Nuclear Theory·nucl-th

Monday·June 5, 2023

11 papers—3 primary·8 cross-listed

01
[Submitted on 2 Jun 2023]
Self-consistent many-body approach to the electroproduction of hypernuclei
P. Bydžovský🇨🇿 · D. Denisova🇨🇿 · D. Petrellis🇨🇿 · D. Skoupil🇨🇿 · P. Veselý🇨🇿 · G. De Gregorio🇮🇹 · F. Knapp🇨🇿 · N. Lo Iudice🇮🇹
The electroproduction of selected $p$ - and $s d$ -shell hypernuclei was studied within a many-body approach using realistic interactions between the constituent baryons. The cross sections were computed in distorted-wave impulse approximation using two elementary amplitudes for the electroproduction of the $Λ$ hyperon. The structure of the hypernuclei was investigated within the framework of the self-consistent $Λ$ -nucleon Tamm-Dancoff approach and its extension known as the $Λ$ -nucleon equation of motion phonon method. Use was made of the NNLOsat chiral potential plus the effective Nijmegen-F YN interaction. The method was first implemented on light nuclei for studying the available experimental data and establishing a relation to other approaches. After this proof test, it was adopted for predicting the electroproduction cross section of the hypernuclei $_{Λ}^{40}$ K and $_{Λ}^{48}$ K in view of the E12-15-008 experiment in preparation at JLab. On the ground of these predictions, appreciable effects on the spectra are expected to be induced by the YN interaction.
Comments:
10 pages, 7 figures (version 2); 11 pages, 9 figures (v1)
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2306.01308 [pdf]
PRC(2023)·10 citations
02
[Submitted on 2 Jun 2023]
Properties of Hot Nuclear Matter
Omar Benhar · Alessandro Lovato · Lucas Tonetto
A fully quantitative description of equilibrium and dynamical properties of hot nuclear matter will be needed for the interpretation of the available and forthcoming astrophysical data, providing information on the post merger phase of a neutron star coalescence. We discuss the results of a recently developed theoretical model,based on a phenomenological nuclear Hamiltonian including two- and three-nucleon potentials, to study the temperature dependence of average and single-particle properties of nuclear matter relevant to astrophysical applications. The potential of the proposed approach for describing dissipative processes leading to the appearance of bulk viscosity in neutron star matter is also outlined.
Comments:
Submitted to Universe for publication in the Special Issue on Many-Body Theory. arXiv admin note: text overlap with arXiv:2208.03131, arXiv:2205.11183
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2306.01351 [pdf]
Universe(2023)·7 citations
03
[Submitted on 2 Jun 2023]
Testing the Paradigm of Nuclear Many-Body Theory
Omar Benhar
Nuclear many-body theory is based on the tenet that nuclear systems can be accurately described as collections of point-like particles. This picture, while providing a remarkably accurate explanation of a wealth of measured properties of atomic nuclei, is bound to break down in the high-density regime, in which degrees of freedom other than protons and neutrons are expected to come into play. Valuable information on the validity of the description of dense nuclear matter in terms of nucleons, needed to firmly establish its limit of applicability, can be obtained from electron-nucleus scattering data at large momentum transfer and low energy transfer. The emergence of y-scaling in this kinematic region, unambiguously showing that the beam particles couple to high-momentum nucleons belonging to strongly correlated pairs, indicates that at densities as large as five times nuclear density -- typical of the neutron star interior -- nuclear matter largely behaves as a collection of nucleons.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2306.01367 [pdf]
Particles(2023)·8 citations
04
[Submitted on 31 May 2023] (cross-list from hep-ph)
Hadron transverse momentum distributions in the Tsallis statistics with escort probabilities
A.S. Parvan🇷🇺
The exact and approximate hadron transverse momentum distributions for the Fermi-Dirac, Bose-Einstein and Maxwell-Boltzmann statistics of particles in the framework of the Tsallis statistics with escort probabilities (the Tsallis-3 statistics) have been derived. The classical and quantum transverse momentum distributions in the zeroth term approximation and the quantum transverse momentum distributions in the factorization approximation introduced in the zeroth term approximation were found. The transverse momentum distributions in the zeroth term approximation and in the factorization approximation of the zeroth term approximation are the same in the Tsallis-3, Tsallis-2 and $q$ -dual statistics. The well-known classical phenomenological Tsallis distribution exactly coincides with the classical transverse momentum distribution of the Tsallis-3 statistics in the zeroth term approximation for which the entropy of system is zero in the whole range of state variables. However, the quantum phenomenological Tsallis distribution does not coincide with either the exact or approximate transverse momentum distributions of the Tsallis-3 statistics. The exact Tsallis-3 classical distribution and the classical phenomenological Tsallis distribution were applied to describe the experimental spectra of the charged pions produced in the proton-proton collisions at high energies. The values of the parameters $(T, q)$ for both these model distributions differ in the whole energy range. Thus, the classical phenomenological Tsallis distribution is an unsatisfactory approximation for the exact classical transverse momentum distribution of the Tsallis-3 statistics.
