Nuclear Theory·nucl-th

Tuesday·August 10, 2021

15 papers—8 primary·7 cross-listed

01
[Submitted on 6 Aug 2021]
Beta equilibrium under neutron star merger conditions
Mark G. Alford🇺🇸 · Alexander Haber🇺🇸 · Steven P. Harris🇺🇸 · Ziyuan Zhang🇺🇸
We calculate the nonzero-temperature correction to the beta equilibrium condition in nuclear matter under neutron star merger conditions, in the temperature range $1$ MeV $< T ≲ 5$ MeV. We improve on previous work by using a consistent description of nuclear matter based on the IUF and SFHo relativistic mean field models. This includes using relativistic dispersion relations for the nucleons, which we show is essential in these models. We find that the nonzero-temperature correction can be of order $10$ to $20$ MeV, and plays an important role in the correct calculation of Urca rates, which can be wrong by factors of $10$ or more if it is neglected.
Comments:
v2: version published in Universe, minor changes in nomenclature, 20 pages, 14 figures v3: corrected typo in Eq.(C19)
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2108.03324 [pdf]
Universe(2021)·60 citations
02
[Submitted on 7 Aug 2021]
Bayesian approach to long-range correlations and multiplicity fluctuations in nucleus-nucleus collisions
Kianusch Vahid Yousefnia🇫🇷 · Atharva Kotibhaskar🇮🇳 · Rajeev Bhalerao🇮🇳 · Jean-Yves Ollitrault🇫🇷
The number of particles detected in a nucleus-nucleus collision strongly depends on the impact parameter of the collision. Therefore, multiplicity fluctuations, as well as rapidity correlations of multiplicities, are dominated by impact parameter fluctuations. We present a method based on Bayesian inference which allows for a robust reconstruction of fluctuations and correlations at fixed impact parameter. We apply the method to ATLAS data on the distribution of charged multiplicity and transverse energy. We argue that multiplicity fluctuations are smaller at large rapidity than around central rapidity. We suggest simple, new analyses, in order to confirm this effect.
Comments:
13 pages, 11 figures; v2: published version with some added explanations and rephrasing of our presentation, especially in Part II. Code for 2D Bayesian reconstruction of ATLAS data is included as ancillary file
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2108.03471 [pdf]
PRC(2022)·19 citations
03
[Submitted on 8 Aug 2021]
Singularities and Accumulation of Singularities of $π$ N Scattering amplitudes
Qu-Zhi Li🇨🇳 · Han-Qing Zheng🇨🇳
It is demonstrated that for the isospin $I = 1/2$ $π$ N scattering amplitude, $T^{I = 1/2} (s, t)$ , $s = (m_{N}^{2} - m_{π}^{2})^{2} / m_{N}^{2}$ and $s = m_{N}^{2} + 2 m_{π}^{2}$ are two accumulation points of poles on the second sheet of complex $s$ plane, and are hence accumulation of singularities of $T^{I = 1/2} (s, t)$ . For $T^{I = 3/2} (s, t)$ , $s = (m_{N}^{2} - m_{π}^{2})^{2} / m_{N}^{2}$ is the accumulation point of poles on the second sheet of complex $s$ plane. The proof is valid up to all orders of chiral expansions.
Comments:
6 pages, one reference added, a bug removed, major conclusions remain unchanged
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Theory (hep-th); Mathematical Physics (math-ph); math.MP (math.MP)
arXiv:
2108.03734 [pdf]
Commun.Theor.Phys.(2022)·9 citations
04
[Submitted on 9 Aug 2021]
Fragment Intrinsic Spins and Fragments' Relative Orbital Angular Momentum in Nuclear Fission
Aurel Bulgac · Ibrahim Abdurrahman · Kyle Godbey · Ionel Stetcu
We present the first fully unrestricted microscopic calculations of the primary fission fragment intrinsic spins and of the fission fragments' relative orbital angular momentum for $^{236}$ U $^{*}$ , $^{240}$ Pu $^{*}$ , and $^{252}$ Cf using the time-dependent density functional theory framework. Within this microscopic approach, free of restrictions and unchecked assumptions and which incorporates the relevant physical observables for describing fission, we evaluate the triple distribution of the fission fragment intrinsic spins and of their fission fragments' relative orbital angular momentum and show that their dynamics is dominated by their bending collective modes, in contradistinction to the predictions of the existing phenomenological models and some interpretations of experimental data.
