Fri·Sep 2, 2016Friday·September 2, 2016

1. 01*

   Search for Tetraneutron by Pion Double Charge Exchange Reaction at J-PARC

   Hiroyuki Fujioka🇯🇵 · Tomokazu Fukuda🇯🇵 · Toru Harada🇯🇵 · Emiko Hiyama🇯🇵 · Kenta Itahashi🇯🇵 · Shunsuke Kanatsuki🇯🇵 · Tomofumi Nagae🇯🇵 · Takuya Nanamura🇯🇵 · Takahiro Nishi🇯🇵

   Tetraneutron (${}^{4}n$) has come back in the limelight, because of recent observation of a candidate resonant state at RIBF. We propose to investigate the pion double charge exchange (DCX) reaction, i.e. ${}^4\mathrm{He}({\pi }^{-},{\pi }^{+})$, as an alternative way to populate tetraneutron. An intense ${\pi }^{-}$ beam with the kinetic energy of ~850 MeV, much higher than that in past experiments at LAMPF and TRIUMF, will open up a possibility to improve the experimental sensitivity of the formation cross section, which will be much smaller than hitherto known DCX cross sections such as ${}^9\mathrm{Be}({\pi }^{-},{\pi }^{+}{)}^9\mathrm{He}(g.s.)$.

   nucl-exnucl-thJPS Conf.Proc.(2017)·2 citations
2. 02*

   Single-particle and collective excitations in ${}^{62}$Ni

   M. Albers🇺🇸 · S. Zhu🇺🇸 · A. D. Ayangeakaa🇺🇸 · R. V. F. Janssens🇺🇸 · J. Gellanki🇳🇱 · I. Ragnarsson · M. Alcorta🇨🇦 · T. Baugher🇺🇸 · P. F. Bertone🇺🇸 · M. P. Carpenter🇺🇸 · C. J. Chiara🇺🇸 · P. Chowdhury🇺🇸 and 12 other authors

   {\bf Background:} Level sequences of rotational character have been observed in several nuclei in the $A=60$ mass region. The importance of the deformation-driving $\pi f_{7/2}$ and $\nu g_{9/2}$ orbitals on the onset of nuclear deformation is stressed.\\ {\bf Purpose:} A measurement was performed in order to identify collective rotational structures in the relatively neutron-rich ${}^{62}$Ni isotope. \\ {\bf Method:} The ${}^{26}$Mg(${}^{48}$Ca,2$\alpha$4$n\gamma$)${}^{62}$Ni complex reaction at beam energies between 275 and 320~MeV was utilized. Reaction products were identified in mass ($A$) and charge ($Z$) with the Fragment Mass Analyzer (FMA) and $\gamma$ rays were detected with the Gammasphere array. \\ {\bf Results:} Two collective bands, built upon states of single-particle character, were identified and sizable deformation was assigned to both sequences based on the measured transitional quadrupole moments, herewith quantifying the deformation at high spin. \\ {\bf Conclusions:} Based on Cranked Nilsson-Strutinsky calculations and comparisons with deformed bands in the $A=60$ mass region, the two rotational bands are understood as being associated with configurations involving multiple $f_{7/2}$ protons and $g_{9/2}$ neutrons, driving the nucleus to sizable prolate deformation.

   nucl-exPRC(2016)·17 citations
3. 03*

   Alpha clustering in ${}^{28}$Si probed through the identification of high-lying $0^{+}$ states

   P. Adsley🇿🇦 · D.G. Jenkins🇬🇧 · J. Cseh · S.S. Dimitriova · J.W. Brümmer🇿🇦 · K.C.W. Li🇿🇦 · D.J. Marín-Lámbarri🇿🇦 · K. Lukyanov · N.Y. Kheswa🇿🇦 · R. Neveling · P. Papka🇿🇦 · L. Pellegri🇿🇦 and 6 other authors

   Aspects of nuclear structure in alpha-conjugate nuclei have long been associated with alpha clustering, including the existence of superdeformed bands. In this paper, an alpha-particle inelastic scattering experiment investigating the location of $0^{+}$ states in ${}^{28}$Si is reported in an attempt to locate possible cluster states. The results are compared to a semi-microscopic model which shows good agreement with the data, and supports the assignment of a newly discovered $0^{+}$ state as the band-head of a previously observed superdeformed band in ${}^{28}$Si

   nucl-exnucl-thPRC(2017)·21 citations
4. 04*

   Search for Hidden-Charm Pentaquark with CLAS12

   V. Kubarovsky🇺🇸 · M.B. Voloshin🇺🇸

   LHCb recently announced the discovery of two exotic structures in the $J/\psi +p$ decay channel, which have been referred to as charmonium-pentaquark states. Resolving between the models and clarifying the nature of the discovered hidden-charm pentaquark peaks, and possibly searching for similar peaks with other quantum numbers, requires further experimental studies. The states were observed in the decay mode $J/\psi +p$. Thus, it is natural to expect that these pentaquarks can be produced in the photoproduction process $\gamma +p\to P_c\to J/\psi +p$ where these states will appear as s-channel resonances at photon energy around 10 GeV. The energy and luminosity of the CLAS12 photon beam permit the detailed studies of the production and decay properties of the pentaquark resonances. By this reason the pentaquark search at Jefferson Laboratory looks extremely attractive.

   ↳ hep-phhep-exnucl-ex15 citations
5. 05*

   Charge symmetry breaking in $\Lambda$ hypernuclei: updated HYP 2015 progress report

   Avraham Gal🇮🇱

   Ongoing progress in understanding and evaluating charge symmetry breaking in $\Lambda$ hypernuclei is discussed in connection to recent measurements of the ${}_{\Lambda }^4\mathrm{H}(0_{g.s.}^{+})$ binding energy at MAMI [A1 Collaboration: PRL 114 (2015) 232501] and of the ${}_{\Lambda }^4\mathrm{He}(1_{\mathrm{exc}}^{+})$ excitation energy at J-PARC [E13 Collaboration: PRL 115 (2015) 222501].

   ↳ nucl-thhep-phnucl-exJPS Conf.Proc.(2017)·2 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.