New definition of TMD parton densities

@inproceedings{Collins2011NewDO,
  title={New definition of TMD parton densities},
  author={John C. Collins},
  year={2011}
}
I give an account of a new definition of transverse-momentum-dependent parton densities. The new definition solves a number of difficulties and inconsistencies in earlier definitions. 
Relating transverse structure of various parton distributions
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Different approaches to the problem of a gauge-invariant operator definition of transverse-momentum dependent parton densities (TMDs) are reviewed and compared from the point of view of theirExpand
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Transverse momentum in double parton scattering: factorisation, evolution and matching
A bstractWe give a description of double parton scattering with measured transverse momenta in the final state, extending the formalism for factorisation and resummation developed by Collins, SoperExpand
A note on Pretzelosity TMD parton distribution
Abstract We show that the transverse-momentum-dependent parton distribution, called as Pretzelosity function, is zero at any order in perturbation theory of QCD for a single massless quark state.Expand
Wilson Lines off the Light-Cone in TMD PDFs
Transverse momentum dependent (TMD) parton distribution functions also take into account the transverse momentum (pT) of the partons. The pT-integrated analogues can be linked directly to quark andExpand
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