Nuclear Theory·nucl-th

Wednesday·January 6, 2016

8 papers—4 primary·4 cross-listed

01
[Submitted on 4 Jan 2016]
Pairing Nambu-Goldstone Modes within Nuclear Density Functional Theory
Nobuo Hinohara · Witold Nazarewicz
We show that the Nambu-Goldstone formalism of the broken gauge symmetry in the presence of the $T = 1$ pairing condensate offers a quantitative description of the binding-energy differences of open-shell superfluid nuclei. We conclude that the pairing-rotational moments of inertia are excellent pairing indicators, which are free from ambiguities attributed to odd-mass systems. We offer a new, unified interpretation of the binding-energy differences traditionally viewed in the shell model picture as signatures of the valence nucleon properties. We present the first systematic analysis of the off-diagonal pairing-rotational moments of inertia and demonstrate the mixing of the neutron and proton pairing-rotational modes in the ground states of even-even nuclei. Finally, we discuss the importance of mass measurements of neutron-rich nuclei for constraining the pairing energy density functional.
Comments:
6 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1601.00677 [pdf]
PRL(2016)·34 citations
02
[Submitted on 5 Jan 2016]
Jet Fragmentation via Recombination of Parton Showers
Kyong Chol Han🇺🇸 · Rainer J. Fries🇺🇸 · Che Ming Ko🇺🇸
We propose to model hadronization of parton showers in QCD jets through a hybrid approach involving quark recombination and string fragmentation. This is achieved by allowing gluons at the end of the perturbative shower evolution to undergo a non-perturbative splitting into quark and antiquark pairs, then applying a Monte-Carlo version of instantaneous quark recombination, and finally subjecting remnant quarks (those which have not found a recombination partner) to Lund string fragmentation. When applied to parton showers from the PYTHIA Monte Carlo event generator, the final hadron spectra from our calculation compare quite well to PYTHIA jets that have been hadronized with the default Lund string fragmentation. Our new approach opens up the possibility to generalize hadronization to jets embedded in a quark gluon plasma.
Comments:
10 Pages, 8 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1601.00708 [pdf]
PRC(2016)·70 citations
03
[Submitted on 5 Jan 2016]
Effects of EoS in viscous hydro+cascade model for the RHIC Beam Energy Scan
Iu. Karpenko🇮🇹 · M. Bleicher🇩🇪 · P. Huovinen🇩🇪 · H. Petersen🇩🇪
A state-of-the-art 3+1 dimensional cascade + viscous hydro + cascade model vHLLE+UrQMD has been applied to heavy ion collisions in RHIC Beam Energy Scan range $s_{NN} = 7.7 \dots 200$ GeV. Based on comparison to available experimental data it was estimated that an effective value of shear viscosity over entropy density ratio $η / s$ in hydrodynamic stage has to decrease from $η / s = 0.2$ to $0.08$ as collision energy increases from $s_{NN} = 7.7$ to $39$ GeV, and to stay at $η / s = 0.08$ for $39 \leq s_{NN} \leq 200$ GeV. In this work we show how an equation of state with first order phase transition affects the hydrodynamic evolution at those collision energies and changes the results of the model as compared to "default scenario" with a crossover type EoS from chiral model.
Comments:
4 pages and 3 figures. Proceedings of Quark Matter 2015, Kobe, Japan
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
1601.00800 [pdf]
NPA(2016)·7 citations
04
[Submitted on 5 Jan 2016]
Anisotropic parton escape is the dominant source of azimuthal anisotropy in transport models
Liang He · Terrence Edmonds · Zi-Wei Lin · Feng Liu · Denes Molnar · Fuqiang Wang
We trace the development of elliptic anisotropy (v2) via parton-parton collision history in two transport models. The parton v2 is studied as a function of the number of collisions of each parton in Au+Au and d+Au collisions at sNN =200 GeV. It is found that the majority of v2 comes from the anisotropic escape probability of partons, with no fundamental difference at low and high transverse momenta. The contribution to v2 from hydrodynamic-type collective flow is found to be small. Only when the parton-parton cross-section is set unrealistically large does this contribution start to take over. Our findings challenge the current paradigm emerged from hydrodynamic comparisons to anisotropy data.
Comments:
