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Nuclear Theory·nucl-th

Wednesday·May 16, 2018

7 papers—4 primary·3 cross-listed

All7Primary4Cross-lists3
  1. 01

    [Submitted on 15 May 2018]

    Chemical potentials of light flavor quarks from yield ratios of negative to positive particles in Au+Au collisions at RHIC

    Ya-Qin Gao🇨🇳 · Hai-Ling Lao🇨🇳 · Fu-Hu Liu🇨🇳

    The transverse momentum spectra of , , , , , and produced in Au+Au collisions at center-of-mass energy , 11.5, 19.6, 27, 39, 62.4, 130, and GeV are analyzed in the framework of a multisource thermal model. The experimental data measured at midrapidity by the STAR Collaboration are fitted by the (two-component) standard distribution. The effective temperature of emission source increases obviously with the increase of the particle mass and the collision energy. At different collision energies, the chemical potentials of up, down, and strange quarks are obtained from the antiparticle to particle yield ratios in given transverse momentum ranges available in experiments. With the increase of logarithmic collision energy, the chemical potentials of light flavor quarks decrease exponentially.

    Comments:
    9 pages, 2 figures. Advances in High Energy Physics, accepted
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    1805.05512 [pdf]
    Adv.High Energy Phys.(2018)·4 citations
  2. 02

    [Submitted on 15 May 2018]

    Nuclear EMC effect through production in semi-inclusive deep-inelastic scattering processes

    Chang Gong🇨🇳 · Bo-Qiang Ma🇨🇳

    We calculate and hadron production cross sections in charged lepton semi-inclusive deep-inelastic scattering off nuclear target (, using iron as an example) and deuteron () target. The results show that the ratio is sensitive to the sea quark content of the nucleus. We adopt three different models to take the nuclear EMC effect into account. The ratio is predicted to be different by these different models.

    Comments:
    9 pages, 10 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1805.05544 [pdf]
    PRC(2018)·3 citations
  3. 03

    [Submitted on 11 May 2018]

    Neutrino Emissivity in the Quark-Hadron Mixed Phase

    William M. Spinella🇺🇸 · Fridolin Weber🇺🇸 · Milva G. Orsaria🇦🇷 · Gustavo A. Contrera🇦🇷

    In this work we investigate the effect a crystalline quark-hadron mixed phase can have on the neutrino emissivity from the cores of neutron stars. To this end we use relativistic mean-field equations of state to model hadronic matter and a nonlocal extension of the three-flavor Nambu-Jona-Lasinio model for quark matter. Next we determine the extent of the quark-hadron mixed phase and its crystalline structure using the Glendenning construction, allowing for the formation of spherical blob, rod, and slab rare phase geometries. Finally we calculate the neutrino emissivity due to electron-lattice interactions utilizing the formalism developed for the analogous process in neutron star crusts. We find that the contribution to the neutrino emissivity due to the presence of a crystalline quark-hadron mixed phase is substantial compared to other mechanisms at fairly low temperatures ( K) and quark fractions (), and that contributions due to lattice vibrations are insignificant compared to static-lattice contributions. There are a number of open issues that need to be addressed in a future study on the neutrino emission rates caused by electron-quark blob bremsstrahlung. Chiefly among them are the role of collective oscillations of matter, electron band structures, and of gaps at the boundaries of the Brillouin zones on bremsstrahlung, as discussed in the summary section of this paper. We hope this paper will stimulate studies addressing these issues.

    Comments:
    14 pages, 9 figures, A special issue of Universe (ISSN 2218-1997): "Compact Stars in the QCD Phase Diagram". arXiv admin note: substantial text overlap with arXiv:1507.06067
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    1805.05772 [pdf]
    Universe(2018)·12 citations
  4. 04

    [Submitted on 15 May 2018]

    Coherent deeply virtual Compton scattering off He

    Sara Fucini🇮🇹 · Sergio Scopetta🇮🇹 · Michele Viviani🇮🇹

    Coherent Deeply virtual Compton scattering off the He nucleus is studied in impulse approximation. A convolution formula for the nuclear Generalized Parton Distribution (GPD) is derived in terms of the He non-diagonal spectral function and of the GPD of the struck nucleon. A model of the nuclear non diagonal spectral function, based on the momentum distribution corresponding to the AV18 nucleon-nucleon interaction, is used in the actual calculation. Typical impulse approximation results are reproduced, in proper limits, for the nuclear form factor and for nuclear parton distributions. The nuclear generalized parton distribution and the Compton form factor are evaluated using, as nucleonic ingredient, a well known generalized parton distribution model. An overall very good agreement is found with the data recently published by the EG6 experiment at the Jefferson Laboratory (JLab). More refined nuclear calculations are addressed and will be necessary for the expected improved accuracy of the next generation of experiments at JLab, with the 12 GeV electron beam and high luminosity.

