Fri·Feb 9, 2018Friday·February 9, 2018

1. 01*

   Nuclear physics uncertainties of the astrophysical gamma-process studied through the 64Zn(p,alpha)61Cu and 64Zn(p,gamma)65Ga reactions

   Gy. Gyürky🇭🇺 · Zs. Fülöp🇭🇺 · Z. Halász · G. G. Kiss🇭🇺 · T. Szücs🇭🇺

   In a recent work, the cross section measurement of the 64Zn(p,alpha)61Cu reaction was used to prove that the standard alpha-nucleus optical potentials used in astrophysical network calculation fail to reproduce the experimental data at energies relevant for heavy element nucleosynthesis. In the present paper the analysis of the obtained experimental data is continued by comparing the results with the predictions using different parameters. It is shown that the recently suggested modification of the standard optical potential leads to a better description of the data.

   nucl-exnucl-thJ.Phys.Conf.Ser.(2018)·2 citations
2. 02*

   Chiral magnetic effect search in p(d)+Au, Au+Au collisions at RHIC

   Jie Zhao (for the STAR collaboration)🇺🇸

   The chiral magnetic effect (CME) refers to charge separation along a strong magnetic field of single-handed quarks, caused by interactions with topological gluon fields from QCD vacuum fluctuations. A major background of CME measurements in heavy-ion collisions comes from resonance decays coupled with elliptical flow anisotropy. These proceedings present two new studies from STAR to shed further light on the background issue: (1) small system p+Au and d+Au collisions where the CME signal is not expected, and (2) pair invariant mass dependence where resonance peaks can be identified.

   nucl-exhep-exhep-phnucl-thInt.J.Mod.Phys.Conf.Ser.(2018)·7 citations
3. 03*

   Heavy Quarkonium Production at Threshold: from JLab to EIC

   Sylvester Joosten🇺🇸 · Zein-Eddine Meziani🇺🇸

   In this contribution we present opportunities to address questions about the origin of mass and spin, probe the existence and nature of the LHCb pentaquark state, and probe the color Van der Waal forces among two color neutral hadrons. The key reaction is elastic production of heavy quarkonia (J/psi and Upsilon) on the nucleon from threshold to large nucleon-quarkonium invariant masses. This is possible when combining the energy range of two high luminosity facilities, Jefferson Lab 12 GeV and an electron ion collider (EIC).

   ↳ hep-exnucl-exPoS(2018)·45 citations
4. 04*

   Transverse Extension of Partons in the Proton probed by Deeply Virtual Compton Scattering

   R. Akhunzyanov · M.G. Alexeev · G.D. Alexeev · A. Amoroso · V. Andrieux · N.V. Anfimov · V. Anosov · A. Antoshkin · K. Augsten · W. Augustyniak · A. Austregesilo · C.D.R. Azevedo and 215 other authors

   We report on the first measurement of exclusive single-photon muoproduction on the proton by COMPASS using 160 GeV/$c$ polarized ${\mu }^{+}$ and ${\mu }^{-}$ beams of the CERN SPS impinging on a liquid hydrogen target. We determine the dependence of the average of the measured ${\mu }^{+}$ and ${\mu }^{-}$ cross sections for deeply virtual Compton scattering on the squared four-momentum transfer $t$ from the initial to the final final proton. The slope $B$ of the $t$-dependence is fitted with a single exponential function, which yields $B=(4.3\pm 0.6_{\text{stat}}\_{-0.3}^{+0.1}{|}_{\text{sys}})(\text{GeV}/c{)}^{-2}$. This result can be converted into an average transverse extension of partons in the proton, $\sqrt{⟨r_{\perp }^2⟩}=(0.58\pm 0.04_{\text{stat}}\_{-0.02}^{+0.01}{|}_{\text{sys}})\text{fm}$. For this measurement, the average virtuality of the photon mediating the interaction is $⟨Q^2⟩=1.8(\text{GeV/}c{)}^2$ and the average value of the Bjorken variable is $⟨x_{\text{Bj}}⟩=0.056$.

   ↳ hep-exnucl-exPLB(2019)·71 citations
5. 05*

   Spectroscopic Criteria for Identification of Nuclear Tetrahedral and Octahedral Symmetries: Illustration on a Rare Earth Nucleus

   J. Dudek🇫🇷 · D. Curien🇫🇷 · I. Dedes🇵🇱 · K. Mazurek🇵🇱 · S. Tagami🇯🇵 · Y. R. Shimizu🇯🇵 · T. Bhattacharjee🇮🇳

   We formulate criteria for identification of the nuclear tetrahedral and octahedral symmetries and illustrate for the first time their possible realization in a Rare Earth nucleus 152Sm. We use realistic nuclear mean-field theory calculations with the phenomenological macroscopic-microscopic method, the Gogny-Hartree-Fock-Bogoliubov approach and the general point-group theory considerations to guide the experimental identification method as illustrated on published experimental data. Following group-theory the examined symmetries imply the existence of exotic rotational bands on whose properties the spectroscopic identification criteria are based. These bands may contain simultaneously states of even and odd spins, of both parities and parity doublets at well defined spins. In the exact-symmetry limit those bands involve no E2-transitions. We show that coexistence of tetrahedral and octahedral deformations is essential when calculating the corresponding energy minima and surrounding barriers and that it has a characteristic impact on the rotational bands. The symmetries in question imply the existence of long-lived shape-isomers and, possibly, new waiting point nuclei -- impacting the nucleosynthesis processes in astrophysics -- and an existence of 16-fold degenerate particle-hole excitations. Specifically designed experiments which aim at strengthening the identification arguments are briefly discussed.

   ↳ nucl-thnucl-exPRC(2018)·33 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.