Comments:
6 pages, 4 figures, accepted version
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2108.03763 [pdf]
PRL(2022)·61 citations
05
[Submitted on 9 Aug 2021]
A brief account of Steven Weinberg's legacy in ab initio many-body theory
Christian Drischler🇺🇸 · Scott K. Bogner🇺🇸
In this contribution to the special issue "Celebrating 30 years of Steven Weinberg's papers on Nuclear Forces from Chiral Lagrangians," we emphasize the important role chiral effective field theory has played in leading nuclear physics into a precision era. To this end, we share our perspective on a few of the recent advances made in ab initio calculations of nuclear structure and nuclear matter observables, as well as Bayesian uncertainty quantification of effective field theory truncation errors.
Comments:
10 pages, 6 figures; invited contribution to the special issue in Few-Body Systems "Celebrating 30 years of Steven Weinberg's papers on Nuclear Forces from Chiral Lagrangians"; minor improvements, close to published version
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2108.03771 [pdf]
Few Body Syst.(2021)·9 citations
06
[Submitted on 9 Aug 2021]
Systematic study of two-proton radioactivity with a screened electrostatic barrier
Y. T. Zou · X. Pan · X. H. Li · H. M. Liu · X. J. Wu · B. He
In this study, a phenomenological model is proposed based on Wentzel-Kramers-Brillouin (WKB) theory and applied to investigate the two-proton ( $2 p$ ) radioactive half-lives of nuclei near or beyond the proton drip line. The total diproton-daughter nucleus interaction potential is composed of the Hulthen-type electrostatic term and the centrifugal term. The calculated $2 p$ radioactive half-lives can accurately reproduce the existing 10 experimental datasets of five true $2 p$ radioactive nuclei with $σ$ = 0.736. In addition, we extend this model to predict the half-lives of possible $2 p$ radioactive nuclei whose $2 p$ radioactivity is energetically allowed or observed but not yet quantified in NUBASE2016. The predicted results are in agreement with those obtained using the Gamow-like model, generalized liquid drop model, Sreeja formula, and Liu formula.
Comments:
9 pages, 6 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2108.03792 [pdf]
CPC(2021)·11 citations
07
[Submitted on 9 Aug 2021]
Learning Langevin dynamics with QCD phase transition
Lingxiao Wang🇩🇪 · Lijia Jiang🇩🇪 · Kai Zhou🇩🇪
In this proceeding, the deep Convolutional Neural Networks (CNNs) are deployed to recognize the order of QCD phase transition and predict the dynamical parameters in Langevin processes. To overcome the intrinsic randomness existed in a stochastic process, we treat the final spectra as image-type inputs which preserve sufficient spatiotemporal correlations. As a practical example, we demonstrate this paradigm for the scalar condensation in QCD matter near the critical point, in which the order parameter of chiral phase transition can be characterized in a $1 + 1$ -dimensional Langevin equation for $σ$ field. The well-trained CNNs accurately classify the first-order phase transition and crossover from $σ$ field configurations with fluctuations, in which the noise does not impair the performance of the recognition. In reconstructing the dynamics, we demonstrate it is robust to extract the damping coefficients $η$ from the intricate field configurations.
Comments:
Contribution to: SQM2021
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex); Data Analysis, Statistics and Probability (physics.data-an)
arXiv:
2108.03987 [pdf]
EPJ Web Conf.(2022)·2 citations
08
[Submitted on 9 Aug 2021]
Global hyperon polarization and effects of decay feeddown
Hui Li🇨🇳 · Xiao-Liang Xia🇨🇳 · Xu-Guang Huang🇨🇳 · Huan Zhong Huang🇨🇳
We study the global polarizations of $Λ$ , $Ξ^{-}$ , and $Ω^{-}$ hyperons in noncentral Au+Au collisions at $s_{NN} =$ 7.7-200 GeV. We highlight the importance of effect of decay feeddown to the measured global polarization. With the decay contributions taken into account, the global polarization ordering $P_{Ω^{-}} > P_{Ξ^{-}} > P_{Λ}$ can be naturally explained, which is consistent with the observation recently reported from the STAR experiment from Au+Au collisions at 200 GeV. We also extend our calculations to predict expectations from the RHIC-BES II data.
