Nuclear Theory·nucl-th

Friday·July 9, 2021

10 papers—5 primary·5 cross-listed

01
[Submitted on 8 Jul 2021]
Parton evolution time dependent transverse shape asymmetry in peripheral Pb-Pb and p-Pb collisions at 5.02 TeV
De-Xian Wei🇨🇳
In this paper, we use a multi-phase transport model to simulate the parton evolution time-dependent transverse asymmetry in peripheral Pb-Pb (b=14-15 fm) and p-Pb (b=0-1 fm) collisions at $s_{N N}$ = 5.02 TeV, respectively. The simulated results showed that the initial spatial asymmetry depends on the collision system, while both the initial momentum asymmetry and final momentum asymmetry are independent on the collision system. It is also shown that the final momentum asymmetry is similar to the initial momentum asymmetry. Furthermore, the averaged transverse shape asymmetry, which includes the initial spatial asymmetry, the initial momentum asymmetry, and the final momentum asymmetry, is significantly dependent on the transverse momentum and particle species identity (PID). The PID scales ordering transverse asymmetry indicated that it provides a possible observation for studying the fluctuating droplet properties of quark-gluon plasma, which may produce in heavy-ion collisions.
Comments:
8 pages, 6 figures, this version is accepted by IJMPE;
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2107.03546 [pdf]
IJMPE(2021)·1 citation
02
[Submitted on 8 Jul 2021]
What hath Weinberg wrought? Reflections on what Weinberg's papers on 'Nuclear Forces from Chiral Lagrangians' did and did not accomplish
Daniel R. Phillips🇺🇸
I discuss selected legacies of Weinberg's application of chiral Lagrangians to nuclear physics: (1) the use of the chiral expansion to organize the interaction of pions and photons with a nucleus; (2) the much-debated question of why and how the potential derived from a chiral Lagrangian should be inserted in the Schrodinger equation; (3) the emergence of "pionless EFT" as a tool for diagnosing universal correlations that are present in quantum few-body systems of very different sizes, and, perhaps most important of all, (4) an epistemological shift in what is expected of a nuclear-physics calculation.
Comments:
20 pages, 3 figures. Contribution to Special Issue of Few-Body Systems: Celebrating 30 years of Steven Weinberg's papers on Nuclear Forces from Chiral Lagrangians. v2: Contains updated discussion of M_N scaling and corrects statements in v1 about Weinberg's choice of regularization and subtraction scheme. v3: Version accepted for publication. Includes additional references to recent work
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2107.03558 [pdf]
Few Body Syst.(2022)·9 citations
03
[Submitted on 8 Jul 2021]
$Ξ$ hyper-nuclear states predicted by NLO chiral baryon-baryon interactions
M. Kohno🇯🇵 · K. Miyagawa🇯🇵
The $Ξ$ single-particle potential obtained in nuclear matter with the next-to-leading order baryon-baryon interactions in chiral effective field theory is applied to finite nuclei by an improved local-density approximation method. As a premise, phase shifts of $Ξ N$ elastic scattering and the results of Faddeev calculations for the $Ξ N N$ bound state problem are presented to show the properties of the $Ξ N$ interactions in the present parametrization. First, the $Ξ$ states in $^{14}$ N are revisited because of the recent experimental progress, including the discussion on the $Ξ N$ spin-orbit interaction that is relevant to the location of the $p$ -state. Then the $Ξ$ levels in $^{56}$ Fe are calculated. In particular, the level shift which is expected to be measured experimentally in the near future is predicted. The smallness of the imaginary part of the $Ξ$ single-particle potential is explicitly demonstrated.
Comments:
7 pages, 7 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2107.03784 [pdf]
2 citations
04
[Submitted on 8 Jul 2021]
Proton number fluctuations in partial chemical equilibrium
Boris Tomasik🇸🇰 · Paula Hillmann🇩🇪 · Marcus Bleicher🇩🇪
