NUSPEQ2023 - International Symposium on Nuclear Spectroscopy for Extreme Quantum Systems

7 Mar 2023, 08:50 → 9 Mar 2023, 21:15 Asia/Tokyo

Plaza Verde Convension Hall B (Numazu, Shizuoka)

Yasuhiro Sakemi (CNS, Univ. of Tokyo)

 

The International Symposium on Nuclear Spectroscopy for Extreme Quantum Systems (NUSPEQ2023) will be held on March 7th-9th, 2023 in Shizuoka Pref. Japan. In the symposium, experimental and theoretical achievements in the nuclear reaction and structure of the last decades will be reviewed and the prospects of nuclear physics will be discussed.

 

2nd shot of the symposium photo will be taken at venue at 12:00 am on March 9th.

 

 

Registration desk opens at 8:30 am on March 8th

Important Dates

31st/Oct./2022 First circular

10th/Dec./2022 2nd circular and Registration starts

6th/Feb./2023 Final circular

7th/Mar./2023 Symposium

 

Hosted by

Center for Nuclear Study, the University of Tokyo,

RIKEN Nishina Center,

Grant-in-aid for scientific research in Innovative areas,

JSPS A3-Foresight program

Supported by

Asian Nuclear Physics Association (ANPhA)

 

Invited speakers

• Prof.  Navin Alahari (GANIL)
• Prof. Angela Bonaccorso (Pisa)
• Prof. Thomas Aumann (GSI)
• Prof. Gianluca C’olo(Milano, online)
• Dr. Rimantas Lazauskas (CNRS, online)
• Prof. Kevin Hahn (IBS)
• Prof. Muhsin Harakh (KVI)
• Prof. Andy Chae (Sungkyunkwan University)
• Prof. Eiji Ideguchi (RCNP, Osaka)
• Prof. Naoyuki Itagaki (Osaka Metropolitan University)
• Prof. Takahiro Kawabata (Osaka)
• Prof. Yosuke Kondo (Tokyo Institute Tech)
• Prof. Augusto Macchiavelli (ORNL)
• Prof. Shin’Ichiro Michimasa (CNS, Tokyo)
• Prof. Kenjiro Miki (Tohoku Univ.)
• Prof. Kazuyuki Ogata (Kyushu)
• Prof. Nigel Orr (LPC-CAEN)
• Prof. Shinsuke Ota (RCNP, Osaka U.)
• Prof. Akito Saito (Hiroshima)
• Prof. Noritaka Shimizu (Tsukuba)
• Prof. Hiro Tamura (Tohoku)
• Prof. Xiaodong Tang (IMP)
• Prof. Alexandre Obertelli (TU Darmstadt)

Organizing Committee

Y. Sakemi (Chair, CNS, U. of Tokyo)

N. Aoi (RCNP, Osaka U)

E. Hiyama (Tohoku/RIKEN)

N. Imai (CNS, U. of Tokyo, Secretary)

Y. Maeda (Miyazaki U/ELPH Tohoku)

M. Matsuo (Niigata U)

S. Michimasa (CNS, U. of Tokyo)

T. Nakamura (Titech)

K. Ogata (Kyushu)

S. Ota (RCNP, Osaka U)

T. Uesaka (RIKEN)

Y. Utsuno (JAEA/CNS, U. of Tokyo)

Y. Yanagisawa (RIKEN)

R. Yokoyama (CNS, U. of Tokyo)

N. Kitamura (CNS, U. of Tokyo)

 

特定商取引法に基づく表記

 

 

1stcircular_NUSPEQ2023.pdf

2ndCircular_nuspeq2023.pdf

FinalCircular_NUSPEQ2023_2.pdf

Payment-NUSEPQ2023.pdf

Tuesday, 7 March ¶

08:50 → 10:20 Session 1¶

08:50 Opening¶

Speaker: Prof. Yasuhiro Sakemi (CNS)

09:00 Probing exotic nuclei with beams far from the dripline¶

The GANIL facility provides a wide range of stable and short-lived unstable beams (ISOL and fragmentation) and more recently, intense beam of neutrons has been added to this repertoire. Coupling these with a variety of unique and state-of-the-art equipments allows study of the evolution of the properties of the quantum many body system, the nucleus, as a function of the three axes of nuclear physics, namely excitation energy, angular momentum and isospin.
The upgraded VAriable MOde Acceptance Spectrometer (VAMOS++), one such device, is a versatile large acceptance spectrometer capable of isotopic identification and dditionally measuring angular distributions of the reaction products ranging from low Z to fission fragments over a wide range of energies. VAMOS++ can be efficiently coupled with a large variety of g-ray and charged particle detector arrays. The program at VAMOS++ exploits stable and radioactive ion beams, using prompt and delayed g rays and charged particles produced in a few nucleon/multi nucleon transfer reactions and fission processes.
In this talk after an introduction to the facility, we will focus on some aspects of these investigations, using stable beams at VAMOS++, to explore the evolution of nuclear structure at high spin - isospin and the quest for the production and characterizing of nuclei around N=126 exploiting fission and
multi-nucleon transfer processes respectively.

Speaker: Prof. Navin Alahari (Grand Accélérateur National d'Ions Lourds,)

09:40 Probing star evolution in deep underground laboratory with JUNA¶

Jinping Underground experiment for Nuclear Astrophysics (JUNA) takes advantage of the ultralow background of the CJPL. Commissioning of mA level high current accelerator based on an ECR source and BGO and 3He detectors finished in 2020. JUNA started experiments to directly study the many crucial reactions occurring at relevant stellar energies during the evolution stars. JUNA performed the direct measurements of 25Mg(p,g)26Al, 19F(p,g)16O, 19F(p,g)20Ne, 13C(a,n)16O, 18O(a,g)22Ne and 12C(a,g)16O. Research highlights, which provide reaction rates in higher precision, wider energy range near Gamow window and their astrophysics implications will be presented

Speaker: Prof. Liu Weiping (CIAE)

10:40 → 12:20 Session 2¶

10:40 The Islands of Inversion from the Nilsson Perspective¶

Speaker: Prof. Augusto Macchiavelli (ORNL)

11:20 Role of neutron pairing in alpha-knockout amplitude¶

The formation of alpha particles in the surface region of medium and heavy nuclei is related to the alpha-particle correlation and formation in low-density nuclear matter and the microscopic description of alpha decay. Recently measured alpha knock-out cross section in a series of Sn isotopes is reported to be correlated with the number of alpha particles in the nuclear surface evaluated with the effective model based on the relativistic mean-field theory [1,2].
In this presentation, we intend to describe the alpha knock-out amplitude based on the nuclear density functional theory that does not treat the explicit alpha-particle degree of freedom. We evaluate the transition matrix elements of the four-nucleon annihilation operator as a function of the coordinate. Within the nuclear density functional theory without neutron-proton mixing, the transition matrix element is a product of the neutron part and proton part,
and the neutron pairing in the initial nucleus of the decay plays a dominant role. In the case of the Sn isotope, the pairing is present only in the neutrons, and the transition matrix element shows a strong correlation with the neutron pairing gap. The square of the transition matrix element explains the relative trend of the experimentally measured alpha knock-out cross-section in 112-124Sn.

