Nuclear Theory·nucl-th

Tuesday·July 16, 2024

25 papers—11 primary·14 cross-listed

01
[Submitted on 13 Jul 2024]
Ab initio study of Z(N) = 6 magicity
H. Li · H. J. Ong · D. Fang · I. A. Mazur · I. J. Shin · A. M. Shirokov · J. P. Vary · P. Yin · X. Zhao · W. Zuo
The existence of magic numbers of protons and neutrons in nuclei is essential for understanding nuclear structure and fundamental nuclear forces. Over decades, researchers have conducted theoretical and experimental studies on the new magic number Z(N) = 6, focusing on observables such as radii, binding energy, electromagnetic transition, and nucleon separation energies. We perform the ab initio no-core shell model calculations for the occupation numbers of the lowest single particle states in the ground states of Z(N) = 6 and Z(N) = 8 isotopes (isotones). Our calculations do not support Z(N) = 6 as a magic number over a span of atomic numbers. However, 14C and 14O exhibit the characteristics of double-magic nuclei.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2407.09734 [pdf]
CPC(2024)·4 citations
02
[Submitted on 13 Jul 2024]
Incoherent solar-neutrino scattering off the stable Tl-isotopes
Dimitrios K. Papoulias🇬🇷 · Matti Hellgren🇫🇮 · Jouni Suhonen🇷🇴
Nuclear-structure calculations for the description of low-energy neutral-current neutrino scattering off the stable $^{203, 205}$ Tl isotopes are performed in the context of the nuclear shell model using the model space jj56pn. Cross-section and event-rate calculations focusing on inelastic solar-neutrino scattering off $^{203, 205}$ Tl are performed. The individual contributions of the various nuclear responses are presented and discussed, and the results are also illustrated in terms of the nuclear recoil energy. Analytical expressions entering the cross sections are given in order to achieve a direct connection with experimental observables.
Comments:
v1: 29 pages, 14 figures, 3 tables. v2: added a discussion on the nuclear recoil factors, matches published version in PRC
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2407.09889 [pdf]
PRC(2024)·4 citations
03
[Submitted on 13 Jul 2024]
Threshold photo-production of $J /Ψ$ off light nuclei
Fangcheng He🇺🇸 · Ismail Zahed🇺🇸
We analyze threshold photoproduction of heavy mesons off a deuteron and Helium-4, using the QCD factorization method. Assuming large skewness, the production amplitude is dominated by the leading twist-2 gluonic energy-momentum tensor (EMT). We use our recent results for the gluonic gravitational form factors of light nuclei in the impulse approximation, to estimate the differential cross sections for $J /Ψ$ production off a deuteron and Helium-4 at current electron facilities.
Comments:
7 pages, 2 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2407.09991 [pdf]
PRC(2025)·4 citations
04
[Submitted on 14 Jul 2024]
Charged hadron spectra and anisotropic flow from the AMPT model with shear viscous transport dynamics simulations at RHIC
Yao Zhang🇨🇳
We utilized the AMPT model to simulate the shear viscous transport dynamics of parton matter in Au+Au collisions at a constant specific shear viscosity and varying phase transition temperatures at 200 GeV. The resulting charged hadron spectra and anisotropic flow profiles correspond closely with experimental data. The transverse momentum spectra and longitudinal decorrelations are essentially unaffected by the phase transition temperature. An increase in the phase transition temperature leads to a rise in particle yields at midrapidity, accompanied by a decrease in both elliptic and triangular flows over a range of transverse momenta and pseudorapidities.
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2407.10060 [pdf]
EPJA(2025)·5 citations
05
[Submitted on 14 Jul 2024]
Nuclear forces and nuclear excited states
Pawan Kumar · Kanhaiya Jha
In this work, the role of the central, spin-force and tensor forces of two-nucleon interaction in building the first 2 $^{+}$ and 4 $^{+}$ states of 20 sd-shell nuclei is studied. Calculations are performed within the framework of the nuclear shell model. It is shown that the central force predominantly contributes to the excitation energy. While the spin-orbit and tensor forces contribute relatively less, their roles are noted crucial in a few cases, such as in $^{22}$ O. Further, it is demonstrated that the Hamiltonian projection approach should be preferred for rightly assessing the contributions of each force to the excitation energy.
Comments:
14 pages, 6 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2407.10219 [pdf]
0 citations
06
[Submitted on 14 Jul 2024]
Solar neutrino capture by 128, 130Te isotopes and Baksan Large Neutrino Telescope Project
A. N. Fazliakhmetov🇷🇺 · Yu. S. Lutostansky🇷🇺 · B. K. Lubsandorzhiev🇷🇺 · G. A. Koroteev🇷🇺 · V. N. Tikhonov🇷🇺
This paper discusses the charge-exchange strength functions $S (E)$ of the isotopes $^{128, 130}$ Te. The experimental data of the $S (E)$ strength functions obtained from $(^{3} He, t)$ reactions, as well as the $S (E)$ strength functions calculated in the microscopic theory of finite fermi-systems, are analyzed. The resonance structure of the strength function $S (E)$ is examined, and the Gamow-Teller and Pygmy resonances are identified. The resonance structure of the strength function $S (E)$ is vital for the calculation and analysis of the process of neutrino capture by atomic nuclei.
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2407.10357 [pdf]
0 citations
07
[Submitted on 15 Jul 2024]
Nuclear contacts of unstable nuclei
Tongqi Liang · Dong bai · Zhongzhou Ren
