Shapes and Symmetries in Nuclei: from Experiment to Theory (SSNET'22 Conference)

Europe/Paris
Costel Petrache (CSNSM, Université Paris Sud and CNRS/IN2P3)
Description

The SSNET 2022 Conference hosted by IJCLab in Orsay, France, was held at the auditorium Pierre Lehmann (building 200 - IJCLab) from May 30 to June 3, 2022.

The conference was organized in a hybrid mode, with 73 participants physically present in Orsay among the 209 registered participants. 45% of the talks have been performed remotely using the Zoom interface.

As in the previous -and successful!- editions, the conference aims at strengthening the international collaboration between the nuclear structure physicists from France, Europe and other laboratories all around the world. It allows fruitful discussions on recent experimental and theoretical aspects of nuclear structure related to the manifestation and description of the various shapes and geometrical symmetries of the nucleus as well as other symmetries and symmetry breaking.

Organizing committee: Costel Petrache (Chair), Alain Astier, Isabelle Deloncle, Amel Korichi, Radomira Lozeva, Jerzy Dudek (co-chair)

Conference secretary: Émilie Bonnardel, Valérie Brouillard

Registration
Registration Form
Participants
  • Abdelghafar Gaamouci
  • Ablaihan Utepov
  • Adam Garnsworthy
  • Adam Maj
  • Adrian Montes Plaza
  • Agota Koszorus
  • Ahsan Ullah
  • Alain Astier
  • Alejandro Algora
  • Alejandro Restrepo Giraldo
  • Alexander Tichai
  • Alexandrina Petrovici
  • Allanur Ansari
  • Aman Rohilla
  • Amel Korichi
  • Amir Jalili Majarshin
  • Amiram Leviatan
  • Amitkumar Pandey
  • Anatoli Afanasjev
  • Andrej Špaček
  • Andres Illana Sison
  • Andrew Briscoe
  • Andriana Martinou
  • Angela Gargano
  • Ashok Kumar Jain
  • Astitva Kathait
  • Azam Kardan
  • Balaram Dey
  • barbara sulignano
  • Bhoomika Maheshwari
  • Bingfeng Lv
  • Bogdan Fornal
  • Bozena Pomorska
  • Cebo Ngwetsheni
  • Chandrani Majumder
  • Changbo Fu
  • Christophe Theisen
  • Chunjian Zhang
  • Corina Andreoiu
  • Costel Petrache
  • Daniel Doherty
  • Dariusz SEWERYNIAK
  • Dennis Bonatsos
  • Desislava Kalaydjieva
  • Dieter Ackermann
  • Ding Bing
  • Dominique Curien
  • Dora Sohler
  • Eiji Ideguchi
  • Elena Lawrie
  • Elena Litvinova
  • Emmanuel Rey-Herme
  • Esperanza Maya Barbecho
  • Fanfei Zeng
  • Filip Kondev
  • Francesco Marino
  • Futoshi Minato
  • Gaël Craveiro
  • George Zimba
  • Georgi Georgiev
  • Gianluca Colò
  • Giovanna Benzoni
  • Giovanni De Gregorio
  • Guilherme Grams
  • Hao Huang
  • Hao Jian
  • Hiroshi Watanabe
  • Houda Naïdja
  • Ignasio Wakudyanaye
  • Ingemar Ragnarsson
  • Iolanda Matea
  • Irene Dedes
  • Isabelle Deloncle
  • Itzhak Kelson
  • Jacek Dobaczewski
  • Jacklyn Gates
  • James Allmond
  • James Cubiss
  • Jan Sarén
  • Janne Pakarinen
  • Javid Sheikh
