Thu·Sep 13, 2018Thursday·September 13, 2018

1. 01*

   Charged-particle decays of highly excited states in ${}^{19}$F

   P. Adsley🇫🇷 · F. Hammache🇫🇷 · N. de Séréville🇫🇷 · M. Assié🇫🇷 · D. Beaumel🇫🇷 · M. Chabot🇫🇷 · M. Degerlier🇫🇷 · C. Delafosse🇫🇷 · F. Flavigny🇫🇷 · A. Georgiadou🇫🇷 · J. Guillot🇫🇷 · V. Guimarães🇫🇷 and 14 other authors

   Neutron-capture reactions on ${}^{18}$F in the helium-burning shell play an important role in the production of ${}^{15}$N during core-collapse supernovae. The competition between the ${}^{18}$F($n,p/\alpha$)${}^{18}$O/${}^{15}$N reactions controls the amount of ${}^{15}$N produced. The strengths of these reactions depend on the decay branching ratios of states in ${}^{19}$F above the neutron threshold. We report on an experiment investigating the decay branching ratios of these states in order to better constrain the strengths of the reactions.

   nucl-exSpringer Proc.Phys.(2019)·0 citations
2. 02*

   Investigation of Amorphous Germanium Contact Properties with Planar Detectors Made from Home-Grown Germanium Crystals

   W.-Z. Wei🇺🇸 · X.-H. Meng🇺🇸 · Y.-Y. Yang🇺🇸 · J. Liu🇺🇸 · G.-J. Wang🇺🇸 · H. Mei · G. Gang · D.-M. Mei · C. Zhang🇺🇸

   The characterization of detectors fabricated from home-grown crystals is the most direct way to study crystal properties. We fabricated planar detectors from high-purity germanium (HPGe) crystals grown at the University of South Dakota (USD). In the fabrication process, a HPGe crystal slice cut from a USD-grown crystal was coated with a high resistivity thin film of amorphous Ge (a-Ge) followed by depositing a thin layer of aluminum on top of the a-Ge film to define the physical area of the contacts. We investigated the detector performance including the $I$-$V$ characteristics, $C$-$V$ characteristics and spectroscopy measurements for a few detectors. The results document the good quality of the USD-grown crystals and electrical contacts.

   ↳ physics.ins-detnucl-exJINST(2018)·17 citations
3. 03*

   High-energy neutrino interaction physics with IceCube

   Spencer R. Klein (for the IceCube Collaboration)🇺🇸

   Although they are best known for studying astrophysical neutrinos, neutrino telescopes like IceCube can study neutrino interactions, at energies far above those that are accessible at accelerators. In this writeup, I present two IceCube analyses of neutrino interactions at energies far above 1 TeV. The first measures neutrino absorption in the Earth, and, from that determines the neutrino-nucleon cross-section at energies between 6.3 and 980 TeV. We find that the cross-sections is 1.30 ${}_{-0.19}^{+0.21}$ (stat.) ${}_{-0.43}^{+0.39}$ (syst.) times the Standard Model cross-section. We also present a measurement of neutrino inelasticity, using ${\nu }_{\mu }$ charged-current interactions that occur within IceCube. We have measured the average inelasticity at energies from 1 TeV to above 100 TeV, and found that it is in agreement with the Standard Model expectations. We have also performed a series of fits to this track sample and a matching cascade sample, to probe aspects of the astrophysical neutrino flux, particularly the flavor ratio.

   ↳ hep-exastro-ph.HEnucl-exEPJ Web Conf.(2019)·2 citations
4. 04*

   The enhancement of $v_4$ in nuclear collisions at the highest densities signals a first order phase transition

   Yasushi Nara🇯🇵 · Jan Steinheimer🇩🇪 · Horst Stoecker🇩🇪

   The beam energy dependence of $v_4$ (the quadrupole moment of the transverse radial flow) is sensitive to the nuclear equation of state (EoS) in mid-central Au + Au collisions at the energy range of $3<\sqrt{s_{NN}}<30$ GeV, which is investigated within the hadronic transport model JAM. Different equations of state, namely, a free hadron gas, a first-order phase transition and a crossover are compared. An enhancement of $v_4$ at $\sqrt{s_{NN}}\approx 6$ GeV is predicted for an EoS with a first-order phase transition. This enhanced $v_4$ flow is driven by both the enhancement of $v_2$ as well as the positive contribution to $v_4$ from the squeeze-out of spectator particles which turn into participants due to the admixture of the strong collective flow in the shocked, compressed nuclear matter.

   ↳ nucl-thhep-phnucl-exEPJA(2018)·18 citations
5. 05*

   Two-dimensional collective Hamiltonian for chiral and wobbling modes II: Electromagnetic transitions

   X. H. Wu🇨🇭 · Q. B. Chen🇩🇪 · P. W. Zhao🇨🇳 · S. Q. Zhang🇨🇳 · J. Meng🇨🇳

   The intraband electromagnetic transitions in the framework of collective Hamiltonian for chiral and wobbling modes are calculated. By going beyond the mean field approximation on the orientations of rotational axis, the collective Hamiltonian provides the descriptions on both yrast band and collective excitation bands. For a system with one $h_{11/2}$ proton particle and one $h_{11/2}$ neutron hole coupled to a triaxial rotor ($\gamma =-30^{\circ }$), the intraband electromagnetic transitions given by the one-dimensional and two-dimensional collective Hamiltonian are compared to the results by the tilted axis cranking approach and particle rotor model. Compared with the tilted axis cranking approach, the electromagnetic transitions given by the collective Hamiltonian have a better agreement with those by the particle rotor model, due to the consideration of the quantum fluctuations.

