Nuclear Theory·nucl-th

Tuesday·July 14, 2020

13 papers—5 primary·8 cross-listed

01
[Submitted on 11 Jul 2020]
$Λ^{*}$ matter and its stability
J. Hrtánková🇨🇿 · M. Schäfer🇨🇿 · J. Mareš🇨🇿 · A. Gal🇮🇱 · E. Friedman🇮🇱 · N. Barnea🇮🇱
We performed calculations of nuclear systems composed solely of $Λ^{*}$ hyperons, aiming at exploring the possibility of existence of absolutely stable $Λ^{*}$ matter. We considered $Λ^{*}$ interaction strengths compatible with the $Λ^{*} Λ^{*}$ binding energy $B_{Λ^{*} Λ^{*}}$ given by the $K ˉ N$ interaction model by Yamazaki and Akaishi [1]. We found that the binding energy per $Λ^{*}$ saturates at values well below 100 MeV for mass number $A \geq 120$ . The $Λ^{*}$ matter is thus highly unstable against strong interaction decay.
Comments:
Proceedings of HADRON2019, 16 - 21 August 2019, Guilin, China, to appear in International Journal of Modern Physics A
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2007.05829 [pdf]
2 citations
02
[Submitted on 13 Jul 2020]
Prolate-to-oblate transition and backbending along the yrast line induced by quasiparticle alignment
Fang-Qi Chen🇨🇳 · Q. B. Chen🇩🇪
The yrast lines in Kr isotopes with $N = 42$ , 44, and 46 are investigated in a beyond mean field framework with both prolate-oblate coexistence and quasiparticle alignment taken into account. Quasiparticle orbitals with high- $j$ and low- $Ω$ on the oblate side are shown to be responsible for the sharp backbending observed in $^{82}$ Kr, by driving the yrast shape from prolate to oblate. This suggests that quasiparticle alignment may not be neglected in the investigation of the shape evolution along the yrast line.
Comments:
6 pages, 5figiures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2007.06217 [pdf]
PLB(2020)·1 citation
03
[Submitted on 13 Jul 2020]
Impurity Lattice Monte Carlo for Hypernuclei
Dillon Frame🇩🇪 · Timo A. Lähde🇩🇪 · Dean Lee🇺🇸 · Ulf-G. Meißner🇩🇪
We consider the problem of including $Λ$ hyperons into the ab initio framework of nuclear lattice effective field theory. In order to avoid large sign oscillations in Monte Carlo simulations, we make use of the fact that the number of hyperons is typically small compared to the number of nucleons in the hypernuclei of interest. This allows us to use the impurity lattice Monte Carlo method, where the minority species of fermions in the full nuclear Hamiltonian is integrated out and treated as a worldline in Euclidean projection time. The majority fermions (nucleons) are treated as explicit degrees of freedom, with their mutual interactions described by auxiliary fields. This is the first application of the impurity lattice Monte Carlo method to systems where the majority particles are interacting. Here, we show how the impurity Monte Carlo method can be applied to compute the binding energy of the light hypernuclei. In this exploratory work we use spin-independent nucleon-nucleon and hyperon-nucleon interactions to test the computational power of the method. We find that the computational effort scales approximately linearly in the number of nucleons. The results are very promising for future studies of larger hypernuclear systems using chiral effective field theory and realistic hyperon-nucleon interactions, as well as applications to other quantum many-body systems.
