Tue·Nov 17, 2015Tuesday·November 17, 2015

1. 01*

   K${}^{-}$ absorption on two nucleons and ppK${}^{-}$ bound state search in the ${\Sigma }^0$p final state

   O. Vazquez Doce🇩🇪 · L. Fabbietti🇩🇪 · M. Cargnelli🇦🇹 · C. Curceanu🇮🇹 · J. Marton🇦🇹 · K. Piscicchia🇮🇹 · A. Scordo🇮🇹 · D. Sirghi🇮🇹 · I. Tucakovic🇮🇹 · S. Wycech🇵🇱 · J. Zmeskal🇦🇹 · A. Anastasi🇮🇹 and 9 other authors

   We report the measurement of K${}^{-}$ absorption processes in the ${\Sigma }^0$p final state and the first exclusive measurement of the two nucleon absorption (2NA) with the KLOE detector. The 2NA process without further interactions is found to be 12\% of the sum of all other contributing processes, including absorption on three and more nucleons or 2NA followed by final state interactions with the residual nucleons. We also determine the possible contribution of the ppK${}^{-}$ bound state to the ${\Sigma }^0$p final state. A yield of ppK${}^{-}/{\mathrm{K}}_{\mathrm{stop}}^{-}$ is found to be $(0.044\pm 0.009sta{t}_{-0.005}^{+0.004}syst)\cdot 10^{-2}$ but its statistical significance based on an F-test is only 1$\sigma$.

   nucl-exPLB(2016)·71 citations
2. 02*

   Stellar 30-keV neutron capture in 94,96Zr and the 90Zr(gamma,n)89Zr photonuclear reaction with a high-power liquid-lithium target

   M. Tessler🇮🇱 · M. Paul🇮🇱 · A. Arenshtam🇮🇱 · G. Feinberg🇮🇱 · M. Friedman · S. Halfon🇮🇱 · D. Kijel🇮🇱 · L. Weissman🇮🇱 · O. Aviv🇮🇱 · D. Berkovits🇮🇱 · Y. Eisen🇮🇱 · I. Eliyahu🇮🇱 and 7 other authors

   A high-power Liquid-Lithium Target (LiLiT) was used for the first time for neutron production via the thick-target 7Li(p,n)7Be reaction and quantitative determination of neutron capture cross sections. Bombarded with a 1-2 mA proton beam at 1.92 MeV from the Soreq Applied Research Accelerator Facility (SARAF), the setup yields a 30-keV quasi-Maxwellian neutron spectrum with an intensity of 3-5e10 n/s, more than one order of magnitude larger than present near-threshold 7Li(p,n) neutron sources. The setup was used here to determine the 30-keV Maxwellian averaged cross section (MACS) of 94Zr and 96Zr as 28.0+-0.6 mb and 12.4+-0.5 mb respectively, based on activation measurements. The precision of the cross section determinations results both from the high neutron yield and from detailed simulations of the entire experimental setup. We plan to extend our experimental studies to low-abundance and radioactive targets. In addition, we show here that the setup yields intense high-energy (17.6 and 14.6 MeV) prompt capture gamma-rays from the 7Li(p,gamma)8Be reaction with yields of ~3e8 gammas/s/mA and ~4e8 gammas/s/mA, respectively, evidenced by the 90Zr(gamma,n)89Zr photonuclear reaction.

   nucl-exPLB(2015)·29 citations
3. 03*

   Search for $2\nu \beta \beta$ decay of ${}^{136}$Xe to the 0${}_1^{+}$ excited state of ${}^{136}$Ba with 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🇺🇸 · J. Chaves🇺🇸 · B. Cleveland🇨🇦 and 78 other authors

   EXO-200 is a single phase liquid xenon detector designed to search for neutrinoless double-beta decay of ${}^{136}$Xe to the ground state of ${}^{136}$Ba. We report here on a search for the two-neutrino double-beta decay of ${}^{136}$Xe to the first $0^{+}$ excited state, $0_1^{+}$, of ${}^{136}$Ba based on a 100 kg$\cdot$yr exposure of ${}^{136}$Xe. Using a specialized analysis employing a machine learning algorithm, we obtain a 90% CL half-life sensitivity of $1.7\times 10^{24}$ yr. We find no statistically significant evidence for the $2\nu \beta \beta$ decay to the excited state resulting in a lower limit of $T_{1/2}^{2\nu }$ ($0^{+}\to 0_1^{+}$) $>6.9\times 10^{23}$ yr at 90% CL. This observed limit is consistent with the estimated half-life of $2.5\times 10^{25}$ yr.

   nucl-exhep-exPRC(2016)·33 citations
4. 04*

   High Resolution Spectroscopic Study of ${}_{\Lambda }^{10}$Be

   T. Gogami🇯🇵 · C. Chen🇺🇸 · D. Kawama🇯🇵 · P. Achenbach🇩🇪 · A. Ahmidouch🇺🇸 · I. Albayrak🇺🇸 · D. Androic🇭🇷 · A. Asaturyan🇦🇲 · R. Asaturyan🇦🇲 · O. Ates🇺🇸 · P. Baturin🇺🇸 · R. Badui🇺🇸 and 74 other authors

   Spectroscopy of a ${}_{\Lambda }^{10}$Be hypernucleus was carried out at JLab Hall C using the $(e,e^{\prime }{K}^{+})$ reaction. A new magnetic spectrometer system (SPL+HES+HKS), specifically designed for high resolution hypernuclear spectroscopy, was used to obtain an energy spectrum with a resolution of 0.78 MeV (FWHM). The well-calibrated spectrometer system of the present experiment using the $p(e,e^{\prime }{K}^{+})\Lambda ,{\Sigma }^0$ reactions allowed us to determine the energy levels, and the binding energy of the ground state peak (mixture of 1${}^{-}$ and 2${}^{-}$ states) was obtained to be B${}_{\Lambda }$=8.55$\pm$0.07(stat.)$\pm$0.11(sys.) MeV. The result indicates that the ground state energy is shallower than that of an emulsion study by about 0.5 MeV which provides valuable experimental information on charge symmetry breaking effect in the $\Lambda N$ interaction.

   nucl-exPRC(2016)·85 citations
5. 05*

   Experiment summary

   Andrea Rossi (Padua University & INFN)🇮🇹

   The measurement of the production of particles coming from hard scattering processes covers a fundamental role in the characterization of the system formed in heavy-ion collisions, allowing to probe the microscopic processes underlying the interaction of high energy partons with the medium. An impressive amount of measurements related to jet, quarkonia, open heavy flavor, and electroweak signal production in nucleus-nucleus as well as p(d)-nucleus collisions was delivered by experiments at RHIC and LHC in past years. In these proceedings, the main experimental results presented during the Hard Probes conference are summarized.

   ↳ hep-exhep-phnucl-exnucl-thNucl.Part.Phys.Proc.(2016)·0 citations
6. 06*

   Probing the dissipative properties of a strongly interacting medium with dileptons

   Gojko Vujanovic🇨🇦 · Chun Shen🇨🇦 · Gabriel S. Denicol🇨🇦 · Bjoern Schenke🇺🇸 · Sangyong Jeon🇨🇦 · Charles Gale🇨🇦

   We investigate the effects of the presence of a non-vanishing net baryon number density and its diffusion on dilepton production, within a hydrodynamical description of the medium created at $\sqrt{s_{NN}}=7.7$ GeV collision energy. This energy value is explored within the Beam Energy Scan (BES) program at Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. Particular attention is devoted to a new dissipative degree of freedom: the net baryon number diffusion ($V^{\mu }$), and to the net baryon number conductivity ($\kappa$) | a transport coefficients governing the overall magnitude of $V^{\mu }$. The effects of $\kappa$ on dilepton production are assessed, with an outlook on how future experimental dilepton data can be used to learn more about $\kappa$.

   ↳ nucl-thnucl-exPPNP(2016)·4 citations
7. 07*

   Direct dark matter search by annual modulation in XMASS-I

   XMASS Collaboration: K. Abe🇯🇵 · K. Hiraide🇯🇵 · K. Ichimura🇯🇵 · Y. Kishimoto🇯🇵 · K. Kobayashi🇯🇵 · M. Kobayashi🇯🇵 · S. Moriyama🇯🇵 · M. Nakahata🇯🇵 · T. Norita🇯🇵 · H. Ogawa🇯🇵 · H. Sekiya🇯🇵 · O. Takachio🇯🇵 and 29 other authors

