Nuclear Theory·nucl-th

Friday·September 11, 2015

14 papers—6 primary·8 cross-listed

07
[Submitted on 9 Sept 2015] (cross-list from hep-ph)
Quasiparticle equation of state for anisotropic hydrodynamics
Mubarak Alqahtani🇺🇸 · Mohammad Nopoush🇺🇸 · Michael Strickland🇺🇸
We present a new method for imposing a realistic equation of state in anisotropic hydrodynamics. The method relies on the introduction of a single finite-temperature quasiparticle mass which is fit to lattice data. By taking moments of the Boltzmann equation, we obtain a set of coupled partial differential equations which can be used to describe the 3+1d spacetime evolution of an anisotropic relativistic system. We then specialize to the case of a 0+1d system undergoing boost-invariant Bjorken expansion and subject to the relaxation-time approximation collisional kernel. Using this setup, we compare results obtained using the new quasiparticle equation of state method with those obtained using the standard method for imposing the equation of state in anisotropic hydrodynamics. We demonstrate that the temperature evolution obtained using the two methods is nearly identical and that there are only small differences in the pressure anisotropy. However, we find that there are significant differences in the evolution of the bulk pressure correction.
Comments:
40 pages, 6 figures; v2 - published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1509.02913 [pdf]
PRC(2015)·75 citations
08
[Submitted on 9 Sept 2015] (cross-list from astro-ph.HE)
Data Selection Criteria for Spectroscopic Measurements of Neutron Star Radii with X-ray Bursts
Feryal Ozel · Dimitrios Psaltis · Tolga Guver
Data selection and the determination of systematic uncertainties in the spectroscopic measurements of neutron star radii from thermonuclear X-ray bursts have been the subject of numerous recent studies. In one approach, the uncertainties and outliers were determined by a data-driven Bayesian mixture model, whereas in a second approach, data selection was performed by requiring that the observations follow theoretical expectations. We show here that, due to inherent limitations in the data, the theoretically expected trends are not discernible in the majority of X-ray bursts even if they are present. Therefore, the proposed theoretical selection criteria are not practical with the current data for distinguishing clean data sets from outliers. Furthermore, when the data limitations are not taken into account, the theoretically motivated approach selects a small subset of bursts with properties that are in fact inconsistent with the underlying assumptions of the method. We conclude that the data-driven selection methods do not suffer from the limitations of this theoretically motivated one.
Comments:
Submitted to ApJ
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
arXiv:
1509.02924 [pdf]
4 citations
09
[Submitted on 9 Sept 2015] (cross-list from hep-ph)
Jet Quenching from QCD Evolution
Yang-Ting Chien🇺🇸 · Alexander Emerman🇺🇸 · Zhong-Bo Kang🇺🇸 · Grigory Ovanesyan🇺🇸 · Ivan Vitev🇺🇸
Recent advances in soft-collinear effective theory with Glauber gluons have led to the development of a new method that gives a unified description of inclusive hadron production in reactions with nucleons and heavy nuclei. We show how this approach, based on the generalization of the DGLAP evolution equations to include final-state medium-induced parton showers, can be combined with initial-state effects for applications to jet quenching phenomenology. We demonstrate that the traditional parton energy loss calculations can be regarded as a special soft-gluon emission limit of the general QCD evolution framework. We present phenomenological comparison of the SCET $_{G}$ -based results on the suppression of inclusive charged hadron and neutral pion production in $s_{N N} = 2.76$ TeV lead-lead collisions at the Large Hadron Collider to experimental data. We also show theoretical predictions for the upcoming $s_{N N} ≃ 5.1$ TeV Pb+Pb run at the LHC.
Comments:
21 pages 6 figures; appendix, figure and references added
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1509.02936 [pdf]
PRD(2016)·142 citations
10
[Submitted on 9 Sept 2015] (cross-list from hep-ph)
Multi-particle long-range rapidity correlations from fluctuation of the fireball longitudinal shape
Adam Bzdak🇵🇱 · Piotr Bozek🇵🇱
