Nuclear Theory·nucl-th

Thursday·March 14, 2024

12 papers—4 primary·8 cross-listed

01
[Submitted on 13 Mar 2024]
Electron scattering on $^{4}$ He from coupled-cluster theory
Joanna E. Sobczyk
We present a coupled-cluster calculation for the electron- $^{4}$ He scattering in the region of the quasi-elastic peak. We show the longitudinal and transverse responses separately, and discuss results within two distinct theoretical methods: the Lorentz integral transform and spectral functions. The comparison between them allows to investigate the role of final state interactions, two-body currents and relativistic effects.
Comments:
10 pages, 2 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2403.08413 [pdf]
Few Body Syst.(2024)·2 citations
02
[Submitted on 13 Mar 2024]
Opportunities and open questions in modern $β$ decay
Leendert Hayen🇫🇷
For well over half a century, precision studies of neutron and nuclear $β$ decays have been at the forefront of searches for exotic electroweak physics. Recent advances in nuclear ab initio theory and the widespread use of effective field theories means that its modern understanding is going through a transitional phase. This has been propelled by current tensions in the global data set leading to renewed scrutiny of its theoretical ingredients. In parallel, a host of novel techniques and methods are being investigated that are able to sidestep many traditional systematic uncertainties and require a diverse palette of skills and collaboration with material science and condensed matter physics. We highlight the current opportunities and open questions with the aim of facilitating the transition to a more modern understanding of $β$ decay.
Comments:
Invited review for Annual Review of Nuclear and Particle Science. 37 pages, 5 figures; (v2) fixed references and minor textual changes
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2403.08485 [pdf]
Ann.Rev.Nucl.Part.Sci.(2024)·18 citations
03
[Submitted on 13 Mar 2024]
Effect of the charge asymmetry and orbital angular momentum in the entrance channel on the hindrance to complete fusion
Elzod Khusanov (1,2,3) · Avazbek Nasirov (1,4) · Mukhtorali Nishonov (2) ((1) Institute of Nuclear Physics, (2) Faculty of Physics, National University of Uzbekistan, (3) Institute of Theoretical Physics, (4) Joint Institute for Nuclear Research)
The hindrance to complete fusion is studied as a function of the charge asymmetry of colliding nuclei and orbital angular momentum of the collision. The formation and evolution of a dinuclear system (DNS) in the heavy ion collisions at energies near the Coulomb barrier is calculated in the framework of the DNS model. The DNS evolution is considered as nucleon transfer between its fragments. The results prove that a hindrance at formation of a compound nucleus (CN) is related with the quasifission process which is breakup of the DNS into products instead to reach the equilibrated state of the CN. The role of the angular momentum in the charge (mass) distribution of the reaction products for the given mass asymmetry of the colliding nuclei has been demonstrated. The results of this work have been compared with the measured data for the quasifission yields in the $^{12}$ C+ $^{204}$ Pb and $^{48}$ Ca+ $^{168}$ Er reactions to show the role of the mass asymmetry of the entrance channel.
Comments:
11 pages, 17 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2403.08489 [pdf]
PRC(2024)·5 citations
04
[Submitted on 13 Mar 2024]
Nuclear coherent $π^{0}$ photoproduction with charge-exchange and spin-flip rescattering
Viacheslav Tsaran🇩🇪 · Marc Vanderhaeghen🇩🇪
In this work, we present an updated model for nuclear $π^{0}$ photoproduction, which incorporates pion second-order rescattering on intermediate excited nuclear states. Our approach is based on the distorted wave impulse approximation in momentum space. The many-body medium effects are incorporated in the complex effective $Δ$ self-energy, employing the results of the recently developed second-order pion-nucleus scattering potential. The experimental data for $^{12}$ C and $^{40}$ Ca are successfully described without the need to fit the model parameters of the photoproduction amplitude as a result of incorporating the second-order part of nuclear photoproduction potential, which involves intermediate nucleon spin-flip and charge exchange.
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2403.08608 [pdf]
PRC(2024)·4 citations
05
[Submitted on 28 Feb 2024] (cross-list from hep-ph)
Collisional energy loss of a heavy quark in a semiquark-gluon plasma
Qianqian Du🇨🇳 · Mudong Du🇨🇳 · Yun Guo🇨🇳
