Wed·Sep 21, 2016Wednesday·September 21, 2016

1. 01*

   Total Absorption Gamma-Ray Spectroscopy of 87Br, 88Br and 94Rb Beta-Delayed Neutron Emitters

   E. Valencia🇪🇸 · J. L. Tain🇪🇸 · A. Algora🇪🇸 · J. Agramunt🇪🇸 · B. Rubio🇪🇸 · S. Rice🇬🇧 · W. Gelletly🇬🇧 · P. Regan🇬🇧 · A.-A. Zakari-Issoufou🇫🇷 · M. Fallot🇫🇷 · A. Porta🇫🇷 · J. Rissanen🇫🇮 and 26 other authors

   We investigate the decay of 87Br, 88Br and 94Rb using total absorption gamma-ray spectroscopy. These important fission products are beta-delayed neutron emitters. Our data show considerable gamma-intensity, so far unobserved in high-resolution gamma-ray spectroscopy, from states at high excitation energy. We also find significant differences with the beta intensity that can be deduced from existing measurements of the beta spectrum. We evaluate the impact of the present data on reactor decay heat using summation calculations. Although the effect is relatively small it helps to reduce the discrepancy between calculations and integral measurements of the photon component for 235U fission at cooling times in the range 1 to 100 s. We also use summation calculations to evaluate the impact of present data on reactor antineutrino spectra. We find a significant effect at antineutrino energies in the range of 5 to 9 MeV. In addition, we observe an unexpected strong probability for gamma emission from neutron unbound states populated in the daughter nucleus. The gamma branching is compared to Hauser-Feshbach calculations which allow one to explain the large value for bromine isotopes as due to nuclear structure. However the branching for 94Rb, although much smaller, hints of the need to increase the radiative width by one order-of-magnitude. This leads to a similar increase in the calculated (n,gamma) cross section for this very neutron-rich nucleus with a potential impact on r-process abundance calculations.

   nucl-exPRC(2017)·56 citations
2. 02*

   Measurements of long-range azimuthal anisotropies and associated Fourier coefficients for $pp$ collisions at $\sqrt{s}=5.02$ and $13$ TeV and $p$+Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV with the ATLAS detector

   ATLAS Collaboration

   ATLAS measurements of two-particle correlations are presented for $\sqrt{s}=5.02$ and $13$ TeV $pp$ collisions and for $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV $p$+Pb collisions at the LHC. The correlation functions are measured as a function of relative azimuthal angle $\Delta \varphi$, and pseudorapidity separation $\Delta \eta$, using charged particles detected within the pseudorapidity interval $|\eta |<2.5$. Azimuthal modulation in the long-range component of the correlation function, with $|\Delta \eta |>2$, is studied using a template fitting procedure to remove a "back-to-back" contribution to the correlation function that primarily arises from hard-scattering processes. In addition to the elliptic, $\cos (2\Delta \varphi )$, modulation observed in a previous measurement, the $pp$ correlation functions exhibit significant $\cos (3\Delta \varphi )$ and $\cos (4\Delta \varphi )$ modulation. The Fourier coefficients $v_{n,n}$ associated with the $\cos (n\Delta \varphi )$ modulation of the correlation functions for $n=$ $2$-$4$ are measured as a function of charged-particle multiplicity and charged-particle transverse momentum. The Fourier coefficients are observed to be compatible with $\cos (n\varphi )$ modulation of per-event single-particle azimuthal angle distributions. The single-particle Fourier coefficients $v_n$ are measured as a function of charged-particle multiplicity, and charged-particle transverse momentum for $n=$ $2$-$4$. The integrated luminosities used in this analysis are, $64$ $\mathrm{n}{\mathrm{b}}^{-1}$ for the $\sqrt{s}=13$ TeV $pp$ data, $170$ $\mathrm{n}{\mathrm{b}}^{-1}$ for the $\sqrt{s}=5.02$ TeV $pp$ data and $28$ $\mathrm{n}{\mathrm{b}}^{-1}$ for the $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV $p$+Pb data.

   nucl-exhep-exPRC(2017)·199 citations
3. 03*

   Development of a low-energy radioactive ion beam facility for the MARA separator

   Philippos Papadakis · Iain Moore🇫🇮 · Ilkka Pohjalainen🇫🇮 · Jan Sarén · Juha Uusitalo

   A low-energy radioactive ion beam facility for the production and study of nuclei produced close to the proton drip line is under development at the Accelerator Laboratory of the University of Jyväskylä, Finland. The facility will take advantage of the mass selectivity of the recently commissioned MARA vacuum-mode mass separator. The ions selected by MARA will be stopped and thermalised in a small-volume gas cell prior to extraction and further mass separation. The gas cell design allows for resonance laser ionisation/spectroscopy both in-gas-cell and in-gas-jet. The facility will include experimental setups allowing ion counting, mass measurement and decay spectroscopy.