  • Jean Yves ZANA
  • Jerzy Dudek
  • Jiangyong Jia
  • Jiawei Cai
  • Jie Meng
  • John Sharpey-Schafer
  • Jonathan Wilson
  • Joonas Ojala
  • José Enrique García Ramos
  • Jozsef Cseh
  • Juergen Gerl
  • Juha Uusitalo
  • Julian Srebrny
  • János Timár
  • Jérôme Giovinazzo
  • Kailong Wang
  • Kalle Auranen
  • Kasia Hadyńska-Klęk
  • Kasia Wrzosek-Lipska
  • Katarzyna Mazurek
  • Khuyagbaatar Jadambaa
  • Kobus Lawrie
  • Konstantin Stoychev
  • Konstantinos Karakatsanis
  • Kosuke Nomura
  • Krzysztof Pomorski
  • Kuankuan Zheng
  • Liam Gaffney
  • Liu Zixin
  • Ludovic Bonneau
  • Lukasz Iskra
  • Lysandra Batail
  • Magda Satrazani
  • Magdalena Gorska
  • Marek Stryjczyk
  • Maria Kmiecik
  • Mark Riley
  • Marta Polettini
  • Martin Venhart
  • Massyl KACI
  • Matthieu Lebois
  • Michal Kowal
  • Michał Ciemała
  • Miguel Angel Rosas Villalobos
  • Min SI
  • Mohamed Amine Ouahid
  • Monika Bírová
  • muhammad Ibrahim Abdulhamid
  • Munera Alrashed
  • Mustafa Rajabali
  • Nameeqa Firdous
  • Natalia Cieplicka-Orynczak
  • Nico Orce
  • Nikita Bernier
  • Nikolay Minkov
  • Nirupama Sensharma
  • Noam Gavrielov Somin
  • Ophir Ruimi
  • Paramasivan Arumugam
  • Parviz Gulshani
  • Patrick Regan
  • Paul Garrett
  • Paul-Gerhard Reinhard
  • Pavol Mosat
  • Pengwei Zhao
  • Pepijn Demol
  • Peter Morley
  • Petr Navratil
  • Philip Walker
  • Piotr Bednarczyk
  • Polytimos Vasileiou
  • Poonam Choudary
  • Pragya Das
  • Praveen Muralidhar Jodidar
  • Praveen Srivastava
  • Punit Punit
  • Qiang Yunhua
  • Qibo Chen
  • quanbo zeng
  • Radomira Lozeva
  • Radu Budaca
  • Rafly Aditya Darmawan
  • RAHBAR ALI
  • Ramda khaled
  • Ramon Wyss
  • Richard Furnstahl
  • Robert Michaels
  • Robert Wadsworth
  • Romain Racham
  • Serge Franchoo
  • Shabir Ahmad Dar
  • Shefali Basak
  • Silvia Leoni
  • Simon Mullins
  • Sinegugu Mthembu
  • Song Guo
  • Sonja Orrigo
  • Sophie PERU
  • Stanislav Antalic
  • Stavros Sotirios Bofos
  • Stefan Frauendorf
  • Stephane HILAIRE
  • Sunil Dutt
  • Syed Peerzada Rouoof Ahmad Shah
  • Takaharu Otsuka
  • Takashi Nakatsukasa
  • Takayuki Miyagi
  • Tianheng Huang
  • Tibor Kibedi
  • Tomoya Naito
  • TUMPA BHATTACHARJEE
  • Tuomas Grahn
  • Umakant Lamani
  • Vandana Tripathi
  • Vijay Sai Kollipara
  • Wataru Horiuchi
  • Wen Hui LONG
  • Xiao-Tao He
  • xujunhong xu
  • yang xq
  • Yanxin Liu
  • Yongde Fang
  • Yuanyuan Wang
  • Zhen-Hua Zhang
  • Zhiheng Wang
  • Zhipan Li
  • zhong liu
  • Zsolt Podolyak
    • Registration
    • Session 1: Recent achievements in the study of ptoron emitters
      Convener: Dariusz Seweryniak (ANL, USA)
      • 1
        Imaging 54mNi radioactivity with ACTAR TPC
        Speaker: Jerome Giovinazzo (IN2IB, Bordeaux, France)
      • 2
        Solving the puzzles of the decay of the heaviest known proton-emitting nucleus 185Bi

