Helicity-dependent generalized parton distributions and composite constituent quarks

Journal Article · Sat Jan 01 04:00:00 EST 2005 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PhysRevD.71.014014· OSTI ID:20705711

Scopetta, Sergio ^[1]; Vento, Vicente ^[2]

---

1. Dipartimento di Fisica, Universita degli Studi di Perugia, via A. Pascoli 06100 Perugia (Italy) and INFN, sezione di Perugia, Perugia (Italy)
2. Departament de Fisica Teorica, Universitat de Valencia, 46100 Burjassot (Valencia), Spain and Institut de Fisica Corpuscular, Consejo Superior de Investigaciones Cientificas, Valencia (Spain)

An approach, recently proposed to calculate the nucleon generalized parton distributions (GPDs) in a constituent quark model (CQM) scenario, in which the constituent quarks are taken as complex systems, is used to obtain helicity-dependent GPDs. They are obtained from the wave functions of the nonrelativistic CQM of Isgur and Karl, convoluted with the helicity-dependent GPDs of the constituent quarks themselves. The latter are modeled by using the polarized structure functions of the constituent quark, the double distribution representation of GPDs, and a phenomenological constituent quark form factor. The present approach permits us to access a kinematical range corresponding to both the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi and the Efremov-Radyushkin-Brodsky-Lepage regions, for small values of the momentum transfer and of the skewedness parameter. In this kinematical region, the present calculation represents a prerequisite for the evaluation of cross sections relevant to deeply virtual Compton scattering. In particular, we have calculated the leading twist helicity-dependent GPD H-tilde and, from our expressions, its general relations with the nonrelativistic definition of the axial form factor and with the leading twist polarized quark density are consistently recovered.

• OSTI ID: 20705711
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 1 Vol. 71; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
COMPTON EFFECT
DISTRIBUTION
FORM FACTORS
HELICITY
MOMENTUM TRANSFER
NUCLEONS
PARTONS
QUARK MODEL
QUARKS
STRUCTURE FUNCTIONS
WAVE FUNCTIONS