Wed·May 31, 2017Wednesday·May 31, 2017

1. 01*

   Missing-mass spectroscopy of the ${}^{12}\mathrm{C}(p,d)$ reaction near the ${\eta }^{\prime }$-meson production threshold

   Y. K. Tanaka🇯🇵 · K. Itahashi🇯🇵 · H. Fujioka🇯🇵 · Y. Ayyad🇯🇵 · J. Benlliure🇪🇸 · K.-T. Brinkmann🇩🇪 · S. Friedrich🇩🇪 · H. Geissel🇩🇪 · J. Gellanki🇳🇱 · C. Guo🇨🇳 · E. Gutz🇩🇪 · E. Haettner🇩🇪 and 42 other authors

   Excitation-energy spectra of ${}^{11}$C nuclei near the ${\eta }^{\prime }$-meson production threshold have been measured by missing-mass spectroscopy using the ${}^{12}$C($p$,$d$) reaction. A carbon target has been irradiated with a 2.5 GeV proton beam supplied by the synchrotron SIS-18 at GSI to produce ${\eta }^{\prime }$ meson bound states in ${}^{11}$C nuclei. Deuterons emitted at $0^{\circ }$ in the reaction have been momentum-analyzed by the fragment separator (FRS) used as a high-resolution spectrometer. No distinct structure due to the formation of ${\eta }^{\prime }$-mesic states is observed although a high statistical sensitivity is achieved in the experimental spectra. Upper limits on the formation cross sections of ${\eta }^{\prime }$-mesic states are determined, and thereby a constraint imposed on the ${\eta }^{\prime }$-nucleus interaction is discussed.

   nucl-exnucl-thPRC(2018)·42 citations
2. 02*

   Hard exclusive neutrino production of a light meson

   B. Pire🇫🇷 · L. Szymanowski🇵🇱 · J. Wagner🇵🇱

   We update the leading order in ${\alpha }_s$ QCD amplitude for deep exclusive neutrino and antineutrino production of a light meson on an unpolarized nucleon. The factorization theorems of the collinear QCD approach allow us to write the amplitude as the convolution of generalized parton distributions (GPDs) and perturbatively calculable coefficient functions. We study both the pseudoscalar meson and longitudinally polarized vector meson cases. It turns out that, contrarily to the electroproduction case, the leading twist scattering amplitudes for $\pi$ and ${\rho }_L$ productions are proportional to one another, which may serve as an interesting new test of the leading twist dominance of exclusive processes at medium scale. The dominance of the gluonic contribution to most cross sections is stressed.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2017)·16 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.