Wed·Jun 14, 2023Wednesday·June 14, 2023

1. 01*

   Rotation of pear-shaped ${}^{100}$Ru nucleus

   A. Karmakar · P. Datta · Soumik Bhattacharya🇮🇳 · Shabir Dar🇮🇳 · S. Bhattacharyya🇮🇳 · G. Mukherjee🇮🇳 · H. Pai🇷🇴 · S. Basu · S. Nandi🇮🇳 · S. S. Nayak · Sneha Das · R. Raut🇮🇳 and 5 other authors

   Atomic nuclei in general can have deformed shapes and nearly all these shapes are symmetric with respect to reflection. Only a few Actinide nuclei have stable reflection asymmetric pear shapes in their ground state and exhibit characteristic rotational bands. In this article, we report on the observation of two alternate parity rotational bands in 100Ru, which are connected by seven interleaved electric dipole transitions and their rates are found to be enhanced. In addition, the moments of inertia associated with these two opposite parity rotational bands have been found to be similar. These experimental observations indicate the rotation of a stable pear-shaped 100Ru nucleus, which is the first such observation outside the Actinide mass region. This shape is built on an excited configuration and originates from the rotational alignment of the angular momenta of a pair of neutrons. This unique observation establishes an alternate mechanism by which an atomic nucleus can assume a pear shape.

   nucl-exnucl-th1 citation
2. 02*

   Strong Interaction Physics at the Luminosity Frontier with 22 GeV Electrons at Jefferson Lab

   A. Accardi🇺🇸 · P. Achenbach🇺🇸 · D. Adhikari🇺🇸 · A. Afanasev🇺🇸 · C.S. Akondi🇺🇸 · N. Akopov🇦🇲 · M. Albaladejo🇪🇸 · H. Albataineh🇺🇸 · M. Albrecht🇺🇸 · B. Almeida-Zamora🇲🇽 · M. Amaryan🇺🇸 · D. Androić🇭🇷 and 432 other authors

   This document presents the initial scientific case for upgrading the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab (JLab) to 22 GeV. It is the result of a community effort, incorporating insights from a series of workshops conducted between March 2022 and April 2023. With a track record of over 25 years in delivering the world's most intense and precise multi-GeV electron beams, CEBAF's potential for a higher energy upgrade presents a unique opportunity for an innovative nuclear physics program, which seamlessly integrates a rich historical background with a promising future. The proposed physics program encompass a diverse range of investigations centered around the nonperturbative dynamics inherent in hadron structure and the exploration of strongly interacting systems. It builds upon the exceptional capabilities of CEBAF in high-luminosity operations, the availability of existing or planned Hall equipment, and recent advancements in accelerator technology. The proposed program cover various scientific topics, including Hadron Spectroscopy, Partonic Structure and Spin, Hadronization and Transverse Momentum, Spatial Structure, Mechanical Properties, Form Factors and Emergent Hadron Mass, Hadron-Quark Transition, and Nuclear Dynamics at Extreme Conditions, as well as QCD Confinement and Fundamental Symmetries. Each topic highlights the key measurements achievable at a 22 GeV CEBAF accelerator. Furthermore, this document outlines the significant physics outcomes and unique aspects of these programs that distinguish them from other existing or planned facilities. In summary, this document provides an exciting rationale for the energy upgrade of CEBAF to 22 GeV, outlining the transformative scientific potential that lies within reach, and the remarkable opportunities it offers for advancing our understanding of hadron physics and related fundamental phenomena.

   nucl-exhep-exhep-phnucl-thEPJA(2024)·225 citations
3. 03*

   Probing DDM and ML quantum concepts in shape phase transitions of $\gamma$-unstable nuclei