[1] J. Tanaka, et al., Science 371, 2360 (2021).
[2] S. Typel, Phys. Rev. C 89, 064321 (2014).

Speaker: Nobuo Hinohara (University of Tsukuba)

11:50 PHANES Project : Investigation of Nucleonic Matter Property¶

Speaker: Shinsuke OTA (RCNP, Osaka University)

14:00 → 15:40 Session 3¶

14:00 Next steps of experimental multi-neutron study¶

Speaker: Dr Kenjiro Miki (Tohoku University)

14:30 Quest(ion)ing (for) the light multineutron systems¶

In this presentation I will make a short overview on the possible existence of light pure neutron systems from the theoretical perspective. Then I will present a model calculations, which explain presence of a sharp four neutron energy distribution observed in [Nature Vol. 606, p. 678], studying fast removal of the alpha-particle from the ${}^8$He nucleus.

Speaker: Dr Rimantas Lazauskas

15:00 TBA¶

Speaker: Prof. Tom Aumann (T.U. Darmstadt)

16:00 → 17:30 Session 4¶

16:00 Machine Learning for Nuclear Astrophysics¶

Phenomenologies are essential in various physics research. They typically contain various parameters to reproduce observational data, where each parameter determination affects the others. Some models include parameters that do not correspond to observables of a system, and frequently ambiguity in the values of unobservables can change the model predictions of observables. Additionally, if the number of unobservable parameters is large, the fitting process will be challenging.
The R-matrix phenomenology is dominantly used in nuclear physics to extract nuclear information from measurements. However, it contains unobservable parameters that disturb the fitting analysis of physical properties as the choices of the parameters are somewhat arbitrary. These parameters have complicated the determinations of the critical properties in nuclear physics. Here, we demonstrate that we can disregard such problematic parameters using deep learning. A deep learning model is trained to predict main nuclear properties from observational data without any information on the unobservables. The model finds patterns of the nuclear properties that appear in the observational data. The model successfully predicts the properties with high performance even in the presence of measurement noises. The methodology is applicable to any other physics phenomenology if one tries to connect the observational data and desired parameters without the others.

Speaker: Prof. Andy Chae (SKKU)

16:30 Recent progress of shell-model calculations and quadrupole collective states¶

While the shell-model calculation is one of the most powerful models to investigate the nuclear structure, the explosive increase of the dimension of the shell-model Hamiltonian matrix hampers us from applying it to heavy nuclei. To overcome this difficulty, we developed the Monte Carlo shell model (MCSM) and its extension, the quasi-particle vacua shell model (QVSM). These methods enable us to study the quadrupole collective states of medium-heavy nuclei. I will
review the recent progress of the numerical aspects of shell-model study and its application to the shape phase transition of the Nd and Sm isotopes. The nuclear matrix element of the neutrinoless double beta decay will also be investigated.

Speaker: Prof. Noritaka Shimizu (Tsukuba University)

17:00 Transition from nucleus to medicine¶

Medical physics is a translational research field that applies knowledge and technologies developed in basic sciences and other fields to medicine. Major medical physics research topics are the evaluation of the performance of newly imported techniques and the development of new medical systems and devices. While the typical goal of medical physics is to establish clinically available systems, these systems have a potential risk of malfunction due to unresolved mechanisms. To explore the exact characteristics of such unresolved mechanisms, I have been working on a relationship between cause and effect in the quality assurance system used in radiotherapy clinical practices. In this presentation, I will introduce the prediction of gamma passing rate, a score of similarity of two dose distributions, using an ab initio-type approach [1,2]. I will also introduce the application of the event-mixing technique to evaluate the predicted gamma passing rate, the automatic calibration of an arbitrarily-set near-infrared camera system is also introduced in the presentation [3,4], and the development of the in-air readout optical computed tomography for gel dosimetry for radiotherapy.

[1] E Shiba, A Saito et al, Medical Physics 46, 999$–$1005 (2019).
[2] E Shiba, A Saito et al, Medical Physics 47, 1349$–$1356 (2020).
[3] A Saito et al, Medical Physics 46, 1163$–$1174 (2019).
[4] A Ohashi, T Nishio, A Saito et al, Physical and Engineering Sciences in Medicine 45, 143$–$155 (2022).

Speaker: Akito Saito (Hiroshima University)

Wednesday, 8 March ¶

09:30 → 10:40 Session 6¶

09:30 Low-energy nuclear physics opportunities in Korea¶

The radioactive ion (RI) beam accelerator facility called RAON is under construction in
Korea.
It will produce RI beams by the ISOL and In-flight methods as well as stable beams. One of
the experimental facilities called KoBRA is expected to carry out nuclear astrophysics and
nuclear structure experiments in the early phase of RAON. Several experiments using both
stable and RI beams of tens of MeV/u are considered for nuclear astrophysics and nuclear
reaction studies. Several detector systems and experimental devices are being developed by
the IBS Center for Exotic Nuclear Studies (CENS). One of the main detectors is an active
target TPC detector called ATOM-X. It will be used for low energy experiments, such as
alpha elastic scattering and the (a,p) reaction related to nuclear astrophysics. We are also
constructing a gas target and silicon detector systems that can be used to study nuclear
reaction and structure studies by (p,d), (p,t), (d,p), (3He,t) etc. HPGe clover detectors and
their support structure for gamma-ray spectroscopy are under construction. We are also
developing a Wien filter, which will be installed in the KoBRA beam line. Status of the
RAON accelerator and research activities at CENS will be discussed.

Speaker: Prof. Kevin Hahn (CENS, IBS)

10:10 Some recent advances in direct reaction studies¶

Speaker: Prof. Kazuyuki Ogata (Kyushu University/RCNP, Osaka University)

11:00 → 12:10 Session 7¶

11:00 Spectroscopy of Λ Hypernuclei¶

Speaker: Prof. Hirokazu Tamura (Tohoku University)

11:40 Nucleon removal, a tool to study rare isotopes¶

Speaker: Prof. Alexndre Obertelli (T.U. Darmstadt)

13:30 → 14:30 Short presentation for the poster contribution¶

13:30 The direct mass measurement of very proton-rich iron isotopes¶

The two-proton radioactivity (2p decay) is an exotic decay mode predicted theoretically in the 1960s and first discovered experimentally in 2002. Two protons are simultaneously emitted from the ground state of some neutron-deficient nuclei such as 19Mg, 45Fe, 48Ni, and 54Zn.
Because the two-proton emitters are very undatable, it is challenging to study their energy structure and the mechanism of 2p decay is not fully established.
In this research, we performed the direct mass measurement of 45Fe and the nucleus in its vicinity to reveal the energy structure and proton separation energy using the Tof-Brho method. We are aiming to evaluate the probability that two-protons tunnel the potential barrier. The present status of the data analysis will be reported in the presentation.

