Tue·Aug 4, 2015Tuesday·August 4, 2015

1. 01*

   ${\Sigma }^{-}p$ emission rates in $K^{-}$ absorptions at rest on ${}^6$Li, ${}^7$Li, ${}^9$Be, ${}^{13}$C and ${}^{16}$O

   FINUDA Collaboration · M. Agnello · L. Benussi · M. Bertani · G. Bonomi · E. Botta · M. Bregant · T. Bressani · S. Bufalino · L. Busso · D. Calvo · P. Camerini and 23 other authors

   An experimental study of the $K_{stop}^{-}A\to {\Sigma }^{-}p{A}^{\prime }$ reaction on $A{=}^6$Li, ${}^7$Li, ${}^9$Be, ${}^{13}$C and ${}^{16}$O $p$-shell nuclei is presented. The data were collected by the FINUDA spectrometer operating at the DA$\Phi$NE $\varphi$-factory (LNF-INFN, Italy). Emission rates for the reaction in the mentioned nuclei are measured and compared with the few existing data. The spectra of several observables are discussed; indications of Quasi-Free absorptions by a $(np)$ pair embedded in the $A$ nucleus can be obtained from the study of the missing mass distributions.

   nucl-exPRC(2015)·10 citations
2. 02*

   Observation of Spin-Dependent Charge Symmetry Breaking in $\Lambda N$ Interaction: Gamma-Ray Spectroscopy of ${}_{\Lambda }^4$He

   T. O. Yamamoto🇯🇵 · M. Agnello🇮🇹 · Y. Akazawa🇯🇵 · N. Amano🇯🇵 · K. Aoki🇯🇵 · E. Botta🇮🇹 · N. Chiga🇯🇵 · H. Ekawa🇯🇵 · P. Evtoukhovitch🇷🇺 · A. Feliciello🇮🇹 · M. Fujita🇯🇵 · T. Gogami🇯🇵 and 42 other authors

   The energy spacing between the ground-state spin doublet of ${}_{\Lambda }^4$He(1${}^{+}$,0${}^{+}$) was determined to be $1406\pm 2\pm 2$ keV, by measuring $\gamma$ rays for the $1^{+}\to 0^{+}$ transition with a high efficiency germanium detector array in coincidence with the ${}^4$He$(K^{-},{\pi }^{-})$ ${}_{\Lambda }^4$He reaction at J-PARC. In comparison to the corresponding energy spacing in the mirror hypernucleus ${}_{\Lambda }^4$H, the present result clearly indicates the existence of charge symmetry breaking (CSB) in $\Lambda N$ interaction. It is also found that the CSB effect is large in the $0^{+}$ ground state but is by one order of magnitude smaller in the $1^{+}$ excited state, demonstrating that the $\Lambda N$ CSB interaction has spin dependence.

   nucl-exnucl-thPRL(2015)·142 citations
3. 03*

   Characteristics of neutrons and proton beams arising from two different Beam Nozzles

   Yeon-Gyeong Choi · Yu-Seok Kim🇰🇷

   Tandem or Van de Graaff accelerator with an energy of 3-MeV is typically used for PIXE analysis. In this study, the beam line design used in PIXE analysis was used to increase the production of isotopes instead of the typical low-energy accelerator from a 13-MeV cyclotron. For PIXE analysis, the proton beam should be focused at the target through the use of a nozzle after degrading the proton beam energy from 13-MeV to 3-MeV using an energy degrader. Previous studies have been conducted to determine the most appropriate material and thickness of the energy degrader. Based on the energy distribution of the degraded proton beam and the neutron occurrence rate at the degrader an aluminum nozzle of X thickness was determined to be the most appropriate nozzle construction. Neutrons are created by the collision of 3-MeV protons into the nozzle after passage through energy degrader. In addition, a sufficient intensity of proton beam is required for non-destructive analysis of PIXE. Therefore, in order to optimize nozzle design, it is necessary to consider the number of neutrons which arise from the collision of protons inside the nozzle, as well as the track direction of the generated secondary neutrons, with the primary aim of ensuring a sufficient number of protons passing through the nozzle as a direct beam. A number of laboratories are currently conducting research related to the design of nozzles used in accelerator fields, mostly relating to medical fields. In this paper, a comparative analysis was carried out for two typical nozzle shapes in order to minimize losses of protons and generation of secondary neutrons. The neutron occurrence rate and the number of protons after passing through the nozzle were analyzed using a Particle and Heavy Ion Transport code System (PHITS) program, in order to identify the nozzle which generated the strongest proton beam.

   ↳ physics.acc-phnucl-exphysics.ins-detJ.Korean Phys.Soc.(2015)·0 citations
4. 04*

   Four-body calculation of elastic deuteron-deuteron scattering

   A. Deltuva🇱🇹 · A. C. Fonseca🇵🇹

   Fully converged calculations of deuteron-deuteron elastic scattering observables are performed at energies above three- and four-body breakup threshold. Differential cross sections and analyzing powers are obtained using realistic nucleon-nucleon force models together with the Coulomb repulsion between protons. For all observables we find a very reasonable agreement with the available experimental data limited to deuteron beam energies up to 25.3 MeV.

   ↳ nucl-thnucl-exPRC(2015)·19 citations
5. 05*

   Effects of TMD evolution and partonic flavor on $e^{+}{e}^{-}$ annihilation into hadrons

   Alessandro Bacchetta🇮🇹 · Miguel G. Echevarria🇳🇱 · Piet J.G. Mulders🇳🇱 · Marco Radici🇮🇹 · Andrea Signori🇳🇱

   We calculate the transverse momentum dependence in the production of two back-to-back hadrons in electron-positron annihilations at the medium/large energy scales of BES-III and BELLE experiments. We use the parameters of the transverse-momentum-dependent (TMD) fragmentation functions that were recently extracted from the semi-inclusive deep-inelastic-scattering multiplicities at low energy from HERMES. TMD evolution is applied according to different approaches and using different parameters for the nonperturbative part of the evolution kernel, thus exploring the sensitivity of our results to these different choices and to the flavor dependence of parton fragmentation functions. We discuss how experimental measurements could discriminate among the various scenarios.

   ↳ hep-phhep-exnucl-exnucl-thJHEP(2015)·52 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.