Nuclear Theory·nucl-th

Thursday·November 9, 2017

8 papers—4 primary·4 cross-listed

01
[Submitted on 8 Nov 2017]
The balance of attractive and repulsive hadronic interactions: the influence of hadronic spectrum and excluded volume effects on lattice thermodynamics and consequences on experiments
Paolo Alba
Repulsive hadronic interactions play a relevant role in the QCD dynamics, attractive ones being represented by resonance formation. In this study we propose different schemes in order to parameterise repulsive interactions, then being able to extract effective sizes of hadrons from fits to lattice QCD simulations. We find that allowing a difference between the strange and light sectors, strange particles are systematically smaller than light ones with equal mass. The very simple implementation of repulsive interactions would in principle allow to extract precise information about all hadronic species once corresponding lattice observables, sensitive to the species of interest, are provided. With the parameterisation which best reproduces lattice data there is also a good description of experimental yields measured by ALICE and STAR experiments.
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1711.02797 [pdf]
PRC(2019)·15 citations
02
[Submitted on 8 Nov 2017]
Possible origin of shoulder in the reactor antineutrino spectrum
Ajit Kumar Mohanty🇮🇳
The re-analysis of measured $^{238} U$ integrated electron spectrum reveals a shape mismatch with respect to the so called ab initio calculation and the ratio resembles well with the recently observed reactor antineutrino shoulder or bump around 5 MeV prompt energy when plotted in a reduced scale where the first two moments (area and average) of the spectrum are made identical (KNO type scaling). However, such bumps are not seen in case of other actinides like $^{235} U$ and $^{239, 241} P u$ isotopes. Since the magnitude of the bump in $^{238} U$ is comparable with the experimental observations, $^{238} U$ can not be the only source of anomaly unless similar contributions come from other uranium and plutonium isotopes as well. Therefore, it is strongly conjectured that the integrated electron spectra of uranium and plutonium isotopes particularly in the $6$ MeV to $8$ MeV energy range may have additional contributions coming from the harder part of the reactor neutron spectrum which may not be present in the thermal measurements.
Comments:
5 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1711.02801 [pdf]
2 citations
03
[Submitted on 8 Nov 2017]
High baryon and energy densities achievable in heavy-ion collisions at $s_{N N} =$ 39 GeV
Yu. B. Ivanov🇷🇺 · A. A. Soldatov🇷🇺
Baryon and energy densities, which are reached in central Au+Au collisions at collision energy of $s_{N N} = 39$ GeV, are estimated within the model of three-fluid dynamics. It is shown that the initial thermalized mean proper baryon and energy densities in a sizable central region approximately are $n_{B} / n_{0} \approx$ 10 and $ε \approx$ 40 GeV/fm $^{3}$ , respectively. The study indicates that the deconfinement transition at the stage of interpenetration of colliding nuclei makes the system quite opaque. The final fragmentation regions in these collisions are formed not only by primordial fragmentation fireballs, i.e. the baryon-rich matter passed through the interaction region (containing approximately 30\% of the total baryon charge), but also by the baryon-rich regions of the central fireball pushed out to peripheral rapidities by the subsequent almost one-dimensional expansion of the central fireball along the beam direction.
Comments:
4 pages, 4 figures, minor corrections, version published in Phys. Rev. C
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1711.03069 [pdf]
PRC(2018)·10 citations
04
[Submitted on 8 Nov 2017]
Bulk viscous corrections to screening and damping in the deconfined phase at high temperature
Adrian Dumitru🇺🇸
Non-equilibrium corrections in a hot QCD medium modify the "hard thermal loops" (HTL) which determine the resummed propagators for gluons with soft momenta as well as the Debye screening and Landau damping mass scales. We focus on bulk viscous corrections to a thermal fixed point. The screening and damping mass scales are sensitive to the bulk pressure and perhaps to (pseudo-) critical dynamical scaling of the bulk viscosity in the vicinity of a second-order critical point. This would affect the properties of quarkonium bound states in the deconfined phase.
Comments:
7 pages; Proceedings of Critical Point and Onset of Deconfinement - CPOD2017; 7--11 August, 2017, Stony Brook University, Stony Brook, NY; to be published in PoS (SISSA)
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1711.03072 [pdf]
PoS(2018)·0 citations
05
[Submitted on 8 Nov 2017] (cross-list from hep-ph)
The Physics Case for the $s_{N N} \approx 10$ GeV Energy Region
J. Cleymans🇿🇦
