is completely different from that of bound 
states, which is another aspect of near-threshold phenomena that 
deviates from the expectations based on the threshold energy rule. 
Finally, we also discuss how the Coulomb interaction affects the 
structure of the near-threshold states.


[1] T. Kinugawa, T. Hyodo, arXiv:2411.12285 [hep-ph], accepted in EPJ A.
[2] T. Hyodo, Phys. Rev. C 90, 055208 (2014).
[3] K. Ikeda, and N. Takizawa, and H. Horiuchi, Prog. Theor. Phys. 
Suppl. E68, 464-475 (1968).
[4] T. Kinugawa and T. Hyodo, Phys. Rev. C 109 , 045205 (2024).
[5] T. Kinugawa and T. Hyodo, arXiv:2403.12635 [hep-ph].

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神谷　有輝
東北大学 大学院理学研究科 物理学専攻
原子核理論研究室
e-mail : yuki.kamiya.d3__AT__tohoku.ac.jp
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Date: Mon, 19 May 2025 13:41:51 +0900
To: ml-np__AT__rcnp.osaka-u.ac.jp, sg-l__AT__yukawa.kyoto-u.ac.jp
Subject: [Sg-l:9389] RIKEN FBSP seminar May 20 by Yamato Suda - Different types of dynamical chiral symmetry breaking in the interacting instanton liquid model
From: yuki kamiya (Sg-l 経由) 

皆様、

理研少数多体系物理研究室のセミナーのお知らせです。
今回は、東京科学大学の須田さんに講演していただきます。
詳細については以下をご覧ください。


Dear all,

Yamato Suda (Institute of Science Tokyo) will give the following seminar 
at the RIKEN FBSP laboratory. The seminar will be held at RIKEN Main 
Research Building, Room 213 and online via Zoom. If you are a subscriber 
of FBSP seminars you will receive the Zoom ID and password by e-mail on 
the day of the seminar. If not, you can get this information at any time 
following this link:
http://snp.riken.jp/seminars.php#2025-05-20 


_____________

Date and time: *Tuesday, May 20, 2025 - 13:30 Japan time*
Place: RIKEN Main Research Building, Room 213
Speaker: *Yamato Suda* (Institute of Science Tokyo)
Title: *Different types of dynamical chiral symmetry breaking in the 
interacting instanton liquid model*

Abstract:

It has been suggested that the vacuum structure of strong interaction 
may depend not only on the fact that chiral symmetry is dynamically 
broken, but also on the mechanism by which it is broken. Specifically, 
different masses of the sigma meson, which is introduced as the chiral 
partner of pions, are predicted depending on the type of dynamical 
chiral symmetry breaking realized in the vacuum. Motivated by 
discussions in chiral effective theories, we investigate dynamical 
chiral symmetry breaking with different origins using a model that 
describes the QCD vacuum as an interacting instanton liquid.

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神谷　有輝
東北大学 大学院理学研究科 物理学専攻
原子核理論研究室
e-mail : yuki.kamiya.d3__AT__tohoku.ac.jp 
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Date: Tue, 17 Jun 2025 12:11:13 +0900
To: ml-np__AT__rcnp.osaka-u.ac.jp, sg-l__AT__yukawa.kyoto-u.ac.jp
Subject: [Sg-l:9457] FBSP seminar Jun 18 by Yuki Kamiya - Study on hadron-hadron interaction with femtoscopic technique
From: yuki kamiya (Sg-l 経由) 

皆様、

理研少数多体系物理研究室のセミナーのお知らせです。
今回は、本研究室の神谷が講演させていただきます。
詳細については以下をご覧ください。

Dear all,

Yuki Kamiya (RIKEN) will give the following seminar at the RIKEN FBSP 
laboratory. The seminar will be held at RIKEN RIBF 2nd floor and online 
via Zoom. If you are a subscriber of FBSP seminars you will receive the 
Zoom ID and password by e-mail on the day of the seminar. If not, you 
can get this information at any time following this link:
http://snp.riken.jp/seminars.php#2025-06-18 


_____________

Date and time: *Wednesday, June 18, 2025 - 10:00 Japan time*
Place: RIKEN RIBF 2nd floor
Speaker: *Yuki Kamiya* (RIKEN)
Title: *Study on hadron-hadron interaction with femtoscopic technique*

Abstract:

The two-particle momentum correlation function from high-energy nuclear 
collisions is beginning to be used to study hadron-hadron interaction. 
Because this observable is sensitive to the low-energy interaction, it 
is useful to study the nature of the near-threshold resonances and the 
underlying mechanism of the interaction. The meson-baryon and 
baryon-baryon interaction in strangeness and charm sector is the good 
target of this approach.

