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Nuclear Theory·nucl-th

Monday·November 26, 2018

20 papers—15 primary·5 cross-listed

All20Primary15Cross-lists5
  1. 16

    Second-Order Leptonic Radiative Corrections for Lepton-Proton Scattering

    R.-D. Bucoveanu🇩🇪 · H. Spiesberger🇩🇪

    The interpretation of high-precision lepton-nucleon scattering experiments requires the knowledge of higher-order radiative corrections. We present a calculation of the cross section for unpolarized lepton-proton scattering including leptonic radiative corrections up to second order, including one- and two-loop corrections, radiation of one and two photons and one-loop corrections for one-photon radiation. Numerical results are given for the planned P2 experiment at the MESA facility in Mainz, and some results are also discussed for Qweak and the suggested MUSE experiment.

    ↳ hep-phnucl-thEPJA(2019)·34 citations
  2. 17

    Hypermassive Neutron Star Disk Outflows and Blue Kilonovae

    Steven Fahlman · Rodrigo Fernández

    We study mass ejection from accretion disks around newly-formed hypermassive neutron stars (HMNS). Standard kilonova model fits to GW170817 require at least a lanthanide-poor ('blue') and lanthanide-rich ('red') component. The existence of a blue component has been used as evidence for a HMNS remnant of finite lifetime, but average disk outflow velocities from existing long-term HMNS simulations fall short of the inferred value () by a factor of . Here we use time-dependent, axisymmetric hydrodynamic simulations of HMNS disks to explore the limits of the model and its ability to account for observations. For physically plausible parameter choices compatible with GW170817, we find that hydrodynamic models that use shear viscosity to transport angular momentum cannot eject matter with mass-averaged velocities larger than . While outflow velocities in our simulations can exceed the asymptotic value for a steady-state neutrino-driven wind, the increase in the average velocity due to viscosity is not sufficient. Therefore, viscous HMNS disk winds cannot reproduce by themselves the ejecta properties inferred from multi-component fits to kilonova light curves from GW170817. Three possible resolutions remain feasible within standard merger ejecta channels: more sophisticated radiative transfer models that allow for photon reprocessing between ejecta components, inclusion of magnetic stresses, or enhancement of the dynamical ejecta. We provide fits to our disk outflow models once they reach homologous expansion.

    ↳ astro-ph.HEastro-ph.SRgr-qcnucl-thApJL(2018)·49 citations
  3. 18

    Model-independent femtoscopic Levy imaging for elastic proton-proton scattering

    T. Csorgo🇨🇭 · R. Pasechnik🇸🇪 · A. Ster🇭🇺

    A model independent Levy expansion method is introduced to describe nearly Levy shaped squared moduli of Fourier transforms. We apply this method to precisely characterize the most recent elastic scattering data of proton-proton collisions at TeV. The results reveal a substructure of protons, which is found to be significantly larger and darker in high energy proton-proton collisions at the TeV scale, as compared to a rather faint and apparently overlooked sub-structure, that we also identify in elastic proton-proton scattering at the ISR energy range of GeV.

    ↳ hep-phhep-exnucl-exnucl-th+1Phys.Part.Nucl.(2020)·8 citations
  4. 19

    Exclusive and photoproduction in ultraperipheral collisions: Predictions of the gluon saturation models for the momentum transfer distributions

    V. P. Goncalves🇧🇷 · F. S. Navarra🇧🇷 · D. Spiering🇧🇷

    In this letter we complement previous studies on exclusive vector meson photoproduction in hadronic collisions presenting a comprehensive analysis of the - spectrum measured in exclusive and photoproduction in collisions at the LHC. We compute the differential cross sections considering two phenomenological models for the gluon saturation effects and present predictions for and collisions. Moreover, we compare our predictions with the recent preliminary CMS data for the exclusive photoproduction. We demonstrate that the gluon saturation models are able to describe the CMS data at small - . On the other hand, the models underestimate the few data point at large -- . Our results indicate that future measurements of the large -- region can be useful to probe the presence or absence of a dip in the -- spectrum and discriminate between the different approaches to the gluon saturation effects.

    ↳ hep-phhep-exnucl-thPLB(2019)·32 citations
  5. 20

    Centrality and Transverse momentum dependencies of Hadrons in Xe+Xe collisions at TeV from a multi-phase transport model

    Lilin Zhu🇨🇳 · Hua Zheng🇨🇳 · Ruimin Kong

    In this paper, we study and predict the charged-particle pseudorapidity multiplicity density (), transverse momentum spectra of identified particles and their ratios in relativistic heavy ion collisions at the Large Hadron Collider (LHC), using the string-melting version of a multi-phase transport (AMPT) model with improved quark coalescence method. Results of the charged-particle pseudorapidity multiplicity density from AMPT model calculations for Pb+Pb collisions at TeV are compared with the experimental data. Good agreements are generally found between theoretical calculations and experimental data. We predict for Xe+Xe collisions at TeV at different centralities, and spectra of charged pions, kaons and protons, and their ratios and in Pb+Pb collisions at TeV and Xe+Xe collisions at TeV that are being studied at LHC. The spectra of identified particles in Pb+Pb collisions from the improved AMPT model are compared and found to be consistent with results from the iEBE-VISHNU hybrid model with TRENTo initial condition.

    ↳ hep-phnucl-thEPJA(2019)·12 citations

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first authorsco-authorsvia INSPIRE