Nuclear Theory·nucl-th

Tuesday·November 24, 2020

11 papers—4 primary·7 cross-listed

01
[Submitted on 22 Nov 2020]
QCD equations of state and speed of sound in neutron stars
Toru Kojo🇨🇳
Neutron stars are cosmic laboratories to study dense matter in Quantum Chromodynamics (QCD). The observable mass-radius relations of neutron stars are determined by QCD equations of state, and can reflect the properties of QCD phase transitions. In the last decade there have been historical discoveries in neutron stars, the discoveries of two-solar mass neutron stars and neutron star merger events, which have imposed tight constraints on equations of state. While a number of equations of state are constructed to satisfy these constraints, a theoretical challenge is how to reconcile those constructions with the microphysics expected from the hadron physics and in-medium calculations. In this short article we briefly go over recent observations and discuss their implications for dense QCD matter, referring to QCD constraints in the low and high density limits, QCD-like theories, and lattice QCD results for baryon-baryon interactions.
Comments:
9 pages, 2 figures, a review contributed to the AAPPS Bulletin; v2 published version
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2011.10940 [pdf]
AAPPS Bull.(2021)·97 citations
02
[Submitted on 22 Nov 2020]
Ultraviolet suppression and nonlocality in optical model potentials for nucleon-nucleus scattering
H. F. Arellano🇨🇱 · G. Blanchon🇫🇷
We investigate the role of high momentum components of optical model potentials for nucleon-nucleus scattering and its incidence on their nonlocal structure in coordinate space. The study covers closed-shell nuclei with mass number in the range $4 \leq A \leq 208$ , for nucleon energies from tens of MeV up to 1 GeV. To this purpose microscopic optical potentials are calculated using density-dependent off-shell $g$ matrices in Brueckner-Hartree-Fock approximation and based on Argonne $v_{18}$ as well as chiral 2 $N$ force up to next-to-next-to-next-to-leading order. We confirm that the gradual suppression of high-momentum contributions of the optical potential results in quite different coordinate-space counterparts, all of them accounting for the same scattering observables. We infer a minimum cutoff momentum $Q$ , function of the target mass number and energy of the process, that filters out irrelevant ultraviolet components of the potential. We find that when ultraviolet suppression is applied to Perey-Buck nonlocal potential or local Woods-Saxon potentials, they also result nonlocal with similar appearance to those obtained from microscopic models in momentum space. We examine the transversal nonlocality, quantity that makes comparable the intrinsic nonlocality of any potential regardless of its representation. We conclude that meaningful comparisons of nonlocal features of alternative potentials require the suppression of their ultraviolet components.
Comments:
12 pages, 15 figures. Accepted for publication in EPJA
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2011.11080 [pdf]
EPJA(2021)·2 citations
03
[Submitted on 23 Nov 2020]
On the energy budget of the transition of a neutron star into the third family branch
David E. Alvarez-Castillo🇵🇱
Transition of a compact star into the third family for an equation of state (EoS) featuring mass twins is considered. The energy released at a baryon number conserving transition for static compact stars configurations is computed for two sets of models for comparison. The EoS of choice is the density dependent functional DD2 EoS with excluded model correction for hadronic matter which suffers a phase transition into deconfined quark matter described by a constant speed of sound approach. The two sets of EoS models feature different compact star mass onsets that maximize the energy and radius difference at the transition while simultaneously fulfilling state-of-the-art constraints from multi-messenger astronomy and empirical nuclear data. It is found that the maximal energy budget at the transitions falls in the range of $1 0^{49}$ - $1 0^{52}$ ergs.
Comments:
5 pages, 6 figures. Typos corrected, Figures 3 and 4 updated
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2011.11145 [pdf]
Astron.Nachr.(2021)·10 citations
04
[Submitted on 23 Nov 2020]
Power counting in chiral effective field theory and nuclear binding
C.-J. Yang🇸🇪 · A. Ekström🇸🇪 · C. Forssén🇸🇪 · G. Hagen🇺🇸
Chiral effective field theory ( $χ$ EFT), as originally proposed by Weinberg, promises a theoretical connection between low-energy nuclear interactions and quantum chromodynamics (QCD). However, the important property of renormalization-group (RG) invariance is not fulfilled in current implementations and its consequences for predicting atomic nuclei beyond two- and three-nucleon systems has remained unknown. In this work we present a first and systematic study of recent RG-invariant formulations of $χ$ EFT and their predictions for the binding energies and other observables of selected nuclear systems with mass-numbers up to $A = 16$ . Specifically, we have carried out ab initio no-core shell-model and coupled cluster calculations of the ground-state energy of $^{3}$ H, $^{3, 4}$ He, $^{6}$ Li, and $^{16}$ O using several recent