Comments:
35 pages, 7 figures. arXiv admin note: text overlap with arXiv:1608.01888
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2306.01003 [pdf]
J.Phys.G(2023)·7 citations
05
[Submitted on 1 Jun 2023] (cross-list from hep-ph)
Proton charge radius extraction from muon scattering at MUSE using dispersively improved chiral effective field theory
F. Gil-Domínguez🇪🇸 · J. M. Alarcón🇪🇸 · C. Weiss🇺🇸
The MUSE experiment at Paul Scherrer Institute will perform the first measurement of low-energy muon-proton elastic scattering (muon lab momenta 115-210 MeV) with the aim of determining the proton charge radius. We study the prospects for the proton radius extraction using the theoretical framework of Dispersively Improved Chiral Effective Field Theory (DI $χ$ EFT). It connects the proton radii with the finite- $Q^{2}$ behavior of the form factors through complex analyticity and enables the use of data up to $Q^{2} \sim$ 0.1 GeV $^{2}$ for radius extraction. We quantify the sensitivity of the $μ p$ cross section to the proton charge radius, the theoretical uncertainty of the cross section predictions, and the size of two-photon exchange corrections. We find that the optimal kinematics for radius extraction at MUSE is at momenta 210 MeV and $Q^{2} \sim$ 0.05-0.08 GeV $^{2}$ . We compare the performance of electron and muon scattering in the same kinematics. As a byproduct, we obtain explicit predictions for the $μ p$ and $e p$ cross sections at MUSE as functions of the assumed value of the proton radius.
Comments:
12 pages, 12 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2306.01037 [pdf]
PRD(2023)·6 citations
06
[Submitted on 2 Jun 2023] (cross-list from hep-ph)
Combined analysis of the $γ n \to K^{0} Σ^{0}$ and $γ n \to K^{+} Σ^{-}$ reactions
Neng-Chang Wei🇨🇳 · Ai-Chao Wang🇨🇳 · Fei Huang🇨🇳
The recently released data on differential cross sections for $γ n \to K^{0} Σ^{0}$ from the A2 and BGOOD Collaborations are used to examine the theoretical model constructed in our previous work [Phys. Rev. D \textbf{105}, 094017 (2022)] for $γ n \to K^{+} Σ^{-}$ , and it is found that the model predictions are able to qualitatively reproduce the A2 data but fail to describe the BGOOD data. Then, a combined analysis of the $γ n \to K^{0} Σ^{0}$ and $γ n \to K^{+} Σ^{-}$ reactions is performed to revise the theoretical model. Due to the inconsistency problem, the A2 and BGOOD data are included in fits separately. In the case of including the A2 data, both the data for $γ n \to K^{0} Σ^{0}$ and $γ n \to K^{+} Σ^{-}$ can be fairly well described, and the contributions from the $N (1710) 1/ 2^{+}$ , $N (1880) 1/ 2^{+}$ , $N (1900) 3/ 2^{+}$ , and $Δ (1920) 3/ 2^{+}$ resonances are found to dominate the reactions in the lower energy region. While in the case of including the BGOOD data, although most of the data for the $γ n \to K^{+} Σ^{-}$ reaction can be described with the exception of some noticeable discrepancies on beam asymmetries at lower energies, the BGOOD data for $γ n \to K^{0} Σ^{0}$ can be only qualitatively described, and the contributions from the $N (1710) 1/ 2^{+}$ , $N (1900) 3/ 2^{+}$ , and $Δ (1910) 1/ 2^{+}$ resonances are found to dominate the reactions in the lower energy region. In both cases, the $t$ -channel $K^{*} (892)$ exchange is found to play a crucial role at forward angles in the higher energy region. Further precise measurements of data for $γ n \to K^{0} Σ^{0}$ are called on to disentangle the discrepancies between the data sets from the A2 and BGOOD Collaborations.