   ↳ physics.ins-detnucl-exHyperfine Interact.(2016)·6 citations
4. 04*

   Primordial Nucleosynthesis

   Alain Coc🇫🇷

   Primordial or big bang nucleosynthesis (BBN) is now a parameter free theory whose predictions are in good overall agreement with observations. However, the 7Li calculated abundance is significantly higher than the one deduced from spectroscopic observations. Most solutions to this lithium problem involve a source of extra neutrons that inevitably leads to an increase of the deuterium abundance. This seems now to be excluded by recent deuterium observations that have drastically reduced the uncertainty on D/H and also calls for improved precision on thermonuclear reaction rates.

   ↳ astro-ph.COnucl-exJ.Phys.Conf.Ser.(2016)·12 citations
5. 05*

   Heavy flavor $R_{\text{AA}}$ and $v_n$ in event-by-event viscous relativistic hydrodynamics

   Caio A. G. Prado🇧🇷 · Jacquelyn Noronha-Hostler🇺🇸 · Mauro R. Cosentino🇧🇷 · Marcelo G. Munhoz🇧🇷 · Jorge Noronha🇧🇷 · Alexandre A. P. Suaide🇧🇷

   Recently it has been shown that a realistic description of the medium via event-by-event viscous hydrodynamics plays an important role in the long-standing $R_{\text{AA}}$ vs. $v_2$ puzzle at high $p_T$. In this proceedings we begin to extend this approach to the heavy flavor sector by investigating the effects of full event-by-event fluctuating hydrodynamic backgrounds on the nuclear suppression factor and $v_2\{2\}$ of heavy flavor mesons and non-photonic electrons at intermediate to high $p_T$. We also show results for $v_3\{2\}$ of $B^0$ and D${}^0$ for PbPb collisions at $\sqrt{s}=2.76$ TeV.

   ↳ nucl-thhep-phnucl-exJ.Phys.Conf.Ser.(2017)·7 citations
6. 06*

   Production of ${\pi }^0$, $K^{\pm }$ and $\eta$ mesons in Pb-Pb and pp collisions at $\sqrt{s_{\mathrm{NN}}}=$2.76 TeV measured with the ALICE detector at the LHC

   Astrid Morreale (the ALICE collaboration)🇫🇷

   One of the key signatures of the Quark-Gluon Plasma (QGP) is the modification of hadron transverse momentum differential cross-sections in heavy-ion collisions (HIC) as compared to proton-proton (pp) collisions. Suppression of hadron production at high transverse momenta ($p_{\mathrm{T}}$) in HIC has been explained by the energy loss of the partons produced in the hard scattering processes which traverse the deconfined quantum chromodynamic (QCD) matter. The dependence of the observed suppression on the $p_{\mathrm{T}}$ of the measured hadron towards higher $p_{\mathrm{T}}$ is an important input for the theoretical understanding of jet quenching effects in the QGP and the nature of the energy loss, while suppression towards lower $p_{\mathrm{T}}$ gives information about collective behaviour. The ALICE experiment at the Large Hadron Collider (LHC) performs a variety of measurements including the spectra of neutral mesons and kaons at mid-rapidity in a wide $p_{\mathrm{T}}$ range in pp, p-Pb and Pb-Pb collisions. An overview of ALICE results in HIC and pp collisions at $\sqrt{s_{NN}}=$2.76 TeV of neutral pions, kaons and eta mesons as a function of transverse momentum ($p_{\mathrm{T}}$) and centrality will be presented. Ratios $\eta$/${\pi }^0$, $K^{\pm }$/${\pi }^{\pm }$ as well as comparisons to model calculations will also be discussed.

   ↳ hep-exnucl-exJ.Phys.Conf.Ser.(2017)·3 citations
7. 07*

   Collisional broadening of angular correlations in a multiphase transport model

   Terrence Edmonds🇺🇸 · Qingfeng Li🇨🇳 · Fuqiang Wang🇺🇸

   Systematic comparisons of jetlike correlation data to radiative and collisional energy loss model calculations are essential to extract transport properties of the quark-gluon medium created in relativistic heavy ion collisions. This paper presents a transport study of collisional broadening of jetlike correlations, by following parton-parton collision history in a multiphase transport (AMPT) model. The correlation shape is studied as a function of the number of parton-parton collisions suffered by a high transverse momentum probe parton ($N_{\mathrm{coll}}$) and the azimuth of the probe relative to the reaction plane (${\varphi }_{fin.}^{\mathrm{probe}}$). Correlation is found to broaden with increasing $N_{\mathrm{coll}}$ and ${\varphi }_{fin.}^{\mathrm{probe}}$ from in- to out-of-plane direction. This study provides a transport model reference for future jet-medium interaction studies.

   ↳ nucl-thnucl-exNPA(2017)·4 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.