In this seminar, we will discuss how interactions can be determined from 
real femtoscopic data. With the actual analysis. As specific examples, 
we will discuss data analysis of Kbar-N and p-phi. We will also consider 
the off-shell ambiguity of the correlation function and discuss how this 
affects the actual data analysis.


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神谷　有輝
東北大学 大学院理学研究科 物理学専攻
原子核理論研究室
e-mail : yuki.kamiya.d3__AT__tohoku.ac.jp 
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Date: Fri, 20 Jun 2025 17:06:36 +0900
To: ml-np__AT__rcnp.osaka-u.ac.jp, sg-l__AT__yukawa.kyoto-u.ac.jp
Subject: [Sg-l:9473] RIKEN FBSP seminar Jun 26 by Hiroshi Toki - Pion Nuclear Physics and (p,p’ pi) reaction proving pionic states
From: yuki kamiya (Sg-l 経由) 

皆様、

理研少数多体系物理研究室のセミナーのお知らせです。
今回は、RCNPの土岐さんにセミナーしていただきます。
詳細については以下をご覧ください。

Hiroshi Toki (RCNP, Osaka) will give the following seminar at the RIKEN 
FBSP laboratory. The seminar will be held at RIKEN RIBF 2nd floor and 
online via Zoom. If you are a subscriber of FBSP seminars you will 
receive the Zoom ID and password by e-mail on the day of the seminar. If 
not, you can get this information at any time following this link:
http://snp.riken.jp/seminars.php#2025-06-26 


_____________

Date and time: *Thursday, June 26, 2025 - 15:00 Japan time*
Place: RIKEN RIBF 2nd floor
Speaker: *Hiroshi Toki* (RCNP, Osaka)
Title: *Pion Nuclear Physics and (p,p’ pi) reaction proving pionic states*

Abstract:

The nucleons, which are the constituent particles of the atomic nucleus, 
are themselves dressed in a thick pion cloud due to the breaking of 
chiral symmetry. Pions also play a central role in the interactions 
between nucleons. The binding energy of the nucleus is provided through 
the strong tensor force mediated by pions. Excited states with high 
momentum generated by the tensor force may exhibit characteristic 
spectra. These are explored through pion knockout reactions (p, p’ pi). 
Nuclear physics is thus described with pions playing the central role.

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神谷　有輝
東北大学 大学院理学研究科 物理学専攻
原子核理論研究室
e-mail : yuki.kamiya.d3__AT__tohoku.ac.jp 
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Date: Thu, 24 Jul 2025 14:51:14 +0900
To: ml-np__AT__rcnp.osaka-u.ac.jp, sg-l__AT__yukawa.kyoto-u.ac.jp
Subject: [Sg-l:9569] Seminar August 4 by Haonan WANG - The production and decay of 𝑿(𝟑𝟖𝟕𝟐) related to 𝑩 meson
From: yuki kamiya (Sg-l 経由) 

皆様、

理研少数多体系物理研究室のセミナーのお知らせです。

今回は、本研究室研修生のWangさんにセミナーしていただきます。

詳細については以下をご覧ください。

Haonan WANG (Institute of Modern Physics, Chinese Academy of Sciences) 
will give the following seminar at the RIKEN FBSP laboratory. The 
seminar will be held at RIKEN Main Research Building, Room 213 and 
online via Zoom. If you are a subscriber of FBSP seminars you will 
receive the Zoom ID and password by e-mail on the day of the seminar. If 
not, you can use the following zoom link only this time:
https://riken-jp.zoom.us/j/97250102657?pwd=KYREUeDHgbiAcA4TRpn4WBhdeKLrpB.1

The seminar information is also available on our laboratory's website:
http://snp.riken.jp/seminars.php#2025-07-29


Date and time: Monday, August 4,14:00 Japan time
Place: RIKEN Main Research Building, Room 213
Speaker: Haonan WANG (Institute of Modern Physics, Chinese Academy of 
Sciences)
Title: The production and decay of 𝑿(𝟑𝟖𝟕𝟐) related to 𝑩 meson

Abstract:

By investigating the production and decay processes of the X(3872) in 
association with B mesons, we have explored various properties of the 
X(3872), with particular emphasis on its coupling structures and 
effective parameters. Our analysis strongly supports the conclusion that 
the X(3872) can’t be interpreted as a pure charmonium state. Instead, 
the results indicate that it possesses a substantial component of a 
hadronic molecular configuration, predominantly composed of a D D-bar* 
bound state. This finding provides further evidence for the exotic 
nature of the X(3872) and highlights the importance of considering 
multi-component structures in the study of near-threshold resonances.


