Nuclear Theory·nucl-th

Friday·February 21, 2020

10 papers—5 primary·5 cross-listed

01
[Submitted on 19 Feb 2020]
Assessment of the beta-delayed proton decay rate of $^{11}$ Be
Alexander Volya
The $^{11}$ Be neutron halo nucleus appears to decay into $^{10}$ Be with a rate that exceeds expectations. Neutron disappearance into dark matter, beta decay of a halo neutron, or beta-delayed proton decay have been offered as explanations. In this work we study the latter option; we carry out shell model calculations and sequential decay analysis examining the beta-delayed proton decay going through a resonance in $^{11}$ B. The narrow energy window, lack of states with sufficient spectroscopic strength, overwhelming alpha decay branch, all make reconciling the observed rate with beta-delayed proton decay difficult.
Comments:
8 pages, 2 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2002.08482 [pdf]
EPL(2020)·16 citations
02
[Submitted on 20 Feb 2020]
Elliptic flow splitting between protons and antiprotons from hadronic potentials
Pengcheng Li🇨🇳 · Yongjia Wang🇨🇳 · Jan Steinheimer🇩🇪 · Qingfeng Li🇨🇳 · Hongfei Zhang🇨🇳
The difference in elliptic flow $v_{2}$ between protons and antiprotons, produced in $^{197} Au +^{197} Au$ collisions at center-of-mass energies $s_{N N} = 5 - 12 GeV$ , is studied within a modified version of the ultrarelativistic quantum molecular dynamics (UrQMD) model. Two different model scenarios are compared: the cascade mode and the mean field mode which includes potential interactions for both formed and pre-formed hadrons. The model results for the elliptic flow of protons and the relative $v_{2}$ difference between protons and antiprotons obtained from the mean field mode agree with the available experimental data, while the $v_{2}$ difference is near zero for the cascade mode. Our results show that the elliptic flow splitting, observed for particles and antiparticles, can be explained by the inclusion of proper hadronic interactions. In addition, the difference in $v_{2}$ between protons and antiprotons depends on the centrality and the rapidity window. With smaller centrality and/or rapidity acceptance, the observed elliptic flow splitting is more sensitive to the beam energy, indicating a strong net baryon density dependence of the effect. We propose to confirm this splitting at the upcoming experiments from Beam Energy Scan (BES) Phase-\Rmnum{2} at Relativistic Heavy Ion Collider (RHIC), the Compressed Baryonic Matter (CBM) at Facility for Antiproton and Ion Research (FAIR), High Intensity heavy ion Accelerator Facility (HIAF) and Nuclotron-based Ion Collider fAcility (NICA).
Comments:
8 pages, 4 figures, submitted
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2002.08574 [pdf]
Mod.Phys.Lett.A(2020)·8 citations
03
[Submitted on 20 Feb 2020]
Evidence for Tetrahedral Structure of Calcium-40
N. S. Manton
More than 100 excited states of the Calcium-40 nucleus, with isospin 0, are classified into rotational-vibrational bands of an intrinsic tetrahedral structure. Almost all observed states below 8 MeV can be accommodated, as well as many high-spin states above 8 MeV. The bands have some similarity to those classifying states of Oxygen-16, but the A-mode vibrational frequency is lower relative to the E-mode and F-mode frequencies than in Oxygen-16. Previously identified rotational bands up to spin 16 and energy above 20 MeV are unified here into a smaller number of tetrahedral bands.
Comments:
17 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2002.08744 [pdf]
IJMPE(2020)·6 citations
04
[Submitted on 20 Feb 2020]
Anisotropic transport properties of Hadron Resonance Gas in magnetic field
Ashutosh Dash🇮🇳 · Subhasis Samanta🇵🇱 · Jayanta Dey🇮🇳 · Utsab Gangopadhyaya🇮🇳 · Sabyasachi Ghosh🇮🇳 · Victor Roy🇮🇳
An intense transient magnetic field is produced in high energy heavy-ion collisions mostly due to the spectator protons inside the two colliding nucleus. The magnetic field introduces anisotropy in the medium and hence the isotropic scalar transport coefficients become anisotropic and split into multiple components. Here we calculate the anisotropic transport coefficients shear, bulk viscosity, electrical conductivity, and the thermal diffusion coefficients for a multicomponent Hadron- Resonance-Gas (HRG) model for a non-zero magnetic field by using the Boltzmann transport equation in a relaxation time approximation (RTA). The anisotropic transport coefficient component along the magnetic field remains unaffected by the magnetic field, while perpendicular dissipation is governed by the interplay of the collisional relaxation time and the magnetic time scale, which is inverse of the cyclotron frequency. We calculate the anisotropic transport coefficients as a function of temperature and magnetic field using the HRG model. The neutral hadrons are unaffected by the Lorentz force and do not contribute to the anisotropic transports, we estimate within the HRG model the relative contribution of isotropic and anisotropic transports as a function of magnetic field and temperature. We also give an estimation of these anisotropic transport coefficients for the hadronic gas at finite baryon chemical potential.
Comments:
15 pages, 7 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2002.08781 [pdf]
PRD(2020)·70 citations
05
[Submitted on 20 Feb 2020]
Correlation coefficient between harmonic and transverse flow in heavy-ion collisions
Piotr Bozek🇵🇱 · Hadi Mehrabpour🇮🇷
The correlation between the harmonic flow and the transverse flow in relativistic heavy ion collisions is calculated in the hydrodynamic model. The partial correlation coefficient, corrected for fluctuations of multiplicity, is compared to experimental data. Estimators of the final transverse and harmonic flow are used to predict the value of the correlation coefficient from the moments of the initial distribution. A good description of the hydrodynamic simulation results is obtained if the estimator for the final transverse flow, besides the most important transverse size and entropy, includes also the eccentricities.
