PaperPanorama
FAQ

Nuclear Theory·nucl-th

Tuesday·March 13, 2018

15 papers—8 primary·7 cross-listed

All15Primary8Cross-lists7
  1. 09

    [Submitted on 9 Mar 2018] (cross-list from hep-ph)

    The groomed and ungroomed jet mass distribution for inclusive jet production at the LHC

    Zhong-Bo Kang🇺🇸 · Kyle Lee🇺🇸 · Xiaohui Liu🇨🇳 · Felix Ringer🇺🇸

    We study jet mass distributions measured in the single inclusive jet production in proton-proton collisions at the LHC. We consider both standard ungroomed jets as well as soft drop groomed jets. Within the Soft Collinear Effective Theory (SCET), we establish QCD factorization theorems for both cases and we study their relation. The developed framework allows for the joint resummation of several classes of logarithmic corrections to all orders in the strong coupling constant. For the ungroomed case, we resum logarithms in the jet radius parameter and in the small jet mass. For the groomed case, we resum in addition the logarithms in the soft threshold parameter which is introduced by the soft drop grooming algorithm. In this way, we are able to reliably determine the absolute normalization of the groomed jet mass distribution in proton-proton collisions. All logarithmic corrections are resummed to the next-to-leading logarithmic accuracy. We present numerical results and compare with the available data from the LHC. For both the groomed and ungroomed jet mass distributions we find very good agreement after including non-perturbative corrections.

    Comments:
    38 pages, 9 figures, published version
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1803.03645 [pdf]
    JHEP(2018)·64 citations
  2. 10

    [Submitted on 10 Mar 2018] (cross-list from astro-ph.HE)

    Nuclear Reactions in the Crusts of Accreting Neutron Stars

    R. Lau · M. Beard · S. S. Gupta · H. Schatz · A. V. Afanasjev · E. F. Brown · A. Deibel · L. R. Gasques · G. W. Hitt · W. R. Hix · L. Keek · P. Möller and 4 other authors

    X-ray observations of transiently accreting neutron stars during quiescence provide information about the structure of neutron star crusts and the properties of dense matter. Interpretation of the observational data requires an understanding of the nuclear reactions that heat and cool the crust during accretion, and define its nonequilibrium composition. We identify here in detail the typical nuclear reaction sequences down to a depth in the inner crust where the mass density is 2E12 g/cm^3 using a full nuclear reaction network for a range of initial compositions. The reaction sequences differ substantially from previous work. We find a robust reduction of crust impurity at the transition to the inner crust regardless of initial composition, though shell effects can delay the formation of a pure crust somewhat to densities beyond 2E12 g/cm^3. This naturally explains the small inner crust impurity inferred from observations of a broad range of systems. The exception are initial compositions with A >= 102 nuclei, where the inner crust remains impure with an impurity parameter of Qimp~20 due to the N = 82 shell closure. In agreement with previous work we find that nuclear heating is relatively robust and independent of initial composition, while cooling via nuclear Urca cycles in the outer crust depends strongly on initial composition. This work forms a basis for future studies of the sensitivity of crust models to nuclear physics and provides profiles of composition for realistic crust models.

    Comments:
    25 Pages, accepted for publication in Ap. J
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
    arXiv:
    1803.03818 [pdf]
    ApJ(2018)·73 citations
  3. 11

    [Submitted on 10 Mar 2018] (cross-list from hep-ph)

    Exploring the hadron resonance gas phase on the QCD phase diagram

    Subhasis Samanta🇮🇳 · Sandeep Chatterjee🇵🇱 · Bedangadas Mohanty🇮🇳

    Lattice computations of strongly interacting matter at finite temperature and baryon chemical potential suggest that the QCD thermodynamics deep in the hadronic phase can be adequately modeled by an ideal hadron resonance gas (I-HRG). However, it is not clear where on the plane this description breaks down, making it essential to account for hadronic interactions and change in the nature of the degrees of freedom. We have studied several thermodynamic functions within the I-HRG model and try to identify the region of the QCD phase diagram where it becomes essential to include non-ideal effects into the I-HRG model. We work with only those thermodynamic quantities that show a monotonic rise with and in I-HRG. Their high temperature limiting values where QCD becomes simply a Stefan-Boltzmann (SB) gas of massless quarks and gluons is known. The rise of these quantities in I-HRG beyond the corresponding SB limit values indicate the need to include interactions into I-HRG to study QCD thermodynamics. This works as a guiding principle on the QCD phase diagram where interacting HRG can take over from I-HRG. For , shoots the SB limit at the smallest , while for higher values of , takes over. We further comment on the relative positions between the freezeout curve obtained by thermal fits to the measured hadron yields and the obtained line where I-HRG overshoots SB limit.

