Tue·Oct 4, 2016Tuesday·October 4, 2016

1. 01*

   Observation of charge-dependent azimuthal correlations in pPb collisions and its implication for the search for the chiral magnetic effect

   CMS Collaboration

   Charge-dependent azimuthal particle correlations with respect to the second-order event plane in pPb and PbPb collisions at a nucleon-nucleon center-of-mass energy of 5.02 TeV have been studied with the CMS experiment at the LHC. The measurement is performed with a three-particle correlation technique, using two particles with the same or opposite charge within the pseudorapidity range abs(eta) < 2.4, and a third particle measured in the hadron forward calorimeters (4.4 < abs(eta) < 5). The observed differences between the same and opposite sign correlations, as functions of multiplicity and eta gap between the two charged particles, are of similar magnitude in pPb and PbPb collisions at the same multiplicities. These results pose a challenge for the interpretation of charge-dependent azimuthal correlations in heavy ion collisions in terms of the chiral magnetic effect.

   nucl-exhep-exPRL(2017)·198 citations
2. 02*

   Spectrum and Structure of Excited Baryons with CLAS

   Volker D. Burkert🇺🇸

   In this contribution we discuss recent results in light quark baryon spectroscopy involving CLAS data and higher level analysis results from the partial wave analysis by the Bonn-Gatchina group. New baryon states were discovered largely based on the open strangeness production channels $\gamma p\to K^{+}\Lambda$ and $\gamma p\to K^{+}{\Sigma }^0$. The data illustrate the great potential of the kaon-hyperon channel in the discovery of higher mass baryon resonances in s-channel production. Other channels with discovery potential, such as $\gamma p\to p\omega$ and $\gamma p\to \varphi p$ are also discussed. In the second part I will demonstrate on data the sensitivity of meson electroproduction to expose the active degrees of freedom underlying resonance transitions as a function of the probed distance scale. For several of the prominent excited states in the lower mass range the short distance behavior is described by a core of three dressed-quarks with running quark mass, and meson-baryon contributions make up significant parts of the excitation strength at large distances. Finally, an outlook is given of baryon resonance physics at the 12 GeV CEBAF electron accelerator.

   nucl-exhep-exhep-lathep-phEPJ Web Conf.(2017)·6 citations
3. 03*

   Two-particle correlations in azimuthal angle and pseudorapidity in inelastic p+p interactions at the CERN Super Proton Synchrotron

   NA61/SHINE Collaboration: A. Aduszkiewicz🇵🇱 · Y. Ali🇵🇱 · E. Andronov🇷🇺 · T. Anticic🇭🇷 · N. Antoniou🇬🇷 · B. Baatar🇷🇺 · F. Bay🇨🇭 · A. Blondel🇨🇭 · M. Bogomilov🇧🇬 · A. Brandin🇷🇺 · A. Bravar🇨🇭 · J. Brzychczyk🇵🇱 and 142 other authors

   Results on two-particle $\Delta \eta \Delta \varphi$ correlations in inelastic p+p interactions at 20, 31, 40, 80, and 158~GeV/c are presented. The measurements were performed using the large acceptance NA61/SHINE hadron spectrometer at the CERN Super Proton Synchrotron. The data show structures which can be attributed mainly to effects of resonance decays, momentum conservation, and quantum statistics. The results are compared with the EPOS and UrQMD models.

   nucl-exEPJC(2017)·22 citations
4. 04*

   Improved Direct Measurement of the 64.5 keV Resonance Strength in the 17O(p,a)14N Reaction at LUNA

   C.G. Bruno · D.A. Scott🇬🇧 · M. Aliotta🇬🇧 · A. Formicola🇮🇹 · A. Best🇮🇹 · A. Boeltzig🇮🇹 · D. Bemmerer🇩🇪 · C. Broggini🇮🇹 · A. Caciolli🇮🇹 · F. Cavanna🇮🇹 · G.F. Ciani🇮🇹 · P. Corvisiero🇮🇹 and 23 other authors

