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Nuclear Theory·nucl-th

Wednesday·September 23, 2020

10 papers—5 primary·5 cross-listed

All10Primary5Cross-lists5
  1. 06

    [Submitted on 21 Sept 2020] (cross-list from hep-ph)

    Analysis of Light Neutrino Exchange and Short-Range Mechanisms in Decay

    Frank F. Deppisch🇬🇧 · Lukas Graf🇩🇪 · Francesco Iachello🇺🇸 · Jenni Kotila🇫🇮

    Neutrinoless double beta decay () is a crucial test for lepton number violation. Observation of this process would have fundamental implications for neutrino physics, theories beyond the Standard Model and cosmology. Focussing on so called short-range operators of and their potential interplay with the standard light Majorana neutrino exchange, we present the first complete calculation of the relevant nuclear matrix elements, performed within the interacting boson model (IBM-2). Furthermore, we calculate the relevant phase space factors using exact Dirac electron wavefunctions, taking into account the finite nuclear size and screening by the electron cloud. The obtained numerical results are presented together with up-to-date limits on the standard mass mechanism and effective short-range operators in the IBM-2 framework. Finally, we interpret the limits in the particle physics scenarios incorporating heavy sterile neutrinos, Left-Right symmetry and R-parity violating supersymmetry.

    Comments:
    54 pages, 10 figures, 14 tables, including appendix, v2 matches published version
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2009.10119 [pdf]
    PRD(2020)·132 citations
  2. 07

    [Submitted on 22 Sept 2020] (cross-list from hep-ph)

    Fully-heavy tetraquarks in strongly interacting medium

    Jiaxing Zhao🇨🇳 · Shuzhe Shi🇨🇦 · Pengfei Zhuang🇨🇳

    We study the properties of fully-heavy tetraquarks at finite temperature and their production in high-energy nuclear collisions. We obtain the masses and wave functions of the exotic hadron states and by solving the four-body Schrödinger equation in vacuum and strongly interacting matter. In vacuum, the tetraquarks are above the corresponding meson-meson mass threshold, and the newly observed exotic state might be a state with quantum number or . In hot medium, the temperature dependence of the tetraquark masses and the dissociation temperatures are calculated. Taking the wave function at finite temperature, we construct the Wigner function for the tetraquark states and calculate, with coalescence mechanism, the production yield and transverse momentum distribution of in heavy-ion collisions at LHC energy. In comparison with nucleon-nucleon collisions, the yield per binary collision is significantly enhanced.

    Comments:
    13 pages, 5 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2009.10319 [pdf]
    PRD(2020)·90 citations
  3. 08

    [Submitted on 22 Sept 2020] (cross-list from hep-ph)

    Medium effects on the electrical and Hall conductivities of a hot and magnetized pion gas

    Pallavi Kalikotay🇮🇳 · Snigdha Ghosh🇮🇳 · Nilanjan Chaudhuri🇮🇳 · Pradip Roy🇮🇳 · Sourav Sarkar🇮🇳

    The electrical and Hall conductivities in a uniform magnetic field are evaluated for an interacting pion gas using the kinetic theory approach within the ambit of relaxation time approximation (RTA). The in-medium cross sections vis-a-vis the relaxation time for scattering are obtained using a one-loop modified thermal propagator for the exchanged and mesons using thermal field theoretic techniques. For higher values of the magnetic field, a monotonic increase of the electrical conductivity with the temperature is observed. However, for a given temperature the conductivity is found to decrease steadily with magnetic field. The Hall conductivity, at lower values of the magnetic field, is found to decrease with temperature more rapidly than the electrical conductivity, whereas at higher values of the magnetic field, a linear increase is seen. Use of the in-medium scattering cross-section is found to produce a significant effect on the temperature dependence of both electrical and Hall conductivities compared to the case where vacuum cross-section is used.

    Comments:
    Version published in Physical Review D
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2009.10493 [pdf]
    PRD(2020)·24 citations
  4. 09

    [Submitted on 22 Sept 2020] (cross-list from nucl-ex)

    PRad-II: A New Upgraded High Precision Measurement of the Proton Charge Radius

    A. Gasparian · H. Gao · D. Dutta · N. Liyanage · E. Pasyuk · D. W. Higinbotham · C. Peng · K. Gnanvo · W. Xiong · X. Bai · the PRad collaboration

    The PRad experiment has credibly demonstrated the advantages of the calorimetric method in e-p scattering experiments to measure the proton root-mean-square (RMS) charge radius with high accuracy. The PRad result, within its experimental uncertainties, is in agreement with the small radius measured in muonic hydrogen spectroscopy experiments and it was a critical input in the recent revision of the CODATA recommendation for the proton charge radius. Consequently, the PRad result is in direct conflict with all modern electron scattering experiments. Most importantly, it is 5.8% smaller than the value from the most precise electron scattering experiment to date, and this difference is about three standard deviations given the precision of the PRad experiment. As the first experiment of its kind, PRad did not reach the highest precision allowed by the calorimetric technique. Here we propose a new (and) upgraded experiment -- PRad-II, which will reduce the overall experimental uncertainties by a factor of 3.8 compared to PRad and address this as yet unsettled controversy in subatomic physics. In addition, PRad-II will be the first lepton scattering experiment to reach the Q^2 range of 10^{-5} GeV^2 allowing a more accurate and robust extraction of the proton charge radius. The muonic hydrogen result with its unprecedented precision (~0.05%) determines the CODATA value of the proton charge radius, hence, it is critical to evaluate possible systematic uncertainties of those experiments, such as the laser frequency calibration that was raised in recent review articles. The PRad-II experiment with its projected total uncertainty of 0.43% could demonstrate whether there is any systematic difference between scattering and muonic hydrogen results. PRad-II will establish a new precision frontier in electron scattering and open doors for future physics opportunities.

    Comments:
    Proposal approved by JLab PAC 48
    Subjects:
    Nuclear Experiment (nucl-ex); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
    arXiv:
    2009.10510 [pdf]
    44 citations
  5. 10

    [Submitted on 22 Sept 2020] (cross-list from hep-ph)

    Global analysis of the Sivers functions at NLO+NNLL in QCD

    Miguel G. Echevarria🇪🇸 · Zhong-Bo Kang🇺🇸 · John Terry🇺🇸

    We perform global fit to the quark Sivers function within the transverse momentum dependent (TMD) factorization formalism in QCD. We simultaneously fit Sivers asymmetry data from Semi-Inclusive Deep Inelastic Scattering (SIDIS) at COMPASS, HERMES, and JLab, from Drell-Yan lepton pair production at COMPASS, and from boson at RHIC. This extraction is performed at next-to-leading order (NLO) and next-to-next-to leading logarithmic (NNLL) accuracy. We find excellent agreement between our extracted asymmetry and the experimental data for SIDIS and Drell-Yan lepton pair production, while tension arises when trying to describe the spin asymmetries of bosons at RHIC. We carefully assess the situation, and we study in details the impact of the RHIC data and their implications through different ways of performing the fit. In addition, we find that the quality of the description of vector boson asymmetry data could be strongly sensitive to the DGLAP evolution of Qiu-Sterman function, besides the usual TMD evolution. We present discussion on this and the implications for measurements of the transverse-spin asymmetries at the future Electron Ion Collider.

    Comments:
    48 pages, 21 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2009.10710 [pdf]
    JHEP(2021)·95 citations

Affiliations

first authorsco-authorsvia INSPIRE