This paper has been withdrawn by the author due to duplication with arXiv:1502.05572
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
1601.00878 [pdf]
Physics Letters B (2016), pp. 506-510
05
[Submitted on 1 Jan 2016] (cross-list from hep-ph)
Calculating Masses of Pentaquarks Composed of Baryons and Mesons
Majid Monemzadeh🇮🇷 · Narges Tazimi🇮🇷 · Shahnaz Babaghodrat🇮🇷
In this paper, we consider an exotic baryon (pentaquark) as a bound state of two-particle systems composed of a baryon (nucleon) and a meson.We used a baryon - meson picture to reduce a complicated five-body problem to a simple two-body problems. The homogeneous Lippmann-Schwinger integral equation is solved in configuration space by using one pion exchange potential. We calculate the masses of pentaquarks $θ_{c} (uu dd c ˉ)$ , $θ_{b} (uu dd b ˉ)$ .
Comments:
we need to checked our calculations again for mor confidence
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1601.00642 [pdf]
Adv.High Energy Phys.(2016)·14 citations
06
[Submitted on 5 Jan 2016] (cross-list from hep-ph)
Charmed meson and charmonium production in PbPb collisions at the LHC
I.P. Lokhtin🇷🇺 · A.V. Belyaev🇷🇺 · G.Kh. Eyyubova🇨🇿 · G. Ponimatkin🇨🇿 · E.Yu. Pronina🇷🇺
The phenomenological analysis of various characteristics of $J / ψ$ and $D$ meson production in PbPb collisions at the center-of-mass energy 2.76 TeV per nucleon pair is presented. The data on momentum spectra and elliptic flow are reproduced by two-component model HYDJET++ including thermal and non-thermal charm production mechanisms. The significant part of $D$ -mesons is found to be in a kinetic equilibrium with the created medium, while $J / ψ$ -mesons are characterized by earlier (as compared to light hadrons) freeze-out.
Comments:
15 pages including 8 figures as EPS-files; prepared using LaTeX package for publication in the Journal of Physics G
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1601.00799 [pdf]
J.Phys.G(2016)·14 citations
07
[Submitted on 5 Jan 2016] (cross-list from hep-ph)
Resonance on top of thresholds: the $Λ_{c} (2595)^{+}$ as an extremely fine-tuned state
Zhi-Hui Guo🇨🇳 · J.A. Oller🇪🇸
A dedicated study of the $π Σ_{c}$ scattering around its threshold is carried out in this work to probe the nature of $Λ_{c} (2595)^{+}$ . We first demonstrate that the effective range expansion approach fails to work near the $Λ_{c} (2595)^{+}$ pole position, due to the presence of a nearby CDD pole around the $π Σ_{c}$ thresholds. We then develop a general framework to properly handle the situation with a CDD pole accompanied by nearby thresholds, which is first elaborated for the single-channel case and then generalized to the coupled-channel study. The isospin breaking effects of the three $π Σ_{c}$ channels with different thresholds are specially taken into account in our study. The finite-width effects from the $Σ_{c}$ baryons are considered and found to be relevant to give the $Λ_{c} (2595)^{+}$ width fully compatible to its experimental value. Through the compositeness analysis, our robust conclusion is that the $π^{0} Σ_{c}^{+}$ component is subdominant inside the $Λ_{c} (2595)^{+}$ .
Comments:
22 pages, 6 figures. To match the published version in Phys.Rev.D
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
1601.00862 [pdf]
PRD(2016)·43 citations
08
[Submitted on 5 Jan 2016] (cross-list from hep-ph)
Charge-dependent correlations from event-by-event anomalous hydrodynamics
Yuji Hirono🇺🇸 · Tetsufumi Hirano🇯🇵 · Dmitri E. Kharzeev🇺🇸
We report on our recent attempt of quantitative modeling of the Chiral Magnetic Effect (CME) in heavy-ion collisions. We perform 3+1 dimensional anomalous hydrodynamic simulations on an event-by-event basis, with constitutive equations that contain the anomaly-induced effects. We also develop a model of the initial condition for the axial charge density that captures the statistical nature of random chirality imbalances created by the color flux tubes. Basing on the event-by-event hydrodynamic simulations for hundreds of thousands of collisions, we calculate the correlation functions that are measured in experiments, and discuss how the anomalous transport affects these observables.
Comments:
4 pages, 1 figure, proceedings of Quark Matter 2015
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1601.00887 [pdf]
NPA(2016)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE