Tue·Oct 6, 2015Tuesday·October 6, 2015

1. 01*

   Energy dependence of hadron spectra and yields in p+p and ${}^7$Be+${}^9$Be collisions from the NA61/SHINE experiment at the CERN SPS

   D.T. Larsen (for the NA61/SHINE Collaboration)🇵🇱

   The NA61/SHINE programme on strong interactions covers the study of the onset of deconfinement and aims to discover the critical point of strongly interacting matter by performing an energy and system-size scan over the full CERN SPS momentum range. So far the scans of p+p, ${}^7$Be+${}^9$Be, as well as Ar+Sc have been completed. Results from p+p and Be+Be collisions are now emerging, in particular the energy dependence of hadron spectra and yields. Status and preliminary results from this effort will be presented.

   nucl-exJ.Phys.Conf.Ser.(2016)·3 citations
2. 02*

   Modifications of Nucleons in Nuclei

   Sebastian E. Kuhn🇺🇸

   I summarize recent results and discuss upcoming and planned experiments that attempt to elucidate how the structure of nucleons might be modified by nuclear binding.

   nucl-exnucl-th1 citation
3. 03*

   Search for two-neutrino double electron capture on ${}^{124}$Xe with the XMASS-I detector

   XMASS Collaboration: K. Abe🇯🇵 · K. Hiraide🇯🇵 · K. Ichimura🇯🇵 · Y. Kishimoto🇯🇵 · K. Kobayashi🇯🇵 · M. Kobayashi🇯🇵 · S. Moriyama🇯🇵 · K. Nakagawa🇯🇵 · M. Nakahata🇯🇵 · T. Norita🇯🇵 · H. Ogawa🇯🇵 · H. Sekiya🇯🇵 and 31 other authors

   Double electron capture is a rare nuclear decay process in which two orbital electrons are captured simultaneously in the same nucleus. Measurement of its two-neutrino mode would provide a new reference for the calculation of nuclear matrix elements whereas observation of its neutrinoless mode would demonstrate lepton number violation. A search for two-neutrino double electron capture on ${}^{124}$Xe is performed using 165.9 days of data collected with the XMASS-I liquid xenon detector. No significant excess above background was observed and we set a lower limit on the half-life as $4.7\times 10^{21}$ years at 90% confidence level. The obtained limit has ruled out parts of some theoretical expectations. We obtain a lower limit on the ${}^{126}$Xe two-neutrino double electron capture half-life of $4.3\times 10^{21}$ years at 90% confidence level as well.

   nucl-exhep-exphysics.ins-detPLB(2016)·20 citations
4. 04*

   3D Structure and Nuclear Targets

   R. Dupré🇫🇷 · S. Scopetta🇮🇹

   Recent experimental and theoretical ideas are laying the ground for a new era in the knowledge of the parton structure of nuclei. We report on two promising directions beyond inclusive deep inelastic scattering experiments, aimed at, among other goals, unveiling the three dimensional structure of the bound nucleon. The 3D structure in coordinate space can be accessed through deep exclusive processes, whose non-perturbative content is parametrized in terms of generalized parton distributions. In this way the distribution of partons in the transverse plane will be obtained, providing a pictorial view of the realization of the European Muon Collaboration effect. In particular, we show how, through the generalized parton distribution framework, non nucleonic degrees of freedom in nuclei can be unveiled. Analogously, the momentum space 3D structure can be accessed by studying transverse momentum dependent parton distributions in semi-inclusive deep inelastic scattering processes. The status of measurements is also summarized, in particular novel coincidence measurements at high luminosity facilities, such as Jefferson Laboratory. Finally the prospects for the next years at future facilities, such as the 12~GeV Jefferson Laboratory and the Electron Ion Collider, are presented.

   nucl-exhep-exhep-phnucl-thEPJA(2016)·35 citations
5. 05*

   Measurement of D-meson production in Pb-Pb collisions at the LHC with ALICE

   Andrea Festanti (for the ALICE Collaboration)🇮🇹

   The measurement of D-meson production in heavy-ion collisions at LHC energy provides insights into the mechanisms of interaction of charm quarks in the hot and dense medium formed in these collisions. ALICE results on the D-meson nuclear modification factor and azimuthal anisotropy in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=2.76$ TeV are presented.

   nucl-exhep-exJ.Phys.Conf.Ser.(2016)·0 citations
6. 06*

   Energy scan of correlations in p+p and Be+Be from NA61/SHINE

   Andrey Seryakov (for NA61/SHINE collaboration)🇷🇺

   The existence of the critical point (CP) of strongly interacting matter is still an open problem. An extensive strong interactions program including a search of the CP and the study of the onset of deconfinement was started by the NA61/SHINE experiment at the CERN SPS. A two dimensional scan of the phase diagram scan is performed to search for the CP and to shed light on the phase transition region. This program includes studies of hadron production in proton-proton, proton-nucleus and nucleus-nucleus interactions measured in a wide range of colliding energy and system size. Correlations between various observables measured at midrapidity as well as in separated rapidity intervals are considered as additional and sensitive tools of this phase diagram scan. We present NA61/SHINE results of studies of energy dependence of two-particle correlations of pseudo-rapidity and azimuthal angle in p+p collisions at the SPS and the first results on correlations between multiplicity and mean transverse momentum in 7Be+9Be collisions at 150A GeV/c obtained for separated pseudo-rapidity intervals (so called long-range correlations). Comparison with data calculations using the EPOS 1.99 model are also discussed.

