Thu·Mar 19, 2020Thursday·March 19, 2020

1. 01*

   Search for the high-spin members of the $\alpha$:2n:$\alpha$ band in ${}^{10}$Be

   Sriteja Upadhyayula🇺🇸 · Grigory V. Rogachev🇺🇸 · Jack Bishop🇺🇸 · Vladilen Z. Goldberg🇺🇸 · Joshua Hooker🇺🇸 · Curtis Hunt · Heshani Jayatissa🇺🇸 · Evgeniy Koshchiy🇺🇸 · Ethan Uberseder🇺🇸 · Alexander Volya🇺🇸 · Brian T. Roeder🇺🇸 · Antti Saastamoinen🇺🇸

   Method: Measuring excitation functions for ${}^6$He+$\alpha$ scattering, populating states in the excitation energy range from 4.5 MeV to 8 MeV in ${}^{10}$Be using a ${}^6$He rare-isotope beam and a thick helium gas target. Results: No new excited states in ${}^{10}$Be have been observed. Stringent limitation on the possible degree of $\alpha$-clustering of the hypothetical yrast 6${}^{+}$ state has been obtained. Conclusions: The high-spin members of the $\alpha$:2n:$\alpha$ molecular-like rotational band configuration, that is considered to have a 0${}^{+}$ bandhead at 6.18 MeV, either do not exist or have small overlap with the ${}^6$He(g.s.)+$\alpha$ channel.

   nucl-exPRC(2020)·9 citations
2. 02*

   Measurement of the Photon Beam Asymmetry in $\vec{\gamma }p\to K^{+}{\Sigma }^0$ at $E_{\gamma }=8.5$ GeV

   The GlueX Collaboration: S. Adhikari🇺🇸 · A. Ali🇩🇪 · M. Amaryan🇺🇸 · A. Austregesilo🇺🇸 · F. Barbosa🇺🇸 · J. Barlow🇺🇸 · E. Barriga🇺🇸 · R. Barsotti🇺🇸 · T. D. Beattie🇨🇦 · V. V. Berdnikov🇷🇺 · T. Black🇺🇸 · W. Boeglin🇺🇸 and 114 other authors

   We report measurements of the photon beam asymmetry $\Sigma$ for the reaction $\vec{\gamma }p\to K^{+}{\Sigma }^0$(1193) using the GlueX spectrometer in Hall D at Jefferson Lab. Data were collected using a linearly polarized photon beam in the energy range of 8.2-8.8 GeV incident on a liquid hydrogen target. The beam asymmetry $\Sigma$ was measured as a function of the Mandelstam variable $t$, and a single value of $\Sigma$ was extracted for events produced in the $u$-channel. These are the first exclusive measurements of the photon beam asymmetry $\Sigma$ for the reaction in this energy range. For the $t$-channel, the measured beam asymmetry is close to unity over the $t$-range studied, $-t=(0.1-1.4)$(GeV/$c$)${}^2$, with an average value of $\Sigma =1.00\pm 0.05$. This agrees with theoretical models that describe the reaction via the natural-parity exchange of the $K^{\ast }$(892) Regge trajectory. A value of $\Sigma =0.41\pm 0.09$ is obtained for the $u$-channel integrated up to $-u=2.0$~(GeV/$c$)${}^2$.

   nucl-exhep-exhep-phPRC(2020)·16 citations
3. 03*

   Enhancement of octupole strength in near spherical nuclei

   L.M. Robledo🇪🇸

   The validity of the rotational formula used to compute E1 and E3 transition strengths in even-even nuclei is analyzed within the Generator Coordinate Method framework based on mean field wave functions. It turns out that those nuclei with spherical or near spherical shapes the E1 and E3 strengths computed with this formula are strongly underestimated and a sound evaluation of them requires angular momentum projected wave functions. Results for several isotopic chains with proton number equal or near magic numbers are analyzed and compared with experimental data. The use of angular momentum projected wave functions greatly improves the agreement with the scarce experimental data.

   ↳ nucl-thnucl-exEPJA(2016)·11 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.