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神谷　有輝
東北大学 大学院理学研究科 物理学専攻
原子核理論研究室
e-mail : yuki.kamiya.d3__AT__tohoku.ac.jp 
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Date: Mon, 29 Sep 2025 13:53:24 +0900
To: sg-l__AT__yukawa.kyoto-u.ac.jp, ml-np__AT__rcnp.osaka-u.ac.jp
Subject: [Sg-l:9723] RIKEN FBSP seminar Oct 7 by Isaac VIDAÑA - Neutron Star Properties and Femtoscopic Constraints
From: yuki kamiya (Sg-l 経由) 

皆さま,

理研少数多体系物理研究室のセミナーのお知らせです。

今回は、Catania大学の Isaac VIDAÑA氏にセミナーをしていただきます。

詳細については以下をご覧ください。


Isaac VIDAÑA (INFN, Università di Catania) will give the following 
seminar at the RIKEN FBSP laboratory. The seminar will be held at RIKEN 
Main Research Building, Room 213 and online via Zoom. You can register 
for the seminar following this link:
https://riken-jp.zoom.us/meeting/register/oStRIzlWQ9KJYUFxP9fbeA 


_____________

Date and time: *Tuesday, October 7, 2025 - 14:00 Japan time*
Place: RIKEN Main Research Building, Room 213
Speaker: *Isaac VIDAÑA *(INFN, Università di Catania)
Title: *Neutron Star Properties and Femtoscopic Constraints*

Abstract:

We construct the equation of state of hypernuclear matter and study the 
structure of neutron stars employing a chiral hyperon-nucleon 
interaction of the Julich–Bonn group tuned to femtoscopic Λp data of the 
ALICE Collaboration, and ΛΛ and ΞN interactions determined from lattice 
QCD calculations by the HAL QCD Collaboration that reproduce the  
femtoscopic ΛΛ and Ξ− p data. We employ the ab-initio microscopic 
Brueckner–Hartree–Fock theory extended to the strange baryon sector. A 
special focus is put on the uncertainties of the hyperon interactions 
and how they are effectively propagated to the composition, equation of 
state, mass-radius relation and tidal deformability of neutron stars. To 
such end, we consider the uncertainty due to the experimental error of 
the femtoscopic Λp data used to fix the chiral hyperon-nucleon 
interaction and the theoretical uncertainty, estimated from the residual 
cut-off dependence of this interaction. We find that the final maximum 
mass of a neutron star with hyperons is in the range 1.3 − 1.4 M⊙, in 
agreement with previous works. The hyperon puzzle, therefore, remains 
still an open issue if only two-body hyperon-nucleon and hyperon-hyperon 
interactions are considered. Predictions for the tidal deformability of 
neutron stars with hyperons are found to be in agreement with the 
observational constraints from the gravitational wave event GW170817 in 
the mass range 1.1 − 1.3 M⊙.

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神谷　有輝
東北大学 大学院理学研究科 物理学専攻
原子核理論研究室
e-mail : yuki.kamiya.d3__AT__tohoku.ac.jp 
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Date: Wed, 1 Oct 2025 14:54:34 +0900
To: sg-l__AT__yukawa.kyoto-u.ac.jp, ml-np__AT__rcnp.osaka-u.ac.jp
Subject: [Sg-l:9729] Re: [CANCELLED] RIKEN FBSP seminar Oct 7 by Isaac VIDAÑA - Neutron Star Properties and Femtoscopic Constraints
From: yuki kamiya (Sg-l 経由) 