        In two experiments at Argonne National Laboratory’s ATLAS facility, utilising both the Fragment Mass Analyzer (FMA) and Argonne Gas-Filled Analyzer (AGFA) we have revisited two long-standing puzzles in the decay of $^{185}$Bi, which is the heaviest known proton-emitting nucleus. Combining the results from the two complementary experiments has established the existence of an isomeric state in $^{185}$Bi and shown that the proton- and alpha-decaying ground state is extremely short. These results, which will be discussed in this seminar, lead to a proton-decay spectroscopic factor which is close to unity and represents the only known example of a ground-state proton decay to a daughter nucleus ($^{184}$Pb) with a major shell closure. The implications for nuclear structure in this important region of the chart will be discussed as will implications for future work studying proton-emitting nuclei - which continue to yield surprising and fascinating results.

        Speaker: Dan Doherty (University of Surrey, UK)
      • 3
        Probing proton emitters using the MARA separator
        Speaker: Kalle Auranen (Jyväskylä University, Finland)
      • 4
        Microscopic description of tri-axially deformed odd-odd proton emitters
        Speaker: Paramasivan Arumugam (IIT Roorkee, India)
    • 10:50 AM
      Coffee break
    • Sesion 2: The science and impact of Bent Herskind (1931 - 2021)
      Convener: Mark Riley (Florida State University, USA)
      • 5
        Introduction and early days when Bent helped trigger the Modern Revolution in Gamma-Ray Spectroscopy and Nuclear Structure Physics
        Speaker: Mark Riley (Florida State University, USA)
      • 6
        A quest for nuclear Jacobi shapes: the impact of Bent Herskind on theory and instrumentation developments

        The possibility of existence in atomic nuclei of the so called “Jacobi shape transitions”, the rapid shape changes at certain narrow angular momentum range from an oblate to a very elongated prolate shape (analogous to those predicted by Jacobi for rotating stellar objects), was postulated by theorists already in the early 1960’s [1,2]. In the 90’s, the Seattle group, and soon after the NBI Copenhagen group, studying the GDR gamma decay from hot rotating 45Sc [3] and 46Ti [4], nuclei observed signals interpreted as the first manifestations of the nuclear Jacobi shape transition.
        However, the direct evidence for the existence of the Jacobi shape transition in 46Ti nucleus came from the experiment performed in Strasbourg [5], where two arrays of gamma-ray detectors, scintillator array HECTOR and the germanium array EUROBALL, were coupled. Moreover, the interpretation of the results has become possible only because of the development of a theoretical approach referred to as Lublin-Strasbourg Drop (LSD) [6], which appeared simple to use by experimentalists.
        Bent Herskind was pivotal to this achievement not only by taking part in the experiment and discussing the results, by also by his strong contribution to the development of the two detector arrays used, and also to the development of the links with the LSD model.
        In the talk I will present the history of the quest for nuclear Jacobi shape transitions and the impact of Bent. In addition, I will present the currents status of understanding of the phenomenon of nuclear Jacobi shape transitions, the status of the instrumentation (especially, construction of the new scintillator array PARIS [7]) and some outlook of the coming perspectives such as the search for the Poincare shape transitions [8].

        References:
        [1] R. Beringer, W.K. Knox, Phys. Rev. 121 (1961) 1195
        [2] S. Cohen, F. Plasil, W.J. Swiatecki, Ann. Phys. (N.Y.) 82 (1974) 557
        [3] M. Kicińska-Habior et al., Phys.Lett. B308 (1993) 225
        [4] A. Maj et al., Nucl.Phys. A687, 192c (2001)
        [5] A. Maj et al., Eur.Phys.J. A 20, 165 (2004)
        [6] K. Pomorski, J. Dudek, Phys. Rev. C67 (2003) 044316
        [7] F. Camera, A. Maj, PARIS White Book, http://rifj.ifj.edu.pl/handle/item/333
        [8] A. Maj et al., Int.J.Mod.Phys. E19, 532 (2010)

        Speaker: Adam Maj (IFJ PAN Krakow, Poland)
      • 7
        Warm nuclei at high spin: the pioneering multi-dimensional vision of Bent Herskind

