Wed·Dec 23, 2015Wednesday·December 23, 2015

1. 01*

   Cosmogenic Backgrounds to 0{\nu}{\beta}{\beta} in EXO-200

   EXO-200 Collaboration: J. B. Albert🇺🇸 · D. J. Auty🇺🇸 · P. S. Barbeau🇺🇸 · D. Beck🇺🇸 · V. Belov🇷🇺 · M. Breidenbach🇺🇸 · T. Brunner🇨🇦 · A. Burenkov🇷🇺 · G. F. Cao🇨🇳 · C. Chambers🇺🇸 · B. Cleveland🇨🇦 · M. Coon🇺🇸 and 74 other authors

   As neutrinoless double-beta decay experiments become more sensitive and intrinsic radioactivity in detector materials is reduced, previously minor contributions to the background must be understood and eliminated. With this in mind, cosmogenic backgrounds have been studied with the EXO-200 experiment. Using the EXO-200 TPC, the muon flux (through a flat horizontal surface) underground at the Waste Isolation Pilot Plant (WIPP) has been measured to be {\Phi} = 4.07 $\pm$ 0.14 (sys) $\pm$ 0.03 (stat) $\times$ $10^{-7}$cm${}^{-2}$ s${}^{-1}$, with a vertical intensity of $I_v$ = 2.97${}_{-0.13}^{+0.14}$ (sys) $\pm$ 0.02 (stat) $\times$ $10^{-7}$cm${}^{-2}$ s${}^{-1}$ sr${}^{-1}$. Simulations of muon-induced backgrounds identified several potential cosmogenic radionuclides, though only 137Xe is a significant background for the 136Xe 0{\nu}{\beta}{\beta} search with EXO-200. Muon-induced neutron backgrounds were measured using {\gamma}-rays from neutron capture on the detector materials. This provided a measurement of 137Xe yield, and a test of the accuracy of the neutron production and transport simulations. The independently measured rates of 136Xe neutron capture and of 137Xe decay agree within uncertainties. Geant4 and FLUKA simulations were performed to estimate neutron capture rates, and these estimates agreed to within ~40% or better with measurements. The ability to identify 136Xe(n,{\gamma}) events will allow for rejection of 137Xe backgrounds in future 0{\nu}{\beta}{\beta} analyses.

   nucl-exhep-exphysics.ins-detJCAP(2016)·44 citations
2. 02*

   Precise measurement of alpha_K and alpha_T for the 150.8-keV E3 transition in 111Cd: Test of internal-conversion theory

   N. Nica🇺🇸 · J.C. Hardy🇺🇸 · V.E. Iacob🇺🇸 · T.A. Werke · C.M. Folden III · L. Pineda · M.B. Trzhaskovskaya🇷🇺

   We have measured the K-shell and total internal conversion coefficients, alpha_K and alpha_T, for the 150.8-keV E3 transition in 111Cd to be 1.449(18) and 2.217(26) respectively. The alpha_K result agrees well with Dirac-Fock calculations in which the effect of the K-shell atomic vacancy is accounted for; it extends our precision tests of alpha_K calculations to Z = 48, the lowest Z yet measured. However, the result for alpha_T disagrees by about two standard deviations from the calculated alpha_T value, whether or not the atomic vacancy is included.

   nucl-exnucl-thPRC(2016)·8 citations
3. 03*

   Strange meson production in Al+Al collisions at 1.9A GeV

   P. Gasik🇵🇱 · K. Piasecki🇵🇱 · N. Herrmann🇩🇪 · Y. Leifels🇩🇪 · T. Matulewicz🇵🇱 · A. Andronic🇩🇪 · R. Averbeck🇩🇪 · V. Barret🇫🇷 · Z. Basrak🇭🇷 · N. Bastid🇫🇷 · M.L. Benabderrahmane🇩🇪 · M. Berger🇩🇪 and 54 other authors

   The production of K${}^{+}$, K${}^{-}$ and $\phi$(1020) mesons is studied in Al+Al collisions at a beam energy of 1.9A GeV which is close or below the production threshold in NN reactions. Inverse slopes, anisotropy parameters, and total emission yields of K${}^{\pm }$ mesons are obtained. A comparison of the ratio of kinetic energy distributions of K${}^{-}$ and K${}^{+}$ mesons to the HSD transport model calculations suggests that the inclusion of the in-medium modifications of kaon properties is necessary to reproduce the ratio. The inverse slope and total yield of $\varphi$ mesons are deduced. The contribution to K${}^{-}$ production from $\varphi$ meson decays is found to be [17 $\pm$ 3 (stat) ${}_{-7}^{+2}$ (syst)] %. The results are in line with previous K${}^{\pm }$ and $\varphi$ data obtained for different colliding systems at similar incident beam energies.