   nucl-exJ.Phys.Conf.Ser.(2016)·2 citations
7. 07*

   To the measurement of the radius via an electron scattering

   B. Wojtsekhowski🇺🇸

   We propose an experiment for an accurate measurement of the proton radius. A key feature of our proposal is an iron-free magnetic spectrometer. Projected systematics uncertainties will allow a 1% level accuracy for the $r_p$ value.

   nucl-ex0 citations
8. 08*

   Experimentally constrained ($p,\gamma$)${}^{89}$Y and ($n,\gamma$)${}^{89}$Y reaction rates relevant to the $p$-process nucleosynthesis

   A. C. Larsen🇳🇴 · M. Guttormsen🇳🇴 · R. Schwengner🇩🇪 · D. L. Bleuel🇺🇸 · S. Goriely🇧🇪 · S. Harissopulos🇬🇷 · F. L. Bello Garrote🇳🇴 · Y. Byun · T. K. Eriksen🇳🇴 · F. Giacoppo🇳🇴 · A. Görgen🇳🇴 · T. W. Hagen🇳🇴 and 9 other authors

   The nuclear level density and the $\gamma$-ray strength function have been extracted for ${}^{89}$Y, using the Oslo Method on ${}^{89}$Y($p,p^{\prime }\gamma$)${}^{89}$Y coincidence data. The $\gamma$-ray strength function displays a low-energy enhancement consistent with previous observations in this mass region (${}^{93-98}$Mo). Shell-model calculations give support that the observed enhancement is due to strong, low-energy $M1$ transitions at high excitation energies. The data were further used as input for calculations of the ${}^{88}$Sr($p,\gamma$)${}^{89}$Y and ${}^{88}$Y($n,\gamma$)${}^{89}$Y cross sections with the TALYS reaction code. Comparison with cross-section data, where available, as well as with values from the BRUSLIB library, shows a satisfying agreement.

   nucl-exPRC(2016)·36 citations
9. 09*

   Direct and indirect constraints on CP-violating Higgs-quark and Higgs-gluon interactions

   Y.-T. Chien🇺🇸 · V. Cirigliano🇺🇸 · W. Dekens🇳🇱 · J. de Vries🇩🇪 · E. Mereghetti🇺🇸

   We investigate direct and indirect constraints on the complete set of anomalous CP-violating Higgs couplings to quarks and gluons originating from dimension-6 operators, by studying their signatures at the LHC and in electric dipole moments (EDMs). We show that existing uncertainties in hadronic and nuclear matrix elements have a significant impact on the interpretation of EDM experiments, and we quantify the improvements needed to fully exploit the power of EDM searches. Currently, the best bounds on the anomalous CP-violating Higgs interactions come from a combination of EDM measurements and the data from LHC Run 1. We argue that Higgs production cross section and branching ratios measurements at the LHC Run 2 will not improve the constraints significantly. On the other hand, the bounds on the couplings scale roughly linearly with EDM limits, so that future theoretical and experimental EDM developments can have a major impact in pinning down interactions of the Higgs.

   ↳ hep-phhep-latnucl-exnucl-thJHEP(2016)·122 citations
10. 10*

    A consistent four-body CDCC model of low-energy reactions: Application to 9Be + 208Pb

    M. S. Hussein🇧🇷 · P. Descouvemont🇧🇪 · L. F. Canto🇧🇷

    We investigate the ${}^9$Be + ${}^{208}$Pb elastic scattering, breakup and fusion at energies around the Coulomb barrier. The three processes are described simultaneously, with identical conditions of calculations. The ${}^9$Be nucleus is defined in an $\alpha +\alpha$ + n three-body model, using the hyperspherical coordinate method. We first analyze spectroscopic properties of ${}^9$Be, and show that the model provides a fairly good description of the low-lying states. The scattering with ${}^{208}$Pb is then studied with the Continuum Discretized Coupled Channel (CDCC) method, where the $\alpha +\alpha$ + n continuum is approximated by a discrete number of pseudostates. Optical potentials for the $\alpha$+ ${}^{208}$Pb and n+ ${}^{208}$Pb systems are taken from the literature. We present elastic-scattering and fusion cross sections at different energies.