   A search for dark matter was conducted by looking for an annual modulation signal due to the Earth's rotation around the Sun using XMASS, a single phase liquid xenon detector. The data used for this analysis was 359.2 live days times 832 kg of exposure accumulated between November 2013 and March 2015. When we assume Weakly Interacting Massive Particle (WIMP) dark matter elastically scattering on the target nuclei, the exclusion upper limit of the WIMP-nucleon cross section 4.3$\times$10${}^{-41}$cm${}^2$ at 8 GeV/c${}^2$ was obtained and we exclude almost all the DAMA/LIBRA allowed region in the 6 to 16 GeV/c${}^2$ range at $\sim$10${}^{-40}$cm${}^2$. The result of a simple modulation analysis, without assuming any specific dark matter model but including electron/$\gamma$ events, showed a slight negative amplitude. The $p$-values obtained with two independent analyses are 0.014 and 0.068 for null hypothesis, respectively. we obtained 90\% C.L. upper bounds that can be used to test various models. This is the first extensive annual modulation search probing this region with an exposure comparable to DAMA/LIBRA.

   ↳ astro-ph.COhep-exnucl-exphysics.ins-detPLB(2016)·84 citations
8. 08*

   Nuclear physics from QCD on lattice

   Takashi Inoue · for HAL QCD Collaboration

   We have presented a strategy to study nuclei and nuclear matters from first principles, namely, from QCD. We first compute nucleon-nucleon potentials numerically in lattice QCD, and then use them to investigate properties of nuclei and nuclear matter by various methods developed in nuclear physics. As a demonstration that this strategy works, mass and structure of ^4^He, ^16^O and ^40^Ca, and equation of state of nuclear matters are determined with the lattice QCD induced two-nucleon potentials in a heavy quark region as an input. We have found that these nuclei and the symmetric nuclear matter are bound at one quark mass corresponding to the pseudo-scalar meson (pion) mass of 469 MeV (the octet baryon (nucleon) mass of 1161 MeV). The obtained binding energy per nucleon has a uniform mass-number A dependence which is consistent to the Bethe-Weizsacker mass formula qualitatively. The present study demonstrates that our strategy works well to investigate various properties of atomic nuclei and nuclear matter starting from QCD, without depending on models or experimental information about the nuclear force.

   ↳ hep-lathep-phnucl-exnucl-thPoS(2016)·6 citations
9. 09*

   Leading-twist parton distribution amplitudes of S-wave heavy-quarkonia

   Minghui Ding🇨🇳 · Fei Gao🇨🇳 · Lei Chang🇨🇳 · Yu-Xin Liu🇨🇳 · Craig D. Roberts🇺🇸

   The leading-twist parton distribution amplitudes (PDAs) of ground-state ${}^1{S}_0$ and ${}^3{S}_1$ $c\bar{c}$- and $b\bar{b}$-quarkonia are calculated using a symmetry-preserving continuum treatment of the meson bound-state problem which unifies the properties of these heavy-quark systems with those of light-quark bound-states, including QCD's Goldstone modes. Analysing the evolution of ${}^1{S}_0$ and ${}^3{S}_1$ PDAs with current-quark mass, ${\hat{m}}_q$, increasing away from the chiral limit, it is found that in all cases there is a value of ${\hat{m}}_q$ for which the PDA matches the asymptotic form appropriate to QCD's conformal limit and hence is insensitive to changes in renormalisation scale, $\zeta$. This mass lies just above that associated with the $s$-quark. At current-quark masses associated with heavy-quarkonia, on the other hand, the PDAs are piecewise convex-concave-convex. They are much narrower than the asymptotic distribution on a large domain of $\zeta$; but nonetheless deviate noticeably from ${\phi }_{Q\bar{Q}}(x)=\delta (x-1/2)$, which is the result in the static-quark limit. There are also material differences between ${}^1{S}_0$ and ${}^3{S}_1$ PDAs, and between the PDAs for different vector-meson polarisations, which vanish slowly with increasing $\zeta$. An analysis of moments of the root-mean-square relative-velocity, $⟨v^{2m}⟩$, in ${}^1{S}_0$ and ${}^3{S}_1$ systems reveals that $⟨v^4⟩$-contributions may be needed in order to obtain a reliable estimate of matrix elements using such an expansion, especially for processes involving heavy pseudoscalar quarkonia.

   ↳ nucl-thhep-exhep-lathep-ph+1PLB(2016)·77 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.