Comments:
14 pages,17 figures; Accepted for publication in Physical Review D
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2306.01453 [pdf]
PRD(2023)·7 citations
07
[Submitted on 2 Jun 2023] (cross-list from cond-mat.quant-gas)
Corrections to Local Density Approximation for superfluid trapped fermionic atoms from the Wigner-Kirkwood $ℏ$ expansion
Peter Schuck🇫🇷 · Michael Urban🇫🇷 · Xavier Viñas🇪🇸
A semiclassical second-order differential equation for the inhomogeneous local gap $Δ (r)$ is derived from a strict second-order $ℏ$ expansion of the anomalous pairing tensor and compared with a similar equation given by Simonucci et al. The second-order normal density matrix is given as well. Several extra gradient terms are revealed. Second-order expressions at finite temperature are given for the first time. The corresponding Ginzburg-Landau equation is presented and it is shown that, compared to the equation of Baranov and Petrov, an extra second-order gradient term is present. Applications to the pairing gap in cold atoms in a harmonic trap are presented.
Comments:
12 pages, 4 figures. To be submitted to the EPJ A Topical Collection devoted to the legacy of Peter Schuck
Subjects:
Quantum Gases (cond-mat.quant-gas); Nuclear Theory (nucl-th)
arXiv:
2306.01472 [pdf]
EPJA(2023)·3 citations
08
[Submitted on 2 Jun 2023] (cross-list from physics.chem-ph)
Equation Generator for Equation-of-Motion Coupled Cluster Assisted by Computer Algebra System
Raúl Quintero-Monsebaiz · Pierre-François Loos
We present an equation generator algorithm that utilizes second-quantized operators in normal order with respect to a correlated or non-correlated reference and the corresponding Wick theorem. The algorithm proposed here, written with \textsc{mathematica}, enables the generation of non-redundant strings of second-quantized operators that, after classification, are directly assigned to intermediate quantities used to construct the coupled-cluster (CC) effective Hamiltonian. We demonstrate the capabilities of the algorithm by computing the CC amplitude equations and various blocks of the equation-of-motion CC effective Hamiltonian. A comprehensive description of this four-step algorithm is provided alongside concrete examples.
Comments:
15 pages, 2 figures
Subjects:
physics.chem-ph (physics.chem-ph); cond-mat.mtrl-sci (cond-mat.mtrl-sci); Strongly Correlated Electrons (cond-mat.str-el); Nuclear Theory (nucl-th)
arXiv:
2306.01573 [pdf]
AIP Adv.(2023)·1 citation
09
[Submitted on 2 Jun 2023] (cross-list from hep-ph)
Combining lattice QCD and phenomenological inputs on generalised parton distributions at moderate skewness
Michael Joseph Riberdy🇫🇷 · Hervé Dutrieux🇫🇷 · Cédric Mezrag🇫🇷 · Paweł Sznajder🇵🇱
We present a systematic study demonstrating the impact of lattice QCD data on the extraction of generalised parton distributions (GPDs). For this purpose, we use a previously developed modelling of GPDs based on machine learning techniques fulfilling the theoretical requirements of polynomiality, a form of positivity constraint and known reduction limits. A special care is given to estimate the uncertainty stemming from the ill-posed character of the connection between GPDs and the experimental processes usually considered to constrain them, like deeply virtual Compton scattering (DVCS). Mock lattice QCD data inputs are included in a Bayesian framework to the prior model which is fitted to reproduce the most experimentally accessible information of a phenomenological model by Goloskov and Kroll. We highlight the impact of the precision, correlation and kinematic coverage of lattice data on GPD extraction at moderate $ξ$ which has only been brushed in the literature so far, paving the way for a joint extraction of GPDs.