power-counting (PC) schemes at leading order (LO) and next-to-leading order (NLO), where the subleading interactions are treated in perturbation theory. Our calculations indicate that RG-invariant and realistic predictions can be obtained for nuclei with mass number $A \leq 4$ . We find, however, that $^{16}$ O is either unbound with respect to the four $α$ -particle threshold, or deformed, or both. Similarly, we find that the $^{6}$ Li ground-state resides above the $α$ -deuteron separation threshold. These results are in stark contrast with experimental data and point to either necessary fine-tuning of all relevant counterterms, or that current state-of-the-art RG-invariant PC schemes at LO in $χ$ EFT lack necessary diagrams -- such as three-nucleon forces -- to realistically describe nuclei with mass number $A > 4$ .
Comments:
18 pages, 12 figures, published version
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2011.11584 [pdf]
PRC(2021)·47 citations
05
[Submitted on 21 Nov 2020] (cross-list from hep-ph)
Equation of state of cold and dense QCD matter in resummed perturbation theory
Yuki Fujimoto🇯🇵 · Kenji Fukushima🇯🇵
We discuss the Hard Dense Loop resummation at finite quark mass and evaluate the equation of state (EoS) of cold and dense QCD matter in $β$ equilibrium. The resummation in the quark sector has an effect of lowering the baryon number density and the EoS turns out to have much smaller uncertainty than the perturbative QCD estimate. Our numerical results favor smooth matching between the EoS from the resummed QCD calculation at high density and the extrapolated EoS from the nuclear matter density region. We also point out that the speed of sound in our EoS slightly exceeds the conformal limit.
Comments:
9 pages, 6 figures; Figs. 5 and 6 are updated, results unchanged
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2011.10891 [pdf]
PRD(2022)·48 citations
06
[Submitted on 22 Nov 2020] (cross-list from hep-ph)
Decoding the nature of $Z_{cs} (3985)$ and establishing the spectrum of charged heavy quarkoniumlike states in chiral effective field theory
Bo Wang🇨🇳 · Lu Meng🇩🇪 · Shi-Lin Zhu🇨🇳
We study the newly observed charmoniumlike state $Z_{cs} (3985)$ in the framework of chiral effective field theory. The interaction kernel of the $D ˉ_{s} D^{*} / D ˉ_{s}^{*} D$ system is calculated up to the next-to-leading order with the explicit chiral dynamics. With the fitted parameters extracted from the $Z_{c} (3900)$ data as inputs, the mass, width and event distributions of the $Z_{cs} (3985)$ are very consistent with the experimental measurements. Our studies strongly support the $Z_{cs} (3985)$ as the partner of the $Z_{c} (3900)$ in the SU(3) $_{f}$ symmetry and the $D ˉ_{s} D^{*} / D ˉ_{s}^{*} D$ molecular resonance with the same dynamical origin as the other charged heavy quarkoniumlike states. We precisely predict the resonance parameters of the unobserved states in $D ˉ_{s}^{*} D^{*}$ , $B_{s}^{*} B ˉ / B_{s} B ˉ^{*}$ and $B_{s}^{*} B ˉ^{*}$ systems, and establish a complete spectrum of the charged charmoniumlike and bottomoniumlike states with the $I (J^{P})$ quantum numbers $1 (1^{+})$ and $\frac{1}{2} (1^{+})$ , respectively.
Comments:
5 pages, 3 figures and 1 table
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2011.10922 [pdf]
PRD(2021)·50 citations
07
[Submitted on 22 Nov 2020] (cross-list from hep-ph)
Mass splitting of vector meson and spontaneous spin polarization under rotation
Minghua Wei🇨🇳 · Yin Jiang🇨🇳 · Mei Huang🇨🇳
In the present paper, we study the effect of the rotation on the masses of scalar meson as well as vector meson in the framework of 2-flavor Nambu--Jona-Lasinio model. The existence of rotation causes a tedious quark propagator and corresponding polarization function. Applying the random phase approximation, the meson mass is calculated numerically. It is found that the behavior of scalar and pseudoscalar meson masses under the angular velocity $ω$ is similar to that at finite chemical potential, both rely on the behavior of constituent quark mass and reflect the property related to the chiral symmetry. However, masses of vector meson $ρ$ have more profound relation with rotation. After tedious calculation, it turns out that at low temperature and small chemical potenial, the mass for spin component $s_{z} = 0, \pm 1$ of vector meson under rotation shows very simple mass splitting relation $m_{ρ}^{s_{z}} (ω) = m_{ρ} (ω = 0) - ω s_{z}$ , similar to the Zeeman splitting of charged meson under magnetic fields. Especially it is noticed that the mass of spin component $s_{z} = 1$ vector meson $ρ$ decreases linearly with $ω$ and reaches zero at $ω_{c} = m_{ρ} (ω = 0)$ , this indicates the system will develop $s_{z} = 1$ vector meson condensation and the system will be spontaneously spin polarized under rotation.
Comments:
15 pages, 3 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2011.10987 [pdf]
CPC(2022)·17 citations
08
[Submitted on 22 Nov 2020] (cross-list from nucl-ex)
Confirmation of $g_{A}$ quenching using the revised spectrum-shape method for the analysis of the $^{113}$ Cd $β$ -decay as measured with the COBRA demonstrator
Joel Kostensalo🇫🇮 · Jouni Suhonen🇫🇮 · Juliane Volkmer🇩🇪 · Stefan Zatschler🇩🇪 · Kai Zuber🇩🇪
