Role of Cahn and Sivers effects in deep inelastic scattering

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

DOI:https://doi.org/10.1103/PhysRevD.71.074006· OSTI ID:20708977

Anselmino, M; Boglione, M; Prokudin, A ^[1]; D'Alesio, U; Murgia, F ^[2]; Kotzinian, A ^[3]

---

1. Dipartimento di Fisica Teorica, Universita di Torino and INFN, Sezione di Torino, Via P. Giuria 1, I-10125 Turin (Italy)
2. INFN, Sezione di Cagliari and Dipartimento di Fisica, Universita di Cagliari, C.P. 170, I-09042 Monserrato, Cagliari (Italy)
3. Dipartimento di Fisica Generale, Universita di Torino and INFN, Sezione di Torino, Via P. Giuria 1, I-10125 Turin (Italy)

The role of intrinsic k {sub perpendicular} in inclusive and semi-inclusive Deep Inelastic Scattering processes (lp{yields}lhX) is studied with exact kinematics within QCD parton model at leading order; the dependence of the unpolarized cross section on the azimuthal angle between the leptonic and the hadron production planes (Cahn effect) is compared with data and used to estimate the average values of k{sub perpendicular} both in quark distribution and fragmentation functions. The resulting picture is applied to the description of the weighted single spin asymmetry A{sub UT}{sup sin({phi}{sub {pi}}{sup -{phi}}{sub S})} recently measured by the HERMES collaboration at DESY; this allows to extract some simple models for the quark Sivers functions. These are compared with the Sivers functions which succeed in describing the data on transverse single spin asymmetries in p{sup {up_arrow}}p{yields}{pi}X processes; the two sets of functions are not inconsistent. The extracted Sivers functions give predictions for the COMPASS measurement of A{sub UT}{sup sin({phi}{sub {pi}}{sup -{phi}}{sub S})} in agreement with recent preliminary data, while their contribution to HERMES A{sub UL}{sup sin{phi}{sub {pi}}} is computed and found to be small. Predictions for A{sub UT}{sup sin({phi}{sub K}{sup -{phi}}{sub S})} for kaon production at HERMES are also given.

• OSTI ID: 20708977
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 7 Vol. 71; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ASYMMETRY
DEEP INELASTIC SCATTERING
DISTRIBUTION
ELECTRON-PROTON INTERACTIONS
HERA STORAGE RING
KAONS
MULTIPARTICLE SPECTROMETERS
PARTICLE IDENTIFICATION
PARTICLE PRODUCTION
PARTON MODEL
POLARIZATION
PROTONS
QUANTUM CHROMODYNAMICS
QUARKS
SPIN