   The ${}^{17}$O(p,$\alpha$)${}^{14}$N reaction plays a key role in various astrophysical scenarios, from asymptotic giant branch stars to classical novae. It affects the synthesis of rare isotopes such as ${}^{17}$O and ${}^{18}$F, which can provide constraints on astrophysical models. A new direct determination of the $E_{\mathrm{R}}=64.5$~keV resonance strength performed at the Laboratory for Underground Nuclear Astrophysics accelerator has led to the most accurate value to date, $\omega \gamma =10.0\pm 1.4_{\mathrm{stat}}\pm 0.7_{\mathrm{syst}}$~neV, thanks to a significant background reduction underground and generally improved experimental conditions. The (bare) proton partial width of the corresponding state at $E_{\mathrm{x}}=5672$~keV in ${}^{18}$F is ${\Gamma }_{\mathrm{p}}=35\pm 5_{\mathrm{stat}}\pm 3_{\mathrm{syst}}$~neV. This width is about a factor of 2 higher than previously estimated thus leading to a factor of 2 increase in the ${}^{17}$O(p,$\alpha$)${}^{14}$N reaction rate at astrophysical temperatures relevant to shell hydrogen-burning in red giant and asymptotic giant branch stars. The new rate implies lower ${}^{17}$O/${}^{16}$O ratios, with important implications on the interpretation of astrophysical observables from these stars.

   nucl-exPRL(2016)·54 citations
5. 05*

   Unbound states in ${}^{12}$C populated by $\gamma$-decay of the $(J^{\pi },T)=(2^{+},1)$ 16.11 MeV state

   K. L. Laursen · H. O. U. Fynbo🇩🇰 · O. S. Kirsebom · K. S. Madsøll · K. Riisager🇩🇰

   The reaction ${}^{11}\text{B}+p$ has been used to populate the $(J^{\pi },T)=(2^{+},1)$ state at an excitation energy of 16.11 MeV in ${}^{12}$C. $\gamma$-decay to unbound states in ${}^{12}$C are identified from analysis of the decay of the populated daughter states. Due to a new technique, $\gamma$-decay to the 10.8 MeV 1${}^{-}$ state is observed for the first time, and transitions to the 9.64 MeV (3${}^{-}$) and 12.71 MeV (1${}^{+}$) are confirmed. Unresolved transitions to natural parity strength at 10 MeV and 11.5-13 MeV are also observed. For all transitions partial widths are deduced

   nucl-exEPJA(2016)·4 citations
6. 06*

   Activation cross sections of proton induced nuclear reactions on palladium up to 80 MeV

   F. Tárkányi · F. Ditrói · S. Takács · J. Csikai · A. Hermanne · S. Uddin · M. Baba

   Activation cross sections of proton induced nuclear reactions on palladium were measured up to 80 MeV by using the stacked foil irradiation technique and gamma ray spectrometry. The beam intensity, the incident energy and the energy degradation were controlled by a method based on flux constancy via normalization to the excitation functions of monitor reactions measured in parallel. Excitation functions for direct and cumulative cross-sections were measured for the production of ${}^{104m,104g,105}$${}^{g,106m,110m}$Ag, ${}^{100,101}$Pd, ${}^{99m,99g,100,}$${}^{101m}$${}^{,101g,102m,102g,105}$Rh and ${}^{103,}$${}^{97}$Ru radioisotopes. The cross section data were compared with the theoretical predictions of TENDL-2014 and -2015 libraries. For practical applications thick target yields were derived from the measured excitation functions. Application in the field of medical radionuclide production is shortly discussed.

   nucl-exphysics.med-phAppl.Radiat.Isot.(2016)·3 citations
7. 07*

   Spin dipole nuclear matrix elements for double beta decay nuclei by charge-exchange reactions

   H. Ejiri🇯🇵 · D. Frekers🇩🇪

   Spin dipole (SD) strengths for double beta-decay (DBD) nuclei were studied experimentally for the first time by using measured cross sections of (3He,t) charge exchange reactions (CERs). Then SD nuclear matrix elements (NMEs) for low-lying 2- states were derived from the experimental SD strengths by referring to the experimental GT (Gamow-Teller) and F (Fermi) strengths. They are consistent with the empirical SD NMEs based on the quasi-particle model with the empirical effective SD coupling constant. The CERs are used to evaluate the SD NME, which is associated with one of the major components of the neutrino-less DBD NME.

   nucl-exnucl-thJ.Phys.G(2016)·16 citations
8. 08*

   Measurement of Elastic pp Scattering at $\sqrt{s}$ = 8 TeV in the Coulomb-Nuclear Interference Region - Determination of the $\rho$-Parameter and the Total Cross-Section