        The physics of warm rotation at high spin in the many-body atomic nucleus will be briefly reviewed with the attempt of providing a historical perspective. This fascinating research topic, investigated in past decades by various research groups in Europe and the US, was greatly inspired by the seminal work carried out at the NBI, with Bent Herskind being the central figure. Bent had unique vision for experimental techniques and analysis methods. He contributed to the birth of Compton-suppressed Ge arrays, and his pioneering multi-dimensional γ-coincidence approaches and statistical data treatment were instrumental in investigating the properties of rotational motion at high excitation energy and chaotic phenomena, also associated with nuclear superdeformation. Perspectives in nuclear structure investigations inspired by Bent legacy will be also briefly discussed.

        Speaker: Silvia Leoni (University of Milan, Italy)
      • 8
        Exploring the extremes of nuclear deformation in Denmark and elsewhere

        Two of the most admirable traits of Bent Herskind were his intense curiosity and his lively imagination which were particularly evident when applied to the search for new physics and the development of new analysis techniques. In this presentation I will give an overview on the research carried out at the Niels Bohr Institute into extreme nuclear deformations (superdeformation, hyperdeformation, Jacobi shapes, etc.) and present some of the important discoveries made by Bent and his collaborators. Finally, I will present some of my own personal thoughts on what promising directions could be explored in the future to continue this important work.

        Speaker: Jon Wilson (IJClab Orsay, France)
      • 9
        Further remembrances and a photo slide show
        Speaker: Mark Riley (Florida State University, USA)
    • 1:15 PM
      Lunch
    • Session 3: Spectroscopy of heavy and super-heavy nuclei
      Convener: Dieter Ackermann (GANIL, France)
      • 10
        Spectroscopy of the deformed 249,251Md

        Despite significant and steady advances in the synthesis of the heaviest elements, reaching the predicted superheavy island of stability is still a distant objective, because of the ever-decreasing cross sections. Nevertheless, nuclear spectroscopy, mass measurements, and laser spectroscopy of the heaviest nuclei have shown their effectiveness by providing information on the quantum nature of extreme mass nuclei. In this context, deformed midshell nuclei near N=152, Z=100, are of great relevance: a large diversity of orbitals are accessible, some of which being involved in the structure of heavier spherical nuclei, i.e., placed just above and below the predicted superheavy spherical shell gaps.
        In a series of experiments performed at the University of Jyväskylä, we have studied different facets of the odd-Z $^{249}$Md and $^{251}$Md isotopes. $^{251}$Md was studied using combined gamma ray and conversion-electron in-beam spectroscopy [1]. Besides the previously known K=1/2$^-$ rotational band [2], a new band has been observed. Using the gamma and electron intensities that depend on the gyromagnetic factor, the ground-state configuration could be inferred. We will also present a new method that allows to derive the gyromagnetic factor using the gamma-ray intensity profile. A comparison of $^{251}$Md with the $^{255}$Lr nucleus [3] revealed unexpected similarities between transition energies. Skyrme-Hartree-Fock-Bogoliubov calculations were performed to investigate the origin of these similarities.
        If time permits, we will discuss new isomers observed in $^{249,251}$Md using decay spectroscopy, interpreted as high-K 3qp configurations [4]. These data were compared to new theoretical calculations using two scenarios: via blocking nuclear states located in proximity to the Fermi surface or/and using the quasiparticle Bardeen–Cooper–Schrieffer method.
        [1] R. Briselet, Ch. Theisen , B. Sulignano et al., Phys. Rev. C 102 (2020) 014307.
        [2] A. Chatillon, C. Theisen et al., Phys. Rev. Lett. 98 (2007) 132503.
        [3] S. Ketelhut, P. T. Greenlees et al., Phys. Rev. Lett. 102 (2009) 212501.
        [4] T. Goigoux, Ch. Theisen, B. Sulignano et al., Eur. Phys. J. A 57 (2021) 57.

