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Nuclear Theory·nucl-th

Wednesday·November 21, 2018

5 papers—1 primary·4 cross-listed

All5Primary1Cross-lists4
  1. 01

    Band crossings in Ta: a particle-number conserving analysis

    Zhen-Hua Zhang · Miao Huang

    The structures of two observed high-spin rotational bands in the doubly-odd nucleus Ta are investigated using the cranked shell model with pairing correlations treated by a particle-number conserving method, in which the blocking effects are taken into account exactly. The experimental moments of inertia and alignments are reproduced very well by the calculations, which confirms the configuration assignments for these two bands in previous works. The backbending and upbending mechanisms in these two bands are analyzed in detail by calculating the occupation probabilities of each orbital close to the Fermi surface and the contributions of each orbital to the total angular momentum alignments. The investigation shows that the level crossings in the first backbending is the neutron crossing and the in second upbending is the proton crossing.

    nucl-thNPA(2019)·1 citation
  2. 02

    Intriguing properties of multiplicity distributions

    Maciej Rybczyński🇵🇱 · Grzegorz Wilk🇵🇱 · Zbigniew Włodarczyk🇵🇱

    Multiplicity distributions exhibit, after closer inspection, peculiarly enhanced void probability and oscillatory behavior of the modified combinants. We discuss the possible sources of these oscillations and their impact on our understanding of the multiparticle production mechanism. Theoretical understanding of both phenomena within the class of compound distributions is presented.

    ↳ hep-phnucl-thPRD(2019)·21 citations
  3. 03

    Developing the MeV potential of DUNE: Detailed considerations of muon-induced spallation and other backgrounds

    Guanying Zhu (Ohio State)🇺🇸 · Shirley Weishi Li (Ohio State & SLAC)🇺🇸 · John F. Beacom (Ohio State)🇺🇸

    The Deep Underground Neutrino Experiment (DUNE) could be revolutionary for MeV neutrino astrophysics, because of its huge detector volume, unique event reconstruction capabilities, and excellent sensitivity to the flavor. However, its backgrounds are not yet known. A major background is expected due to muon spallation of argon, which produces unstable isotopes that later beta decay. We present the first comprehensive study of MeV spallation backgrounds in argon, detailing isotope production mechanisms and decay properties, analyzing beta energy and time distributions, and proposing experimental cuts. We show that above a nominal detection threshold of 5-MeV electron energy, the most important backgrounds are --- surprisingly --- due to low-A isotopes, such as Li, Be, and B, even though high-A isotopes near argon are abundantly produced. We show that spallation backgrounds can be powerfully rejected by simple cuts, with clear paths for improvements. We compare these background rates to rates of possible MeV astrophysical neutrino signals in DUNE, including solar neutrinos (detailed in a companion paper [Capozzi et al. arXiv:1808.08232 [hep-ph]]), supernova burst neutrinos, and the diffuse supernova neutrino background. Further, to aid trigger strategies, in the Appendixes we quantify the rates of single and multiple MeV events due to spallation, radiogenic neutron capture, and other backgrounds, including through pileup. Our overall conclusion is that DUNE has high potential for MeV neutrino astrophysics, but reaching this potential requires new experimental initiatives.

    ↳ hep-phastro-ph.HEnucl-thPRC(2019)·61 citations
  4. 04

    The topological objects near the chiral crossover transition in QCD

    Rasmus N. Larsen🇺🇸 · Sayantan Sharma🇮🇳 · Edward Shuryak🇺🇸

    We study the underlying topology of gauge fields in 2+1 flavor QCD with domain wall fermions on lattices of size , at and immediately above the chiral crossover transition. Using valence overlap fermions with exact index theorem, we focus on its zero modes for different choices of periodicity phases along the temporal direction. Our studies show that the zero modes are due to fractionally charged topological objects, the instanton-dyons. We further provide qualitative study of the interactions between those and compare with the available semi-classical results, finding remarkably accurate agreement in all cases.

    ↳ hep-lathep-thnucl-thPLB(2019)·16 citations
  5. 05

    Probing vorticity in heavy ion collision with dilepton production

    Jitesh R Bhatt🇮🇳 · Hiranmaya Mishra🇮🇳 · Balbeer Singh🇮🇳

    We study the effect of vorticity present in heavy ion collisions (HICs) on the temperature evolution of hot quark-gluon plasma in the presence of spin-vorticity coupling. The initial global rotation entails a nontrivial dependence of the longitudinal flow velocity on the transverse coordinates and also develops a transverse velocity component that depends upon the longitudinal coordinate. Both of these velocities lead to a 2+1 dimensional expansion of the fireball. It is observed that with finite vorticity and spin-polarization the fireball cools faster as compared to the case without vorticity. Furthermore, we discuss the consequence of this on the production of thermal dileptons.

    ↳ hep-phnucl-thPRD(2019)·13 citations

Affiliations

first authorsco-authorsvia INSPIRE