   TOTEM Collaboration: G. Antchev🇨🇿 · P. Aspell🇨🇭 · I. Atanassov🇨🇿 · V. Avati🇵🇱 · J. Baechler🇨🇭 · V. Berardi🇮🇹 · M. Berretti🇨🇭 · E. Bossini🇮🇹 · U. Bottigli🇮🇹 · M. Bozzo🇮🇹 · P. Broulím🇨🇿 · H. Burkhardt🇨🇭 and 77 other authors

   The TOTEM experiment at the CERN LHC has measured elastic proton-proton scattering at the centre-of-mass energy $\sqrt{s}$ = 8 TeV and four-momentum transfers squared, |t|, from 6 x $10^{-4}$ GeV${}^2$ to 0.2 GeV${}^2$. Near the lower end of the |t|-interval the differential cross-section is sensitive to the interference between the hadronic and the electromagnetic scattering amplitudes. This article presents the elastic cross-section measurement and the constraints it imposes on the functional forms of the modulus and phase of the hadronic elastic amplitude. The data exclude the traditional Simplified West and Yennie interference formula that requires a constant phase and a purely exponential modulus of the hadronic amplitude. For parametrisations of the hadronic modulus with second- or third-order polynomials in the exponent, the data are compatible with hadronic phase functions giving either central or peripheral behaviour in the impact parameter picture of elastic scattering. In both cases, the $\rho$-parameter is found to be 0.12 $\pm$ 0.03. The results for the total hadronic cross-section are ${\sigma }_{tot}$ = (102.9 $\pm$ 2.3) mb and (103.0 $\pm$ 2.3) mb for central and peripheral phase formulations, respectively. Both are consistent with previous TOTEM measurements.

   nucl-exhep-exhep-phEPJC(2016)·181 citations
9. 09*

   Suppression and azimuthal anisotropy of prompt and nonprompt J/psi production in PbPb collisions at sqrt(s[NN]) = 2.76 TeV

   CMS Collaboration

   The nuclear modification factor RAA and the azimuthal anisotropy coefficient v[2] of prompt and nonprompt (i.e. those from decays of b hadrons) J/psi mesons, measured from PbPb and pp collisions at sqrt(s[NN]) = 2.76 TeV at the LHC, are reported. The results are presented in several event centrality intervals and several kinematic regions, for transverse momenta pt > 6.5 GeV/c and rapidity abs(y) < 2.4, extending down to pt = 3 GeV/c in the 1.6 < abs(y) < 2.4 range. The v[2] of prompt J/psi is found to be nonzero, but with no strong dependence on centrality, rapidity, or pt over the full kinematic range studied. The measured v[2] of nonprompt J/psi is consistent with zero. The RAA of prompt J/psi exhibits a suppression that increases from peripheral to central collisions but does not vary as a function of either y or pt in the fiducial range. The nonprompt J/psi RAA shows a suppression which becomes stronger as rapidity or pt increase. The v[2] and nuclear suppression of open and hidden charm, and of open charm and beauty, are compared.

   nucl-exhep-exEPJC(2017)·183 citations
10. 10*

    The first moment of azimuthal anisotropy in nuclear collisions from AGS to LHC energies

    Subhash Singha🇺🇸 · Prashanth Shanmuganathan🇺🇸 · Declan Keane🇺🇸

    We review topics related to the first moment of azimuthal anisotropy ($v_1$), commonly known as directed flow, focusing on both charged particles and identified particles from heavy-ion collisions. Beam energies from the highest available, at the CERN LHC, down to projectile kinetic energies per nucleon of a few GeV per nucleon, as studied in experiments at the Brookhaven AGS, fall within our scope. We focus on experimental measurements and on theoretical work where direct comparisons with experiment have been emphasized. The physics addressed or potentially addressed by this review topic includes the study of Quark Gluon Plasma, and more generally, investigation of the Quantum Chromodynamics phase diagram and the equation of state describing the accessible phases.

    nucl-exhep-exhep-phnucl-thAdv.High Energy Phys.(2016)·40 citations
11. 11*

    Separating Double-Beta Decay Events from Solar Neutrino Interactions in a Kiloton-Scale Liquid Scintillator Detector By Fast Timing

