Wed·Nov 23, 2016Wednesday·November 23, 2016

1. 01*

   Electric dipole polarizability of ${}^{48}$Ca and implications for the neutron skin

   J. Birkhan (1) · M. Miorelli (2,3) · S. Bacca (2,4)🇨🇦 · S. Bassauer (1) · C.A. Bertulani (5)🇺🇸 · G. Hagen (6,7)🇺🇸 · H. Matsubara (8,9)🇯🇵 · P. von Neumann-Cosel (1)🇩🇪 · T. Papenbrock (6,7)🇺🇸 · N. Pietralla (1)🇩🇪 · V.Yu. Ponomarev (1)🇩🇪 · A. Richter (1)🇩🇪 · A. Schwenk (1,10,11)🇩🇪 · A. Tamii (8) ((1) Institut fuer Kernphysik, Technische Universitaet Darmstadt, (2) TRIUMF, (3) Department of Physics and Astronomy, University of British Columbia, Vancouver, (4) Department of Physics and Astronomy, University of Manitoba, (5) Department of Physics and Astronomy, Texas AandM University-Commerce, (6) Physics Division, Oak Ridge National Laboratory, (7) Department of Physics and Astronomy, University of Tennessee, Knoxville, (8) Research Center for Nuclear Physics, Osaka University, (9) Tokyo Women's Medical University, (10) ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, (11) Max-Planck-Institut fuer Kernphysik)🇯🇵

   The electric dipole strength distribution in Ca-48 between 5 and 25 MeV has been determined at RCNP, Osaka, from proton inelastic scattering experiments at forward angles. Combined with photoabsorption data at higher excitation energy, this enables for the first time the extraction of the electric dipole polarizability alpha_D(Ca-48) = 2.07(22) fm^3. Remarkably, the dipole response of Ca-48 is found to be very similar to that of Ca-40, consistent with a small neutron skin in Ca-48. The experimental results are in good agreement with ab initio calculations based on chiral effective field theory interactions and with state-of-the-art density-functional calculations, implying a neutron skin in Ca-48 of 0.14 - 0.20 fm.

   nucl-exnucl-thPRL(2017)·211 citations
2. 02*

   The legacy of the experimental hadron physics programme at COSY

   Colin Wilkin🇬🇧

   The experimental hadronic physics programme at the COoler SYnchrotron of the Forschungszentrum Juelich terminated at the end of 2014. After describing the accelerator and the associated facilities, a review is presented of the major achievements in the field realized over the twenty years of intense research activity.

   nucl-exnucl-thEPJA(2017)·41 citations
3. 03*

   Higher Moments of Net-Kaon Multiplicity Distributions at STAR

   Ji Xu (for the STAR Collaboration)🇨🇳

   Fluctuations of conserved quantities such as baryon number (B), electric charge number (Q), and strangeness number (S), are sensitive to the correlation length and can be used to probe non-gaussian fluctuations near the critical point. Experimentally, higher moments of the multiplicity distributions have been used to search for the QCD critical point in heavy-ion collisions. In this paper, we report the efficiency-corrected cumulants and their ratios of mid- rapidity (|y| < 0.5) net-kaon multiplicity distributions in Au+Au collisions at 7.7, 11.5, 14.5, 19.6, 27, 39, 62.4, and 200 GeV collected in 2010, 2011, and 2014 with STAR at RHIC. The centrality and energy dependence of the cumulants and their ratios, are presented. Furthermore, the comparisons with baseline calculations (Poisson) and non-critical-point models (UrQMD) are also discussed.

   ↳ hep-exnucl-exJ.Phys.Conf.Ser.(2017)·6 citations
4. 04*

   Energy Dependence of Moments of Net-Proton, Net-Kaon, and Net-Charge Multiplicity Distributions at STAR

   Ji Xu (for the STAR Collaboration)🇨🇳

   One of the main goals of the RHIC Beam Energy Scan (BES) program is to study the QCD phase structure, which includes the search for the QCD critical point, over a wide range of chemical potential. Theoretical calculations predict that fluctuations of conserved quantities, such as baryon number (B), charge (Q), and strangeness (S), are sensitive to the correlation length of the dynamical system. Experimentally, higher moments of multiplicity distributions have been utilized to search for the QCD critical point in heavy-ion collisions. In this paper, we report recent efficiency-corrected cumulants and cumulants ratios of the net- proton, net-kaon, and net-charge multiplicity distributions in Au+Au collisions at 7.7, 11.5, 14.5, 19.6, 27, 39, 62.4, and 200 GeV collected in the years 2010, 2011, and 2014 with STAR at RHIC. The centrality and energy dependence of the cumulants up to the fourth order, as well as their ratios, are presented. Furthermore, the comparisons with baseline calculations (Poisson) and non-critical-point models (UrQMD) will also be discussed.