    ↳ nucl-thnucl-exEPJ Web Conf.(2016)·1 citation
11. 11*

    Systematic investigations of deep sub-barrier fusion reactions using an adiabatic approach

    Takatoshi Ichikawa🇯🇵

    To describe fusion hindrance observed in fusion reactions at extremely low incident energies, I propose a novel extension of the standard CC model by introducing a damping factor that describes a smooth transition from sudden to adiabatic processes. I demonstrate the performance of this model by systematically investigating various deep sub-barrier fusion reactions. I extend the standard CC model by introducing a damping factor into the coupling matrix elements in the standard CC model. I adopt the Yukawa-plus-exponential (YPE) model as a basic heavy ion-ion potential, which is advantageous for a unified description of the one- and two-body potentials. For the purpose of these systematic investigations, I approximate the one-body potential with a third-order polynomial function based on the YPE model. Calculated fusion cross sections for the medium-heavy mass systems of ${}^{64}$Ni + ${}^{64}$Ni, ${}^{58}$Ni + ${}^{58}$Ni, and ${}^{58}$Ni + ${}^{54}$Fe, the medium-light mass systems of ${}^{40}$Ca + ${}^{40}$Ca, ${}^{48}$Ca + ${}^{48}$Ca, and ${}^{24}$Mg + ${}^{30}$Si, and the mass-asymmetric systems of ${}^{48}$Ca + ${}^{96}$Zr and ${}^{16}$O + ${}^{208}$Pb are consistent with the experimental data. The astrophysical S factor and logarithmic derivative representations of these are also in good agreement with the experimental data. Since the results calculated with the damping factor are in excellent agreement with the experimental data in all systems, I conclude that the smooth transition from the sudden to adiabatic processes occurs and that a coordinate-dependent coupling strength is responsible for the fusion hindrance. In all systems, the potential energies at the touching point $V_{\mathrm{Touch}}$ strongly correlate with the incident threshold energies for which the fusion hindrance starts to emerge, except for the medium-light mass systems.

    ↳ nucl-thnucl-exPRC(2015)·52 citations
12. 12*

    The nature of near-threshold XYZ states

    Martin Cleven🇨🇳 · Feng-Kun Guo🇨🇳 · Christoph Hanhart🇩🇪 · Qian Wang🇩🇪 · Qiang Zhao🇨🇳

    We demonstrate that the recently observed $X$, $Y$, $Z$ states cannot be purely from kinematic effect. Especially the narrow near-threshold structures in elastic channels call for nearby poles of the $S$-matrix which are qualified as states. We propose a way to distinguish cusp effects from genuine states and demonstrate that (not all of) the recently observed $X$, $Y$, $Z$ states cannot be purely from kinematic effects. Especially, we show that the narrow near-threshold structures in elastic channels call for nearby poles of the $S$-matrix, since the normal kinematic cusp effect cannot produce that narrow structures in the elastic channels in contrast to genuine $S$-matrix poles. In addition, it is also discussed how spectra can be used to distinguish different scenarios proposed for the structure of those poles, such as hadro-quarkonia, tetraquarks and hadronic molecules. The basic tool employed is heavy quark spin symmetry.

    ↳ hep-phhep-exnucl-exnucl-thJPS Conf.Proc.(2016)·6 citations
13. 13*

    Impact of phonon coupling on the radiative nuclear reaction characteristics

    Oleg Achakovskiy · Alexander Avdeenkov · Sergei Kamerdzhiev

    The pygmy dipole resonance and photon strength functions (PSF) in stable and unstable Ni and Sn isotopes are calculated within the microscopic self-consistent version of the extended theory of finite fermi systems in the quasiparticle time blocking approximation. The approach includes phonon coupling (PC) effects in addition to the standard QRPA approach. The Skyrme force SLy4 is used. A pygmy dipole resonance in 72Ni is predicted at the mean energy of 12.4 MeV exhausting 25.7% of the total energy-weighted sum rule. With our microscopic E1 PSFs in the EMPIRE 3.1 code, the following radiative nuclear reaction characteristics have been calculated for several stable and unstable even-even Sn and Ni isotopes: 1) neutron capture cross sections, 2) corresponding neutron capture gamma-spectra, 3) average radiative widths of neutron resonances. Here, three variants of the microscopic nuclear level density models have been used and a comparison with the phenomenological generalized superfluid model (GSM) has been performed. In all the considered properties, including the recent experimental data for PSF in Sn isotopes, the PC contributions turned out to be significant, as compared with the QRPA one, and necessary to explain the available experimental data. The phenomenological GSM NLD model used in EMPIRE3.1 gives, on the whole, the worse results than the microscopic HFB plus combinatorial NLD model.

    ↳ nucl-thnucl-exEPJ Web Conf.(2016)·2 citations
14. 14*

    Photoproduction of the Scalar Meson $f_0(500)$

    Je-Hee Lee🇰🇷 · Hui-Young Ryu🇰🇷 · Byung-Geel Yu🇰🇷 · Hyun-Chul Kim🇰🇷

    In the present talk, we report a recent investigation on photoproduction of the $\gamma N\to f_0(500)N$ within a framework of the effective Lagrangian. We include the nucleon resonances with pin $1/2$ in the $s$ channel. The coupling constants have been etermined by assuming that the decay process $N^{\ast }\to (\pi \pi {)}_{I=0,J=0}N$ can be regarded as $N^{\ast }\to f_0(500)N$. We discuss the numerical results for the total cross sections and possible extension of the present work.

    ↳ hep-phhep-exnucl-exnucl-thJPS Conf.Proc.(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.