    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1803.03844 [pdf]
    J.Phys.G(2019)·7 citations
  4. 12

    [Submitted on 11 Mar 2018] (cross-list from hep-ph)

    Target-normal single-spin asymmetry in elastic electron-nucleon scattering

    Oleksandr Koshchii🇺🇸 · Andrei Afanasev🇺🇸

    We estimate the target-normal single-spin asymmetry at nearly forward angles in elastic electron-nucleon scattering. In the leading-order approximation, this asymmetry is proportional to the imaginary part of the two-photon exchange (TPE) amplitude, which can be expressed as an integral over the doubly virtual Compton scattering (VVCS) tensor. We develop a model that parametrizes the VVCS tensor for the case of nearly forward scattering angles. Our parametrization ensures a proper normalization of the imaginary part of the TPE amplitude on the well-known forward limit expression, which is given in terms of nucleon structure functions measurable in inelastic electron-nucleon scattering experiments. We discuss applicability limits of our theory and provide target-normal single-spin asymmetry predictions for both elastic electron-proton and electron-neutron scattering.

    Comments:
    14 pages, 6 figures; v2: contains extended discussions, results are unchanged; v3: minor changes, matches published version; v4: corrected Fig. 5
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1803.04004 [pdf]
    PRD(2018)·16 citations
  5. 13

    [Submitted on 12 Mar 2018] (cross-list from hep-ph)

    Electromagnetic form factors of singly heavy baryons in the self-consistent SU(3) chiral quark-soliton model

    June-Young Kim🇰🇷 · Hyun-Chul Kim🇰🇷

    The self-consistent chiral quark-soliton model is a relativistic pion mean-field approach in the large limit, which describes both light and heavy baryons on an equal footing. In the limit of the infinitely heavy mass of the heavy quark, a heavy baryon can be regarded as valence quarks bound by the pion mean fields, leaving the heavy quark as a color static source. The structure of the heavy baryon in this scheme is mainly governed by the light-quark degrees of freedom. Based on this framework, we evaluate the electromagnetic form factors of the lowest-lying heavy baryons. The rotational and strange current quark mass corrections in linear order are considered. We discuss the electric charge and magnetic densities of heavy baryons in comparison with those of the nucleons. The results of the electric charge radii of the positive-charged heavy baryons show explicitly that the heavy baryon is a compact object. The electric form factors are presented. The form factor of is compared with that from a lattice QCD. We also discuss the results of the magnetic form factors. The magnetic moments of the baryon sextet with spin 1/2 and the magnetic radii are compared with other works and the lattice data.

    Comments:
    21 pages, 13 figures. The version which will appear in Physical Review 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:
    1803.04069 [pdf]
    PRD(2018)·52 citations
  6. 14

    [Submitted on 12 Mar 2018] (cross-list from hep-ph)

    Characterization of quark gluon plasma as seen through the energy loss of heavy quarks

    Ashik Ikbal Sheikh🇮🇳 · Zubayer Ahammed🇮🇳

    The shear viscosity to entropy density ratio ({\eta}/s) of quark gluon plasma produced in ultra- relativistic heavy-ion collisions has been studied from the energy loss of heavy quarks in QGP medium. We have also studied the bulk viscosity to entropy density ratio ({\zeta}/s) and fluidity measure(F) of the medium using the obtained {\eta}/s values. In addition to that, we have estimated the heavy quark bound state potential (V) inside this medium. Our finding of {\eta}/s agrees well with the results obtained by Lattice QCD (LQCD) and functional renormalization group technique.

    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1803.04123 [pdf]
    0 citations
  7. 15

    [Submitted on 12 Mar 2018] (cross-list from hep-lat)

    Lattice Calculation of Parton Distribution Function from LaMET at Physical Pion Mass with Large Nucleon Momentum

    Jiunn-Wei Chen🇹🇼 · Luchang Jin🇺🇸 · Huey-Wen Lin🇺🇸 · Yu-Sheng Liu🇨🇳 · Yi-Bo Yang🇺🇸 · Jian-Hui Zhang🇩🇪 · Yong Zhao🇺🇸

    We present a lattice-QCD calculation of the unpolarized isovector parton distribution function (PDF) using ensembles at the physical pion mass with large proton boost momenta ~GeV within the framework of large-momentum effective theory (LaMET). In contrast to our previous physical-pion PDF result, we increase the statistics significantly, double the boost momentum, increase the investment in excited-state contamination systematics, and switch to operator to avoid mixing with scalar matrix elements. We use four source-sink separations in our analysis to control the systematics associated with excited-state contamination. The one-loop LaMET matching corresponding to the new operator is calculated and applied to our lattice data. We detail the systematics that affect PDF calculations, providing guidelines to improve the precision of future lattice PDF calculations. We find our final parton distribution to be in reasonable agreement with the PDF provided by the latest phenomenological analysis.

    Comments:
    6 pages, 4 figures
    Subjects:
    High Energy Physics — Lattice (hep-lat); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1803.04393 [pdf]
    110 citations

Affiliations

first authorsco-authorsvia INSPIRE