Comments:
4 pages, 2 figures, contribution to 19th International Conference on Strangeness in Quark Matter (SQM2021)
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2108.04111 [pdf]
EPJ Web Conf.(2022)·8 citations
09
[Submitted on 6 Aug 2021] (cross-list from hep-ph)
Radiative corrections to semileptonic beta decays: Progress and challenges
Chien-Yeah Seng🇩🇪
We review some recent progress in the theory of electroweak radiative corrections in semileptonic decay processes. The resurrection of the so-called Sirlin's representation based on current algebra relations permits a clear separation between the perturbatively-calculable and incalculable pieces in the $O (G_{F} α)$ radiative corrections. The latter are expressed as compact hadronic matrix elements that allow systematic non-perturbative analysis such as dispersion relation and lattice QCD. This brings substantial improvements to the precision of the electroweak radiative corrections in semileptonic decays of pion, kaon, free neutron and $J^{P} = 0^{+}$ nuclei that are important theory inputs in precision tests of the Standard Model. Unresolved issues and future prospects are discussed.
Comments:
Version accepted for publication
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:
2108.03279 [pdf]
Particles(2021)·29 citations
10
[Submitted on 6 Aug 2021] (cross-list from hep-ph)
Unified formalism for electromagnetic and gravitational probes: densities
Adam Freese🇺🇸 · Gerald A. Miller🇺🇸
The use of light front coordinates allows a fully relativistic description of a hadron's spatial densities to be obtained. These densities must be two-dimensional and transverse to a chosen spatial direction. We explore their relationship to the three-dimensional, non-relativistic densities, with a focus on densities associated with the energy momentum tensor. The two-dimensional non-relativistic densities can be obtained from the light front densities through a non-relativistic limit, and can subsequently be transformed into three-dimensional non-relativistic densities through an inverse Abel transform. However, this operation is not invertible, and moreover the application of the inverse Abel transform to the light front densities does not produce a physically meaningful result. We additionally find that the Abel transforms of so-called Breit-frame densities generally differ significantly from the true light front densities. Numerical examples are provided to illustrate the various differences between the light front, Breit frame, and non-relativistic treatment of densities.
Comments:
19 pages, 5 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2108.03301 [pdf]
PRD(2022)·65 citations
11
[Submitted on 7 Aug 2021] (cross-list from physics.app-ph)
A new production route of Gadolinium-148 for use in Radioisotope Thermoelectric Generators
Ozan Artun
The production of Gd-148 had challenges for available methods in the literature, such as its high cost and low production amount. Therefore, we recommended a new production route of Gd-148 on natural Sm and Eu targets via particle accelerators. For this aim, we calculated and simulated cross-section, activity, the yield of product, and integral yield curves for 21 different nuclear reaction processes under certain conditions. Based on the obtained results, we proposed the radioisotope Gd-148 to use Radioisotope Thermoelectric Generators for deep space and planetary explorations in spacecraft and space-probes as a suitable energy source, instead of Pu-238.
Comments:
13 pages, 5 figures, 1 Teble
Subjects:
physics.app-ph (physics.app-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2108.03430 [pdf]
Appl.Radiat.Isot.(2022)·0 citations
12
[Submitted on 8 Aug 2021] (cross-list from hep-ph)
Quark Sivers Function at Small $x$ : Spin-Dependent Odderon and the Sub-Eikonal Evolution
Yuri V. Kovchegov🇺🇸 · M. Gabriel Santiago🇺🇸
We apply the formalism developed earlier for studying transverse momentum dependent parton distribution functions (TMDs) at small Bjorken $x$ to construct the small- $x$ asymptotics of the quark Sivers function. First, we explicitly construct the complete fundamental "polarized Wilson line" operator to sub-sub-eikonal order: this object can be used to study a variety of quark TMDs at small- $x$ . We then express the quark Sivers function in terms of dipole scattering amplitudes containing various components of the "polarized Wilson line" and show that the dominant (eikonal) term which contributes to the quark Sivers function at small $x$ is the spin-dependent odderon, confirming the recent results of Dong, Zheng and Zhou. Our conclusion is also similar to the case of the gluon Sivers function derived by Boer, Echevarria, Mulders and Zhou (see also the work by Szymanowski and Zhou). We also analyze the sub-eikonal corrections to the quark Sivers function using the constructed "polarized Wilson line" operator. We derive new small- $x$ evolution equations re-summing double-logarithmic powers of $α_{s} ln^{2} (1/ x)$ with $α_{s}$ the strong coupling constant. We solve the corresponding novel evolution equations in the large- $N_{c}$ limit, obtaining a sub-eikonal correction to the spin-dependent odderon contribution. We conclude that the quark Sivers function at small $x$ receives contributions from two terms and is given by \begin{align} f_{1 \: T}^{\perp \: q} (x, k_T^2) = C_O (x, k_T^2) \, \frac{1}{x} + C_1 (k_T^2) \, \left( \frac{1}{x} \right)^0 + \ldots \end{align} with the function $C_{O} (x, k_{T}^{2})$ varying slowly with $x$ and the ellipsis denoting the sub-asymptotic and sub-sub-eikonal (order- $x$ ) corrections.