Speaker: Shutaro Hanai (CNS,the university of Tokyo)

13:35 Study of heavy-ion fusion reactions in inverse kinematic systems using low-energy 136Xe beam¶

Although currently extended to element 118, the periodic table of the elements is still far from reaching the end. Search for the Island of Stability has been one of the most attractive problems. The existence of the Island of Stability is predicted based on the Shell Model lighter than Pb, thus energies of single-particle levels require further confirmation when extrapolating to the Super Heavy (SH) region. However, nuclear structure information in the region between Pb and SH region, namely Very Heavy (VH) region, is lack exploration.
The heavy-ion fusion-evaporation reaction is a powerful tool in expanding the chart of nuclides as well as probing the nuclear structure beyond Pb. To design the experiments to study VH/SH nuclei and towards the Island of Stability, we need a reaction model that can precisely give the cross sections, while the fusion dynamics have not been established yet. In particular, the so-called “fusion hindrance” effect caused by Quasi-Fission has not been understood quantitively. Therefore, a series of experiments have been designed to evaluate the fusion hindrance effect quantitively.
To commission the experimental setup, a fusion reaction using the low-energy ${}^{136}$Xe beam to bombard the ${}^{nat}$Zn target was performed in July 2022 at HIMAC. Two-newly developed detectors were applied in the experiment. A ToF spectrometer based on Micro Channel Plate was applied to measure the ToF of the beam, and thus the beam energy can be determined. A position-sensitive mosaic-type detector consisting of 128 Si PIN Photo-Diodes was used to measure the decayed alpha particles from Evaporation Residues (ERs). Partial ERs were identified by the in-beam alpha measurement and off-beam activation measurement, independently. Experimental spectra were compared with realistic Monte-Carlo simulations. Cross sections of partial ERs were extracted and compared with the calculations of the statistical models. The introduction of the experimental setups and the results of the analysis will be given in detail.

Speaker: Jiatai Li (Center for Nuclear Study, University of Tokyo)

13:40 Moments of inertia of paring rotation calculated with BCS model for the pairing Hamiltonian¶

Among open-shell nuclei, systematic difference is found in ground-state energies between odd-even and even-even nuclei.
This is because the pairing interaction lowers the ground-state energy of even-even nuclei.
If we focus on the second-order terms of expansion of the ground-state energy with respect to the neutron number difference from one nuclide, nuclei in an isotopic chain may form a pairing rotational band.
Experimentally measured energies are also supporting the interpretation of this pairing rotational band.
The pairing correlations could lead to the breaking of the gauge symmetry.
The state has a specific orientation in the gauge space because of the spontaneous breaking of the gauge symmetry. As a result, it has a new rotational degree of freedom and a moment of inertia.

For a simple model of Sn isotopes, I adopt the BCS model for the pairing Hamiltonian and study the pairing rotational bands and their moments of inertia.
Next, I perform the particle-number projection of the obtained BCS states to obtain particle-number eigenstates.
In order to determine the pairing strength G, I study the dependence of the moments of inertia on G, then examine whether the pairing rotational bands and the moment of inertia are reproduced with the projected states.

Speaker: Chisato Ruike (College of physics, School of science and engineering, University of Tsukuba)

13:45 Systematic measurement project of ISGMR in nuclear chart including unstable nuclei using CNS Active Target (CAT-M)¶

The equation of state of nuclear matter (EOS) plays an important role not only in nucleus but also in extreme quantum systems such as neutron stars. Incompressibility of symmetric nuclear matter ($K_0$) and isospin dependence ($K_{\tau }$) are the parameters of EOS, and they can be extracted from the nuclear incompressibility $K_A$ measured from the isoscalar giant monopole resonance (ISGMR).

Previous studies have reported $K_0=240\pm 20$ MeV and $K_{\tau }=-550\pm 100$ MeV. The larger error in the $K_{\tau }$ arises from the limited asymmetry parameter in the stable isotopes and also from the uncertainty in the assumption of the surface term in the expansion of nuclear incompressibilities. Systematic ISGMR measurements including unstable nuclei enable quantitative evaluation of surface effects.

An active target CAT-M has been developed for the systematic measurement including unstable nuclei. The CAT-M consists of a time projection chamber (TPC) with an active volume of $300\times 300\times 200$ mm${}^3$ and a dipole magnetic field inside the TPC and an array of twelve strip silicon detectors with a sensitive area of $96\times 96$ mm${}^2$ for measuring recoil particles, and a small TPC with an active volume of $30\times 30\times 10$ mm${}^3$ for beam particle measurement. The dipole magnet was introduced recently to eliminate the delta-rays, which induce the noise in the recoil region. The signal-to-noise ratio was improved by $100$ times under high-intensity heavy ion beam irradiation.

The systematic measurement for various isotopes including ${}^{132}\mathrm{Xe}$, ${}^{136}\mathrm{Xe}$, and ${}^{80}\mathrm{Kr}$, ${}^{84}\mathrm{Kr}$, ${}^{86}\mathrm{Kr}$ was performed in these years at an accelerator facility HIMAC in Chiba. We will report an overview of the project and the ISGMR measurement using the ${}^{86}\mathrm{Kr}$ $(d,d^{\prime })$ reaction.

Speaker: Fumitaka Endo (Tohoku Univ)

13:50 Effect of the Coulomb interaction on nuclear deformation and drip lines¶

The energy density functional method is able to provide systematic analysis on properties of nuclei all over the nuclear chart.
We perform the calculations for nuclei from the proton to the neutron drip lines including superheavy nuclei.
Using HFBTHO program(Axially deformed solution of the Skyrme-Hartree–Fock–Bogoliubov equations using the transformed harmonic oscillator basis (II)), the effect of Coulomb interaction on the detormation of even-even nuclei and drip line is reported.
The results show that the Coulomb interaction increases the deformation of nuclei in the large mass number range and stretches the drip line toward the neutron side.
It is interesting to find that the Coulomb interaction gives additional binding to nuclei near the neutron drip line.
In order to understand microscopic mechanisms of these effects, we plan to report results of calculations with constraints on deformation, radius, etc.