    Comments:
    11 pages, 9 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    1805.05877 [pdf]
    PRC(2018)·23 citations
  5. 05

    [Submitted on 14 May 2018] (cross-list from astro-ph.HE)

    Effects of thermonuclear X-ray bursts on non-burst emissions in the soft state of 4U 1728--34

    Sudip Bhattacharyya (TIFR, India) · J. S. Yadav (TIFR, India) · Navin Sridhar (IISER-Bhopal, India) · Jai Verdhan Chauhan (TIFR, India) · P. C. Agrawal (CEBS, India) · H. M. Antia (TIFR, India) · Mayukh Pahari (University of Southampton, UK) · Ranjeev Misra (IUCAA, India) · Tilak Katoch (TIFR, India) · R. K. Manchanda (University of Mumbai, India) · Biswajit Paul (RRI, India)

    It has recently been shown that the persistent emission of a neutron star low-mass X-ray binary (LMXB) evolves during a thermonuclear (type-I) X-ray burst. The reason of this evolution, however, is not securely known. This uncertainty can introduce significant systematics in the neutron star radius measurement using burst spectra, particularly if an unknown but significant fraction of the burst emission, which is reprocessed, contributes to the changes in the persistent emission during the burst. Here, by analyzing individual burst data of AstroSat/LAXPC from the neutron star LMXB 4U 1728--34 in the soft state, we show that the burst emission is not significantly reprocessed by a corona covering the neutron star. Rather, our analysis suggests that the burst emission enhances the accretion disk emission, possibly by increasing the accretion rate via disk. This enhanced disk emission, which is Comptonized by a corona covering the disk, can explain an increased persistent emission observed during the burst. This finding provides an understanding of persistent emission components, and their interaction with the thermonuclear burst emission. Furthermore, since burst photons are not significantly reprocessed, non-burst and burst emissions can be reliably separated, which is required to reduce systematic uncertainties in the stellar radius measurement.

    Comments:
    8 pages, 3 tables, 1 figure, accepted for publication in The Astrophysical Journal
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
    arXiv:
    1805.05393 [pdf]
    ApJ(2018)·16 citations
  6. 06

    [Submitted on 15 May 2018] (cross-list from hep-ph)

    Forward di-hadron back-to-back correlations in collisions from rcBK evolution

    Javier L. Albacete🇪🇸 · Giuliano Giacalone🇫🇷 · Cyrille Marquet🇫🇷 · Marek Matas🇨🇿

    We study the disappearance of the away-side peak of the di-hadron correlation function in p+A vs p+p collisions at forward rapidities, when the scaterring process presents a manifest dilute-dense asymmetry. We improve the state-of-the-art description of this phenomenon in the framework of the Color Glass Condensate (CGC), for hadrons produced nearly back-to-back. In that case, the gluon content of the saturated nuclear target can be described with transverse-momentum-dependent gluon distributions, whose small- evolution we calculate numerically by solving the Balitsky-Kovchegov equation with running coupling corrections. We first show that our formalism provides a good description of the disappearance of the away-side azimuthal correlations in d+Au collisions observed at BNL Relativistic Heavy Ion Collider (RHIC) energies. Then, we predict the away-side peak of upcoming p+Au data at GeV to be suppressed by about a factor 2 with respect to p+p collisions, and we propose to study the rapidity dependence of that suppression as a complementary strong evidence of gluon saturation in experimental data.

    Comments:
    13 pages; 6 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1805.05711 [pdf]
    PRD(2019)·74 citations
  7. 07

    [Submitted on 15 May 2018] (cross-list from nucl-ex)

    Deuteron analysing powers in deuteron-proton elastic scattering at 1.2 and 2.27 GeV

    D.Mchedlishvili🇬🇪 · Z.Bagdasarian🇬🇪 · S.Barsov🇷🇺 · S.Dymov🇩🇪 · R.Engels🇩🇪 · R.Gebel🇩🇪 · K.Grigoryev🇩🇪 · J.Haidenbauer🇩🇪 · M.Hartmann🇩🇪 · A.Kacharava🇩🇪 · I.Keshelashvili🇩🇪 · A.Khoukaz🇩🇪 and 22 other authors

    The vector and tensor analysing powers in deuteron-proton elastic scattering have been measured in the forward hemisphere at deuteron kinetic energies of 1.2 GeV and 2.27 GeV using the ANKE spectrometer at the COSY storage ring. The results are compared with other experimental data and with predictions made within the framework of Glauber multiple scattering theory.

    Comments:
    11 pages with 8 figures. To be submitted for publication
    Subjects:
    Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1805.05778 [pdf]
    NPA(2018)·8 citations

Affiliations

first authorsco-authorsvia INSPIRE