TY - JOUR
T1 - Leading-twist single-transverse-spin asymmetries
T2 - Drell-Yan and deep-inelastic scattering
AU - Collins, John C.
N1 - Funding Information:
This work was supported in part by the US Department of Energy under grant number DE-FG02-90ER-40577. I would like to thank Stan Brodsky, Steve Heppelmann, Jianwei Qiu and Mark Strikman for useful discussions.
PY - 2002/5/30
Y1 - 2002/5/30
N2 - Recently, Brodsky, Hwang and Schmidt have proposed a new mechanism that gives a transverse spin symmetry at leading twist in semi-inclusive deep-inelastic scattering. I show that the new mechanism is compatible with factorization and is due to a transverse-spin asymmetry in the kT distribution of quarks in a hadron (the "Sivers asymmetry"). An earlier proof that the Sivers asymmetry vanishes because of time-reversal invariance is invalidated by the path-ordered exponential of the gluon field in the operator definition of parton densities. Instead, the time-reversal argument shows that the Sivers asymmetry is reversed in sign in hadron-induced hard processes (e.g., Drell-Yan), thereby violating naive universality of parton densities. Previous phenomenology with time-reversal-odd parton densities is validated.
AB - Recently, Brodsky, Hwang and Schmidt have proposed a new mechanism that gives a transverse spin symmetry at leading twist in semi-inclusive deep-inelastic scattering. I show that the new mechanism is compatible with factorization and is due to a transverse-spin asymmetry in the kT distribution of quarks in a hadron (the "Sivers asymmetry"). An earlier proof that the Sivers asymmetry vanishes because of time-reversal invariance is invalidated by the path-ordered exponential of the gluon field in the operator definition of parton densities. Instead, the time-reversal argument shows that the Sivers asymmetry is reversed in sign in hadron-induced hard processes (e.g., Drell-Yan), thereby violating naive universality of parton densities. Previous phenomenology with time-reversal-odd parton densities is validated.
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U2 - 10.1016/S0370-2693(02)01819-1
DO - 10.1016/S0370-2693(02)01819-1
M3 - Article
AN - SCOPUS:0037198616
SN - 0370-2693
VL - 536
SP - 43
EP - 48
JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
IS - 1-2
ER -