Speaker: kenta hagihara (University of Tsukuba)

13:55 Nuclear Structure Study of Neutron-Rich Odd Xe Nuclei by β-γ Spectroscopy¶

Shape evolution from spherical to deformed nuclear system is being studied to reveal the effect of nuclear interactions as an increase of neutron number in finite quantum many-body system. Neutron-rich odd Xe nuclei with $A$ ~ 140 are located at the northeast transitional-mass region of the doubly-magic ${}^{132}$Sn ($Z$ > 50 and $N$ > 82). Various nuclear structure with prolate collectivity and octupole correlation are expected to appear this mass region, which is also located around ${}^{144}$Ba ($N$ = 88), well known for octupole collective properties.
Neutron-rich Xe nuclei are investigated as a part of EURICA campaign at RIBF, RIKEN, based on $\beta$- and isomer-decay spectroscopy. Neutron-rich nuclei with $A$ ~ 140 were produced by in-flight fission of ${}^{238}$U beam with energy of 345 MeV/nucleon and intensity of ~5 pnA, bombarding on a 3 mm Be target. The fragments were then separated and identified through BigRIPS separator and ZeroDegree spectrometer. Ion and $\beta$ ray were detected by WAS3ABi which consists of 5 DSSSD with 60 vertical and 40 horizontal strips. The parent $\beta$ decaying nucleus was identified by the same detected position of ion and $\beta$ ray at the WAS3ABi. Gamma ray was detected by using EURICA, a $\gamma$ ray detector array consisting of 12 cluster-type Ge detectors.
In this work, neutron-rich odd Xe nuclei are investigated by the $\beta$ decay and the $\beta$-delayed neutron decay of I isotopes and the decay schemes were carefully constructed. Nuclear structure in low-lying states in odd Xe nuclei will be discussed.

Speaker: Nurhafiza M. Nor (Dept. of Phys., Osaka Univ.)

14:00 The search for double Gamow--Teller giant resonance with the (12C,12Be(02+)) reaction¶

The double Gamow–Teller (DGT) transition is a nuclear process such that the spin and isospin are changed twice by a $(\sigma \tau {)}^2$ operator. Existence of giant resonance in DGT (DGT giant resonance, DGTGR) was first proposed in 1989 [1], but it remains undiscovered experimentally. We are aiming at the observation of the DGTGR. The experimental observation of DGTGR will provide information about two-phonon excitations with the nuclear spin-dependent correlations. In addition, it is also important in neutrino physics since the observables such as the transition strength and centroid energy of the DGTGR are suggested to be strongly correlated with the nuclear matrix element for a neutrinoless double $\beta$ decay [2].
We utilize the double-charge exchange reaction (${}^{12}$C, ${}^{12}$Be(0${}_2^{+}$)) for the observation of the DGTGR. This reaction has mainly two advantages to observe the DGTGR. First, the transition from ${}^{12}$C(0${}_{\mathrm{g}.\mathrm{s}.}^{+}$) to ${}^{12}$Be(0${}_2^{+}$) through the intermediate state of ${}^{12}$B(1${}^{+}$) is expected to be strong since these states are all dominated by $0\hslash \omega$ configurations. Second, Be(0${}_2^{+}$) decays into the ground state by emitting an electron-positron pair. Detecting the delayed-$\gamma$ ray from the ${}^{12}$Be(0${}_2^{+}$) serves to tag the events of the double spin-flip mode.
We performed the first measurement of the (${}^{12}$C, ${}^{12}$Be(0${}_2^{+}$)) at RIBF in May 2021. In this experiment, we used a part of BigRIPS separator, F0--F5, as a spectrometer [3]. The ${}^{12}$C primary beam of 250 MeV/u and ${}^{48}$Ca and ${}^{116}$Cd target were used for the reaction. The momentum spread of the primary beam was suppressed by applying the dispersion-matching optics and we achieved the energy resolution of 1.6 MeV. The delayed-$\gamma$ ray was detected by DALI2. The observed timing spectrum of the photon is consistent with the known lifetime of ${}^{12}$Be(0${}_2^{+}$). This suggests that ${}^{12}$Be(0${}_2^{+}$) is successfully detected.
In the preliminary spectrum of the excitation energy of ${}^{48}$Ti, there seems to be an enhancement in the energy region where the DGTGR is expected to be observed, especially in the forward angle.
In this contribution, the outline of the experiment and the preliminary result will be reported.

[1] N. Auerbach, L.Zamick, and D. Zheng, Annals of Phys. 192, 77 (1989).
[2] N. Shimizu, J. Men\'{e}ndez, and K.Yako, Phys. Rev. Lett. 120, 142502 (2018).
[3] T. Nishi et al., Nucl. Instrum. Methods Phys. Res. B 317, 290 (2013).

Speaker: Akane Sakaue (CNS)

14:05 Radial moments of charge density distributions in stable and unstable nuclei¶

Nuclear charge radius is one of the most fundamental quantities in describing the structure of a nucleus. So far, the elastic electron scattering experiments have provided information on the charge distribution of stable and quasi-stable nuclei. Now, there are new methods available to measure the charge radius in unstable nuclei of shorter life times. Furthermore, precision in the isotope shift measurements has been significantly improved.

In this study, we aim to explore the second-order (and higher-order) moments of the charge distribution in nuclei, especially for calcium isotopes, using the energy density functional method. We investigate correlations among nucleons in comparison with recent experimental data, and try to identify microscopic mechanisms which contribute to properties of the charge distribution.

Speaker: Kota Yoshinaga (University of Tsukuba)

14:10 The study of core-excited component in 11Li¶

${}^{11}$Li nucleus is one of the flagship drip-line nuclei in the field of nuclear physics. A spatially extended structure of neutrons in ${}^{11}$Li, which is now widely known as “halo” structure, opened the very active field of research with unstable nuclear beams. ${}^{11}$Li have the nature of Borromean.[1] In many cases, ${}^{11}$Li is considered as a 3-body system of ${}^9$Li + 2 neutrons. However, recent theoretical studies pointed out that contribution of the excited ${}^9$Li core can be significant. According to the interpretation of [2], the ground state of ${}^{11}$Li has components which contain excited state of the core. In Ref [3], they showed that the E1 cluster sum rule value should be reduced by about 15% due to the ${}^9$Li core excitation. Currently no experiment has succeeded in providing a direct information of the excited ${}^9$Li core in ${}^{11}$Li.
In this work, with the data of SAMURAI18 experiment, the quasi-free ${}^{11}$Li(p,pn)${}^9$Li* reaction was employed to study the excited ${}^9$Li core. Because of spin-parity constraints, the first bound excited state of ${}^9$Li cannot contribute much and the 2nd state, which is unbound, can give the major contribution. Therefore, the ${}^9$Li excited core will decay into the ${}^8$Li + neutron. After eliminating most of CrossTalk events, using the invariant mass spectrum and dalitz plot of ${}^8$Li + 2 neutrons, we could get the direct information of the exited ${}^9$Li core in ${}^{11}$Li.
[1] M. V. Zhukov, et al., Phys. Rep. 231, 151 (1993).
[2] G. Potel, F. Barranco, E. Vigezzi, and R. A. Broglia, Phys. Rev. Lett. 105, 172502 (2010)
[3] Y. Kikuchi, et al., Phys. Rev. C 87, 034606 (2013).