Comments:
10 pages, 4 figures, some more explanations and references, version published in EPJA
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Computational Physics (physics.comp-ph)
arXiv:
2007.06335 [pdf]
EPJA(2020)·22 citations
04
[Submitted on 13 Jul 2020]
Probing chemical freeze-out criteria in relativistic nuclear collisions with coarse grained transport simulations
Tom Reichert🇩🇪 · Gabriele Inghirami🇫🇮 · Marcus Bleicher🇩🇪
We introduce a novel approach based on elastic and inelastic scattering rates to extract the hyper-surface of the chemical freeze-out from a hadronic transport model in the energy range from E $_{lab} = 1.23$ AGeV to $s_{NN} = 62.4$ GeV. For this study, the Ultra-relativistic Quantum Molecular Dynamics (UrQMD) model combined with a coarse-graining method is employed. The chemical freeze-out distribution is reconstructed from the pions through several decay and re-formation chains involving resonances and taking into account inelastic, pseudo-elastic and string excitation reactions. The extracted average temperature and baryon chemical potential are then compared to statistical model analysis. Finally we investigate various freeze-out criteria suggested in the literature. We confirm within this microscopic dynamical simulation, that the chemical freeze-out at all energies coincides with $⟨ E ⟩ / ⟨ N ⟩ \approx 1$ GeV, while other criteria, like $s / T^{3} = 7$ and $n_{B} + n_{B ˉ} \approx 0.12$ fm $^{- 3}$ are limited to higher collision energies.
Comments:
9 pages, 10 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2007.06440 [pdf]
EPJA(2020)·20 citations
05
[Submitted on 13 Jul 2020]
Radius and equation of state constraints from massive neutron stars and GW190814
Yeunhwan Lim · Anirban Bhattacharya · Jeremy W. Holt · Debdeep Pati
Motivated by the unknown nature of the $2.50 - 2.67 M_{⊙}$ compact object in the binary merger event GW190814, we study the maximum neutron star mass based on constraints from low-energy nuclear physics, neutron star tidal deformabilities from GW170817, and simultaneous mass-radius measurements of PSR J0030+045 from NICER. Our prior distribution is based on a combination of nuclear modeling valid in the vicinity of normal nuclear densities together with the assumption of a maximally stiff equation of state at high densities, a choice that enables us to probe the connection between observed heavy neutron stars and the transition density at which conventional nuclear physics models must break down. We demonstrate that a modification of the highly uncertain supra-saturation density equation of state beyond 2.64 times normal nuclear density is required in order for chiral effective field theory models to be consistent with current neutron star observations and the existence of $2.6 M_{⊙}$ neutron stars. We also show that the existence of very massive neutron stars strongly impacts the radii of $\sim 2.0 M_{⊙}$ neutron stars (but not necessarily the radii of $1.4 M_{⊙}$ neutron stars), which further motivates future NICER radius measurements of PSR J1614-2230 and PSR J0740+6620.
Comments:
6 pages, 4 figures, revised figures
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2007.06526 [pdf]
PRC(2021)·60 citations
06
[Submitted on 10 Jul 2020] (cross-list from hep-ph)
Magnetic effects of QCD parameters from finite energy sum rules
Cristian Villavicencio🇨🇱 · C. A. Dominguez🇿🇦 · M. Loewe🇨🇱
One of the advantages of the finite energy sum rules is the fact that every operator in the operator product expansion series can be selected individually by the use of an appropriate kernel function which removes other operator poles. This characteristic is maintained by QCD systems in the presence of external homogeneous magnetic field, providing interesting information about the magnetic evolution of QCD and hadronic parameters. In this work finite energy sum rules are applied on QCD in the light quark sector, combining axial and pseudoscalar channels in the presence of an external homogeneous magnetic field, obtaining the magnetic evolution of the light quark masses, pion mass, the pion decay constant, the gluon condensate and the continuum hadronic threshold.
Comments:
8 pages, 6 figures, contribution to proceedings of the 36th Winter Workshop on Nuclear Dynamics (WWND 2020)
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2007.05642 [pdf]
J.Phys.Conf.Ser.(2020)·3 citations
07
[Submitted on 11 Jul 2020] (cross-list from hep-ph)
Vacuum and thermal fluctuation energies of a soliton at finite temperatures
Song Shu🇨🇳 · Xiaogang Li🇨🇳 · Jia-Rong Li🇨🇳
We have studied the vacuum and thermal fluctuation energies of a soliton at finite temperatures. First the vacuum energy coming from the Dirac sea is calculated by a summation of the discrete and continuum energy spectrum of the Dirac equation in the background field of a soliton. And all the divergences are removed by the same renormalization scheme at zero temperature. Then the vacuum energy and thermal fluctuation energy at finite temperatures in a temperature dependent soliton background are calculated. And the numerical results are analyzed and discussed.