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2002.08832 [pdf]
PRC(2020)·44 citations
06
[Submitted on 19 Feb 2020] (cross-list from hep-ph)
Origin of single transverse-spin asymmetries in high-energy collisions
Justin Cammarota🇺🇸 · Leonard Gamberg🇺🇸 · Zhong-Bo Kang🇺🇸 · Joshua A. Miller🇺🇸 · Daniel Pitonyak🇺🇸 · Alexei Prokudin🇺🇸 · Ted C. Rogers🇺🇸 · Nobuo Sato🇺🇸
In this paper we perform the first simultaneous QCD global analysis of data from semi-inclusive deep inelastic scattering, Drell-Yan, $e^{+} e^{-}$ annihilation into hadron pairs, and proton-proton collisions. Consequently, we are able to extract a universal set of non-perturbative functions that describes the observed asymmetries in these reactions. The outcome of our analysis indicates single transverse-spin asymmetries in high-energy collisions have a common origin. Furthermore, we achieve the first phenomenological agreement with lattice QCD on the up and down quark tensor charges.
Comments:
8 pages, 6 figures, matches published version
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:
2002.08384 [pdf]
PRD(2020)·167 citations
07
[Submitted on 19 Feb 2020] (cross-list from nucl-ex)
Recent results on Light Flavor from STAR
Jie Zhao (for the STAR collaboration)🇺🇸
These proceedings present an overview of the recent results on light flavor by the STAR experiment at RHIC.
Comments:
7 pages, 8 figures, Strangeness in Quark Matter 2019
Subjects:
Nuclear Experiment (nucl-ex); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2002.08407 [pdf]
Springer Proc.Phys.(2020)·0 citations
08
[Submitted on 20 Feb 2020] (cross-list from hep-ph)
Understanding long-range near-side ridge correlations in p $-$ p collisions using rope hadronization at LHC energies
Pritam Chakraborty🇮🇳 · Sadhana Dash🇮🇳
The observation of long range ridge-like structure in the near-side region of the two particle $Δ η - Δ ϕ$ correlations as measured by LHC experiments in high multiplicity p $-$ p collisions indicated towards the presence of collective effects which are similar to that observed in p $-$ A(nucleon-nucleus) and A $-$ A (nucleus-nucleus) collisions. The two particle correlation between the charged particles in $Δ η - Δ ϕ$ for p $-$ p collisions at $s$ = 7 TeV and 13 TeV is studied using Pythia 8 event generator within the framework of final-state partonic color reconnection effects as well as the microscopic rope hadronization model. The rope hadronization relies on the formation of ropes due to overlapping of strings in high multiplicity events followed by string shoving. A near side ridge-like structure which is qualitatively similar to the observed ridge in data was observed for high-multiplicity events when the mechanism of rope hadronization (with shoving) was enabled.
Comments:
7 pages, 3 captioned figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2002.08581 [pdf]
PRC(2020)·7 citations
09
[Submitted on 19 Feb 2020] (cross-list from hep-ph)
Heavy-flavour in relativistic nuclear collisions: recent developments
Andrea Beraudo🇮🇹
Transport calculations represent the major tool to simulate the modifications induced by the presence of a hot-deconfined medium on the production of heavy-flavour particles in high-energy nuclear collisions. After a brief description of the approach and of the major achievements in its phenomenological applications we discuss some recent developments. In particular we focus on observables arising from event-by-event fluctuations in the distribution of deposited energy (odd flow harmonics, event-shape-engineering) and from the tilting of the initial geometry with respect to the beam axis (directed flow), with a possible role played by the strong magnetic field generated by the spectator nucleons.
Comments:
6 pages, proceedings of the "LFC19: Strong dynamics for physics within and beyond the Standard Model at LHC and Future Colliders" workshop. arXiv admin note: substantial text overlap with arXiv:1910.03886
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2002.08763 [pdf]
0 citations
10
[Submitted on 20 Feb 2020] (cross-list from astro-ph.HE)
Bayesian Inference of Dense Matter Equation of State within Relativistic Mean Field Models using Astrophysical Measurements
Silvia Traversi · Prasanta Char · Giuseppe Pagliara
We present a Bayesian analysis to constrain the equation of state of dense nucleonic matter by exploiting the available data from symmetric nuclear matter at saturation and from observations of compact X-ray sources and from the gravitational wave event GW170817. For the first time, such analysis is performed by using a class of models, the relativistic mean field models, which allow to consistently construct an equation of state in a wide range of densities, isospin asymmetries and temperatures. The selected class of models contains five nuclear physics empirical parameters at saturation for which we construct the joint posterior distributions. By exploring different types of priors, we find that the equations of state with the largest evidence are the ones featuring a strong reduction of the effective mass of the nucleons in dense matter which can be interpreted as an indication of a phase transition to a chiral symmetry restored phase. Those equations of state in turn predict $R_{1.4} \sim 12$ km. Finally, we present a preliminary investigation on the effect of including $Λ$ hyperons showing that they appear in stars more massive than about $1.6 M_{⊙}$ and lead to radii larger than about $R_{1.4} \sim 14$ km. Within the model here explored, the formation of such particles provide a poor agreement with the constraints from GW170817.
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2002.08951 [pdf]
ApJ(2020)·94 citations

Affiliations

first authorsco-authorsvia INSPIRE