Effects of transversity in deep-inelastic scattering by polarized protons

Physikalisches Institut, Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
Physics Letters B (Impact Factor: 6.13). 09/2010; 693(1):11-16. DOI: 10.1016/j.physletb.2010.08.012


Single-spin asymmetries for pions and charged kaons are measured in semi-inclusive deep-inelastic scattering of positrons and electrons off a transversely nuclear-polarized hydrogen target. The dependence of the cross section on the azimuthal angles of the target polarization (ϕS) and the produced hadron (ϕ) is found to have a substantial sin(ϕ+ϕS) modulation for the production of π+, π− and K+. This Fourier component can be interpreted in terms of non-zero transversity distribution functions and non-zero favored and disfavored Collins fragmentation functions with opposite sign. For π0 and K− production the amplitude of this Fourier component is consistent with zero.

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Available from: Vahagn Gharibyan
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    • "These Transverse Momentum Dependent distribution and fragmentation functions (collectively here called " TMDs " ) can be accessed in several types of processes, one of the most important is single particle hadron production in Semi-Inclusive Deep Inelastic Scattering (SIDIS) of leptons on nucleons. A significant amount of data on spin-azimuthal distributions of hadrons in SIDIS, providing access to TMDs has been accumulated in recent years by several collaborations, including HERMES, COMPASS and Halls A,B and C at JLab [6] [7] [8] [9] [10] [11] [12] [13] [14] [15]. At least an order of magnitude more data is expected in coming years of running of JLab 12 [1]. "
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