By utilizing a background field effective theory, we compute the collisional energy loss of a heavy quark moving through a semiquark-gluon plasma characterized by nontrivial holonomy for Polyakov loops. We consider the elastic scatterings between the incident heavy quark and the thermal partons with both hard and soft momentum transfers. As compared to the energy loss obtained from the perturbation theory, the hard processes get modified through the thermal distribution functions that depend on the background field, while the proper treatment of the soft processes strongly relies on the use of the hard-thermal-loop resummed gluon propagator derived from the background field effective theory. Our results show that the heavy quark energy loss is significantly suppressed in the semiquark-gluon plasma due to a background field that is self-consistently generated in the effective theory. On the other hand, the suppression has a strong dependence on the temperature of the plasma which becomes negligible above $2 - 3$ times the critical temperature. For a realistic coupling constant, ignoring a relatively weak dependence on the heavy quark velocity, the suppression on the collisional energy loss can be approximated by an overall factor determined solely by the background field. This simple conclusion is expected to be useful for phenomenological applications in the heavy flavor physics.
Comments:
final version, published in PRD
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2402.18004 [pdf]
PRD(2024)·11 citations
06
[Submitted on 11 Mar 2024] (cross-list from hep-ph)
Energy loss of a heavy fermion in a collisional QED plasma
Yun Guo🇨🇳 · Luhua Qiu🇨🇳 · Ruizhe Zhao🇨🇳 · Michael Strickland🇺🇸
We compute the energy loss of heavy fermions moving in a plasma, taking into account the modification of the photon collective modes induced by collisions using a Bhatnagar-Gross-Krook collisional kernel. We include contributions from both hard and soft scatterings of the heavy fermion using a collisionally modified hard-thermal-loop resummed propagator. Using this method, one does not need to introduce a separation scale between hard- and soft-momentum exchanges. To place our calculation in context, we review other theoretical approaches to computing the collisional energy loss of fermions and discuss the systematics and results obtained in each approach compared to using a resummed propagator for both hard and soft momentum exchanges. Our final results indicate that self-consistently including the effect of collisions in the self-energies of the resummed propagator results in an increased energy loss compared to using collisionless hard-thermal-loop propagators. The effect becomes larger as the magnitude of the coupling constant and the velocity of the fermion increase.
Comments:
25 pages, 7 figures, final version published in PRD
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2403.06739 [pdf]
PRD(2024)·8 citations
07
[Submitted on 12 Mar 2024] (cross-list from hep-ph)
SPINAS: Spinor Amplitude Subroutines for Constructive Diagram Evaluations
Neil Christensen🇺🇸
SPINAS is a C++ package created for the implementation and numerical computation of phase-space points of constructive amplitudes in particle physics. This package contains a suite of classes and methods for handling particles, propagators, spinor products, and processes. SPINAS is structured to offer straightforward usability while ensuring maximum efficiency. This is achieved through a design that emphasizes the storage and reuse of intermediate results within amplitude calculations for each phase-space point. We include a user guide describing how to use the components, a complete example of how to use SPINAS for a scattering amplitude, a discussion of the design and implementation useful for those wishing to contribute, and a discussion of our validation of this package, including both a validation of individual components of the package and a comparison of a complete set of Standard Model processes with Feynman diagrams.
Comments:
39 pages, 0 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2403.07981 [pdf]
EPJC(2024)·5 citations
08
[Submitted on 12 Mar 2024] (cross-list from hep-ph)
Nucleon charge and magnetisation distributions: flavour separation and zeroes
Zhao-Qian Yao🇨🇳 · Daniele Binosi🇮🇹 · Zhu-Fang Cu🇨🇳 · Craig D. Roberts🇨🇳
A symmetry-preserving truncation of the quantum field equations describing hadron properties is used to deliver parameter-free predictions for all nucleon elastic electromagnetic form factors and their flavour separation to large values of momentum transfer, $Q^{2}$ . The proton electric form factor, $G_{E}^{p}$ , possesses a zero, whereas that of the neutron, $G_{E}^{n}$ , does not. The difference owes to the behaviour of the Pauli form factor of the proton's singly-represented valence $d$ -quark. Consequently, $G_{E}^{n} > G_{E}^{p}$ on a material large- $Q^{2}$ domain. These predictions can be tested in modern experiments.
Comments:
