The exclusive reaction of pion quasi-elastic knockout from nucleon p(e, e′ π)B to various states of the final baryon-spectator B and the quark models for the pion cloud of nucleon

Abstract

Abstract:The pion momentum distributions (MDs) in four channels of virtual decay p → B + π, B = N, ∆, N 1/2 − (1535), N 1/2 + (1440) are calculated in two models, the microscopic model of 3 P 0 scalar qq fluctuation with the pion as a composite qq-system and the chiral semi-microscopic model of πq interaction with the pion as a structureless Goldstone boson. The results of the above models are similar for the baryon states B = N, ∆, N 1/2 − (1535) but are rather different for the Roper resonance N 1/2 + (1440) which corresponds to excitation of two oscillator quanta in the nucleon. The experimental investigation of pion MDs by means of the reaction of quasi-elastic knockout of pion by an electron of a few GeV energy p(e, e π)B may be very suitable for Jefferson Laboratory, Virginia (JLab).