        Speaker: Christoph Theisen (CEA Saclay, France)
      • 11
        Decay spectroscopy of isotopes above Fermium

        The deformation of atomic nuclei is one of the important features significantly influencing the properties of the heaviest isotopes far above uranium. It is a decisive factor for their single-particle level structure, with an essential impact on the decay properties and, afterwards, the stability of heaviest nuclei with an odd number of protons or neutrons. Nuclear deformation is also crucial for the existence of phenomena like K isomers. Although there are available theoretical predictions for low-lying single-particle states of isotopes above fermium (see for example [1–3]), experimental data are scarce in this region. For many of these isotopes, even the ground-state or first excited states remain unassigned.
        The use of sensitive α- and γ-decay studies combined with conversion-electron (CE) spectroscopy allowed detailed experimental studies of many isotopes in the region of heaviest nuclei (A > 250). This approach was applied in an extensive program aimed at nuclear structure studies of isotopes above fermium using α-CE, α-γ and CE-γ spectroscopy at the velocity filter SHIP of GSI Darmstadt.
        This seminar will summarize some recent results obtained for the examples of recent studies – mainly isomeric states in $^{255}$Rf [4,5] and $^{247}$Md [6]. In addition, open problems for the single-particle level systematics of odd-Z isotopes will be discussed, as well.

        [1] S. Ćwiok et al., Nucl. Phys. A 573, 356 (1994).
        [2] A. Parkhomenko and A. Sobiczewski, Acta Phys. Pol. B35, 2447 (2004).
        [3] A. Parkhomenko and A. Sobiczewski, Acta Phys. Pol. B36, 3115 (2005).
        [4] S. Antalic et al., Eur. Phys. J. A 51, 41 (2015).
        [5] P. Mošať et al., Phys. Rev. C 101, 034310 (2020).
        [6] F.P. Heßberger et al., Eur. Phys. J A 58, 11 (2022)

        Speaker: Stanislav Antalic (Department of Nuclear Physics and Biophysics, Comenius University Bratislava, Slovakia)
      • 12
        Candidates for long-lived high-K ground states and isomers in superheavy nuclei

        By selecting the lowest lying of more than 2000 excitations we found the candidates for high-K ground states / K-isomers in Md - Rg nuclei.
        Energies of nuclear configurations are calculated within the microscopic-macroscopic model with the Woods-Saxon potential in two scenarios: via blocking or/and using quasi-particle BCS method. Optimal deformations for a fixed configuration as well as for ground states are found by the four-dimensional energy minimization over deformations. Obtained excitation energies are discussed and compared with available experimental data.

        Speaker: Michal Kowal (NCBJ Warsaw, Poland)
      • 13
        Spectroscopy of deformed trans-fermium nuclei using the Argonne Gas-Filled Analyser
        Speaker: Dariusz Seweryniak (ANL, USA)
      • 14
        Superheavy Elements with FIONA (remote)

        The search for new elements has netted us six additions to the periodic table this decade, bringing the total to 118 known elements. These elements must be formed one-atom-at-a-time in complete-fusion evaporation reaction. Once formed, the atoms typically exist for just seconds or less before they decay into other elements. While we have made great progress in making and studying these elements, there is much that is still unknown – including things as basic as the proton and neutron numbers of the recently discovered elements.

        Recently, the Berkeley Gas-filled Separator (BGS) at the Lawrence Berkeley National Laboratory (LBNL) was coupled to a new mass analyzer, FIONA. The goal of BGS+FIONA is to provide a M/$\Delta$M separation of ~300 and transport nuclear reaction products to a shielded detector station on the tens of milliseconds timescale. These upgrades will allow for direct A and Z identification of ii) new actinide and transactinide isotopes with ambiguous decay signatures such as electron capture or spontaneous fission decay and i) superheavy nuclei such as those produced in the $^{48}$Ca + actinide reactions. Here we will present recent results from first FIONA scientific experiments.

        Speaker: Jacklyn Gates (awrence Berkeley National Laboratory)
    • 4:35 PM <