Nuclear Theory·nucl-th

Thu·May 9, 2024Thursday·May 9, 2024

12 papers—7 primary·5 cross-listed

01
Comment on "Spin-trap isomers in deformed, odd-odd nuclei in the light rare-earth region near $N = 98$ "
M. Stryjczyk🇫🇮 · A. Jaries🇫🇮 · A. Kankainen🇫🇮 · T. Eronen🇫🇮
A new isomeric $(4^{-})$ state at 285.5(32) keV in $^{162}$ Tb was reported by R. Orford et al. [Phys. Rev. C 102, 011303(R) (2020)] based on a Penning-trap mass measurement. Here we show that this result is not compatible with existing experimental data. The state identified as $^{162}$ Tb $^{m}$ with a mass-excess value of $- 65593.9 (25)$ keV is actually the $1^{-}$ ground state. The state identified as the ground state of $^{162}$ Tb is most likely a molecular contaminant with the same mass-over-charge ratio.
nucl-thnucl-exPRC(2025)·3 citations
02
Inter-band B(E1) Strengths in Heavy Nuclei based on the Proxy-SU(3) Scheme
Alejandro Restrepo · José P. Valencia🇨🇴
Rotational bands of positive and negative parity are frequently found experimentally in heavy deformed even-even nuclei along with their corresponding $E 2$ intra-band and $E 1$ inter-band transitions. In $S U (3)$ symmetry-based models, calculating the $B (E 2)$ strengths is relatively straightforward due to the relation between the $E 2$ operator and the quadrupole generator of the algebra. However, calculating the $B (E 1)$ strengths is a more difficult task, requiring computations involving the shell-model expansion of the dipole operator and multi-shell matrix elements. In this work the $E 1$ operator is expanded in $S U (3)$ second quantization and applied to calculate the inter-band $B (E 1)$ strengths of the isotope $^{224}$ Th using the semi-microscopic algebraic quartet model (SAQM) based on the recently proposed proxy- $S U (3)$ scheme.
nucl-thPRC(2025)·2 citations
03
Collective-subspace requantization for sub-barrier fusion reactions: Inertial functions for collective motions
Chisato Ruike · Kai Wen🇺🇸 · Nobuo Hinohara🇯🇵 · Takashi Nakatsukasa🇯🇵
The adiabatic self-consistent collective coordinate (ASCC) method is used to determine the optimum reaction path and to calculate the potential and the inertial functions of the reaction model. The properties of the inertial functions are investigated with the ASCC method, in comparison with those of the cranking formulae. In addition, the properties of the pair rotation are investigated in the BCS pair model. The moments of inertia for rotation in both the real and the gauge spaces may decrease as the deformation develops.
nucl-thEPJ Web Conf.(2024)·1 citation
04
Effect of dark matter interaction on hybrid star in the light of the recent astrophysical observations
Suman Pal🇮🇳 · Gargi Chaudhuri🇮🇳
We have explored the effect of dark matter interaction on hybrid star (HS) in the light of recent astrophysical observational constraints. The presence of dark matter is assumed to be there in both the hadron as well as the quark sector. The dark matter particle interacts with both hadron and quark matter through the exchange of a scalar as well as a vector meson. The equation of state (EOS) of the hadron part is computed using the NL3 version of the relativistic mean field(RMF) model, whereas the quark part is taken care of using the well-known MIT Bag model with the vector interaction. We investigate the effect of the dark matter density and the mass of the dark matter particle on various observables like mass, radius, tidal deformability of the dark matter admixed hybrid star(DMAHS). In this study, we have noted an intriguing aspect that is the speed of sound in the DMAHS is insensitive to both the mass as well as the density of dark matter. We also observe a striking similarity in the variation of transition mass and its corresponding radius, as well as the maximum mass of neutron stars, with dark matter density and mass. We employ observational constraints from neutron stars to narrow down the allowed range of the parameters of dark matter.
nucl-thhep-phJCAP(2024)·13 citations
05
Isospin symmetry breaking in atomic nuclei
J. A. Sheikh · S. P. Rouoof · R. N. Ali · N. Rather · Chandan Sarma🇬🇧 · P. C. Srivastava🇮🇳
The importance of the isospin symmetry and its breaking in elucidating the properties of atomic nuclei is reviewed. The quark mass splitting and the electromagnetic origin of the isospin symmetry breaking (ISB) for nuclear many-body problem is discussed. The experimental data on isobaric analogue states cannot be described only with the Coulomb interaction, and ISB terms in the nucleon-nucleon interaction are needed to discern the observed properties. In the present work, the ISB terms are explicitly considered in nuclear energy density functional and spherical shell model approaches, and a detailed investigation of the analogue states and other properties of nuclei is performed. It is observed that isospin mixing is largest for the $N = Z$ system in the density functional approach.