皆さま、

先日ご案内した10月7日のIsaac VIDAÑA氏のセミナーですが、
都合によりキャンセルになりましたので、
ご連絡いたします。

神谷


On 2025/09/29 13:53, yuki kamiya wrote:
>
> 皆さま,
>
> 理研少数多体系物理研究室のセミナーのお知らせです。
> 
今回は、Catania大学の Isaac VIDAÑA氏にセミナーをしていただきます。
> 
詳細については以下をご覧ください。
>
>
> Isaac VIDAÑA (INFN, Università di Catania) will give the following 
> seminar at the RIKEN FBSP laboratory. The seminar will be held at 
> RIKEN Main Research Building, Room 213 and online via Zoom. You can 
> register for the seminar following this link:
> https://riken-jp.zoom.us/meeting/register/oStRIzlWQ9KJYUFxP9fbeA 
> 
>
> _____________
>
> Date and time: *Tuesday, October 7, 2025 - 14:00 Japan time*
> Place: RIKEN Main Research Building, Room 213
> Speaker: *Isaac VIDAÑA *(INFN, Università di Catania)
> Title: *Neutron Star Properties and Femtoscopic Constraints*
>
> Abstract:
>
> We construct the equation of state of hypernuclear matter and study 
> the structure of neutron stars employing a chiral hyperon-nucleon 
> interaction of the Julich–Bonn group tuned to femtoscopic Λp data of 
> the ALICE Collaboration, and ΛΛ and ΞN interactions determined from 
> lattice QCD calculations by the HAL QCD Collaboration that reproduce 
> the  femtoscopic ΛΛ and Ξ− p data. We employ the ab-initio microscopic 
> Brueckner–Hartree–Fock theory extended to the strange baryon sector. A 
> special focus is put on the uncertainties of the hyperon interactions 
> and how they are effectively propagated to the composition, equation 
> of state, mass-radius relation and tidal deformability of neutron 
> stars. To such end, we consider the uncertainty due to the 
> experimental error of the femtoscopic Λp data used to fix the chiral 
> hyperon-nucleon interaction and the theoretical uncertainty, estimated 
> from the residual cut-off dependence of this interaction. We find that 
> the final maximum mass of a neutron star with hyperons is in the range 
> 1.3 − 1.4 M⊙, in agreement with previous works. The hyperon puzzle, 
> therefore, remains still an open issue if only two-body 
> hyperon-nucleon and hyperon-hyperon interactions are considered. 
> Predictions for the tidal deformability of neutron stars with hyperons 
> are found to be in agreement with the observational constraints from 
> the gravitational wave event GW170817 in the mass range 1.1 − 1.3 M⊙.
>
> ******************************************
> 神谷　有輝
> 東北大学 大学院理学研究科 物理学専攻
> 原子核理論研究室
> e-mail : yuki.kamiya.d3__AT__tohoku.ac.jp 
> ******************************************
>
>
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神谷　有輝
東北大学 大学院理学研究科 物理学専攻
原子核理論研究室
e-mail : yuki.kamiya.d3__AT__tohoku.ac.jp 
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Date: Fri, 3 Oct 2025 18:55:46 +0900
To: sg-l__AT__yukawa.kyoto-u.ac.jp, ml-np__AT__rcnp.osaka-u.ac.jp
Subject: [Sg-l:9737] RIKEN FBSP Seminar Oct 20 by Hyun-Chul KIM - Chiral effective theory for the nucleon and singly heavy baryons from the instanton vacuum
From: yuki kamiya (Sg-l 経由) 

皆様、

理研少数多体系物理研究室のセミナーのお知らせです。

今回は、Inha大学のHyun-Chul KIM氏にセミナーしていただきます。

詳細については以下をご覧ください。

続けて、YAKHSHIEV氏のセミナー予定についての案内を行いますので、
そちらもご確認ください。

Hyun-Chul KIM (Inha University) will give the following seminar at the 
RIKEN FBSP laboratory. The seminar will be held at RIKEN Main Research 
Building, Room 213 and online via Zoom. You can register for the seminar 
following this link:
https://riken-jp.zoom.us/meeting/register/jd3P-50sQmqAfIQFO4FBSg 


_____________

Date and time: *Monday, October 20, 2025 - 14:00*
Place: RIKEN Main Research Building, Room 213
Speaker: *Hyun-Chul KIM* (Inha University)
Title: *Chiral effective theory for the nucleon and singly heavy baryons 
from the instanton vacuum*

Abstract:

Hadron structure in quantum chromodynamics are theoretically studied by 
considering QCD quark-gluon operators, which consist of an essential 
part of understanding the soft and nonperturbative component of QCD. 
These operators are also in line with the physics program that will be 
pursued at the Eletron-Ion Collider (EIC), which will be constructed at 
the Brookhaven National Laboratory (BNL). Thus, it is crucial to 
construct an effective theory for the quark-qluon dynamics in the 
structure of baryons. In the present talk, we present an effective 
chiral theory for the nucleon based on the low-energy effective QCD 
partition function from the QCD instanton vacuum. The nucleon 
constitutes $N_c$ valence quarks bound by the pion mean field that is 
created self-consistently by their presence. Using a self-consistent 
method, we derive the classical mass of the nucleon, yielding $M_{cl}$ = 
1.2680 GeV. While the results are comparable with the local chiral 
quark-soliton model, the contributions from the Dirac continuum are more 
enhanced by the momentum-dependent quark mass. The zeo-mode quantization 
furnish the nucleon with proper quantum numbers such as the spin and 
isospin. We compute the moment of inertia I = 1.3853 fm, which yields 
the ∆ − N mass splitting $M_{∆−N}$ = 213.67 MeV and that of the singly 
heavy baryons $M_{Σ_c−Λ_c}$ = 206.20 MeV. The effective chiral theory 
developed in the present work is compatible with large $N_c$ QCD, and 
will provide a solid theoretical framework to investigate quark-gluon 
observables of both the light and singly heavy baryons.

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神谷　有輝
東北大学 大学院理学研究科 物理学専攻
原子核理論研究室
e-mail : yuki.kamiya.d3__AT__tohoku.ac.jp 
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Date: Fri, 3 Oct 2025 18:56:13 +0900
To: sg-l__AT__yukawa.kyoto-u.ac.jp, ml-np__AT__rcnp.osaka-u.ac.jp
Subject: [Sg-l:9738] RIKEN FBSP Seminar Oct 24 by Ulugbek YAKHSHIEV - Properties of neutron stars from the pion-mean field approach
From: yuki kamiya (Sg-l 経由) 

皆さま、


理研少数多体系物理研究室のセミナーのお知らせです。

今回は、Inha 大学の Ulugbek YAKHSHIEV 氏にセミナーをしていただきます。

詳細については以下をご覧ください。

また先ほどKIM氏のセミナー情報もご案内しましたので、
そちらもご確認ください。

Ulugbek YAKHSHIEV (Inha University) will give the following seminar at 
the RIKEN FBSP laboratory. The seminar will be held at RIKEN Main 
Research Building, Room 213 and online via Zoom. You can register for 
the seminar following this link:
https://riken-jp.zoom.us/meeting/register/tStFHcXASQWZ1WdupOX3-w 


_____________

Date and time: *Friday, October 24, 2025****- 14:00 Japan time*
Place: RIKEN Main Research Building, Room 213
Speaker: *Ulugbek YAKHSHIEV* (Inha University)
Title: *Properties of neutron stars from the pion-mean field approach*

Abstract:

We discuss the properties of the neutron stars and strangeness-mixed 
stars, based on the pion mean-field approach. Within this approach the 
empirical data on the pion-nucleus scattering and bulk properties of 
nuclear matter played the role of fixing all of the parameters in the 
Lagrangian. As a result, we had the modification of nucleons and 
hyperons in various nuclear media. Further, the approach was used to 
examine the energy, pressure and the central density behaviour in 
various neutron stars. The mass-radius relations will also be discussed. 
We also present our studies on the strangeness-mixed stars using several 
sets of parameters. We will show that if the strangeness content of 
strange matter increases, the corresponding equation of state becomes 
softened.

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神谷　有輝
東北大学 大学院理学研究科 物理学専攻
原子核理論研究室
e-mail : yuki.kamiya.d3__AT__tohoku.ac.jp 
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Date: Fri, 24 Oct 2025 17:24:07 +0900
To: sg-l__AT__yukawa.kyoto-u.ac.jp, ml-np__AT__rcnp.osaka-u.ac.jp
Subject: [Sg-l:9796] RIKEN FBSP Seminar Nov 10 by Jesper LEVINSEN - Role of impurity statistics and constraints on the medium response in polaron-polaron interactions
From: yuki kamiya (Sg-l 経由) 

皆さま、

理研少数多体系物理研究室のセミナーのお知らせです。

今回は、Monash 大学の Jesper LEVINSEN 氏にセミナーをしていただきます。

詳細については以下をご覧ください。

Jesper LEVINSEN (Monash University) will give the following seminar at 
the RIKEN FBSP laboratory. The seminar will be held at RIKEN Main 
Research Building, Room 213 and online via Zoom. You can register for 
the seminar following this link:
https://riken-jp.zoom.us/meeting/register/wnlTXXBaQC6UtNwhtRQhPg 


_____________

Date and time: *Monday, November 10, 2025 - 14:00*
Place: RIKEN Main Research Building, Room 213
Speaker: *Jesper LEVINSEN* (Monash University)
Title: *Role of impurity statistics and constraints on the medium 
response in polaron-polaron interactions*

Abstract:

We consider the behaviour of a small density of mobile impurities 
(polarons) immersed in a quantum gas, a generic scenario that can be 
realized in cold atomic gases, liquid helium mixtures and doped 
semiconductors. We present a unified theoretical framework for 
understanding polaron quasiparticles beyond the single-impurity limit, 
and we identify two key factors that control the polaron-polaron 
interactions: (i) the statistics of the impurities, including whether or 
not they are degenerate, and (ii) the constraints on the medium 
response, i.e., whether the medium density or chemical potential is held 
fixed. By constructing wave functions for two bosonic, fermionic, or 
distinguishable impurities immersed in a Bose or Fermi gas, we derive 
rigorous results for the polaron interactions in the limit of weak 
impurity-medium interactions. We furthermore obtain an exact 
relationship between the polaron interactions at fixed medium density 
and at fixed chemical potential, a result which is valid for arbitrary 
interaction strength. Our work provides an important guide for 
understanding experiments, and it acts as a starting point for future 
strong-coupling theories of polaron interactions that capture all of the 
effects identified in this work.

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神谷　有輝
東北大学 大学院理学研究科 物理学専攻
原子核理論研究室
e-mail : yuki.kamiya.d3__AT__tohoku.ac.jp 
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Date: Wed, 3 Dec 2025 13:43:48 +0900
To: sg-l__AT__yukawa.kyoto-u.ac.jp, ml-np__AT__rcnp.osaka-u.ac.jp
Subject: [Sg-l:9907] RIKEN FBSP Seminar Dec 16 by Tokuro FUKUI - Theoretical study of three-baryon forces
From: yuki kamiya (Sg-l 経由) 

皆さま、

理研少数多体系物理研究室のセミナーのお知らせです。

今回は、九州大学の福井徳朗氏にセミナーをしていただきます。

詳細については以下をご覧ください。

Tokuro FUKUI (Kyushu University) will give the following seminar at the 
RIKEN FBSP laboratory. The seminar will be held at RIKEN Main Research 
Building, Room 213 and online via Zoom. You can register for the seminar 
following this link:
https://riken-jp.zoom.us/meeting/register/fqLJibdZTEOkl42yRXB_vQ 


_____________

Date and time: *Tuesday, December 16, 2025 - 14:00*
Place: RIKEN Main Research Building, Room 213
Speaker: *Tokuro FUKUI* (Kyushu University)
Title: *Theoretical study of three-baryon forces*

Abstract:

First, I briefly review the role of three-baryon forces in nuclear and 
hypernuclear systems. Then, I present our recent study that clarifies 
how the chiral three-nucleon force contributes to spin–orbit splitting 
in light and medium-heavy nuclei. In this work, we introduced a novel 
technique to decompose the three-nucleon force. Finally, I discuss our 
latest research, in which we derived the XiNN three-baryon force from 
SU(3) chiral effective field theory for the first time. We examined its 
role through a femtoscopic analysis of the deuteron–Xi correlation function.

******************************************
神谷　有輝
東北大学 大学院理学研究科 物理学専攻
原子核理論研究室
e-mail : yuki.kamiya.d3__AT__tohoku.ac.jp 
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Date: Fri, 19 Dec 2025 11:18:25 +0900
To: sg-l__AT__yukawa.kyoto-u.ac.jp, ml-np__AT__rcnp.osaka-u.ac.jp
Subject: [Sg-l:9945] RIKEN FBSP Seminar Jan 27 by Philipp GUBLER - Studying proton-nucleus collisions to extract the behavior of vector and axial-vector mesons in nuclear matter
From: yuki kamiya (Sg-l 経由) 