We calculate volume-independent ratios of cumulants of the net-proton number distribution up to sixth order in a fireball that cools down after the chemical freeze-out. A hadron resonance gas model is used together with the assumption of partial chemical equilibrium, which fixes the number of observed stable hadrons after the chemical freeze-out. It is shown that due to only weak departure from the statistical Boltzmann distribution, also the volume-independent ratios of higher-order cumulants of the net-proton number show only weak dependence on the temperature. This observation supports the possibility to measure non-critical cumulants at chemical freeze-out even after subsequent cooling in the hadronic phase. Cumulants of the net-baryon number behave similarly, while those for the kaon number vary more strongly with the temperature. Our results are relevant for the current fluctuation studies of the RHIC-BES runs.
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2107.03830 [pdf]
PRC(2021)·6 citations
05
[Submitted on 8 Jul 2021]
Structure Calculations Without Effective Interactions
J. A. Secrest · J. M. Conroy · H. G. Miller
Good approximate eigenstates of a Hamiltionian operator which poesses a point as well as a continuous spectrum have beeen obtained using the Lanczos algorithm. Iterating with the bare Hamiltonian operator yields spurious solutions which can easily be identified. The rms radius of the ground state eigenvector, for example, is calculated using the bare operator.
Comments:
arXiv admin note: text overlap with arXiv:0711.3529
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2107.03921 [pdf]
0 citations
06
[Submitted on 7 Jul 2021] (cross-list from hep-ph)
Vector-meson production and vector meson dominance
Yin-Zhen Xu🇨🇳 · Si-Yang Chen🇨🇳 · Zhao-Qian Yao🇨🇳 · Daniele Binosi🇮🇹 · Zhu-Fang Cui🇨🇳 · Craig D. Roberts🇨🇳
We consider the fidelity of the vector meson dominance (VMD) assumption as an instrument for relating the electromagnetic vector-meson production reaction $e + p \to e^{'} + V + p$ to the purely hadronic process $V + p \to V + p$ . Analyses of the photon vacuum polarisation and the photon-quark vertex reveal that such a VMD Ansatz might be reasonable for light vector-mesons. However, when the vector-mesons are described by momentum-dependent bound-state amplitudes, VMD fails for heavy vector-mesons: it cannot be used reliably to estimate either a photon-to-vector-meson transition strength or the momentum dependence of those integrands that would arise in calculations of the different reaction amplitudes. Consequently, for processes involving heavy mesons, the veracity of both cross-section estimates and conclusions based on the VMD assumption should be reviewed, e.g., those relating to hidden-charm pentaquark production and the origin of the proton mass.
Comments:
12 pages, 2 figures, 2 tables
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:
2107.03488 [pdf]
EPJC(2021)·66 citations
07
[Submitted on 8 Jul 2021] (cross-list from astro-ph.SR)
Nuclear fission chain reaction in cooling white dwarf stars
C. J. Horowitz · M. E. Caplan
The first solids that form as a white dwarf (WD) starts to crystallize are expected to be greatly enriched in actinides. Previously [PRL 126, 1311010] we found that these solids might support a nuclear fission chain reaction that could ignite carbon burning and provide a new Type Ia supernova (SN Ia) mechanism involving an {\it isolated} WD. Here we explore this fission mechanism in more detail and calculate the final temperature and density after the chain reaction and discuss a number of open physics questions.
Comments:
8 pages, 4 figures
Subjects:
Solar and Stellar Astrophysics (astro-ph.SR); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2107.03568 [pdf]
3 citations
08
[Submitted on 8 Jul 2021] (cross-list from cond-mat.quant-gas)
Quantum Many-Body Calculations using Body-Centered Cubic Lattices
Young-Ho Song🇰🇷 · Youngman Kim🇰🇷 · Ning Li🇨🇳 · Bing-Nan Lu🇨🇳 · Rongzheng He🇺🇸 · Dean Lee🇺🇸
