Wed·Aug 16, 2017Wednesday·August 16, 2017

1. 01*

   Comment on arXiv:1612.01502 'Is the Trineutron Resonance Lower in Energy than a Tetraneutron Resonance ?'

   P. Truöl🇨🇭 · J.P. MIller🇺🇸

   Comment on the article by S. Gandolfi et al. Phys.Rev.Letters 118 (2017), 232501; arXiv:1612.01502 [nucl-th]

   nucl-ex3 citations
2. 02*

   COHERENT constraints on nonstandard neutrino interactions

   Jiajun Liao🇺🇸 · Danny Marfatia🇺🇸

   Coherent elastic neutrino-nucleus scattering consistent with the standard model has been observed by the COHERENT experiment. We study nonstandard neutrino interactions using the detected spectrum. For the case in which the nonstandard interactions (NSI) are induced by a vector mediator lighter than 50 MeV, we obtain constraints on the coupling of the mediator. For a heavier mediator, we find that degeneracies between the NSI parameters severely weaken the constraints. However, these degeneracies do not affect COHERENT constraints on the effective NSI parameters for matter propagation in the Earth.

   ↳ hep-phhep-exnucl-exPLB(2017)·186 citations
3. 03*

   The symmetry energy in nucleon and quark matter

   Lie-Wen Chen🇨🇳

   The symmetry energy characterizes the isospin dependent part of the equation of state of isospin asymmetric strong interaction matter and it plays a critical role in many issues of nuclear physics and astrophysics. In this talk, we briefly review the current status on the determination of the symmetry energy in nucleon (nuclear) and quark matter. For nuclear matter, while the subsaturation density behaviors of the symmetry energy are relatively well-determined and significant progress has been made on the symmetry energy around saturation density, the determination of the suprasaturation density behaviors of the symmetry energy remains a big challenge. For quark matter, which is expected to appear in dense matter at high baryon densities, we briefly review the recent work about the effects of quark matter symmetry energy on the properties of quark stars and the implication of possible existence of heavy quark stars on quark matter symmetry energy. The results indicate that the $u$ and $d$ quarks could feel very different interactions in isospin asymmetric quark matter, which may have important implications on the isospin effects of partonic dynamics in relativistic heavy-ion collisions.

   ↳ nucl-thastro-ph.HEhep-phnucl-exNucl.Phys.Rev.(2017)·32 citations
4. 04*

   A novel technique for determining luminosity in electron-scattering/positron-scattering experiments from multi-interaction events

   A. Schmidt🇺🇸 · C. O'Connor🇺🇸 · J. C. Bernauer🇺🇸 · R. Milner🇺🇸

   The OLYMPUS experiment measured the cross-section ratio of positron-proton elastic scattering relative to electron-proton elastic scattering to look for evidence of hard two-photon exchange. To make this measurement, the experiment alternated between electron beam and positron beam running modes, with the relative integrated luminosities of the two running modes providing the crucial normalization. For this reason, OLYMPUS had several redundant luminosity monitoring systems, including a pair of electromagnetic calorimeters positioned downstream from the target to detect symmetric Mø ller and Bhabha scattering from atomic electrons in the hydrogen gas target. Though this system was designed to monitor the rate of events with single Mø ller/Bhabha interactions, we found that a more accurate determination of relative luminosity could be made by additionally considering the rate of events with both a Mø ller/Bhabha interaction and a concurrent elastic $ep$ interaction. This method was improved by small corrections for the variance of the current within bunches in the storage ring and for the probability of three interactions occurring within a bunch. After accounting for systematic effects, we estimate that the method is accurate in determining the relative luminosity to within 0.36\%. This precise technique can be employed in future electron-proton and positron-proton scattering experiments to monitor relative luminosity between different running modes.

   ↳ physics.ins-detnucl-exphysics.acc-phNucl.Instrum.Meth.A(2018)·11 citations
5. 05*

   Mass number and excitation energy dependence of the ${\Theta }_{eff}/{\Theta }_{rig}$ parameter of the spin cut-off factor in the formation of an isomeric pair

   S. Sudár (1) · S. M. Qaim (2) ((1) Institute of Experimental Physics, University of Debrecen, Hungary, (2) Institut für Neurowissenschaften und Medizin, INM-5: Nuklearchemie, Forschungszentrum Jülich GmbH, Germany)

   The ${\Theta }_{eff}/{\Theta }_{rig}$ parameter of the spin distribution of the level density was determined for 61 nuclei covering the mass range of 44 to 200. The experimental isomeric cross-section ratios for 25 isomeric pairs were compared with the model calculation to find the best fit to the experimental data. The model calculations were carried out with the TALYS code using the BSFG model for the level density. The reduced ${\chi }^2$ values were calculated to describe the deviation of the experimental data from the model calculation. An ${\eta }_d$ was introduced calculating the ${\Theta }_{eff}/{\Theta }_{rig}$ value from the low energy discrete levels of the nucleus. The $\eta /{\eta }_d$ values seem to be independent of the mass number, their average value near to one. The $\eta /{\eta }_d$ values also seem to be independent of the average excitation energy in the continuum, indicating that $\eta$ is independent of the excitation energy. The mass number and (N-Z) dependence of the $\eta$ values were studied. The $\eta$ values for the nuclei with odd mass number show an exponential decrease as a function of A or (N-Z). The $\eta$ values for the odd-odd type of nuclei appear to be constant, near one, up to the mass number 110 or (N-Z) of 13. Above these values, the $\eta$ values show exponential decrease. The $\eta$ values for even-even type nuclei decrease exponentially up to A equal to 142 or (N-Z) equal to 20. The values are lower than those for the nearby odd-odd type nuclei. The $\eta$ values increase for nuclei with A between 142 and 156 and (N-Z) between 20 and 28, and they finally reach the value of odd-odd type systematics.

   ↳ nucl-thnucl-exNPA(2018)·19 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.