Comments:
41 pages, 11 figures, 1 table. Added new discussion paragraphs in section III.A and section IV, added a footnote in section IV, corrected typos, updated references. v3: Minor typos corrected, the sub-eikonal term in the asymptotics of the Sivers function is revised in the follow up paper, see footnote on page 23
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2108.03667 [pdf]
JHEP(2021)·59 citations
13
[Submitted on 8 Aug 2021] (cross-list from hep-ph)
A general-mass scheme for prompt charm production at hadron colliders
Keping Xie🇺🇸 · John M. Campbell🇺🇸 · Pavel M. Nadolsky🇺🇸
In these proceedings, we apply the recently developed S-ACOT-MPS factorization scheme at the next-to-leading order to prompt charm production at hadron colliders. It provides a good agreement with experimental data on charm meson production measured by LHCb at 7 and 13 TeV. The low- $p_{T}$ data are on the margins of the theoretical error bands, emphasizing the importance of including contributions beyond the next-to-leading order.
Comments:
Submission to SciPost
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2108.03741 [pdf]
SciPost Phys.Proc.(2022)·12 citations
14
[Submitted on 9 Aug 2021] (cross-list from nucl-ex)
Progress in Nuclear Astrophysics of East and Southeast Asia
Azni Abdul Aziz🇲🇾 · Nor Sofiah Ahmad🇲🇾 · S. Ahn🇰🇷 · Wako Aoki🇯🇵 · Muruthujaya Bhuyan🇲🇾 · Ke-Jung Chen🇹🇼 · Gang Guo🇹🇼 · K. I. Hahn🇰🇷 · Toshitaka Kajino🇯🇵 · Hasan Abu Kassim🇲🇾 · D. Kim🇰🇷 · Shigeru Kubono🇯🇵 and 16 other authors
Nuclear astrophysics is an interdisciplinary research field of nuclear physics and astrophysics, seeking for the answer to a question, how to understand the evolution of the Universe with the nuclear processes which we learn. We review the research activities of nuclear astrophysics in east and southeast Asia which includes astronomy, experimental and theoretical nuclear physics and astrophysics. Several hot topics such as the Li problems, critical nuclear reactions and properties in stars, properties of dense matter, r-process nucleosynthesis and $ν$ -process nucleosynthesis are chosen and discussed in further details. Some future Asian facilities, together with physics perspectives, are introduced.
Comments:
49 pages, 10 figures, published in AAPPS (Association of Asia Pacific Physical Societies) Bulletin
Subjects:
Nuclear Experiment (nucl-ex); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
arXiv:
2108.03814 [pdf]
AAPPS Bull.(2021)·6 citations
15
[Submitted on 9 Aug 2021] (cross-list from hep-ph)
Nucleon structure from basis light-front quantization
Siqi Xu🇨🇳 · Chandan Mondal🇨🇳 · Jiangshan Lan🇨🇳 · Xingbo Zhao🇨🇳 · Yang Li🇨🇳 · James P. Vary🇺🇸
We produce the light-front wave functions (LFWFs) of the nucleon from a basis light-front ap- proach in the leading Fock sector representation. We solve for the mass eigenstates from a light-front effective Hamiltonian, which includes a confining potential adopted from light-front holography in the transverse direction, a longitudinal confinement, and a one-gluon exchange interaction with fixed coupling. We then employ the LFWFs to obtain the electromagnetic and axial form factors, the par- ton distribution functions (PDFs) and the generalized parton distribution functions for the nucleon. The electromagnetic and axial form factors of the proton agree with the experimental data, whereas the neutron form factors deviate somewhat from the experiments in the low momentum transfer region. The unpolarized, the helicity, and the transversity valence quark PDFs, after QCD scale evolution, are fairly consistent with the global fits to the data at the relevant experimental scales. The helicity asymmetry for the down quark also agrees well with the measurements, however, the asymmetry for the up quark shows a deviation from the data, especially in the small x region. We also find that the tensor charge agrees well with the extracted data and the lattice QCD predictions, while the axial charge is somewhat outside the experimental error bar. The electromagnetic radii of the proton, the magnetic radius of the neutron, and the axial radius are in excellent agreement with the measurements, while the neutron charge radius deviates from experiment.
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2108.03909 [pdf]
PRD(2021)·93 citations

Affiliations

first authorsco-authorsvia INSPIRE