Fri·May 3, 2019Friday·May 3, 2019

1. 01*

   Probing for high momentum protons in ${}^4$He via the ${}^{4}He(e,e^{\prime }p)X$ reaction

   S. Iqbal · F. Benmokhtar · M. Ivanov · N. See · K. Aniol · D. W. Higinbotham · C. Boyd · A. Gadsby · S. Gilad · A. Saha · J.M. Udias · J. S. Goodwill and 98 other authors

   Experimental cross sections for the ${}^{4}He(e,e^{\prime }p)X$ reaction up to a missing momentum of 0.632 GeV/$c$ at $x_B=1.24$ and $Q^2$=2(GeV/$c$)${}^2$ are reported. The data are compared to Relativistic Distorted Wave Impulse Approximation(RDWIA) calculations for ${}^{4}He(e,e^{\prime }p{)}^{3}H$ channel. Significantly more events in the triton mass region are measured for $p_m$$>$0.45 GeV/$c$ than are predicted by the theoretical model, suggesting that the effects of initial-state multi-nucleon correlations are stronger than expected by the RDWIA model.

   nucl-exPRC(2022)·0 citations
2. 02*

   Electromagnetic properties of the $d^{\ast }(2380)$ hexaquark

   M. Bashkanov🇬🇧 · D.P. Watts🇬🇧 · A. Pastore🇬🇧

   Experiments with intense photon and electron beams have the potential to provide access to nontrivial properties of the recently discovered $d^{\ast }(2380)$ hexaquark including its size, structure, magnetic moment, quadrupole and octupole deformations. In this paper we investigate the sensitivity of ongoing and planned experiments to various properties of the $d^{\ast }(2380)$, employing models based on both constituent quark and pion cloud frameworks. Our calculations indicate that for photoinduced reactions on the deuteron the $d^{\ast }(2380)$ is predominantly produced from the $D-wave$ component of the deuteron. We confirm earlier findings that the intrinsic quadrupole deformation of the $d^{\ast }(2380)$ should be small. We also demonstrate an ability to extract the $d^{\ast }(2380)$ magnetic moment and put constrains on the $d^{\ast }(2380)$ $M3/E2$ ratio.

   ↳ nucl-thnucl-exPRC(2019)·11 citations
3. 03*

   Radiative corrections of order O(alpha E_e/m_N) to Sirlin's radiative corrections of order O(alpha/pi) to neutron lifetime

   A. N. Ivanov🇦🇹 · R. Höllwieser🇦🇹 · N. I. Troitskaya🇦🇹 · M. Wellenzohn🇦🇹 · Ya. A. Berdnikov🇷🇺

   We calculate the radiative corrections of order O(alpha E_e/m_N) as next-to-leading order corrections in the large nucleon mass expansion to Sirlin's radiative corrections of order O(alpha/pi) to the neutron lifetime. The calculation is carried out within a quantum field theoretic model of strong low-energy pion--nucleon interactions described by the linear sigma-model (LsM) with chiral SU(2)xSU(2) symmetry and electroweak hadron-hadron, hadron-lepton and lepton-lepton interactions for the electron-lepton family with SU(2)_L x U(1)_Y symmetry of the Standard Electroweak Model (SEM). Such a quantum field theoretic model is some kind a hadronized version of the Standard Model (SM). From a gauge invariant set of the Feynman diagrams with one-photon exchanges we reproduce Sirlin's radiative corrections of order O(alpha/pi), calculated to leading order in the large nucleon mass expansion, and calculate next-to-leading corrections of order O(alpha E_e/m_N). This confirms Sirlin's confidence level of the radiative corrections O(alpha E_e/m_N). The contributions of the LsM are taken in the limit of the infinite mass of the scalar isoscalar sigma-meson. In such a limit the LsM reproduces the results of the current algebra (Weinberg, Phys. Rev. Lett. {\bf 18}, 188 (1967)) in the form of effective chiral Lagrangians of pion-nucleon interactions with non--linear realization of chiral SU(2)xSU(2) symmetry. In such a limit the L$\sigma$M is also equivalent to Gasser-Leutwyler's chiral quantum field theory or chiral perturbation theory (ChPT) with chiral SU(2)xSU(2)symmetry and the exponential parametrization of a pion-field (Ecker, Prog. Part. Nucl. Phys. {\bf 35}, 1 (1995)).

   ↳ hep-phhep-exnucl-exPRD(2019)·9 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.