Comments:
13 pages, 7 figures; some paragraphs and references are added
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2007.05731 [pdf]
NPA(2021)·2 citations
08
[Submitted on 11 Jul 2020] (cross-list from hep-ph)
Momentum dependence of light nuclei production in pp, p-Pb and Pb-Pb collisions at the CERN Large Hadron Collider
Rui-Qin Wang🇨🇳 · Feng-Lan Shao🇨🇳 · Jun Song🇨🇳
We study the momentum dependence of the production of light nuclei in high energy collisions in the nucleon coalescence/recombination mechanism. We derive formulas of the momentum distributions of deuterons ( $d$ ) and helions ( $^{3}$ He). We obtain the analytic expressions of the coalescence factor $B_{A}$ 's ( $B_{2}$ for $d$ and $B_{3}$ for $^{3}$ He) as functions of the collision system size and the momentum. We apply the deduced results to p-p, p-Pb and Pb-Pb collisions to naturally explain the interesting behaviors of $B_{A}$ observed in experiments at the CERN Large Hadron Collider.
Comments:
11 pages, 5 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2007.05745 [pdf]
PRC(2021)·13 citations
09
[Submitted on 11 Jul 2020] (cross-list from quant-ph)
Recoil Momentum Effects in Quantum Processes Induced by Twisted Photons
Andrei Afanasev🇺🇸 · Carl E. Carlson🇺🇸 · Asmita Mukherjee🇮🇳
We consider physical processes caused by the twisted photons for a wide range of energy scales, from optical (eV) to nuclear (MeV) to high-energy gamma-rays (TeV). We demonstrate that in order to satisfy angular momentum conservation, absorption of a twisted photon leads to a transverse recoil of the final particle or a system of particles leading to increased threshold energy required for the reaction to proceed. Modification of the threshold energy is predicted for (a) Photo-absorption on colds trapped ions of $^{40}$ Ca, along with emerging new transverse-motion sidebands, (b) photo-disintegration of deuterium and (c) photo-production of electron-positron pairs in astrophysics environment.
Comments:
9 pages, 8 figures
Subjects:
Quantum Physics (quant-ph); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2007.05816 [pdf]
PRResearch(2021)·19 citations
10
[Submitted on 12 Jul 2020] (cross-list from hep-ph)
Hidden and open heavy-flavor hadronic states
H. Garcilazo🇲🇽 · A. Valcarce🇪🇸
We discuss the stability of hidden and open heavy-flavor hadronic states made of either two or three mesons. References are made in passing to studies regarding two and three-body systems containing baryons. We perform a comparative study analyzing the results in terms of quark and hadron degrees of freedom. Compact and molecular states are found to exist in very specific situations. We estimate the decay width for the different scenarios: weak decays for bound states by the strong interaction, and strong decays for hadronic resonances above a decay threshold. The experimental observation of narrow hadrons lying well above their lowest decay threshold is theoretically justified.
Comments:
Paper commissioned to Prof. H. Garcilazo for the special issue "New Trends in Hadron Physics: a Few-Body Perspective" of Few Body Systems. 20 pages, 13 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2007.06046 [pdf]
Few Body Syst.(2020)·6 citations
11
[Submitted on 12 Jul 2020] (cross-list from astro-ph.HE)
On the nature of GW190814 and its impact on the understanding of supranuclear matter
Ingo Tews🇺🇸 · Peter T. H. Pang🇳🇱 · Tim Dietrich🇩🇪 · Michael W. Coughlin🇺🇸 · Sarah Antier🇫🇷 · Mattia Bulla🇸🇪 · Jack Heinzel🇺🇸 · Lina Issa🇸🇪
The observation of a compact object with a mass of $2.50 - 2.67 M_{⊙}$ on August 14, 2019, by the LIGO Scientific and Virgo collaborations (LVC) has the potential to improve our understanding of the supranuclear equation of state. While the gravitational-wave analysis of the LVC suggests that GW190814 likely was a binary black hole system, the secondary component could also have been the heaviest neutron star observed to date. We use our previously derived nuclear-physics-multimessenger astrophysics framework to address the nature of this object. Based on our findings, we determine GW190814 to be a binary black hole merger with a probability of $> 99.9%$ . Even if we weaken previously employed constraints on the maximum mass of neutron stars, the probability of a binary black hole origin is still $\sim 81%$ . Furthermore, we study the impact that this observation has on our understanding of the nuclear equation of state by analyzing the allowed region in the mass-radius diagram of neutron stars for both a binary black hole or neutron star--black hole scenario. We find that the unlikely scenario in which the secondary object was a neutron star requires rather stiff equations of state with a maximum speed of sound $c_{s} \geq 0.6$ times the speed of light, while the binary black hole scenario does not offer any new insight.
