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Nuclear Theory·nucl-th

Thursday·July 30, 2020

9 papers—3 primary·6 cross-listed

All9Primary3Cross-lists6
  1. 04

    [Submitted on 28 Jul 2020] (cross-list from hep-ph)

    QCD resummation on single hadron transverse momentum distribution with the thrust axis

    Zhong-Bo Kang🇺🇸 · Ding Yu Shao🇺🇸 · Fanyi Zhao🇺🇸

    We derive the transverse momentum dependent (TMD) factorization and resummation formula of the unpolarized transverse momentum distribution () for the single hadron production with the thrust axis in electron-positron collision. Two different kinematic regions are considered, including small transverse momentum limit , and joint transverse momentum and threshold limit , where and are the hard scattering energy and the observed hadron momentum fraction. Using effective theory methods, we resum logarithms and to all orders. In the end we present the differential cross sections and Gaussian widths calculated for the inclusive charged pion production and find that our results are consistent with the measurements reported by the Belle collaboration.

    Comments:
    25 pages, 5 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2007.14425 [pdf]
    JHEP(2020)·28 citations
  2. 05

    [Submitted on 28 Jul 2020] (cross-list from hep-ex)

    The Large Hadron-Electron Collider at the HL-LHC

    P. Agostini🇪🇸 · H. Aksakal🇹🇷 · S. Alekhin🇩🇪 · P. P. Allport🇬🇧 · N. Andari🇫🇷 · K. D. J. Andre🇬🇧 · D. Angal-Kalinin🇬🇧 · S. Antusch🇨🇭 · L. Aperio Bella🇨🇳 · L. Apolinario🇵🇹 · R. Apsimon🇬🇧 · A. Apyan🇦🇲 and 325 other authors

    The Large Hadron electron Collider (LHeC) is designed to move the field of deep inelastic scattering (DIS) to the energy and intensity frontier of particle physics. Exploiting energy recovery technology, it collides a novel, intense electron beam with a proton or ion beam from the High Luminosity--Large Hadron Collider (HL-LHC). The accelerator and interaction region are designed for concurrent electron-proton and proton-proton operation. This report represents an update of the Conceptual Design Report (CDR) of the LHeC, published in 2012. It comprises new results on parton structure of the proton and heavier nuclei, QCD dynamics, electroweak and top-quark physics. It is shown how the LHeC will open a new chapter of nuclear particle physics in extending the accessible kinematic range in lepton-nucleus scattering by several orders of magnitude. Due to enhanced luminosity, large energy and the cleanliness of the hadronic final states, the LHeC has a strong Higgs physics programme and its own discovery potential for new physics. Building on the 2012 CDR, the report represents a detailed updated design of the energy recovery electron linac (ERL) including new lattice, magnet, superconducting radio frequency technology and further components. Challenges of energy recovery are described and the lower energy, high current, 3-turn ERL facility, PERLE at Orsay, is presented which uses the LHeC characteristics serving as a development facility for the design and operation of the LHeC. An updated detector design is presented corresponding to the acceptance, resolution and calibration goals which arise from the Higgs and parton density function physics programmes. The paper also presents novel results on the Future Circular Collider in electron-hadron mode, FCC-eh, which utilises the same ERL technology to further extend the reach of DIS to even higher centre-of-mass energies.

    Comments:
    373 pages, many figures, to be published by J. Phys. G
    Subjects:
    High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2007.14491 [pdf]
    J.Phys.G(2021)·441 citations
  3. 06

    [Submitted on 29 Jul 2020] (cross-list from hep-ph)

    Full resummation analysis of jet quenching and tests of the QCD Equation of State

    Xabier Feal🇺🇸

    Jet quenching has become a fundamental tool to study the hot QCD matter produced in heavy ion collisions. While important theoretical and experimental advances have been made in the last two decades, the extraction of the medium properties and the comparison with finite temperature QCD is still particularly worrisome. In this work we show that improvements in the calculation of the medium-induced gluon spectrum are required for a correct extraction of the parameters without temperature issues. In particular, we employ an improved numerical implementation of multiple hard scatterings that resums all terms in the opacity expansion beyond the Gaussian approximation. We find significant differences in the extracted medium parameters when comparing with two of the most used approximations in phenomenological analyses to date, the first order opacity expansion and the Gaussian approximation. We also make a first attempt to compare the extracted medium parameters with lattice results.