We calculate the genuine long-range multi-particle rapidity correlation functions, $C_{n} (y_{1}, ..., y_{n})$ for $n = 3, 4, 5, 6$ , originating from fluctuations of the fireball longitudinal shape. In these correlation functions any contribution from the short-range two-particle correlations, and in general up to $(n - 1)$ -particle in $C_{n}$ , is suppressed. The information about the fluctuating fireball shape in rapidity is encoded in the cumulants of coefficients of the orthogonal polynomial expansion of particle distributions in rapidity.
Comments:
8 pages
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
1509.02967 [pdf]
PRC(2016)·20 citations
11
[Submitted on 10 Sept 2015] (cross-list from hep-th)
Finite coupling corrections to holographic predictions for hot QCD
Sebastian Waeber🇩🇪 · Andreas Schaefer🇩🇪 · Aleksi Vuorinen🇫🇮 · Laurence G. Yaffe🇺🇸
Finite 't Hooft coupling corrections to multiple physical observables in strongly coupled $N = 4$ supersymmetric Yang-Mills plasma are examined, in an attempt to assess the stability of the expansion in inverse powers of the 't Hooft coupling $λ$ . Observables considered include thermodynamic quantities, transport coefficients, and quasinormal mode frequencies. Although large $λ$ expansions for quasinormal mode frequencies are notably less well behaved than the expansions of other quantities, we find that a partial resummation of higher order corrections can significantly reduce the sensitivity of the results to the value of $λ$ .
Comments:
22 pages, typos fixed, numerics improved
Subjects:
High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
1509.02983 [pdf]
JHEP(2015)·55 citations
12
[Submitted on 10 Sept 2015] (cross-list from hep-ph)
Strong Couplings of Charmed Mesons and Quarkonia
Wolfgang Lucha🇦🇹 · Dmitri Melikhov🇷🇺 · Hagop Sazdjian🇫🇷 · Silvano Simula🇮🇹
We extract the strong coupling constants of three mesons, each of which is composed of either two charm quarks or one charm quark and one light (i.e., $u$ , $d$ , or $s$ ) quark, from the matrix elements for the transitions of two of these mesons induced by appropriate quark currents within the framework of a relativistic dispersion approach to the constituent-quark picture of mesons. Among others, we also analyse the impact of the violation of the SU(3) flavour symmetry by the quark masses. In the case of mesons containing one light quark, we observe, in two respects, discrepancies between our findings and the predictions of QCD sum rules: our strong couplings exceed considerably the ones emerging from QCD sum rules, and, in our approach, the replacement of a light quark by a strange quark entails, in contrast to QCD sum rules, a reduction of the magnitudes of the strong couplings.
Comments:
6 pages, 3 figures, contributed to "The European Physical Society Conference on High Energy Physics - EPS-HEP 2015" (22 - 29 July 2015, Vienna, Austria)
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1509.03089 [pdf]
PoS(2015)·1 citation
13
[Submitted on 10 Sept 2015] (cross-list from hep-ph)
Photon and dilepton spectra from nonlinear QED effects in supercritical magnetic fields induced by heavy-ion collisions
Koichi Hattori🇯🇵 · Kazunori Itakura🇯🇵
We discuss properties of photons in extremely strong magnetic fields induced by the relativistic heavy-ion collisions. We investigate the vacuum birefringence, the real-photon decay, and the photon splitting which are all forbidden in the ordinary vacuum, but become possible in strong magnetic fields. These effects potentially give rise to anisotropies in photon and dilepton spectra.
Comments:
4 pages, 6 figures. Contribution to the proceedings of Hard Probes 2015
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
1509.03217 [pdf]
Nucl.Part.Phys.Proc.(2016)·3 citations
14
[Submitted on 10 Sept 2015] (cross-list from hep-ph)
Hanbury-Brown-Twiss measurements at large rapidity separations, or can we measure the proton radius in p-A collisions?
T. Altinoluk🇪🇸 · N. Armesto🇪🇸 · G. Beuf🇮🇱 · A. Kovner🇺🇸 · M. Lublinsky🇮🇱
We point out that current calculations of inclusive two-particle correlations in p-A collisions based on the Color Glass Condensate approach exhibit a contribution from Hanbury-Brown-Twiss correlations. These HBT correlations are quite distinct from the standard ones, in that they are apparent for particles widely separated in rapidity. The transverse size of the emitter which is reflected in these correlations is the gluonic size of the proton. This raises an interesting possibility of measuring the proton size directly by the HBT effect of particle pairs produced in p-A collisions.
Comments:
11 pages, 3 eps figures; v2: comments, discussions, references and acknowledgements added, conclusions unchanged, final version
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1509.03223 [pdf]
PLB(2016)·35 citations

Affiliations

first authorsco-authorsvia INSPIRE