Speaker: Mr Yutian Li (RIKEN Nishina Center)

14:30 → 15:50 Poster Session¶

15:00 Pair condensation energy and Higgs response in two-neutron transfer¶

Two-neutron transfer reaction is known to be a sensitive probe to the pairing correlation in nuclei. In open shell nuclei, such as stable Sn isotopes, the pair correlated ground state is regarded as a superfluid state with the pairing gap  in an analogy to the BCS theory of the superconductors. One of the characteristic features of the neutral superfluid is the presence of pairing collective modes, the Nambu-Goldstone mode (Anderson-Bogoliubov phonon) and the Higgs mode. They correspond to strong ground-to-ground and ground-to-excited transitions of the two-neutron transfer, called the pair rotation and the pair vibration[1].

In the present study, we propose a new viewpoint to the pairing collective modes in nuclei by extending the idea of the pair rotation and pair vibration. As a new observable to probe the two-neutron transfers, we introduce an operator, Higgs operator, combining both pair-addition and -removal operators. We then consider response of the system against the Higgs operator and the associated strength function. With use of the sum-rule technique, we show that the Higgs response carries an information on the pair condensation energy, which characterizes the magnitude of the pair correlation in an aspect different from the pairing gap.

Using numerical examples for Sn isotopes obtained with the Skyrme-Hartree-Fock-Bogoliubov mean-field model and the quasiparticle random-phase approximation, we demonstrate how this new approach works, and the pair condensation energy carries a rich information, shape and depth, of the pairing potential energy.

[1] D. M. Brink and R. A. Broglia, “Nuclear Superfluidity: Pairing in Finite Systems” (Cambridge University Press)

Speaker: Masayuki Matsuo (Faculty of Science, Niigata University)

15:05 Treating Radioactive Waste: Measurement of 93Zr + d Reactions at 30 MeV/u¶

Treating nuclear waste, in particular long-lived fission products (LLFPs), remains a worldwide problem for the future long-term sustainability of nuclear energy. A promising solution uses nuclear transmutation reactions to convert LLFPs into stable and short-lived nuclear matter for simpler, safer storage. Transmutation studies typically use neutron-induced fission, however, the LLFP ${}^{93}$Zr (half-life ~ 10${}^6$ years) poses the challenge that stable Zr isotopes in the waste, namely ${}^{91}$Zr and ${}^{92}$Zr, may be transformed into ${}^{93}$Zr by neutron capture. Consequently, transmuting ${}^{93}$Zr by neutron capture is not practical. An alternative transmutation process uses deuteron-induced pre-equilibrium reactions on ${}^{93}$Zr, but there’s a lack of cross-section data at energies below 50 MeV/u. To address this knowledge gap, the ${}^{93}$Zr+d pre-equilibrium cross-sections were measured at ~ 30 MeV/u as part of the ImPACT program using the BigRIPS-OEDO beamline at the RIBF in RIKEN, Japan. A radioactive ${}^{93}$Zr beam was produced and separated by BigRIPS. Using OEDO the beam was decelerated and focused onto the cryogenically cooled deuterium gas target. Reaction products were momentum-analyzed by part of the SHARAQ spectrometer and then identified using the Bρ-dE-range method. This poster presents the experimental procedure and preliminary results.

Speaker: Thomas Chillery

15:10 Collective effects and resonances in (n,) reactions on neutron-rich nuclei: a continuum RPA approach¶

The radiative neutron capture is one of the elementary processes which play key roles in the r-process nucleosynthesis. The nuclei on the r-process path have a small neutron separation energy of typically ~2 MeV, and hence the statistical neutron-capture model often adopted to describe the s-process may not be appropriate. In the present work, we formulate a novel theory [1,2] which describes the (n,) reaction in a single microscopic many-body framework with no statistical assumptions using the continuum random-phase approximation (cRPA) based on the nuclear density functional theory.

With the cRPA approach, it is possible to describe various excitation modes present in the (n,) reaction, including soft dipole excitation, the giant resonances as well as non-collective excitations and the single-particle resonances. Furthermore, it enables us to describe the (n,) reaction where the final states of the gamma transition are low-lying surface vibrational states. We demonstrate the theory by performing numerical calculation for the reaction 139Sn (n,) 140Sn. We discuss various new features which are beyond the exiting models; presence of narrow and wide resonances originating from non-collective and collective excitations and roles of low-lying quadrupole and octupole vibrational states.

[1] T. Saito and M. Matsuo, Phys. Rev. C 104, 034305 (2021).
[2] T. Saito and M. Matsuo, arXiv.2208.09455

Speakers: Teruyuki Saito (Graduate School of Science and Technology, Niigata University), Masayuki Matsuo (Faculty of Science, Niigata University)

15:15 In-beam γ-ray spectroscopy of 32Mg¶

In the so-called "island of inversion," the ground states of neutron-rich nuclei around $N=20$ exhibit strong admixtures of intruder configurations, which lead to the breakdown of the $N=20$ shell gap. At the heart of the island of inversion is ${}^{32}$Mg, and from both experimental and theoretical perspectives, this nucleus serves as a critical benchmark.
In this contribution, we report on a precision in-beam $\gamma$-ray measurement of ${}^{32}$Mg using two direct-reaction probes, one-neutron (two-proton) removal from ${}^{33}$Mg (${}^{34}$Si). By combining observables obtained in this measurement, a significantly updated level scheme for ${}^{32}$Mg was constructed, and various structures coexisting in this key nucleus were unraveled. The experimental results were compared with predictions by state-of-the-art theoretical models. However, unexplained discrepancies remain, meaning that the structure of ${}^{32}$Mg is not yet fully understood.

Speaker: Noritaka Kitamura

15:20 New implantation detectors for decay spectroscopy at fragmentation facilities¶

The study of β-decays far from stability is essential to understand the evolution of nuclear
structure and nucleosynthesis processes. β-decay experiments with such exotic nuclei involve
intense cocktail beams from fragmentation facilities. The role of an implantation detector in
these experiments is to measure the energy and the positions of both heavy ion implantation
and β-ray emission to correlate the identified ion with β-decay events.
Due to the lack of time resolution of conventional Silicon strip detectors, we have developed
a new implantation detector using a segmented YSO (Yttrium Orthosilicate) scintillator array
for time-of-flight spectroscopy of the β-delayed neutron emission. The new detector was
implemented in β-delayed neutron measurement experiments at RIKEN RI Beam Factory,
and it was confirmed that the YSO detector correlates β and implant events better due to its
higher effective atomic number Z~35.
The success of the YSO detector motivated us to develop a new detector using heavier
scintillator material. We will report on the design of the new detector using
(Gd,139La)2Si2O7:Ce (A=139 enriched La-GPS) crystal which has a much higher effective
atomic number (Z~51) and is expected to have better β-implant efficiency with a lower
background.

Speaker: Dr Rin Yokoyama

15:25 A Theory of General Particle Transfer Potential from Atom-Molecule to Quark-Gluon Systems¶

A Theory of General Particle Transfer Potential from Atom-Molecule to Quark-Gluon Systems
\\
Shinsho Oryu\
Department of Physics, Faculty of Science and Technology, Tokyo University of Science,
Noda, Chiba 278-8510, Japan.
e-mail:oryu@rs.noda.tus.ac.jp\\
A structure of a general particle transfer (GPT) potential based on the quasi two-body equation in the three-body system is investigated. It was found that the quasi two-body threshold with one particle creation has a 1/r-type singularity
for the electromagnetic interactions, hadronic interactions and quark-quark interactions. Although the theory was developed in a framework of non-relativistic three-body AGS equation, however it could be automatically generalized into the relativistic three-body equation. The GPT potential generates not only the short range Yukawa-type potential but also the long range 1/r^n-type potential. A relation between the index number n and the transferred particle mass was found where the fundamental particle of the atom-molecular system is an electron (and/or a positron), while a pion is the fundamental particle in the hadronic systems. On the other hand, the negative index number represents the quark-gluon system which is illustrated in the unphysical Riemann sheet. Therefore, one could imagine that they could not be observed in the usual experiments. The potential structure illustrates a fundamental and a unique property in the dispersion theoretical framework. The many-body effects in the three-hadronic Faddeev equation reveal a non-linearity which are integrated into a three-body short range force (3BSF) and a three-body long range force (3BLF). The 3BSF has been discussed in a strongly coupled nuclear systems, while the 3BLF has not been investigated yet, however it represents the loosely coupled three-body system such as the nuclear halo and/or the Borromean systems, while the Efimov potential belongs to the 3BLF which is connected with the 3BSF by the GPT theoretical framework. \
Finally, it should be emphasized that the GPT potential could represent from the atom-molecule system to the quark-gluon system by a unique potential with the relevant particle exchange, where pico-meter physics would be highlighted anyhow in the future. \
Some applications for historical few-body problems in physics will be summarized.\
Ref.: Oryu, S., J. Phys. Commun. 6 (2022)015009.

Speaker: Prof. Shinsho Oryu (Department of Physics, Faculty of Science and Technology, Tokyo University of Science)

15:30 Local alpha strength functions in nuclei¶

Alpha knock-out reaction is a useful tool to investigate properties of the alpha particle formation in the nuclear surface region. In order to give a qualitative measure for the alpha particle formation probability as a function of the location inside the nucleus, we define the local alpha strength function S(r,E). When an alpha particle is removed from the position r inside the nucleus, S(r,E) provides a transition probability distribution of the daughter nucleus as a function of excitation energy E. The numerical calculations are performed with a mean-field approximation (HF+BCS). The method is particularly useful for heavy nuclei with the pairing correlations. The enhancement due to the pairing correlation is clearly observed. We compare S(r,E=E(gs)) with recent alpha knockout reaction experiment in Sn isotopes.

Speaker: Takashi Nakatsukasa (University of Tsukuba)

16:10 → 17:40 Session 8¶

16:10 Structure and correlations in light neutron-rich unbound systems¶

Investigating the properties of nuclei far from the line of beta-stability is one of the central themes of present day nuclear physics. In this presentation, experiments employing nucleon removal from high-energy secondary beams to explore the most neutron-rich isotopes of beryllium through nitrogen will be briefly discussed through selected examples. In terms of the evolution of shell structure, these nuclei are of particular interest as they encompass the N=14 and 16 sub-shell closures below doubly magic 22,24O. Furthermore, in the case of the two-neutron unbound systems, they offer a possible window on neutron-neutron correlations.

Prospects at the RIBF, associated with an ongoing upgrade in the neutron detection capabilities, will also be briefly touched on.

Speaker: Prof. Nigel Orr (LPC CAEN)

16:40 Visualization of nuclear cluster correlations in microscopic wave functions¶

In general, the quantum many-body wave function obtained by theoretical calculation contains an enormous amount of information about many-body correlations. However, theoretical analyses in nuclear physics are mainly performed for quantities such as one- and two-body densities, which are obtained after integrating out most of the information in a many-body wave function.
On the other hand, in the field of quantum chemistry, methods have been developed to visualize the information on the correlations among all the electrons and applied to the structure studies of molecular systems [1]. We are attempting to apply such a method to nuclear systems. As the first step, we start with finding the most probable arrangement of nucleon coordinates, i.e, the set of position and spin coordinates that maximizes the square of the many-body wave function.
In this talk, we apply this method to Hartree-Fock and Hartree-Fock+BCS wave functions of p-shell and sd-shell nuclei [2]. We find some alpha-cluster-like correlations out of the wave functions obtained without any assumption of cluster structure. Effects of pairing correlation on the cluster structure are discussed by comparing the results between HF and HF+BCS. We also investigate the relationship between deformation and the cluster structure with constrained HF+BCS wave functions. We believe that this study gives a new viewpoint to the microscopic nuclear wave function.
[1] Yu Liu, Terry J. Frankcombe, and Timothy W. Schmidt, Phys. Chem. Chem. Phys. 18, 13385 (2016).
[2] Moemi Matsumoto and Yusuke Tanimura, Phys. Rev. C 106, 014307 (2022).

Speaker: Moemi Matsumoto (Tohoku University)

17:10 Determination of strengths of cluster states near reaction threshold¶

${}^{12}$C($\alpha$,$\gamma$)${}^{16}$O, ${}^{13}$C($\alpha$,$n$)${}^{16}$O and ${}^{12}$C+${}^{12}$C are the crucial reactions in the evolution of stars. These reactions create carbon and oxygen in our universe, provide neutrons to synthesize the elements heavier than iron, and define the explosive conditions of superburst. Due to the nuclear clustering effect, resonances form near the thresholds of these reactions and dominate the contribution of the reaction cross sections at stellar energies. In the past seven decades, direct and indirect measurements, together with a number of theoretical approaches, have been endeavored to achieve the precision required by astrophysical models. In this talk, the recent progress in the studies of these reactions will be reviewed and my perspectives on future experiments will also be provided.