nucl-thSymmetry(2024)·9 citations
06
Formal Theory of Heavy Ion Double Charge Exchange Reactions
Horst Lenske🇩🇪 · Jessica Bellone🇮🇹 · Maria Colonna🇮🇹 · Danilo Gambacurta🇮🇹 · Jose-Antonio Lay🇪🇸
The theory of heavy ion double charge exchange (DCE) reactions $A (Z, N) \to A (Z \pm 2, N \mp 2)$ is recapitulated emphasizing the role of Double Single Charge Exchange (DSCE) and pion-nucleon Majorana DCE (MDCE) reactions. DSCE reactions are of second--order distorted wave character, mediated by isovector nucleon-nucleon (NN) interactions. The DSCE response functions resemble the nuclear matrix elements (NME) of $2 ν 2 β$ decay. The MDCE process proceeds by a dynamically generated effective rank-2 isotensor interaction, defined by off--shell pion--nucleon DCE scattering. In closure approximation pion potentials and two--nucleon correlations are obtained, similar to the neutrino potentials and the intranuclear exchange of Majorana neutrinos in $0 ν 2 β$ Majorana double beta decay (MDBD).
nucl-thnucl-exEPJ Web Conf.(2024)·3 citations
07
Ab initio computations of strongly deformed nuclei around $^{80}$ Zr
B. S. Hu🇨🇦 · Z. H. Sun · G. Hagen🇺🇸 · T. Papenbrock🇺🇸
Nuclei around $N \approx Z \approx 40$ are strongly deformed and exhibit coexistence of shapes. These phenomena have challenged nuclear models. Here we perform ab initio coupled-cluster computations of low-lying collective states and electromagnetic quadrupole transitions of the even-even nuclei $^{72}$ Kr, $^{76, 78}$ Sr, $^{78, 80}$ Zr and $^{84}$ Mo starting from chiral nucleon-nucleon and three-nucleon forces. Our calculations reproduce the coexistence of oblate and prolate shapes in these nuclei, yield rotational bands and strong electromagnetic transitions, but are not accurate for some observables and nuclei. These results highlight the advances and challenges of ab initio computations of heavy deformed nuclei.
nucl-thnucl-exPRC(2024)·37 citations
08
Baryon-number -flavor separation in the topological expansion of QCD
David Frenklakh🇺🇸 · Dmitri Kharzeev🇺🇸 · Giancarlo Rossi🇮🇹 · Gabriele Veneziano🇨🇭
Gauge invariance of QCD dictates the presence of string junctions in the wave functions of baryons. In high-energy inclusive processes, these baryon junctions have been predicted to induce the separation of the flows of baryon number and flavor. In this paper we describe this phenomenon using the analog-gas model of multiparticle production proposed long time ago by Feynman and Wilson and adapted here to accommodate the topological expansion in QCD. In this framework, duality arguments suggest the existence of two degenerate junction-antijunction glueball Regge trajectories of opposite $C$ -parity with intercept close to 1/2. The corresponding results for the energy and rapidity dependence of baryon stopping are in reasonably good agreement with recent experimental findings from STAR and ALICE experiments. We show that accounting for correlations between the fragmenting strings further improves agreement with the data, and outline additional experimental tests of our picture at the existing (RHIC, LHC, JLab) and future (EIC) facilities.
↳ hep-phhep-thnucl-thJHEP(2024)·9 citations
09
Onset of scaling violation in pion and kaon elastic electromagnetic form factors
Zhao-Qian Yao🇮🇹 · Daniele Binosi🇮🇹 · Craig D. Roberts🇨🇳
Using a symmetry-preserving truncation of the quantum field equations describing hadron properties, parameter-free predictions are delivered for pion and kaon elastic electromagnetic form factors, $F_{P = π, K}$ , thereby unifying them with kindred results for nucleon elastic electromagnetic form factors. Regarding positive-charge states, the analysis stresses that the presence of scaling violations in QCD entails that $Q^{2} F_{P} (Q^{2})$ should exhibit a single maximum on $Q^{2} > 0$ . Locating such a maximum is both necessary and sufficient to establish the existence of scaling violations. The study predicts that, for charged $π$ , $K$ mesons, the $Q^{2} F_{P} (Q^{2})$ maximum lies in the neighbourhood $Q^{2} ≃ 5$ GeV $^{2}$ . Foreseeable experiments will test these predictions and, providing their $Q^{2}$ reach meets expectations, potentially also provide details on the momentum dependence of meson form factor scaling violation.
↳ hep-phhep-exhep-latnucl-ex+1PLB(2024)·27 citations
10
Amplitude analysis of $B^{0} \to K_{S}^{0} K^{+} K^{-}$ decays in a quasi-two-body QCD factorization approach
J.-P. Dedonder🇫🇷 · R. Kamiński🇵🇱 · L. Leśniak🇵🇱 · B. Loiseau🇫🇷 · P. Żenczykowski🇵🇱