   S. Ait El Korchi · M. Chabab🇲🇦 · A. El Batoul · A. Lahbas · M. Oulne🇲🇦

   In a recent paper (S. Ait El Korchi et al. 2020 EPL 132 52001), we explored, inside the context of Critical Point Symmetries (CPSs) X(3) and Z(4), a correlation between two exceedingly known quantum concepts, the Minimal Length (ML) and the Deformation-Dependent Mass (DDM), that are commonly applied in various areas of physics. Such a correlation has been strongly identified in transition nuclei by calculating some physical observables of that quantum system, like as energy spectra, moments of inertia and transition probabilities. In this paper we extend that study to E(5) dynamical symmetry corresponding to the shape phase transition U(5)$\leftrightarrow$O(6). The experimental realization of the models was found to occur in some nuclei, using the existing phenomenological potentials : Infinite Square Well, Davidson and Kratzer, whose models fits provide the best agreement. Importantly the calculations performed in this work using these potentials corroborate the fact that the revealed correlation between both quantum concepts is not destructively affected by the presence of other model parameters and hence its existence is independent of the form or type of the used potential. Undoubtedly, the present work will open the way for more investigations of this correlation in the limits of other critical points symmetries in nuclear shape phase transitions which play today a major role in nuclear structure research from theoretical as well as experimental point of view.

   ↳ nucl-thnucl-exNPA(2023)·2 citations
4. 04*

   Interplay between non-interfering neutrino exchange mechanisms and nuclear matrix elements in $0\nu \beta \beta$ decay

   Eligio Lisi🇮🇹 · Antonio Marrone🇮🇹 · Newton Nath🇮🇹

   We revisit the phenomenology of neutrinoless double beta ($0\nu \beta \beta$) decay mediated by non-interfering exchange of light and heavy Majorana neutrinos, in the context of current and prospective ton-scale experimental searches, as well as of recent calculations of nuclear matrix elements (NME) in different nuclear models. We derive joint upper bounds on the light and heavy contributions to $0\nu \beta \beta$ decay, for different sets of NME, through separate and combined data coming from the following experiments (and isotopes): KamLAND-Zen and EXO (Xe), GERDA, and MAJORANA (Ge) and CUORE (Te). We further consider three proposed projects that could provide, within current bounds, possible $0\nu \beta \beta$ decay signals at $>3\sigma$ level with an exposure of 10 ton years: nEXO (Xe), LEGEND (Ge) and CUPID (Mo). Separate and combined (Xe, Ge, Mo) signals are studied for different representative cases and NME sets, and the conditions leading to (non)degenerate light and heavy neutrino mechanisms are discussed. In particular, the role of heavy-to-light NME ratios in different isotopes is highlighted through appropriate graphical representations. By using different sets of "true" and "test" NME as a proxy for nuclear uncertainties, it is shown that the relative contributions of light and heavy neutrino exchange to $0\nu \beta \beta$ signals may be significantly biased in some cases. Implications for theoretical models connecting light and heavy Majorana neutrino masses are also briefly illustrated. These results provide further motivations to improve NME calculations, so as to better exploit the physics potential of future multi-isotope $0\nu \beta \beta$ searches at the ton scale.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2023)·8 citations
5. 05*

   An observation of the $f_0(1710)$ meson in the $\omega \varphi$ system in the Pion-$Be$ Interaction at Momentum of 29 GeV

   V.A.Dorofeev🇷🇺 · D.R.Eremeev🇷🇺 · V.G.Gotman🇷🇺 · A.V.Ivashin🇷🇺 · I.A.Kachaev🇷🇺 · Yu.A.Khokhlov🇷🇺 · M.S.Kholodenko🇷🇺 · V.F.Konstantinov🇷🇺 · V.I.Lisin🇷🇺 · V.D.Matveev🇷🇺 · E.V.Nazarov🇷🇺 · V.I.Nikolaenko🇷🇺 and 5 other authors

   The charge-exchange reaction ${\pi }^{-}p\to n\omega (783)\varphi (1020)$, $\omega \to {\pi }^{+}{\pi }^{-}{\pi }^0$, $\varphi \to K^{+}{K}^{-}$ is studied with the upgraded VES facility (U-70, Protvino) in the interaction of a 29 GeV pion beam with a beryllium target. The distribution over the invariant mass of the system $M_{\omega \varphi }$ shows a near-threshold signal. A partial wave analysis reveals that the scalar state ($J^{PC}=0^{++}$) dominates in this mass region. The observed signal can be described with a contribution of the known resonance $f_0(1710)$. Using OPE approximation for the reaction ${\pi }^{-}p\to n{f}_0(1710)$ the product of branching fractions is found to be: $Br(f_0(1710)\to \pi \pi )\cdot Br(f_0(1710)\to \omega \varphi )=(4.8\pm 1.2)\cdot 10^{-3}$.

   ↳ hep-exnucl-exEPJA(2024)·3 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.