   ↳ hep-exnucl-exJ.Phys.Conf.Ser.(2016)·10 citations
5. 05*

   Backward charmonium production in $\pi N$ collisions

   B. Pire🇫🇷 · K. Semenov-Tian-Shansky🇷🇺 · L. Szymanowski🇵🇱

   The QCD collinear factorization framework allows to describe exclusive backward production of a $J/\psi$ meson in pion-nucleon collisions in terms of pion-to-nucleon transition distribution amplitudes. We calculate the scattering amplitude at the leading order in the strong coupling constant and estimate the cross section of this reaction in the backward kinematical region for a medium energy pion beam available at the J-Parc experimental facility.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2017)·13 citations
6. 06*

   Characterization of a cylindrical plastic {\beta}-detector with Monte Carlo simulations of optical photons

   V. Guadilla🇪🇸 · A. Algora🇪🇸 · J.L. Tain🇪🇸 · J. Agramunt🇪🇸 · J. Äystö🇫🇮 · J.A. Briz🇫🇷 · A. Cucoanes🇫🇷 · T. Eronen🇫🇮 · M. Estienne🇫🇷 · M. Fallot🇫🇷 · L.M. Fraile🇪🇸 · E. Ganioglu🇹🇷 and 30 other authors

   In this work we report on the Monte Carlo study performed to understand and reproduce experimental measurements of a new plastic \b{eta}-detector with cylindrical geometry. Since energy deposition simulations differ from the experimental measurements for such a geometry, we show how the simulation of production and transport of optical photons does allow one to obtain the shapes of the experimental spectra. Moreover, taking into account the computational effort associated with this kind of simulation, we develop a method to convert the simulations of energy deposited into light collected, depending only on the interaction point in the detector. This method represents a useful solution when extensive simulations have to be done, as in the case of the calculation of the response function of the spectrometer in a total absorption {\gamma}-ray spectroscopy analysis.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2017)·3 citations
7. 07*

   Multi-mirror imaging optics for low-loss transport of divergent neutron beams and tailored wavelength spectra

   Oliver Zimmer🇫🇷

   A neutron optical transport system is proposed which comprises nested short elliptical mirrors located halfway between two common focal points M and M'. It images cold neutrons from a diverging beam or a source with finite size at M by single reflections onto a spot of similar size at M'. Direct view onto the neutron source is blocked by a central absorber with little impact on the transported solid angle. Geometric neutron losses due to source size can be kept small using modern supermirrors and distances M-M' of a few tens of metres. Very short flat mirrors can be used in practical implementations. Transport with a minimum of reflections remedies losses due to multiple reflections that are common in long elliptical neutron guides. Moreover, well-defined reflection angles lead to new possibilities for enhancing the spectral quality of primary beams, such as clear-cut discrimination of short neutron wavelengths or beam monochromation using bandpass supermirrors. Multi-mirror imaging systems may thus complement or even replace ordinary neutron guides, in particular at the European Spallation Source.

   ↳ physics.ins-dethep-exnucl-ex7 citations
8. 08*

   Bridging the gap between event-by-event fluctuation measurements and theory predictions in relativistic nuclear collisions

   P. Braun-Munzinger🇩🇪 · A. Rustamov🇦🇿 · J. Stachel🇩🇪

   We develop methods to deal with non-dynamical contributions to event-by-event fluctuation measurements of net-particle numbers in relativistic nuclear collisions. These contributions arise from impact parameter fluctuations and from the requirement of overall net-baryon number or net-charge conservation and may mask the dynamical fluctuations of interest, such as those due to critical endpoints in the QCD phase diagram. Within a model of independent particle sources we derive formulae for net-particle fluctuations and develop a rigorous approach to take into account contributions from participant fluctuations in realistic experimental environments and at any cumulant order. Interestingly, contributions from participant fluctuations to the second and third cumulants of net-baryon distributions are found to vanish at mid-rapidity for LHC energies while higher cumulants of even order are non-zero even when the net-baryon number at mid-rapidity is zero. At lower beam energies the effect of participant fluctuations increases and induces spurious higher moments. The necessary corrections become large and need to be carefully taken into account before comparison to theory. We also provide a procedure for selecting the optimal phase-space coverage of particles for fluctuation analyses and discuss quantitatively the necessary correction due to global charge conservation.

   ↳ nucl-thnucl-exNPA(2017)·153 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.