9 pages, 9 figures, 1 table. Version to appear in Fundamental Research
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2403.08088 [pdf]
Fund.Res.(2026)·22 citations
09
[Submitted on 13 Mar 2024] (cross-list from nucl-ex)
First identification of a doublet wobbling excitation mode in $^{105}$ Pd
A. Karmakar · P. Datta · N. Rather · S. Pal · R. Palit · A. Goswami · G.H. Bhat · J. A. Sheikh · S. Jehangir · S. Chattopadhyay · S. Frauendorf
An experimental investigation of $^{105}$ Pd has revealed, for the first time, the existence of two wobbling bands, both having one phonon configuration and originating from excitation which is the wobbling from the yrast band with the $h_{11/2}$ quasineutron fully aligned with the short axis, and from an excited band with the same quasineutron but with less alignment along the short axis. These observations have been drawn from the measured ratios of the inter-band and intra-band gamma transition rates. Model calculations based on the triaxial projected shell model (TPSM) approach have been performed and are found to be in good agreement with the experimental energies and relative transition probabilities. The analysis of the TPSM results provides an insight into the nature of the observed structures at a microscopic level.
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2403.08235 [pdf]
PRC(2025)·7 citations
10
[Submitted on 13 Mar 2024] (cross-list from quant-ph)
Variance Minimisation of the Lipkin-Meshkov-Glick Model on a Quantum Computer
Isaac Hobday🇬🇧 · Paul Stevenson🇬🇧 · James Benstead🇬🇧
Quantum computing can potentially provide advantages for specific computational tasks. The simulation of fermionic systems is one such task that lends itself well to quantum computation, with applications in nuclear physics and electronic systems. Here we present work in which we use a variance minimisation method to find the full spectrum of energy eigenvalues of the Lipkin-Meshkov-Glick model; an exactly-solvable nuclear shell model-type system. We perform these calculations using both quantum simulators and real quantum hardware accessed via IBM cloud-based quantum computers. Using these IBM quantum computers we are able to obtain all eigenvalues for the cases of three and seven fermions (nucleons) in the Lipkin-Meshkov-Glick model.
Comments:
8 pages, 7 figures, submitted to Physical Review C
Subjects:
Quantum Physics (quant-ph); Nuclear Theory (nucl-th)
arXiv:
2403.08625 [pdf]
3 citations
11
[Submitted on 13 Mar 2024] (cross-list from hep-ph)
BHAC-QGP: three-dimensional MHD simulations of relativistic heavy-ion collisions, I. Methods and tests
Markus Mayer🇩🇪 · Ashutosh Dash🇩🇪 · Gabriele Inghirami🇩🇪 · Hannah Elfner🇩🇪 · Luciano Rezzolla🇩🇪 · Dirk H. Rischke🇩🇪
We present BHAC-QGP, a new numerical code to simulate the evolution of matter created in heavy-ion collisions in the presence of electromagnetic fields. It is derived from the Black Hole Accretion Code (BHAC), which has been designed to model astrophysical processes in a general-relativistic magnetohydrodynamical description. As the original Black Hole Accretion Code, BHAC-QGP benefits from the use of Adaptive Mesh Refinement (AMR), which allows us to dynamically adjust the resolution where necessary, and makes use of time-dependent Milne coordinates and the ultrarelativistic equation of state, $P = e /3$ . We demonstrate that BHAC-QGP accurately passes a number of systematic and rigorous tests.
Comments:
20 pages, 9 figures, new sections and figures added
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2403.08668 [pdf]
PRC(2025)·10 citations
12
[Submitted on 13 Mar 2024] (cross-list from hep-ph)
BHAC-QGP: three-dimensional MHD simulations of relativistic heavy-ion collisions, II. Application to Au-Au collisions
Markus Mayer🇩🇪 · Ashutosh Dash🇩🇪 · Gabriele Inghirami🇩🇪 · Hannah Elfner🇩🇪 · Luciano Rezzolla🇩🇪 · Dirk H. Rischke🇩🇪
We present BHAC-QGP, a new numerical code to simulate the evolution of matter created in heavy-ion collisions. BHAC-QGP is based on the Black Hole Accretion Code (BHAC), which has been designed to model astrophysical processes through the solution of the equations of general-relativistic magnetohydrodynamics. Like the mother code, BHAC-QGP uses Adaptive Mesh Refinement (AMR), which allows for a dynamic adjustment of the resolution in regions of the computational domain where a particularly high accuracy is needed. We here discuss a number of applications of BHAC-QGP to Au-Au collisions at Relativistic Heavy-Ion Collider (RHIC) energies and show that the code is able to reproduce results of other simulations of these scenarios, but with much higher accuracy.
Comments:
19 pages, 14 figures, new sections and figures added
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2403.08669 [pdf]
PRC(2025)·20 citations

Affiliations

first authorsco-authorsvia INSPIRE