皆さま、

理研少数多体系物理研究室のセミナーのお知らせです。

今回は、原研のPhilipp GUBLER氏にセミナーをしていただきます。

詳細については以下をご覧ください。

Philipp GUBLER (JAEA) will give the following seminar at the RIKEN FBSP 
laboratory. The seminar will be held at RIKEN Main Research Building, 
Room 213 and online via Zoom. You can register for the seminar following 
this link:
https://riken-jp.zoom.us/meeting/register/0Fvr0DJkRw-oZAfqUSmIqg 


_____________

Date and time: *Tuesday, January 27, 2026 - 14:00*
Place: RIKEN Main Research Building, Room 213
Speaker: *Philipp GUBLER* (JAEA)
Title: *Studying proton-nucleus collisions to extract the behavior of 
vector and axial-vector mesons in nuclear matter*

Abstract:

At present, there is no clear consensus regarding how the mass and width 
of the phi meson are modified in a dense environment such as nuclear 
matter, nor on the strength of its chiral mixing with the axial-vector 
chiral partner. Although a number of theoretical studies have addressed 
these questions, establishing a direct connection with experimental 
observables remains a significant challenge. This difficulty arises in 
part because the phi meson in nuclear matter is typically produced in 
proton–nucleus (pA) reactions, which are inherently non-equilibrium 
processes. In this seminar, I will review the current status of 
theoretical research on the in-medium properties of the phi meson, with 
a particular emphasis on ongoing transport simulations of pA reactions 
that produce phi mesons inside nuclei. These reactions are being 
explored experimentally at KEK E325 and in the J-PARC E16 and E88 
experiments.

******************************************
神谷　有輝
東北大学 大学院理学研究科 物理学専攻
原子核理論研究室
e-mail : yuki.kamiya.d3__AT__tohoku.ac.jp 
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Date: Thu, 5 Feb 2026 11:07:46 +0900
To: ml-np__AT__rcnp.osaka-u.ac.jp, sg-l__AT__yukawa.kyoto-u.ac.jp
Subject: [Sg-l:10062] RIKEN FBSP Seminar Feb 26 by Samson Clymton -Production mechanism of the hidden charm pentaquark states
From: yuki kamiya (Sg-l 経由) 

皆さま、

理研少数多体系物理研究室のセミナーのお知らせです。

今回は韓国APCTPのSamson Clymton氏にセミナーをしていただきます。
セミナーは以下のZoomによるオンラインのみとなります。

https://riken-jp.zoom.us/w/95339728690?tk=E32FUsTeS8JMe86aRDsZwdrhCnDLbCtaxpFSvXWiEA8.DQkAAAAWMrDPMhY5bmowTWlxOFFWdTZ1THpUemw0RW93AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA&pwd=rmRZUG0egeJa8ladQbfTX50HgtYFHb.1

詳細については以下をご覧ください。

*Samson CLYMTON's seminar*
Date & Time 	Feb 26, 2026 03:30 PM Osaka, Sapporo, Tokyo
Webinar ID 	953 3972 8690
Participant ID 	401422
Passcode 	hpydh7RLSB
Description 	Date and time: Thursday, February 26, 2026 - 15:30
Speaker: Samson Clymton (APCTP)
Title: Production mechanism of the hidden charm pentaquark states

Abstract:

The LHCb collaboration’s discovery of pentaquarks has revitalized 
interest in heavy exotic baryon
spectroscopy, motivating extensive searches for new states. In this 
work, we investigate hidden charm pentaquark states in heavy meson and 
singly heavy baryon systems by employing an off-shell
coupled-channel formalism. The interaction kernel is constructed from 
meson exchange diagrams
using an effective Lagrangian that respects both heavy quark spin 
symmetry and hidden local
symmetry. In this talk, I will present our study of the production 
mechanisms of hidden-charm
pentaquark states ranging from S = 0 to S = −3 in strangeness. Several 
key findings will be dis cussed: the suppression of Pcc¯ signals in J/ψ 
photoproduction; the two-pole structure of Pccs¯ (4459);
predictions of I = 3/2 Pcc¯ and I = 1 Pccs¯ states; and predictions of 
eight Pccss ¯ and two Pccsss ¯
states. These findings provide insights into the production dynamics and 
properties of pentaquark
states while offering predictions that can guide future experimental 
observations.

******************************************
神谷　有輝
東北大学 大学院理学研究科 物理学専攻
原子核理論研究室
e-mail : yuki.kamiya.d3__AT__tohoku.ac.jp 
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