In this article we present an updated spectrum-shape analysis of the $^{113}$ Cd fourfold forbidden non-unique $β$ -decay transition in order to address the quenching of the weak axial-vector coupling $g_{A}$ in low-momentum exchange nuclear processes. The experimental data were collected in a dedicated low-threshold run with the COBRA demonstrator at the LNGS and resulted in 44 individual $^{113}$ Cd spectra. These data are evaluated in the context of three nuclear model frameworks based on a revised version of the spectrum-shape method and the conserved vector current hypothesis. The novel idea devised in the present work is to fit the value of the small relativistic nuclear matrix element (s-NME) driving the nuclear model calculations, which remained essentially as a free parameter in previous studies. This is done by tuning the nuclear structure calculations and making use of the interplay of $g_{A}$ and the s-NME such that the experimentally known $^{113}$ Cd half-life gets reproducible by the different frameworks. In this way, a best fit s-NME value can be derived for each of the considered nuclear models, which finally enters the template calculations used to perform the spectrum-shape analysis for each of the obtained $^{113}$ Cd spectra. The primary analysis strategy results in significantly quenched values of the axial-vector coupling for all three nuclear models: $g_{A} (ISM) = 0.907 \pm 0.064$ , $g_{A} (MQPM) = 0.993 \pm 0.063$ and $g_{A} (IBFM-2) = 0.828 \pm 0.140$ . Moreover, with our data-driven approach one of the main shortcomings of the spectrum-shape method has been resolved. This achievement is a milestone in the description of strongly forbidden $β$ -decays and adds to the indications for the existence of a quenching of $g_{A}$ in low-momentum exchange nuclear processes.
Comments:
16 pages, 12 figures
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2011.11061 [pdf]
PLB(2021)·29 citations
09
[Submitted on 23 Nov 2020] (cross-list from astro-ph.CO)
A new tension in the cosmological model from primordial deuterium?
Cyril Pitrou🇫🇷 · Alain Coc🇫🇷 · Jean-Philippe Uzan🇫🇷 · Elisabeth Vangioni🇫🇷
Recent measurements of the D(p, $γ)^{3}$ He, nuclear reaction cross-section and of the neutron lifetime, along with the reevaluation of the cosmological baryon abundance from cosmic microwave background (CMB) analysis, call for an update of abundance predictions for light elements produced during the big-bang nucleosynthesis (BBN). While considered as a pillar of the hot big-bang model in its early days, BBN constraining power mostly rests on deuterium abundance. We point out a new $≃ 1.8 σ$ -tension on the baryonic density, or equivalently on the D/H abundance, between the value inferred on one hand from the analysis of the primordial abundances of light elements and, on the other hand, from the combination of CMB and baryonic oscillation data. This draws the attention on this sector of the theory and gives us the opportunity to reevaluate the status of BBN in the context of precision cosmology. Finally, this paper presents an upgrade of the BBN code PRIMAT.
Comments:
10 pages, 4 figures. Accepted in MNRAS
Subjects:
Cosmology and Nongalactic Astrophysics (astro-ph.CO); Nuclear Theory (nucl-th)
arXiv:
2011.11320 [pdf]
MNRAS(2021)·122 citations
10
[Submitted on 23 Nov 2020] (cross-list from hep-ph)
Impact of scale, nuclear PDF and temperature variations on the interpretation of medium-modified jet production data from the LHC
A. Andronic🇩🇪 · J. Honermann🇩🇪 · M. Klasen🇩🇪 · C. Klein-Bösing🇩🇪 · J. Salomon🇩🇪
In this paper we present a study of in-medium jet modifications performed with JEWEL and PYTHIA 6.4, focusing on the uncertainties related to variations of the perturbative scales and nuclear parton distribution functions (PDFs) and on the impact of the initial and crossover temperature variations of the medium. The simulations are compared to LHC data for the jet spectrum and the nuclear modification factor. We assess the interplay between the choice of nuclear PDFs and different medium parameters and study the impact of nuclear PDFs and the medium on the jet structure via the Lund plane.
Comments:
22 pages, 11 figures. Version accepted for publication in JHEP
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2011.11470 [pdf]
JHEP(2021)·3 citations
11
[Submitted on 23 Nov 2020] (cross-list from hep-ph)
Femtoscopy of the Origin of the Nucleon Mass
G. Krein🇧🇷 · T.C. Peixoto🇧🇷
We study the prospects of using femtoscopic low-momentum correlation measurements at the Large Hadron Collider to access properties of the J/psi-nucleon interaction. The QCD multipole expansion in terms of the J/psi chromopolarizability relates the forward scattering amplitude to a key matrix element to the origin of the nucleon mass problem, the average chromoelectric gluon distribution in the nucleon. We use information on the J/psi-nucleon interaction provided by lattice QCD simulations and phenomenological models to compute J/psi-nucleon correlation functions. The computed correlation functions show clear sensitivity to the interaction, in particular to the J/psi chromopolarizability.
Comments:
9 pages, 4 figures
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:
2011.11615 [pdf]
Few Body Syst.(2020)·25 citations

Affiliations

first authorsco-authorsvia INSPIRE