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Nuclear Theory·nucl-th

Thursday·September 30, 2021

8 papers—3 primary·5 cross-listed

All8Primary3Cross-lists5
  1. 04

    [Submitted on 28 Sept 2021] (cross-list from hep-th)

    Dense matter equation of state and phase transitions from a Generalized Skyrme model

    Christoph Adam🇪🇸 · Alberto Garcia Martin-Caro🇪🇸 · Miguel Huidobro🇪🇸 · Ricardo Vazquez🇪🇸 · Andrzej Wereszczynski🇵🇱

    Skyrmion crystals are the field configurations which minimize the energy per baryon in the infinitely large topological charge sector of the Skyrme model, at least for sufficiently high density. They are, therefore, an important tool to describe the ground state of cold, symmetric nuclear matter at high density regimes. In this work, we analyze different crystalline phases and the existence of phase transitions between them within the generalized Skyrme model, with the ultimate goal of describing symmetric nuclear matter in a wide regime of densities. Furthermore, we propose a new energy-minimizing phase for densities lower than the nuclear saturation point () which also presents a good qualitative behavior in the zero density limit, thereby improving the description of strongly interacting matter in the region .

    Comments:
    16 pages, 10 figures; v2: presentation slightly improved, some references added
    Subjects:
    High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2109.13946 [pdf]
    PRD(2022)·15 citations
  2. 05

    [Submitted on 29 Sept 2021] (cross-list from astro-ph.SR)

    Theoretical estimate of the half-life for the radioactive Cs and Cs in astrophysical scenarios

    S. Taioli · D. Vescovi · M. Busso · S. Palmerini · S. Cristallo · A. Mengoni · S. Simonucci

    We analyze the CsBa and CsBa decays, which are crucial production channels for Ba isotopes in Asymptotic Giant Branch (AGB) stars. We reckon, from relativistic quantum mechanis, the effects of multichannel scattering onto weak decays, including nuclear and electronic excited states (ES) populated above 10 keV, for both parent and daughter nuclei. We find increases in the half-lives for K (by more than a factor 3 for Cs) as compared to previous works based on systematics. We also discuss our method in view of these previous calculations. An important impact on half-lives comes from nuclear ES decays, while including electronic temperatures yields further increases of about 20\% at energies 10-30 keV, typical of AGB stars of moderate mass (). Despite properly considering these effects, the new rates remain sensitively lower than the TY values, implying longer half-lives at least above 8-9 keV. Our rate predictions are in substantial accord with recent results based on the shell model, and strongly modify branching ratios along the -process path previously adopted. With our new rate, nucleosynthesis models well account for the isotopic admixtures of Ba in presolar SiC grains and in the Sun.

    Comments:
    15 pages, 3 figures, 5 tables. Accepted for publication in ApJ
    Subjects:
    Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
    arXiv:
    2109.14230 [pdf]
    ApJ(2022)·12 citations
  3. 06

    [Submitted on 29 Sept 2021] (cross-list from hep-ph)

    Enhancement of baryon-to-meson ratios around jets as a signature of medium response

    Ao Luo🇨🇳 · Ya-Xian Mao🇨🇳 · Guang-You Qin🇨🇳 · En-Ke Wang🇨🇳 · Han-Zhong Zhang🇨🇳

    We present a unique signal of jet-induced medium excitations: the enhancement of baryon-to-meson ratios around the quenched jets.To illustrate this, we study jet-particle correlations and the distributions of jet-induced identified particles with respect to the jet direction in Pb+Pb collisions at the LHC via a multi-phase transport model.We find a strong enhancement of baryon-to-meson ratios for associated particles at intermediate transverse momentum around the triggered jets in Pb+Pb collisions relative to p+p collisions, due to the coalescence of jet-excited medium partons.Since the lost energy from jets can diffuse to large angles, such baryon-to-meson-ratio enhancement is more pronounced for larger relative distance from the jet axis.We argue that the experimental confirmation of the enhancement of jet-induced baryon-to-meson ratios around the jets will provide an unambiguous evidence for the medium response to jet quenching in heavy-ion collisions.

    Comments:
    6 pages, 3 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2109.14314 [pdf]
    PLB(2023)·35 citations
  4. 07

    [Submitted on 29 Sept 2021] (cross-list from hep-ph)

    Induced fission-like process of hadronic molecular states

    Jun He🇨🇳 · Dian-Yong Chen🇨🇳 · Zhan-Wei Liu🇨🇳 · Xiang Liu🇨🇳

    In this work, we predict a new physical phenomenon, induced fission-like process and chain reaction of hadronic molecular states. As a molecular state, if induced by a meson, the can split into final state which is forbidden due to the spin-parity conservation. The breeding of the meson of the reaction, such as , makes the chain reaction of matter possible. We estimate the cross section of the meson induced fission-like process of into two mesons. With very small beam momentum of 1 eV, the total cross section reaches an order of 1000 b, and decreases rapidly with the increasing of beam momentum. With the transition of meson in molecular states to a meson, the can release large energy, which is acquired by the final mesons. The momentum distributions of the final mesons are analyzed. In the laboratory frame, the spectator meson in molecular state concentrates in the low momentum area. The energy from the transition frim to meson is mainly acquired by two scattered mesons. The results suggest that the meson environment will lead to the induced fission-like process and chain reaction of the . Such phenomenon can be extended to other hadronic molecular states.

    Comments:
    5 pages and 3 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
    arXiv:
    2109.14395 [pdf]
    Chin.Phys.Lett.(2022)·5 citations
  5. 08

    [Submitted on 29 Sept 2021] (cross-list from nucl-ex)

    Search for a bound di-neutron by comparing He(e,e'p)d and H(e,e'p)X measurements

    D. Nguyen🇺🇸 · C. Neuburger🇮🇱 · R. Cruz-Torres🇺🇸 · A. Schmidt🇺🇸 · D.W. Higinbotham🇺🇸 · J. Kahlbow🇺🇸 · P. Monaghan🇺🇸 · E. Piasetzky🇮🇱 · O. Hen🇺🇸

    We report on a search for a bound di-neutron by comparing electron-induced proton-knockout measurements from Helium-3 (He) and Tritium (H). The measurements were performed at Jefferson Lab Hall A with a 4.326 GeV electron beam, and kinematics of large momentum transfer (GeV/) and , to minimize contributions from non quasi-elastic (QE) reaction mechanisms. Analyzing the measured He missing mass () and missing energy () distributions, we can distinguish the two-body break-up reaction, in which the residual proton-neutron system remains bound as a deuteron. In the H mirror case, under the exact same kinematic conditions, we do not identify a signature for a bound di-neutron with similar binding energy to that of the deuteron. We calculate exclusion limits as a function of the di-neutron binding energy and find that, for binding equivalent to the deuteron, the two-body break-up cross section on H is less than 0.9% of that on He in the measured kinematics at the 95% confidence level.

    Comments:
    6 pages, 3 figures
    Subjects:
    Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2109.14524 [pdf]
    PLB(2022)·6 citations

Affiliations

first authorsco-authorsvia INSPIRE