2020   04   en   p.32-43 S.K. Abdullayev, M.Sh. Gojayev,
Longitudinal spin asymmetries in semi-inclusive deep-inelastic scattering of polarized leptons by polarized nucleons


Within the framework of the Standard Model, the processes of semi-inclusive deep inelastic scattering of longitudinally polarized leptons (antileptons) by polarized nucleons are considered: 𝓁 -(𝓁 +)N → 𝓁 -(𝓁 +) h±X, here 𝓁 -(𝓁 +) – an electron or muon (positron or antimuon), h± – charged π± - or K± -meson, X – a system of undetected hadrons. By introducing non-polarization and polarization structure functions of hadrons and taking into account the longitudinal polarizations of the lepton and target nucleon, analytical expressions are obtained for the differential cross sections of the processes. All structure functions of hadrons are found in the quark-parton model; they depend on the distribution and fragmentation functions of quarks and antiquarks. The longitudinal spin asymmetries ANh+-h-, ANh+, ANh-and others are determined, the dependence of the asymme-tries on the invariant variables x, y and z is studied. The longitudinal spin asymmetry Adπ+-π- is compared with the experi-mental data of the COMPASS collaboration.

Keywords: Semi-inclusive deep inelastic scattering, structure functions, longitudinal spin asymmetries, spiral amplitudes, distribution func-tions, fragmentation functions.
PACS: 12.15.-Y, 13.60.-R, 13.85.NI, 13.87.FH

Received: 17.11.2020


Baku State University, Azerbaijan, AZ 1148, Baku, acad. Z. Khalilov, 23
E-mail: m_qocayev@mail.ru

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