There are indications that the beam energy region $s_{N N} \approx 10$ GeV for heavy-ion collisions is an interesting one. The final state has the highest net baryon density at this beam energy. A transition from a baryon dominated to a meson dominated final state takes place around this beam energy. Ratios of strange particles to mesons show clear and pronounced maxima around this beam energy. The theoretical interpretation can be clarified by covering fully this energy region. In particular the strangeness content needs to be determined, data covering the full phase space ( $4 π$ ) would be helpful to establish the properties of this energy region.
Comments:
6 pages 6 figures Walter Greiner memorial
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1711.02882 [pdf]
6 citations
06
[Submitted on 8 Nov 2017] (cross-list from hep-lat)
Chiral phase transition of three flavor QCD with nonzero magnetic field using standard staggered fermions
Akio Tomiya🇨🇳 · Heng-Tong Ding🇨🇳 · Swagato Mukherjee🇺🇸 · Christian Schmidt🇩🇪 · Xiao-Dan Wang🇨🇳
Lattice simulations for (2+1)-flavor QCD with external magnetic field demonstrated that the quark mass is one of the important parameters responsible for the (inverse) magnetic catalysis. We discuss the dependences of chiral condensates and susceptibilities, the Polyakov loop on the magnetic field and quark mass in three degenerate flavor QCD. The lattice simulations are performed using standard staggered fermions and the plaquette action with spatial sizes Ns = 16 and 24 and a fixed temporal size Nt = 4. The value of the quark masses are chosen such that the system undergoes a first order chiral phase transition and crossover with zero magnetic field. We find that in light mass regime, the quark chiral condensate undergoes magnetic catalysis in the whole temperature region and the phase transition tend to become stronger as the magnetic field increases. In crossover regime, deconfinement transition temperature is shifted by the magnetic field when quark mass ma is less than 0.4. The lattice cutoff effects are also discussed.
Comments:
8 pages, 6 figures. Proceedings of the 35th International Symposium on Lattice Field Theory, 18-24 June 2017, Granada, Spain
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1711.02884 [pdf]
EPJ Web Conf.(2018)·8 citations
07
[Submitted on 8 Nov 2017] (cross-list from hep-ph)
Exclusive vector meson photoproduction with a leading baryon in photon - hadron interactions at hadronic colliders
F. Carvalho🇧🇷 · V.P. Goncalves🇧🇷 · F.S. Navarra🇧🇷 · D. Spiering🇧🇷
Exclusive vector meson photoproduction associated with a leading baryon ( $B = n, Δ^{+}, Δ^{0}$ ) in $pp$ and $p A$ collisions at RHIC and LHC energies is investigated using the color dipole formalism and taking into account nonlinear effects in the QCD dynamics. In particular, we compute the cross sections for $ρ$ , $ϕ$ and $J /Ψ$ production together with a $Δ$ and compare the predictions with those obtained for a leading neutron. Our results show that the $V + Δ$ cross section is almost 30 % of the $V + n$ one. Our results also show that a future experimental analysis of these processes is, in principle, feasible and can be useful to study leading particle production.
Comments:
7 pages, 4 figures, 1 table
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1711.02957 [pdf]
PRD(2018)·6 citations
08
[Submitted on 8 Nov 2017] (cross-list from hep-ph)
Transverse momentum spectra of hadrons in $p + p$ collisions at CERN SPS energies from the UrQMD transport model
Vitalii Ozvenchuk🇵🇱 · Andrzej Rybicki🇵🇱
The UrQMD transport model, version 3.4, is used to study the new experimental data on transverse momentum spectra of $π^{\pm}$ , $K^{\pm}$ , $p$ and $p ˉ$ produced in inelastic $p + p$ interactions at SPS energies, recently published by the NA61/SHINE Collaboration. The comparison of model predictions to these new measurements is presented as a function of collision energy for central and forward particle rapidity intervals. In addition, the inverse slope parameters characterizing the transverse momentum distributions are extracted from the predicted spectra and compared to the corresponding values obtained from NA61/SHINE distributions, as a function of particle rapidity and collision energy. A complex pattern of deviations between the experimental data and the UrQMD model emerges. For charged pions, the fair agreement visible at top SPS energies deteriorates with the decreasing energy. For charged $K$ mesons, UrQMD significantly underpredicts positive kaon production at lower beam momenta. It also underpredicts the central rapidity proton yield at top collision energy and overpredicts antiproton production at all considered energies. We conclude that the new experimental data analyzed in this paper still constitute a challenge for the present version of the model.
Comments:
15 pages, 10 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1711.02963 [pdf]
NPA(2018)·5 citations

Affiliations

first authorsco-authorsvia INSPIRE