    Andrey Elagin🇺🇸 · Henry Frisch🇺🇸 · Brian Naranjo🇺🇸 · Jonathan Ouellet🇺🇸 · Lindley Winslow🇺🇸 · Taritree Wongjirad🇺🇸

    We present a technique for separating nuclear double beta decay ($\beta \beta$-decay) events from background neutrino interactions due to ${}^8$B decays in the sun. This background becomes dominant in a kiloton-scale liquid-scintillator detector deep underground and is usually considered as irreducible due to an overlap in deposited energy with the signal. However, electrons from 0$\nu \beta \beta$-decay often exceed the Cherenkov threshold in liquid scintillator, producing photons that are prompt and correlated in direction with the initial electron direction. The use of large-area fast photodetectors allows some separation of these prompt photons from delayed isotropic scintillation light and, thus, the possibility of reconstructing the event topology. Using a simulation of a 6.5~m radius liquid scintillator detector with 100~ps resolution photodetectors, we show that a spherical harmonics analysis of early-arrival light can discriminate between 0$\nu \beta \beta$-decay signal and ${}^8$B solar neutrino background events on a statistical basis. Good separation will require the development of a slow scintillator with a 5 nsec risetime.

    ↳ physics.ins-dethep-exnucl-exNucl.Instrum.Meth.A(2017)·38 citations
12. 12*

    Origins and Impacts of High-Density Symmetry Energy

    Bao-An Li🇺🇸

    What is nuclear symmetry energy? Why is it important? What do we know about it? Why is it so uncertain especially at high densities? Can the total symmetry energy or its kinetic part be negative? What are the effects of three-body and/or tensor force on symmetry energy? How can we probe the density dependence of nuclear symmetry energy with terrestrial nuclear experiments? What observables of heavy-ion reactions are sensitive to the high-density behavior of nuclear symmetry energy? How does the symmetry energy affect properties of neutron stars, gravitational waves and our understanding about the nature of strong-field gravity? In this lecture, we try to answer these questions as best as we can based on some of our recent work and/or understanding of research done by others. This note summarizes the main points of the lecture.

    ↳ nucl-thastro-ph.SRnucl-exAIP Conf.Proc.(2017)·4 citations
13. 13*

    A non-equilibrium microscopic description of spallation

    P. Napolitani🇫🇷 · M. Colonna🇮🇹

    We investigate the prompt emission of few intermediate-mass fragments in spallation reactions induced by protons and deuterons in the 1 GeV range. Such emission has a minor contribution to the total reaction cross section, but it may overcome evaporation and fission channels in the formation of light nuclides. The role of mean-field dynamics and phase-space fluctuations in these reactions is investigated through the Boltzmann-Langevin transport equation. We found that a process of frustrated fragmentation and re-aggregation is a prominent mechanism of production of IMFs which can not be assimilated to the statistical decay of a compound nucleus. Very interestingly, this process may yield a small number of IMF in the exit channel, which may even reduce to two, and be wrongly confused with ordinary asymmetric fission. This interpretation, inspired by nuclear-spallation experiments, can be generalised to heavy-ion collisions approaching the fragmentation threshold.

    ↳ nucl-thnucl-exNuovo Cim.C(2017)·3 citations
14. 14*

    The NEW detector: construction, commissioning and first results

    M. Nebot-Guinot (for the NEXT Collaboration)🇪🇸

    NEXT (Neutrino Experiment with a Xenon TPC) is a neutrinoless double-beta (\beta\beta 0\nu) decay experiment at the Canfranc Underground Laboratory (LSC). It seeks to detect the (\beta\beta 0\nu) decay of Xe-136 using a high pressure xenon gas TPC with electroluminescent (EL) amplification. The NEXT-White (NEW) detector, with an active xenon mass of about 10 kg at 15 bar, is the first NEXT prototype installed at LSC. It implements the NEXT detector concept tested in smaller prototypes using the same radiopure sensors and materials that will be used in the future NEXT-100, serving as a benchmark for technical solutions as well as for the signal selection and background rejection algorithms. NEW is currently under commissioning at the LSC. In this poster proceedings we describe the technical solutions adopted for NEW construction, the lessons learned from the commissioning phase, and the first results on energy calibration and energy resolution obtained with low-energy radioactive source data.

    ↳ physics.ins-dethep-exnucl-exJ.Phys.Conf.Ser.(2017)·1 citation

* 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.