Speaker: Xiaodong Tang (Institute of Modern Physics, CAS)

Thursday, 9 March ¶

09:00 → 10:00 Session 9¶

09:00 Nuclear reaction cross sections and the optical potentials for the n-12C and N-12C scattering¶

Realistic nuclear reaction cross-section models are an essential ingredient of reliable heavy-ion
transport codes. Such codes are used for risk evaluation of manned space exploration missions
as well as for ion-beam therapy dose calculations and treatment planning [1]. Comparison between
data and reaction cross section theoretical calculations, mostly performed within the Glauber model
[2] with folded potentials (f.p.) [3; 4], have been performed for many years [5; 6]. Also since the
beginning of physics with RIBs the method has been applied to deduce density distributions of exotic
nuclei as well as their root mean square radii (rms) [7–14] and the core-target survival probability
in knockout reactions [15]. In order to improve the calculations of nucleus-nucleus folded potentials,
usually called double folded potentials (d.f) Satchler and Love [3] proposed the calculate single folded
(s.f) potentials using projectile densities together with phenomenological nucleon-target potentials.
In this talk we will show that for 9Be and 12C very good agreement with experimental data can be
found using nucleon-target (n-T) phenomenological potentials which we have obtained fitting the
n+T cross section in a very large energy range and also the nucleus-target (N-T) cross sections at
high energy. The advantage of s.f. potentials is to avoid the dependence on the target density choice
as well as the choice of the parameters to describe the free n-n-amplitude in the Glauber model and
to naturally include medium effects beyond the simple nn scattering.

[1] F Luoni and F Horst and C A Reidel and A
Quarz and L Bagnale and L Sihver and U We-
ber and R B Norman and W de Wet and M Gi-
raudo and G Santin and J W Norbury and M

Durante, New Journal of Physics 10, 101201(2021).
https://dx.doi.org/10.1088/1367-2630/ac27e1
[2] R.J. Glauber, in: W.E. Brittin, L.G. Dunham (Eds.),
Lectures in Theoretical Physics, Vol. 1, Interscience, New
York, 1959, p. 315.
[3] G.R. Satchler and W.G. Love, Phys. Rep. 55 183 (1979).
[4] G.R. Satchler, Proceedings of La Rabida international
Summer School on Heavy Ion Collisions
[5] R.M. De Vries, J.C. Peng, Phys. Rev. C 22 (1980) 1055.
[6] S. Kox et al., Phys. Rev. C35,1678 (1987)
[7] I. Tanihata et al., Phys. Letters B 160 (1985) 380.
[8] Isao Tanihata, Herve Savajols, Rituparna Kanungo,
Prog. Part. Nucl. Phys. 68 (2013) 215, and references
therein.
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(2001). A. Ozawa, AIP Conf. Proc. 865, 57 (2006);
http://dx.doi.org/10.1063/1.2398828
[10] M. Tanaka et al. Phys. Rev. Lett. 124, 102501 (2020).
[11] D. T. Tran, et al., Phys. Rev. C 94, 064604 (2016).
[12] M. Takechi et al., Phys. Rev. C 79, 061601(R) (2009).

[13] W. Horiuchi, Y. Suzuki, B. Abu-Ibrahim, and A. Ko-
hama, Phys. Rev. C 75, 044607 (2007).

[14] B. Abu-Ibrahim, W. Horiuchi, A. Kohama, and Y.
Suzuki, Phys. Rev. C 77, 034607 (2008)
[15] A. Bonaccorso, Prog. Part. Nucl. Phys. 101, 1 (2018).

Speaker: Prof. Angela Bonaccorso (INFN-Pisa)

09:30 Determination of GT + Strength and its Astrophysical Implications¶

Charge-exchange isovector collective modes have been studied extensively in the last four decades. The Gamow-Teller (GT) resonance is the most studied because GT transitions, aside from their interest from the nuclear structure point of view, play very important roles in various phenomena in nature [1]. In nucleosynthesis, the beta-decay of nuclei along the s- and r-processes determine the paths that these processes follow and the abundances of the elements synthesized.
In supernova collisions, GT transitions are of paramount importance in the pre-supernova phase where electron capture occurs on neutron-rich fp-shell nuclei at the high temperatures of giant stars. Electron capture is mediated by GT transitions. Electron capture removes the electron pressure that keeps the star from collapsing precipitating a cataclysmic implosion followed by a huge explosion throwing much of the star material into space and leaving a neutron star or black hole behind [2,3]. Also, the charge-exchange isovector spin giant monopole resonance(IVSGMR) and isovector spin giant dipole resonance (IVSGDR) have been discovered and have been studied in a few nuclei. Their macroscopic as well as microscopic properties have been　determined [4,5]. In this talk, I will concentrate on measurements of GT + strength via the (d, 2 He) reaction.

[1] M. N. Harakeh and A. van der Woude, Giant Resonances: Fundamental High-Frequency
Modes of Nuclear Excitations (Oxford University Press, New York, 2001).
[2] H. A. Bethe et al., Nucl. Phys. A324, 487 (1979).
[3] G. M. Fuller, W. A. Fowler, M. J. Newman, Astrophys. J. 293, 1 (1985), and references
therein.
[4] H. Akimune et al., Phys. Rev. C 52, 604 (1995)
[5] R.G.T. Zegers et al., Phys. Rev. Lett. 90, 202501 (2003).

Speaker: Prof. Muhsin Harakeh (University of Groningen)

10:20 → 12:00 Session 10¶

10:20 Collective Inertial Masses in Nuclear Reactions¶

Toward the microscopic theoretical description for large amplitude collective dynamics, we calculate the coefficients of inertial masses for low-energy nuclear reactions. Under the scheme of energy density functional, we apply the adiabatic self-consistent collective coordinate (ASCC) method, as well as the Inglis' cranking formula to calculate the inertias for the translational and the relative motions, in addition to those for the rotational motion. Taking the scattering between two α particles as an example, we investigate the impact of the time-odd components of the mean-field potential on the collective inertial masses. The ASCC method asymptotically reproduces the exact masses for both the relative and translational motions. On the other hand, the cranking formula fails to do so when the time-odd components exist.

