A first measurement of the longitudinal beam spin asymmetry A(LU) in the semi inclusive electroproduction of pairs of charged pions is reported. A(LU) is a higher twist observable and offers the cleanest access to the nucleon twist-3 parton distribution function e(x). Data have been collected in the Hall-B at Jefferson Lab by impinging a 5.498-GeV electron beam on a liquid-hydrogen target, and reconstructing the scattered electron and the pion pair with the CLAS detector. One-dimensional projections of the A(LU)(sin phi R) moments are extracted for the kinematic variables of interest in the valence quark region. The understanding of dihadron production is essential for the interpretation of observables in single-hadron production in semi-inclusive DIS, and pioneering measurements of single-spin asymmetries in dihadron production open a new avenue in studies of QCD dynamics.
Mirazita, M., Avakian, H., Courtoy, A., Pisano, S., Adhikari, S., Amaryan, M.j., et al. (2021). Beam spin asymmetry in semi-inclusive electroproduction of hadron pairs. PHYSICAL REVIEW LETTERS, 126(6), 1-6 [10.1103/PhysRevLett.126.062002].
Beam spin asymmetry in semi-inclusive electroproduction of hadron pairs
Pisano S.Formal Analysis
;D'Angelo A.Membro del Collaboration Group
;Lanza L.;Rizzo A.Membro del Collaboration Group
;
2021-02-12
Abstract
A first measurement of the longitudinal beam spin asymmetry A(LU) in the semi inclusive electroproduction of pairs of charged pions is reported. A(LU) is a higher twist observable and offers the cleanest access to the nucleon twist-3 parton distribution function e(x). Data have been collected in the Hall-B at Jefferson Lab by impinging a 5.498-GeV electron beam on a liquid-hydrogen target, and reconstructing the scattered electron and the pion pair with the CLAS detector. One-dimensional projections of the A(LU)(sin phi R) moments are extracted for the kinematic variables of interest in the valence quark region. The understanding of dihadron production is essential for the interpretation of observables in single-hadron production in semi-inclusive DIS, and pioneering measurements of single-spin asymmetries in dihadron production open a new avenue in studies of QCD dynamics.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