   nucl-exEPJA(2016)·18 citations
4. 04*

   Statistical model analysis of hadron yields in proton-nucleus and heavy-ion collisions at SIS 18 energies

   G. Agakishiev🇷🇺 · O. Arnold🇩🇪 · A. Balanda🇵🇱 · D. Belver🇪🇸 · A. Belyaev🇷🇺 · J. C. Berger-Chen🇩🇪 · A. Blanco🇵🇹 · M. Böhmer🇩🇪 · J. L. Boyard🇫🇷 · P. Cabanelas🇪🇸 · E. Castro🇪🇸 · S. Chernenko🇷🇺 and 98 other authors

   The HADES data from p+Nb collisions at center of mass energy of $\sqrt{s_{NN}}$= 3.2 GeV are analyzed by employing a statistical model. Accounting for the identified hadrons ${\pi }^0$, $\eta$, $\Lambda$, $K_s^0$, $\omega$ allows a surprisingly good description of their abundances with parameters $T_{chem}=(99\pm 11)$ MeV and ${\mu }_b=(619\pm 34)$ MeV, which fits well in the chemical freeze-out systematics found in heavy-ion collisions. In supplement we reanalyze our previous HADES data from Ar+KCl collisions at $\sqrt{s_{NN}}$= 2.6 GeV with an updated version of the statistical model. We address equilibration in heavy-ion collisions by testing two aspects: the description of yields and the regularity of freeze-out parameters from a statistical model fit. Special emphasis is put on feed-down contributions from higher-lying resonance states which have been proposed to explain the experimentally observed ${\Xi }^{-}$ excess present in both data samples.

   nucl-exhep-exnucl-thEPJA(2016)·73 citations
5. 05*

   Mass measurements of neutron-rich Rb and Sr isotopes

   R. Klawitter🇨🇦 · A. Bader🇨🇦 · M. Brodeur🇺🇸 · U. Chowdhury🇨🇦 · A. Chausdhuri · J. Fallis🇨🇦 · A.T. Gallant🇨🇦 · A. Grossheim🇨🇦 · A.A. Kwiatkowski🇨🇦 · D. Lascar🇨🇦 · K.G. Leach🇨🇦 · A. Lennarz🇨🇦 and 7 other authors

   We report on the mass measurements of several neutron-rich $\mathrm{Rb}$ and $\mathrm{Sr}$ isotopes in the $A\approx 100$ region with the TITAN Penning-trap mass spectrometer. Using highly charged ions in the charge state $q=10+$, the masses of ${}^{98,99}\mathrm{Rb}$ and ${}^{98-100}\mathrm{Sr}$ have been determined with a precision of $6-12\mathrm{keV}$, making their uncertainty negligible for r-process nucleosynthesis network calculations. The mass of ${}^{101}\mathrm{Sr}$ has been determined directly for the first time with a precision eight times higher than the previous indirect measurement and a deviation of $3\sigma$ when compared to the Atomic Mass Evaluation. We also confirm the mass of ${}^{100}\mathrm{Rb}$ from a previous measurement. Furthermore, our data indicates the existance of a low-lying isomer with $80\mathrm{keV}$ excitation energy in ${}^{98}\mathrm{Rb}$. We show that our updated mass values lead to minor changes in the r-process by calculating fractional abundances in the $A\approx 100$ region of the nuclear chart.

   nucl-exPRC(2016)·21 citations
6. 06*

   Jet fragmentation functions in proton-proton collisions using soft-collinear effective theory

   Yang-Ting Chien🇺🇸 · Zhong-Bo Kang🇺🇸 · Felix Ringer🇺🇸 · Ivan Vitev🇺🇸 · Hongxi Xing🇺🇸

   The jet fragmentation function describes the longitudinal momentum distribution of hadrons inside a reconstructed jet. We study the jet fragmentation function in proton-proton collisions in the framework of soft-collinear effective theory (SCET). We find that, up to power corrections, the jet fragmentation function can be expressed as the ratio of the fragmenting jet function and the unmeasured jet function. Using renormalization group techniques, we are able to resum large logarithms of jet radii R in the perturbative expansion of the cross section. We use our theoretical formalism to describe the jet fragmentation functions for light hadron and heavy meson production measured at the Large Hadron Collider (LHC). Our calculations agree very well with the experimental data for the light hadron production. On the other hand, although our calculations for the heavy meson production inside jets are consistent with the PYTHIA simulation, they fail to describe the LHC data. We find that the jet fragmentation function for heavy meson production is very sensitive to the gluon-to-heavy-meson fragmentation function.

