5,470 research outputs found
Collins Fragmentation and the Single Transverse Spin Asymmetry
We study the Collins mechanism for the single transverse spin asymmetry in
the collinear factorization approach. The correspondent twist-three
fragmentation function is identified. We show that the Collins function
calculated in this approach is universal. We further examine its contribution
to the single transverse spin asymmetry of semi-inclusive hadron production in
deep inelastic scattering and demonstrate that the transverse momentum
dependent and twist-three collinear approaches are consistent in the
intermediate transverse momentum region where both apply.Comment: 10 pages, 2 figure
Transverse Momentum Dependent Parton Distributions at Small-x
We study the transverse momentum dependent (TMD) parton distributions at
small-x in a consistent framework that takes into account the TMD evolution and
small-x evolution simultaneously. The small-x evolution effects are included by
computing the TMDs at appropriate scales in terms of the dipole scattering
amplitudes, which obey the relevant Balitsky-Kovchegov equation. Meanwhile, the
TMD evolution is obtained by resumming the Collins-Soper type large logarithms
emerged from the calculations in small-x formalism into Sudakov factors.Comment: 23 pages, 9 figure
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