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2306.01647 [pdf]
EPJC(2024)·25 citations
10
[Submitted on 2 Jun 2023] (cross-list from hep-ph)
Helicity Evolution at Small $x$ : Revised Asymptotic Results at Large $N_{c} & N_{f}$
Daniel Adamiak🇺🇸 · Yuri V. Kovchegov🇺🇸 · Yossathorn Tawabutr🇺🇸
We present a numerical solution of the revised version of the small- $x$ helicity evolution equations at large $N_{c}$ and $N_{f}$ . (Here $N_{c}$ and $N_{f}$ are the numbers of quark colors and flavors, respectively.) The evolution equations are double-logarithmic in the Bjorken $x$ variable, resumming powers of $α_{s} ln^{2} (1/ x)$ with $α_{s}$ the strong coupling constant. The large- $N_{c} & N_{f}$ evolution we consider includes contributions of small- $x$ quark emissions and is thus more realistic than the large- $N_{c}$ one, which only involves gluon emissons. The evolution equations are written for the so-called ``polarized dipole amplitudes", which are related to the helicity distribution functions and the $g_{1}$ structure function. Unlike the previously reported solution of the earlier version of helicity evolution equations at large $N_{c} & N_{f}$ , our solution does not exhibit periodic oscillations in $ln (1/ x)$ for $N_{f} < 2 N_{c}$ , while only showing occasional sign reversals. For $N_{f} = 2 N_{c}$ , we report oscillations with $ln (1/ x)$ , similar to those found earlier. We determine the intercept of our evolution for $N_{f} < 2 N_{c}$ as well as the parameters of the oscillatory behavior for $N_{f} = 2 N_{c}$ . We compare our results to the existing resummation and finite-order calculations for helicity-dependent quantities in the literature.
Comments:
39 pages, 16 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2306.01651 [pdf]
PRD(2023)·36 citations
11
[Submitted on 2 Jun 2023] (cross-list from astro-ph.SR)
Impacts of the $^{12} C (α, γ)^{16} O$ reaction rate on $^{56} Ni$ nucleosynthesis in pair-instability supernovae
Hiroki Kawashimo · Ryo Sawada · Yudai Suwa · Takashi J. Moriya · Ataru Tanikawa · Nozomu Tominaga
Nuclear reactions are key to our understanding of stellar evolution, particularly the $^{12} C (α, γ)^{16} O$ rate, which is known to significantly influence the lower and upper ends of the black hole (BH) mass distribution due to pair-instability supernovae (PISNe). However, these reaction rates have not been sufficiently determined. We use the $MESA$ stellar evolution code to explore the impact of uncertainty in the $^{12} C (α, γ)^{16} O$ rate on PISN explosions, focusing on nucleosynthesis and explosion energy by considering the high resolution of the initial mass. Our findings show that the mass of synthesized radioactive nickel ( $^{56} Ni$ ) and the explosion energy increase with $^{12} C (α, γ)^{16} O$ rate for the same initial mass, except in the high-mass edge region. With a high (about twice the $STARLIB$ standard value) rate, the maximum amount of nickel produced falls below 70 $M_{⊙}$ , while with a low rate (about half of the standard value) it increases up to 83.9 $M_{⊙}$ . These results highlight that carbon "preheating" plays a crucial role in PISNe by determining core concentration when a star initiates expansion. Our results also suggest that the onset of the expansion, which means the end of compression, competes with collapse caused by helium photodisintegration, and the maximum mass that can lead to an explosion depends on the $^{12} C (α, γ)^{16} O$ reaction rate.
Comments:
17 pages, 12 figures
Subjects:
Solar and Stellar Astrophysics (astro-ph.SR); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2306.01682 [pdf]
MNRAS(2024)·9 citations

Affiliations

first authorsco-authorsvia INSPIRE