It is often computationally advantageous to model space as a discrete set of points forming a lattice grid. This technique is particularly useful for computationally difficult problems such as quantum many-body systems. For reasons of simplicity and familiarity, nearly all quantum many-body calculations have been performed on simple cubic lattices. Since the removal of lattice artifacts is often an important concern, it would be useful to perform calculations using more than one lattice geometry. In this work we show how to perform quantum many-body calculations using auxiliary-field Monte Carlo simulations on a three-dimensional body-centered cubic (BCC) lattice. As a benchmark test we compute the ground state energy of 33 spin-up and 33 spin-down fermions in the unitary limit, which is an idealized limit where the interaction range is zero and scattering length is infinite. As a fraction of the free Fermi gas energy $E_{FG}$ , we find that the ground state energy is $E_{0} / E_{FG} = 0.369 (2), 0.371 (2),$ using two different definitions of the finite-system energy ratio. This is in excellent agreement with recent results obtained on a cubic lattice \cite{He:2019ipt}. We find that the computational effort and performance on a BCC lattice is approximately the same as that for a cubic lattice with the same number of lattice points. We discuss how the lattice simulations with different geometries can be used to constrain the size lattice artifacts in simulations of continuum quantum many-body systems.
Comments:
13 pages, 7 figures
Subjects:
Quantum Gases (cond-mat.quant-gas); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2107.03626 [pdf]
PRC(2021)·2 citations
09
[Submitted on 8 Jul 2021] (cross-list from hep-ph)
Non-Abelian Electric Field Correlator at NLO for Dark Matter Relic Abundance and Quarkonium Transport
Tobias Binder🇯🇵 · Kyohei Mukaida🇯🇵 · Bruno Scheihing-Hitschfeld🇺🇸 · Xiaojun Yao🇺🇸
We perform a complete next-to-leading order calculation of the non-Abelian electric field correlator in a SU( $N_{c}$ ) plasma, which encodes properties of the plasma relevant for heavy particle bound state formation and dissociation, and is different from the correlator for the heavy quark diffusion coefficient. The calculation is carried out in the real-time formalism of thermal field theory and includes both vacuum and finite temperature contributions. By working in the $R_{ξ}$ gauge, we explicitly show the results are gauge independent, infrared and collinear safe. The renormalization group equation of this electric field correlator is determined by that of the strong coupling constant. Our next-to-leading order calculation can be directly applied to any dipole singlet-adjoint transition of heavy particle pairs. For example, it can be used to describe dissociation and (re)generation of heavy quarkonia inside the quark-gluon plasma well below the melting temperature, as well as heavy dark matter pairs (or charged co-annihilating partners) in the early universe.
Comments:
86 pages, 13 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); Nuclear Theory (nucl-th)
arXiv:
2107.03945 [pdf]
JHEP(2022)·56 citations
10
[Submitted on 8 Jul 2021] (cross-list from hep-lat)
Three-body dynamics of the $a_{1} (1260)$ resonance from lattice QCD
Maxim Mai🇺🇸 · Andrei Alexandru🇺🇸 · Ruairí Brett🇺🇸 · Chris Culver🇬🇧 · Michael Döring🇺🇸 · Frank X. Lee🇺🇸 · Daniel Sadasivan🇺🇸
Resonant hadronic systems often exhibit a complicated decay pattern in which three-body dynamics play a relevant or even dominant role. In this work we focus on the $a_{1} (1260)$ resonance. For the first time, the pole position and branching ratios of a three-body resonance are calculated from lattice QCD using one-, two-, and three-meson interpolators and a three-body finite-volume formalism extended to spin and coupled channels. This marks a new milestone for ab-initio studies of ordinary resonances along with hybrid and exotic hadrons involving three-body dynamics.
Comments:
14 pages, 7 figures
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2107.03973 [pdf]
PRL(2021)·78 citations

Affiliations

first authorsco-authorsvia INSPIRE