New Insight in the $Q^2$-Dependence of Proton Generalized Polarizabilities

J. Beričič , L. Correa (1) , M. Benali (1) , P. Achenbach , C. Ayerbe Gayoso , J.C. Bernauer , A. Blomberg , R. Böhm , D. Bosnar , L. Debenjak , A. Denig , M.O. Distler , E.J. Downie , A. Esser , H. Fonvieille (1) , I. Friščić , S. Kegel , Y. Kohl , M. Makek , H. Merkel , D.G. Middleton , M. Mihovilovič , U. Müller , L. Nungesser , M. Paolone , J. Pochodzalla , S. Sánchez Majos , B.S. Schlimme , M. Schoth , F. Schulz , C. Sfienti , S. Širca , N. Sparveris , S. Štajner , M. Thiel , A. Tyukin , A. Weber , M. Weinriefer

1 LPC - Laboratoire de Physique de Clermont

Virtual Compton scattering on the proton has been investigated at three yet unexplored values of the four-momentum transfer Q2: 0.10, 0.20, and 0.45  GeV2, at the Mainz Microtron. Fits performed using either the low-energy theorem or dispersion relations allowed the extraction of the structure functions PLL-PTT/ε and PLT, as well as the electric and magnetic generalized polarizabilities αE1(Q2) and βM1(Q2). These new results show a smooth and rapid falloff of αE1(Q2), in contrast to previous measurements at Q2=0.33  GeV2, and provide for the first time a precise mapping of βM1(Q2) in the low-Q2 region.

Mots clés: 13.60.Fz; 14.20.Dh; 25.30.Dh; Nuclear Physics

Domaines: Physique Nucléaire Expérimentale [nucl-ex]

J. Beričič, L. Correa, M. Benali, P. Achenbach, C. Ayerbe Gayoso, et al.. New Insight in the $Q^2$-Dependence of Proton Generalized Polarizabilities. Physical Review Letters, 2019, 123 (19), pp.192302. ⟨10.1103/PhysRevLett.123.192302⟩. ⟨hal-02277901⟩