Fri·Mar 23, 2018Friday·March 23, 2018

1. 01*

   Universal Formula for Baryon Spectra in Heavy-ion Collisions and its Implications

   Rudolph C. Hwa🇺🇸 · Lilin Zhu🇨🇳

   In an unconventional presentation of the data on the transverse momentum spectra of baryons produced in heavy-ion collisions, regularities are found that make possible the discovery of a universal formula valid for $p,\Lambda ,\Xi$ and $\Omega$. The formula describes the baryon distributions over wide ranges of $p_T(0.5{}_{\sim }^{<}{p}_T{}_{\sim }^{<}5$ GeV/c) for $0.06{}_{\sim }^{<}\sqrt{s_{NN}}{}_{\sim }^{<}3$ TeV, except for very peripheral collisions. Some aspects of their empirical properties are derived in the recombination model, resulting in a revelation of some features of the light and strange quark distributions before hadronization. Interpretation of the inverse slopes of their exponential behavior leads to an implication that cannot accommodate the conventional description of fluid flow. This is mainly a study of phenomenology without detailed model input.

   nucl-exhep-phnucl-thPRC(2018)·10 citations
2. 02*

   Activation cross-section measurement of proton induced reactions on cerium

   F. Tárkányi🇭🇺 · A. Hermanne · F. Ditrói🇭🇺 · S. Takács🇭🇺 · I. Spahn · S. Spellerberg

   In the framework of a systematic study of proton induced nuclear reactions on lanthanides we have measured the excitation functions on natural cerium for the production of 142,139,138m,137Pr, 141,139,137m,137g,135Ce and 133La up to 65 MeV proton energy using the activation method with stacked-foil irradiation technique and high-resolution gamma-ray spectrometry. The cross-sections of the investigated reactions were compared with the data retrieved from the TENDL-2014 and TENDL-2015 libraries, based on the latest version of the TALYS code system. No earlier experimental data were found in the literature. The measured cross-section data are important for further improvement of nuclear reaction models and for practical applications in nuclear medicine, other labeling and activation studies.

   nucl-exNucl.Instrum.Meth.B(2017)·3 citations
3. 03*

   Activation cross sections of Proton Induced Nuclear Reactions on neodymium up to 65 MeV

   F. Tárkányi🇭🇺 · A. Hermanne · F. Ditrói🇭🇺 · S. Takács🇭🇺

   In the frame of a systematic study of the activation cross sections of charged particle induced nuclear reactions on rare earths for production of therapeutic radionuclides, proton induced reactions on neodymium were measured up to 65 MeV energy, above 45 MeV for the first time. The excitation functions of the natNd(p,x)150,149,148m,148g,146,144,143,141Pm, 149,147,141,140,139m,138Nd, 142,138mPr and 139gCe nuclear reactions were assessed by using stacked foil activation technique and high resolution gamma-spectrometry. The excitation functions were compared to the theoretical predictions, available in the TENDL-2015 library based on latest version of the TALYS code. The application of the data for medical isotope production is shortly discussed.

   nucl-exJ.Radioanal.Nucl.Chem.(2017)·1 citation
4. 04*

   Study of activation cross sections of deuteron induced reactions on erbium in the 32-50 MeV energy range

   F. Tárkányi🇭🇺 · A. Hermanne · F. Ditrói🇭🇺 · S. Takács🇭🇺

   Activation cross sections of the natEr(d,x)163,165,166,167,168,170Tm and natEr(d,x)171,161Er nuclear reactions have been measured in the 32-50 MeV energy range, above 40 MeV for the first time. The activation method with stacked foil irradiation technique and gamma-ray spectroscopy were used. The experimental cross sections were compared with the theoretical predictions in the TENDL-2015 library.

   nucl-exAppl.Radiat.Isot.(2018)·1 citation
5. 05*

   Comments on Proton Emission after Muon Capture

   Ed V Hungerford🇺🇸

   The emission of particles after atomic muon capture was studied extensively during the early 70's. In particular, proton and neutron spectra were measured in order to determine whether nuclear emission was due to a direct or a thermalized process. It was found that protons emitted after atomic muon capture decreased from a probability of 15% in light nuclei (C, N, O) to essentially 0% for heavy systems such as Sn, and that only 10% of this emission could be ascribed to statistical processes. On the other hand a significant thermal spectrum of neutrons in addition to a direct component was found. Unfortunately these studies were not always self consistent so that information of relevance to the MECO experiment is ambiguous.

   nucl-ex4 citations
6. 06*

   Energy and Centrality Dependent Study of Deconfinement Phase Transition in a Color String Percolation Approach at RHIC Energies

   Pragati Sahoo🇮🇳 · Sudipan De🇮🇳 · Swatantra Kumar Tiwari🇮🇳 · Raghunath Sahoo🇮🇳

   We take the experimental data for transverse momentum spectra of identified charged hadrons in different centrality classes for nucleus-nucleus (A+A) collisions at various Relativistic Heavy-Ion Collider (RHIC) energies measured by the STAR collaboration. We analyse these data in the framework of color string percolation model (CSPM) in order to extract various percolation parameters at different centralities at RHIC energies to study the effect of collision geometry and collision energy. We use these parameters to study the centrality dependent behaviour of initial temperature of the percolation cluster, energy density, average transverse momentum, shear viscosity to entropy density ratio ($\eta /s$) and trace anomaly for different energies at RHIC from $\sqrt{s_{\mathrm{NN}}}$ = 19.6 to 200 GeV. These observables are found to strongly depend on centrality at various collision energies. The critical percolation density, which is related to the deconfinement phase transition is achieved in the most central nucleus-nucleus collisions, while it fails in the peripheral collisions. A universal scaling is observed in color suppression factor and initial temperatures when studied as a function of charged particle pseudorapidity distribution scaled by nuclear overlap area at RHIC energies. The minimum of $\eta /s$ is observed in the most central collisions at $\sqrt{s_{\mathrm{NN}}}$ = 130 and 200 GeV.

   ↳ hep-phhep-exnucl-exnucl-thEPJA(2018)·39 citations
7. 07*

   Particle physics origin of the 5 MeV bump in the reactor antineutrino spectrum?

   Jeffrey M. Berryman🇺🇸 · Vedran Brdar🇩🇪 · Patrick Huber🇺🇸

   One of the most puzzling questions in neutrino physics is the origin of the excess at 5 MeV in the reactor antineutrino spectrum. In this paper, we explore the excess via the reaction ${}^{13}$C$(\overline{\nu },{\overline{\nu }}^{\prime }n{)}^{12}$C${}^{\ast }$ in organic scintillator detectors. The de-excitation of ${}^{12}$C${}^{\ast }$ yields a prompt $4.4$ MeV photon, while the thermalization of the product neutron causes proton recoils, which in turn yield an additional prompt energy contribution with finite width. Together, these effects can mimic an inverse beta decay event with around 5 MeV energy. We consider several non-standard neutrino interactions to produce such a process and find that the parameter space preferred by Daya Bay is disfavored by measurements of neutrino-induced deuteron disintegration and coherent elastic neutrino-nucleus scattering. While non-minimal particle physics scenarios may be viable, a nuclear physics solution to this anomaly appears more appealing.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2019)·40 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.