The $B^{0} \to K_{S}^{0} K^{+} K^{-}$ decay amplitude is derived within a quasi-two-body QCD factorization framework in terms of kaon form factors and $B^{0}$ to two-kaon-transition functions. The final state kaon-kaon interactions in the $S$ , $P$ , and $D$ waves are taken into account. The unitarity constraints are satisfied for the two kaons in scalar states. It is shown that with few terms of the full decay amplitude one may reach a fair agreement with the total branching fraction and Dalitz-plot projections published in 2010 by the Belle Collaboration and in 2012 by the $BABAR$ Collaboration. With 13 free parameters, our model fits the corresponding 422 data with a $χ^{2}$ of 583.6 which leads to a $χ^{2}$ per degree of freedom equal to 1.43. The dominant branching fraction arises from the $f_{0} (K^{+} K^{-}) K_{S}^{0}$ mode with 83.0 $%$ of the total branching. The next important mode is dominated by $ϕ K_{S}^{0}$ plus small $ω K_{S}^{0}$ and $ρ^{0} K_{S}^{0}$ modes with 18.3 $%$ of the total. Then follows the $a_{0}^{\pm} K^{\mp}$ mode with 6.2 $%$ . Adding the other smaller modes, the total percentage sum is 107.7 $%$ which indicates a small interference contribution. In most regions of the Dalitz plot, our model gives rather small $C P$ asymmetry, but in some parts its values can be large and positive or negative. Its predicted total value is equal to -0.11 $%$ . The calculated time dependent $CP$ -asymmetry parameters agree, within errors, with those obtained by the $BABAR$ analysis. Our model amplitude can be the basis for a parametrization in experimental Dalitz plot analyses of LHCb and Belle II Collaborations.
↳ hep-phnucl-thPRD(2024)·1 citation
11
Longitudinal spin polarization in a thermal model with dissipative corrections
Soham Banerjee🇮🇳 · Samapan Bhadury🇵🇱 · Wojciech Florkowski🇵🇱 · Amaresh Jaiswal🇮🇳 · Radoslaw Ryblewski🇵🇱
In this work, we address the problem of longitudinal spin polarization of the $Λ$ hyperons produced in relativistic heavy-ion collisions. We combine a relativistic kinetic-theory framework that includes spin degrees of freedom treated in a classical way with the freeze-out parametrization used in previous investigations. The use of the kinetic theory allows us to incorporate dissipative corrections (due to the thermal shear and gradients of thermal vorticity) into the Pauli-Lubanski vector that determines spin polarization and can be directly compared with the experimental data. As in earlier similar studies, it turns out that a successful description of data can only be achieved with additional assumptions -- in our case, they involve the use of projected thermal vorticity and a suitably adjusted time for spin relaxation ( $τ_{s}$ ). From our analysis, we find that $τ_{s} \sim 5$ fm/ $c$ , which is comparable with other estimates.
↳ hep-phhep-thnucl-thPRC(2025)·25 citations
12
The Ghent Hybrid Model in NuWro: a new neutrino single-pion production model in the GeV regime
Qiyu Yan🇨🇳 · Kajetan Niewczas🇧🇪 · Alexis Nikolakopoulos🇺🇸 · Raúl González-Jiménez🇪🇸 · Natalie Jachowicz🇧🇪 · Xianguo Lu🇬🇧 · Jan Sobczyk🇵🇱 · Yangheng Zheng🇨🇳
Neutrino-induced single-pion production constitutes an essential interaction channel in modern neutrino oscillation experiments, with its products building up a significant fraction of the observable hadronic final states. Frameworks of oscillation analyses strongly rely on Monte Carlo neutrino event generators, which provide theoretical predictions of neutrino interactions on nuclear targets. Thus, it is crucial to integrate state-of-the-art single-pion production models with Monte Carlo simulations to prepare for the upcoming systematics-dominated landscape of neutrino measurements. In this work, we present the implementation of the Ghent Hybrid model for neutrino-induced single-pion production in the NuWro Monte Carlo event generator. The interaction dynamics includes coherently-added contributions from nucleon resonances and a non-resonant background, merged into the pythia branching predictions in the deep-inelastic regime, as instrumented by NuWro. This neutrino-nucleon interaction model is fully incorporated into the nuclear framework of the generator, allowing it to account for the influence of both initial- and final-state nuclear medium effects. We compare the predictions of this integrated implementation with recent pion production data from accelerator-based neutrino experiments. The results of the novel model show improved agreement of the generator predictions with the data and point to the significance of the refined treatment of the description of pion-production processes beyond the $Δ$ region.
↳ hep-phhep-exnucl-thJHEP(2024)·23 citations

Affiliations

first authorsco-authorsvia INSPIRE