Speaker: Dr Kai Wen (University of Tsukuba)

10:50 Proton-Induced Energy-Dissipation Reactions on ⁹³Zr at 27 MeV/u in Inverse Kinematics¶

Nuclear reactions induced at a few tens of MeV/u are generally governed by the compound and pre-equilibrium processes. During these processes the kinetic energy of a projectile is dissipated into other nucleons in a target. Such energy-dissipation reactions are expected to be a useful tool to produce neutron-deficient nuclei. The present experiment studied the ⁹³Zr+p reaction at 27 MeV/u under inverse kinematics, and the production cross sections for each isotope were measured. The large production cross sections of a few hundred mb were measured for ^91,92Nb expected to be important in nuclear transmutation. Alpha-emission channels producing yttrium isotopes were observed as well. The global reaction code TALYS reproduced the measured results and confirmed the primary reaction mechanisms were the compound and pre-equilibrium processes. In this poster presentation we will report the experimental details, the preliminary results of the recent experiment on ⁹³Zr+p, and the possible interpretation of the results.

Speaker: Dr Jongwon Hwang (Center for Exotic Nuclear Studies, Institute for Basic Science)

11:20 Alpha cluster structures in nuclei and their related issues in nuclear astrophysics¶

Cluster correlation is an important concept in nuclear physics
especially for light nuclei. Alpha cluster structures are expected to emerge near the alpha-decay threshold energies. We are interested in the cluster structures in p- and sd-shell nuclei, and experimentally examine them.
The alpha cluster structures are also deeply related to the nucleosynthesis in the universe because 4He is the second abundant nuclei next to 1H. For example, the triple alpha reaction is one of the most important reactions in the nucleosynthesis. This reaction proceeds via the triple α resonances such as the 0+2, 3-1, and 2+2 states. Therefore, these resonance states should be examined to precisely determine the triple alpha reaction rate. In the present talk, we will present our recent experimental results on the alpha cluster structures and their relevancy to the nuclear astrophysics.

Speaker: Prof. Takahiro Kawabata (Osaka University)

13:30 → 15:30 Session 11¶

13:30 Study of light-mass neutron unbound nuclei by multi-neutron detection¶

Speaker: Dr Yosuke Kondo (Titech)

14:00 Consistent description of cluster and shell models¶

Speaker: Prof. Naoyuki Itagaki (Osaka Metropolitan University)

14:30 Shape coexistence and E0 transition from the superdeformed band in 40Ca¶

The spherical doubly magic nucleus, 40Ca, is a good example exhibiting shape coexistence [1]. A unique feature of this nucleus is an appearance of low-lying 0+ states. First exited state is 0+ at 3.3 MeV and the second excited 0+ state closely locates at 5.2 MeV. These states are understood as band heads of the normal deformed and the superdeformed bands, respectively [2,3], which corresponds to the multiple shape coexistence in 40Ca.
Existence of the superdeformed band starting from the 0+ band head is another unique feature of 40Ca. Although the existence of superdeformed nuclei are reported in many nuclei of various mass regions, A=60, 80, 130, 150, 190 [4], the superdeformed band head 0+ states are only observed in mass 40 region [5,6], and in the fission isomer region [4]. Such situation makes it difficult to understand the property of superdeformed state, such as the mixing of the states with different configurations. Therefore, 40Ca is a quite unique nucleus where one can study the electric monopole (E0) transition strength between the band head of superdeformed state and the spherical ground state, which directly reflects the shape mixing [7]. In order to study the property of superdeformed state of 40Ca, we have performed an experiment to measure the E0 transition from the excited 0+ states. Experiment was carried out using a 40Ca(p,p’) reaction at the 14UD tandem accelerator facility in Australian National University. The Super-e pair spectrometer [8,9,10], a superconducting magnetic-lens spectrometer, is employed to measure conversion electrons and electron-positron pairs with excellent background suppression. A single germanium detector was also used to measure gamma transitions from the excited states simultaneously.
In the presentation, the experimental results on E0 transition strength from the normal deformed and superdeformed band in 40Ca and the theoretical studies based on the large-scale shell model calculation will be discussed.

[1] K. Heyde and J.L. Wood, Rev. of Mod. Phys. 83, 1467 (2011)
[2] E. Ideguchi et al., Phys. Rev. Lett. 87, 222501 (2001)
[3] C.J. Chiara, et al., Phys. Rev. C 67, 041303(R) (2003).
[4] B. Singh, R. Zywina, R.B. Firestone, Nucl. Data Sheets 97, 241 (2002)
[5] C.E. Svensson et al., Phys. Rev. Lett. 85, 2693 (2000)
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[10] J. T. H. Dowie, et al., Phys. Lett. B 811, 135855 (2020).

Speaker: Eiji Ideguchi (RCNP)

15:00 Gamma-ray linear polarization measurement by multi-layer CdTe Compton camera and segmented Ge detector¶

Nuclear properties of unstable nuclei, such as masses, half-lives, excited levels, and spin-parities are important to understand the structural evolution in extreme quantum system. About 3000 isotopes of 118 elements have been discovered so far by the continuous effort of developing new accelerators and detection techniques, while the spin-parity of the ground- and excited-states remain to be determined. Linear polarization and angular distribution measurements of gamma-ray are usually applied to determine the electromagnetic multipolarity of gamma-ray. However, the detection techniques have not been applied in the wide range of nuclei due to the limited statistics since the methods usually require the coincidence and intensity distribution measurements of gamma-ray at multiple angles.
　To overcome this difficulty, we are developing a new, highly efficient experimental technique for gamma-ray linear polarization measurements by adopting a multi-layer CdTe semiconductor detector array, which has been developed in the X- and gamma-ray observatory field. We conducted a proof-of-principle experiment at the RIKEN Pelletron facility. The first excited state of ${}^{56}$Fe was populated by inelastic scattering of protons. The de-excited gamma-rays of 847 keV were measured by the multi-layer CdTe Compton Camera (CdTe20CC) and the segmented Ge detector (CNS-GRAPE) placed at 90 degrees to the incident proton beam. The linear polarization of gamma-ray was successfully observed by both detector systems. In this presentation, we will show the experimental results and discuss future applications of the detector system for in-beam gamma-ray and decay spectroscopy on rare isotopes.

Speaker: Dr Shintaro Go (RIKEN Nishina Center)

15:50 → 17:10 Session 12¶

15:50 Puzzles and solutions for the nuclear Equation of State¶

Even the basic parameters that govern the nuclear Equation of State (EoS) are still not known with enough precision. This is true both for the EoS of symmetric matter (in particular, for the nuclear incompressibility) and also for the symmetry energy.
In this talk, I will discuss recent developments in our understanding of the nuclear EoS, starting from calculations of nuclear giant resonances and comparison with experiment.

Speaker: Prof. Gianluca colò (INFN Milano)

16:20 Mass measurements of exotic nuclei at OEDO-SHARAQ¶

Speaker: Shin'ichiro Michimasa (Center for Nuclear Study, the Univ. of Tokyo)

16:50 Closing¶

Speaker: Prof. Takashi Nakamura (TITECH)

18:00 → 20:00 Symposium Banquet¶