Wed·Apr 29, 2015Wednesday·April 29, 2015

1. 01*

   $\gamma$ ray spectroscopy of ${}^{19}$C via single neutron knock-out reaction

   Zs. Vajta🇭🇺 · Zs. Dombrádi · Z. Elekes🇩🇪 · T. Aiba · N. Aoi🇯🇵 · H. Baba🇯🇵 · D. Bemmerer🇩🇪 · Zs. Fülöp🇭🇺 · N. Iwasa🇯🇵 · Á. Kiss · T. Kobayashi🇯🇵 · Y. Kondo🇯🇵 and 11 other authors

   The one neutron knock-out reaction ${}^1$H(${}^{20}$C,${}^{19}$C$\gamma$) was studied at RIKEN using the DALI2 array. A $\gamma$ ray transition was observed at 198(10) keV. Based on the comparison between the experimental production cross section and theoretical predictions, the transition was assigned to the decay of the 3/2${}_1^{+}$ state to the ground state.

   nucl-exPRC(2015)·4 citations
2. 02*

   Estimations and integral measurements for the spectral yield of neutrons from thick beryllium target bombarded with 16 MeV protons

   A. Fenyvesi

   Spectral yield of p+Be neutrons emitted by thick (stopping) beryllium target bombarded by 16 MeV protons was estimated via extrapolation of literature data. The spectrum was validated via multi-foil activation method and irradiation of 2N2222 transistors. The hardness parameter (NIEL scaling factor) for displacement damage in bulk silicon was calculated and measured and kappa = 1.26 +- 0.1 was obtained.

   nucl-exphysics.ins-det0 citations
3. 03*

   Search for long-lived superheavy eka-tungsten with radiopure ZnWO${}_4$ crystal scintillator

   P. Belli (1)🇮🇹 · R. Bernabei (1,2)🇮🇹 · F. Cappella (3)🇮🇹 · R. Cerulli (3)🇮🇹 · F.A. Danevich (4)🇺🇦 · V.Yu. Denisov (4) · A. d'Angelo (5)🇮🇹 · A. Incicchitti (5)🇮🇹 · V.V. Kobychev (4)🇺🇦 · D.V. Poda (4,6)🇺🇦 · O.G. Polischuk (5,4)🇺🇦 · V.I. Tretyak (5,4) ((1) INFN Roma Tor Vergata, (2) Univ. Roma Tor Vergata, (3) INFN LNGS, (4) INR Kiev, (5) INFN Roma, (6) CSNSM Orsay)🇺🇦

   The data collected with a radioactively pure ZnWO${}_4$ crystal scintillator (699 g) in low background measurements during 2130 h at the underground (3600 m w.e.) Laboratori Nazionali del Gran Sasso (INFN, Italy) were used to set a limit on possible concentration of superheavy eka-W (seaborgium Sg, Z = 106) in the crystal. Assuming that one of the daughters in a chain of decays of the initial Sg nucleus decays with emission of high energy $\alpha$ particle ($Q_{\alpha }>8$ MeV) and analyzing the high energy part of the measured $\alpha$ spectrum, the limit N(Sg)/N(W) < 5.5 $\times$ 10${}^{-14}$ atoms/atom at 90% C.L. was obtained (for Sg half-life of 10${}^9$ yr). In addition, a limit on the concentration of eka-Bi was set by analysing the data collected with a large BGO scintillation bolometer in an experiment performed by another group [L. Cardani et al., JINST 7 (2012) P10022]: N(eka-Bi)/N(Bi) < 1.1 $\times$ 10${}^{-13}$ atoms/atom with 90% C.L. Both the limits are comparable with those obtained in recent experiments which instead look for spontaneous fission of superheavy elements or use the accelerator mass spectrometry.

   nucl-exPhys.Scripta(2015)·13 citations
4. 04*

   First Measurement of the Atomic Electric Dipole Moment of ${}^{225}$Ra

   R.H. Parker🇺🇸 · M.R. Dietrich🇺🇸 · M.R. Kalita🇮🇳 · N.D. Lemke🇺🇸 · K.G. Bailey🇺🇸 · M.N. Bishof🇺🇸 · J.P. Greene🇺🇸 · R.J. Holt🇺🇸 · W. Korsch🇺🇸 · Z.-T. Lu🇺🇸 · P. Mueller🇺🇸 · T.P. O'Connor🇺🇸 · J.T. Singh🇺🇸

   The radioactive radium-225 (${}^{225}$Ra) atom is a favorable case to search for a permanent electric dipole moment (EDM). Due to its strong nuclear octupole deformation and large atomic mass, ${}^{225}$Ra is particularly sensitive to interactions in the nuclear medium that violate both time-reversal symmetry and parity. We have developed a cold-atom technique to study the spin precession of ${}^{225}$Ra atoms held in an optical dipole trap, and demonstrated the principle of this method by completing the first measurement of its atomic EDM, reaching an upper limit of $|$$d$(${}^{225}$Ra)$|$ $<$ $5.0\times 10^{-22}$ $e\cdot$cm (95$\%$ confidence).

   nucl-exphysics.atom-phPRL(2015)·141 citations
5. 05*

   Role of $\Lambda (1670)$ in the $\gamma p\to K^{+}\eta \Lambda$ reaction near threshold

   Li-Ye Xiao🇨🇳 · Qi-Fang Lü🇨🇳 · Ju-Jun Xie🇨🇳 · Xian-Hui Zhong🇨🇳

   The role of the $\Lambda (1670)$ resonance in the $\gamma p\to K^{+}\eta \Lambda$ reaction near threshold is studied within an effective Lagrangian approach. We perform a calculation for the total and differential cross section of the $\gamma p\to K^{+}\eta \Lambda$ reaction by including the contributions from the $\Lambda (1670)$ intermediate state decaying into $\eta \Lambda$ dominated by $K^{-}$ and $K^{\ast -}$ mesons exchanges, the nucleon pole and $N^{\ast }(1535)$ resonance decaying into $K^{+}\Lambda$ dominated by exchanges of $\omega$ and $K^{-}$ mesons. Besides, the non-resonance process and contact terms to keep the total scattering amplitude gauge invariant are also considered. With our model parameters, the total cross section of this reaction is of the order of $1$ nanobarn at photon beam energy $E_{\gamma }\sim 2.5$ GeV. It is expected that our model predictions could be tested by future experiments.

   ↳ nucl-thhep-phnucl-exEPJA(2015)·6 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.