   ↳ hep-phhep-exnucl-exnucl-thJHEP(2016)·75 citations
7. 07*

   Light flavor results in p-Pb collisions with ALICE

   Antonio Ortiz (for the ALICE Collaboration)🇲🇽

   Particle ratios provide insight into the hadrochemistry of the event and the mechanisms for particle production. In Pb-Pb collisions the relative multi-strange baryon yields exhibit an enhancement with respect to pp collisions, whereas the short-lived K${}^{\ast 0}$ resonance is suppressed in the most central events due to re-scattering of its decay daughter particles. Measurements in p-Pb allow us to investigate the development of these effects as a function of the system size. We report comprehensive results on light-flavor hadron production measured with the ALICE detector in p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV, covering a wide range of particle species which includes long-lived hadrons, resonances and multi-strange baryons. The measurements include the transverse momentum spectra and the ratios of spectra among different species, and extend over a very large transverse momentum region, from $\approx$100 MeV/$c$ to $\approx$20 GeV/$c$, depending on the particle species.

   ↳ hep-exnucl-exNPA(2016)·1 citation
8. 08*

   Recent developments in heavy-ion fusion reactions around the Coulomb barrier

   K. Hagino🇯🇵 · N. Rowley🇫🇷 · J.M. Yao🇯🇵

   The nuclear fusion is a reaction to form a compound nucleus. It plays an important role in several circumstances in nuclear physics as well as in nuclear astrophysics, such as synthesis of superheavy elements and nucleosynthesis in stars. Here we discuss two recent theoretical developments in heavy-ion fusion reactions at energies around the Coulomb barrier. The first topic is a generalization of the Wong formula for fusion cross sections in a single-channel problem. By introducing an energy dependence to the barrier parameters, we show that the generalized formula leads to results practically indistinguishable from a full quantal calculation, even for light symmetric systems such as ${}^{12}$C+${}^{12}$C, for which fusion cross sections show an oscillatory behavior. We then discuss a semi-microscopic modeling of heavy-ion fusion reactions, which combine the coupled-channels approach to the state-of-the-art nuclear structure calculations for low-lying collective motions. We apply this method to subbarrier fusion reactions of ${}^{58}$Ni+${}^{58}$Ni and ${}^{40}$Ca+${}^{58}$Ni systems, and discuss the role of anharmonicity of the low-lying vibrational motions.

   ↳ nucl-thnucl-exEPJ Web Conf.(2016)·0 citations
9. 09*

   Physics Opportunities with a Secondary K0_L Beam at JLab

   Moskov Amaryan🇺🇸

   Following a Letter of Intent submitted to PAC43 at JLab in this talk we discuss the possibility to create a secondary K0_L beam in Hall-D to be used with GlueX detector for spectroscopy of excited hyperons.

   ↳ physics.ins-dethep-exnucl-exAIP Conf.Proc.(2016)·4 citations
10. 10*

    Long wavelength perfect fluidity from short distance jet transport in quark-gluon plasmas

    Jiechen Xu🇺🇸 · Jinfeng Liao🇺🇸 · Miklos Gyulassy🇺🇸

    We build a new phenomenological framework that bridges the long wavelength bulk viscous transport properties of the strongly-coupled quark-gluon plasma (sQGP) and short distance hard jet transport properties in the QGP. The full nonperturbative chromo-electric (E) and chromo-magnetic (M) structure of the near "perfect fluid" like sQGP in the critical transition region are integrated into a semi-Quark-Gluon-Monopole Plasma (sQGMP) model lattice-compatibly and implemented into the new CUJET3.0 jet quenching framework. All observables computed from CUJET3.0 are found to be consistent with available data at RHIC and LHC simultaneously. A quantitative connection between the shear viscosity and jet transport parameter is rigorously established within this framework. We deduce the $T=160-600$ MeV dependence of the QGP's $\eta /s$: its near vanishing value in the near $T_c$ regime is determined by the composition of E and M charges, it increases as $T$ rises, and its high $T$ limit is fixed by color screening scales.

    ↳ nucl-thhep-phnucl-exNPA(2016)·0 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.