   ↳ nucl-thnucl-exPRC(2018)·20 citations
6. 06*

   Two-neutrino double electron capture on ${}^{124}$Xe based on an effective theory and the nuclear shell model

   E. A. Coello Pérez🇩🇪 · J. Menéndez🇯🇵 · A. Schwenk🇩🇪

   We study the two-neutrino double electron capture on ${}^{124}$Xe based on an effective theory (ET) and large-scale shell model calculations, two modern nuclear structure approaches that have been tested against Gamow-Teller and double-beta decay data. In the ET, the low-energy constants are fit to electron capture and ${\beta }^{-}$ transitions around xenon. For the nuclear shell model, we use an interaction in a large configuration space that reproduces the spectroscopy of nuclei in this mass region. For the dominant transition to the ${}^{124}$Te ground state, we find half-lives $T_{1/2}^{2\nu \mathrm{ECEC}}=(1.3-18)\times 10^{22}$ y for the ET and $T_{1/2}^{2\nu \mathrm{ECEC}}=(0.43-2.9)\times 10^{22}$ y for the shell model. The ET uncertainty leads to a half-life almost entirely consistent with present experimental limits and largely within the reach of ongoing experiments. The shell model half-life range overlaps with the ET, but extends less beyond current limits. Our findings thus suggest that the two-neutrino double electron capture on ${}^{124}$Xe has a good chance to be discovered by ongoing or future experiments. In addition, we present results for the two-neutrino double electron capture to excited states of ${}^{124}$Te.

   ↳ nucl-thnucl-exPLB(2019)·35 citations
7. 07*

   A Comparison of the Effects of Neutron and Gamma Radiation in Silicon Photomultipliers

   B. Biró🇭🇺 · G. David🇺🇸 · A. Fenyvesi🇭🇺 · J.S. Haggerty🇺🇸 · J. Kierstead🇺🇸 · E.J. Mannel🇺🇸 · T. Majoros🇭🇺 · J. Molnar🇭🇺 · F. Nagy🇭🇺 · S. Stoll🇺🇸 · B. Ujvari🇭🇺 · C.L. Woody🇺🇸

   The effects of radiation damage in silicon photomultipliers (SiPMs) from gamma rays have been measured and compared with the damage produced by neutrons. Several types of MPPCs from Hamamatsu were exposed to gamma rays and neutrons at the Solid State Gamma Ray Irradiation Facility (SSGRIF) at Brookhaven National Lab and the Institute for Nuclear Research (Atomki) in Debrecen, Hungary. The gamma ray exposures ranged from 1 krad to 1 Mrad and the neutron exposures ranged from 10${}^8$ n/cm${}^2$ to 10${}^{12}$ n/cm${}^2$. The main effect of gamma ray damage is an increase in the noise and leakage current in the irradiated devices, similar to what is seen from neutron damage, but the level of damage is considerably less at comparable high levels of exposure. In addition, the damage from gamma rays saturates after a few hundred krad, while the damage from neutrons shows no sign of saturation, suggestive of different damage mechanisms in the two cases. The change in optical absorption in the window material of the SiPMs due to radiation was also measured. This study was carried out in order to evaluate the use of SiPMs for particle physics applications with moderate levels of radiation exposures.

   ↳ physics.ins-dethep-exnucl-exIEEE Trans.Nucl.Sci.(2019)·9 citations
8. 08*

   Effect of centrality bin width corrections on two-particle number and transverse momentum differential correlation functions

   Victor Gonzalez🇪🇸 · Ana Marin🇩🇪 · Pedro Ladron de Guevara🇪🇸 · Jinjin Pan🇺🇸 · Sumit Basu🇺🇸 · Claude Pruneau🇺🇸

   Two-particle number and transverse momentum differential correlation functions are powerful tools for unveiling the detailed dynamics and particle production mechanisms involved in relativistic heavy-ion collisions. Measurements of transverse momentum correlators $P_2$ and $G_2$, in particular, provide added information not readily accessible with better known number correlation functions $R_2$. However, it is found that the $R_2$ and $G_2$ correlators are somewhat sensitive to the details of the experimental procedure used to measure them. They exhibit, in particular, a dependence on the collision centrality bin width, which may have a rather detrimental impact on their physical interpretation. A technique to correct these correlators for collision centrality bin-width averaging is presented. The technique is based on the hypothesis that the shape of single- and pair- probability densities vary slower with collision centrality than the corresponding integrated yields. The technique is tested with Pb-Pb simulations based on the HIJING and ultrarelativistic quantum molecular dynamics models and shown to enable a precision better than 1% for particles in the kinematic range $0.2\le p_{\mathrm{T}}\le 2.0$ GeV/$c$.

   ↳ physics.data-anhep-exhep-phnucl-ex+1PRC(2019)·6 citations
9. 09*

   Commissioning of the J-PET detector in view of the positron annihilation lifetime spectroscopy

   K. Dulski · C. Curceanu · E. Czerwiński · A. Gajos · M. Gorgol · N. Gupta-Sharma · B. C. Hiesmayr · B. Jasińska · K. Kacprzak Ł. Kapłon · D. Kisielewska · K. Klimaszewski · G. Korcyl and 21 other authors

   The Jagiellonian Positron Emission Tomograph (J-PET) is the first PET device built from plastic scintillators. It is a multi-purpose detector designed for medical imaging and for studies of properties of positronium atoms in porous matter and in living organisms. In this article we report on the commissioning of the J-PET detector in view of studies of positronium decays. We present results of analysis of the positron lifetime measured in the porous polymer. The obtained results prove that J-PET is capable of performing simultaneous imaging of the density distribution of annihilation points as well as positron annihilation lifetime spectroscopy.

   ↳ physics.ins-detnucl-exHyperfine Interact.(2018)·10 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.