    Comments:
    7 pages, 2 figures; 10th International Conference on Hard and Electromagnetic Probes of High-Energy Nuclear Collisions
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2007.14834 [pdf]
    PoS(2021)·0 citations
  4. 07

    [Submitted on 29 Jul 2020] (cross-list from hep-ph)

    Neutrinoless Double-Electron Capture

    K. Blaum🇩🇪 · S. Eliseev🇩🇪 · F. A. Danevich🇺🇦 · V. I. Tretyak🇺🇦 · Sergey Kovalenko🇨🇱 · M. I. Krivoruchenko🇷🇺 · Yu. N. Novikov🇷🇺 · J. Suhonen🇫🇮

    Double-beta processes play a key role in the exploration of neutrino and weak interaction properties, and in the searches for effects beyond the Standard Model. During the last half century many attempts were undertaken to search for double-beta decay with emission of two electrons, especially for its neutrinoless mode (), the latter being still not observed. Double-electron capture (2EC) was not in focus so far because of its in general lower transition probability. However, the rate of neutrinoless double-electron capture (EC) can experience a resonance enhancement by many orders of magnitude in case the initial and final states are energetically degenerate. In the resonant case, the sensitivity of the EC process can approach the sensitivity of the decay in the search for the Majorana mass of neutrinos, right-handed currents, and other new physics. We present an overview of the main experimental and theoretical results obtained during the last decade in this field. The experimental part outlines search results of 2EC processes and measurements of the decay energies for possible resonant 2EC transitions. An unprecedented precision in the determination of decay energies with Penning traps has allowed one to refine the values of the degeneracy parameter for all previously known near-resonant decays and has reduced the rather large uncertainties in the estimate of the EC half-lives. The theoretical part contains an updated analysis of the electron shell effects and an overview of the nuclear structure models, in which the nuclear matrix elements of the EC decays are calculated. One can conclude that the decay probability of 2EC can experience a significant enhancement in several nuclides.

    Comments:
    68 pages, 14 tables, 19 figures, accepted for publication in Reviews of Modern Physics
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th); Atomic Physics (physics.atom-ph)
    arXiv:
    2007.14908 [pdf]
    RMP(2020)·68 citations
  5. 08

    [Submitted on 29 Jul 2020] (cross-list from hep-ph)

    Photon radiation from quark-gluon plasma by means of chiral anomalies without magnetic field

    Kirill Tuchin🇺🇸

    We discuss a new channel of photon emission from the quark-gluon plasma, which opens up as photon acquires a tachyonic mass in the presence of the CP-odd topological domains generated by the chiral anomaly. It allows photon radiation through the decay and annihilation processes closely related to the chiral Cherenkov radiation. Unlike previous proposals this mechanism does not require an external magnetic field. The differential photon emission rate per unit volume is computed and shown to be comparable to the rate of photon emission in conventional processes.

    Comments:
    contribution to the "10th International Conference on Hard and Electromagnetic Probes of High-Energy Nuclear Collisions"
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2007.14939 [pdf]
    PoS(2021)·0 citations
  6. 09

    [Submitted on 29 Jul 2020] (cross-list from hep-ph)

    Dynamics of QCD Matter -- current status

    Amaresh Jaiswal🇮🇳 · Najmul Haque🇮🇳 · Aman Abhishek🇮🇳 · Raktim Abir🇮🇳 · Aritra Bandyopadhyay🇧🇷 · Khatiza Banu🇮🇳 · Samapan Bhadury🇮🇳 · Sumana Bhattacharyya🇮🇳 · Trambak Bhattacharyya🇷🇺 · Deeptak Biswas🇮🇳 · H. C. Chandola🇮🇳 · Vinod Chandra🇮🇳 and 49 other authors

    In this article, there are 18 sections discussing various current topics in the field of relativistic heavy-ion collisions and related phenomena, which will serve as a snapshot of the current state of the art. Section 1 reviews experimental results of some recent light-flavored particle production data from ALICE collaboration. Other sections are mostly theoretical in nature. Very strong but transient magnetic field created in relativistic heavy-ion collisions could have important observational consequences. This has generated a lot of theoretical activity in the last decade. Sections 2, 7, 9, 10 and 11 deal with the effects of the magnetic field on the properties of the QCD matter. There are several unanswered questions about the QCD phase diagram. Sections 3, 11 and 18 discuss various aspects of the QCD phase diagram and phase transitions. Recent years have witnessed interesting developments in foundational aspects of hydrodynamics and their application to heavy-ion collisions. Sections 12, 15, 16 and 17 of this article probe some aspects of this exciting field. Transport coefficients together with their temperature- and density-dependence, are essential inputs in hydrodynamical calculations. Sections 5, 8 and 14 deal with calculation/estimation of various transport coefficients (shear and bulk viscosity, thermal conductivity, relaxation times, etc.) of quark matter and hadronic matter. Sections 4, 6 and 13 deals with interesting new developments in the field. Section 4 discusses color dipole gluon distribution function at small transverse momentum in the form of a series of Bells polynomials. Section 6 discusses the properties of Higgs boson in the quark gluon plasma using Higgs-quark interaction. Section 13 discusses modification of coalescence model to incorporate viscous corrections and application of this model.

    Comments:
    109 pages, 49 captioned figures, compilation of the contributions as presented in the `Workshop on Dynamics of QCD Matter', 15th to 17th August 2019, NISER Bhubaneswar, India, published version
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
    arXiv:
    2007.14959 [pdf]
    IJMPE(2021)·39 citations

Affiliations

first authorsco-authorsvia INSPIRE