Measurement of Compton Scattering at MAMI for the Extraction of the Electric and Magnetic Polarizabilities of the Proton

Le résumé fourni par la source

A precise measurement of the differential cross sections $d\ensuremath{\sigma}/d\mathrm{\ensuremath{\Omega}}$ and the linearly polarized photon beam asymmetry ${\mathrm{\ensuremath{\Sigma}}}_{3}$ for Compton scattering on the proton below pion threshold has been performed with a tagged photon beam and almost $4\ensuremath{\pi}$ detector at the Mainz Microtron. The incident photons were produced by the recently upgraded Glasgow-Mainz photon tagging facility and impinged on a cryogenic liquid hydrogen target, with the scattered photons detected in the Crystal Ball/TAPS setup. Using the highest statistics Compton scattering data ever measured on the proton along with two effective field theories (both covariant baryon and heavy-baryon) and one fixed-$t$ dispersion relation model, constraining the fits with the Baldin sum rule, we have obtained the proton electric and magnetic polarizabilities with unprecedented precision: ${\ensuremath{\alpha}}_{E1}=10.99\ifmmode\pm\else\textpm\fi{}0.16\ifmmode\pm\else\textpm\fi{}0.47\ifmmode\pm\else\textpm\fi{}0.17\ifmmode\pm\else\textpm\fi{}0.34$, ${\ensuremath{\beta}}_{M1}=3.14\ifmmode\pm\else\textpm\fi{}0.21\ifmmode\pm\else\textpm\fi{}0.24\ifmmode\pm\else\textpm\fi{}0.20\ifmmode\pm\else\textpm\fi{}0.35$; in units of ${10}^{\ensuremath{-}4}\text{ }\text{ }{\mathrm{fm}}^{3}$ where the errors are statistical, systematic, spin polarizability dependent, and model dependent.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.