Comments:
9 pages, 3 figures, published version
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
arXiv:
2007.06057 [pdf]
ApJL(2021)·128 citations
12
[Submitted on 13 Jul 2020] (cross-list from nucl-ex)
Total and differential cross sections of the $dp \to^{3} He η$ reaction at excess energies between 1 and 15 MeV
C. Fritzsch🇩🇪 · S. Barsov🇷🇺 · I. Burmeister🇩🇪 · S. Dymov🇩🇪 · R. Gebel🇩🇪 · M. Hartmann🇩🇪 · A. Kacharava🇩🇪 · A. Khoukaz🇩🇪 · V. Komarov🇷🇺 · P. Kulessa🇵🇱 · A. Kulikov🇷🇺 · A. Lehrach🇩🇪 and 14 other authors
New high precision total and differential cross sections are reported for the $d p \to^{3} He η$ reaction close to threshold. The measurements were performed using the magnetic spectrometer ANKE, which is an internal fixed target facility at the COSY cooler synchrotron. The data were taken for deuteron beam momenta between $3.14641 GeV / c$ and $3.20416 GeV / c$ , which corresponds to the range in excess energy $Q$ for this reaction between $1.14 MeV$ and $15.01 MeV$ . The normalization was established through the measurement in parallel of deuteron-proton elastic scattering and this was checked through the study of the $d p \to^{3} He π^{0}$ reaction. The previously indicated possible change of sign of the slope of the differential cross sections near the production threshold, which could be explained by a rapid variation of the $s$ - and $p$ -wave interference term, is not confirmed by the new data. The energy dependence of the total cross section and the $9 0^{\circ}$ slope parameter are well explained by describing the final state interaction in terms of a complex Jost function and the results are significant in the discussion of $η$ -mesic nuclei. In combination with recently published WASA-at-COSY data [P. Adlarson $e t a l .$ , Phys. Lett. B 782, 297 (2018)], a smooth variation of the slope parameter is achieved up to an excess energy of $80.9 MeV$ .
Comments:
12 pages, 11 figures, preprint submitted to Physical Review C
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2007.06274 [pdf]
PRC(2020)·0 citations
13
[Submitted on 13 Jul 2020] (cross-list from hep-ph)
Thermodynamic properties of interacting bosons with zero chemical potential
O. S. Stashko🇺🇦 · D. V. Anchishkin🇺🇦 · O. V. Savchuk🇺🇦 · M. I. Gorenstein🇺🇦
Thermodynamics properties of an interacting system of bosons are considered at finite temperatures and zero chemical potential within the Skyrme-like mean-field model. An interplay between attractive and repulsive interactions is investigated. As a particular example an equilibrium system of pions is discussed. Several modifications of thermodynamic properties in the considered system are found with increasing a strength of attractive forces. Different types of the first order phase transition are classified. Some of these transitions exist also in the Boltzmann approximation. However, effects of the Bose statistics introduce the notable additional changes in the thermodynamic quantities due to a possibility of the Bose-Einstein condensation.
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2007.06321 [pdf]
J.Phys.G(2021)·8 citations

Affiliations

first authorsco-authorsvia INSPIRE