Nuclear contact is a key quantity to describe the nucleon-nucleon short-range correlations (SRCs). While they have been determined by electron scattering experiments for selected stable nuclei, nuclear contacts are largely unknown for unstable nuclei. In this work, we study nuclear contacts for a number of nuclei in the vicinity of the doubly magic $^{132}$ Sn from the theoretical perspective, with special emphasis on unstable nuclei. We find that the proton-proton contact generally gets suppressed by the excess neutrons for the Sn isotopes, resembling the suppression of $α$ -cluster formation reported recently for the same isotopic chain [J. Tanaka $et al .$ , Science $371$ , 260 (2021)]. This indicates a hidden universal aspect of SRCs and $α$ clustering, two different kinds of nuclear correlations. Meanwhile, a linear relation is found between the proton-proton contact and the proton number for the $N = 82$ isotones. Our results can be helpful for future experimental studies of SRCs in unstable nuclei at advanced facilities worldwide.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2407.10378 [pdf]
PLB(2024)·7 citations
08
[Submitted on 15 Jul 2024]
A Semi-Empirical Formula for Two-Neutrino Double-Beta Decay
Ovidiu Niţescu🇸🇰 · Fedor Šimkovic🇸🇰
We propose a semi-empirical formula (SEF) for calculating the nuclear matrix elements (NMEs) for two-neutrino double-beta decay. The SEF's dependence on the proton and neutron numbers, the pairing, isospin, and deformation properties of the initial and final nuclei is inspired by the insights offered by nuclear many-body methods and trends in experimental data. Compared with the previous phenomenological and nuclear models, the SEF yields the best agreement with the experimental NMEs. Its stability and predictive power are cross-validated, and predictions are provided for nuclear systems of experimental interest.
Comments:
9 pages, 1 figure, 3 tables
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2407.10422 [pdf]
PRC(2025)·4 citations
09
[Submitted on 15 Jul 2024]
Polarized $ϕ$ meson rates with viscous corrections at RHIC
Eduardo Grossi🇮🇹 · Andrea Palermo🇺🇸 · Ismail Zahed🇺🇸
We discuss the emission of $ϕ$ mesons with longitudinal and transverse polarization in ultra-relativistic heavy ion collisions. In the hadronic phase and in leading order in the kaon diluteness, $ϕ$ emission is isotropic and driven by the flavor singlet and octet vector spectral functions. At next to leading order, the emissivities receive a non-isotropic correction from the flavor octet spectral function, and the non-equilibrium contributions originating from the shear and bulk viscosities. Implications for the $ϕ$ meson alignment in heavy-ion collisions are discussed.
Comments:
20 pages,5 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2407.10524 [pdf]
PRC(2025)·10 citations
10
[Submitted on 15 Jul 2024]
Probing QGP droplets with charmonium in high-multiplicity proton-proton collisions
Yunfan Bai🇬🇧 · Baoyi Chen🇨🇳
We study the hot medium effects in high-multiplicity proton-proton (pp) collisions at $s_{N N} = 13$ TeV via the charmonium probes. The hot medium is described with the hydrodynamic model, while charmonium evolutions in the medium are studied with a time-dependent Schrödinger equation. The hot medium dissociation on charmonium is considered with the temperature-dependent complex potential parametrized with the results from lattice QCD calculations. The ratio $σ_{ψ (2 S)} / σ_{J / ψ}$ of $J / ψ$ and $ψ (2 S)$ production cross sections are calculated and compared with the LHCb experimental data in pp collisions. Our calculations explain the charmonium relative suppression in different transverse momentum and multiplicity bins. The suppression of this ratio is mainly affected by the effects of the deconfined medium. It is less affected by the initial effects before the generation of the heavy quark pair. We suggest this to be a clear signal of the small QGP droplets generated in high multiplicity pp collisions.
Comments:
8 pages, 10 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2407.10566 [pdf]
EPJC(2024)·8 citations
11
[Submitted on 15 Jul 2024]
Comparing matching prescriptions between pre-equilibrium and hydrodynamic models in high-energy nuclear collisions
Nicolas Borghini🇩🇪 · Renata Krupczak🇩🇪 · Hendrik Roch🇺🇸
State-of-the-art simulations of high-energy nuclear collisions rely on hybrid setups, involving in particular a pre-equilibrium stage to let the system evolve from a far-from-equilibrium initial condition towards a near-equilibrated state after which fluid dynamics can be applied meaningfully. A known issue is the mismatch between the equation of state in the fluid-dynamical evolution and the effective one in the previous stage, which leads to discontinuities at the interface between the two models. Here we introduce a new matching prescription at this interface, based on the entropy, and we compare it with the standard one relying on local energy conservation. We study the behavior of various quantities at the switching time between the models and investigate a number of final-state hadronic observables. For the latter, we show that they are not modified significantly by the choice of matching prescription, provided an appropriate normalization is chosen for the initial state. In turn, our approach reduces sizeably the ratio of bulk over thermodynamic pressure at the beginning of the fluid-dynamical stage.
Comments:
8 pages, 3 figures. v2: published version
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2407.10634 [pdf]
EPJC(2024)·5 citations

Affiliations

first authorsco-authorsvia INSPIRE