Next-to-leading order evolution of polarized and unpolarized fragmentation functions

Stratmann, M.; Vogelsang, Werner

doi:10.1016/s0550-3213(97)00182-x

Cited by 80 publications

(105 citation statements)

References 48 publications

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“…A consequence of factorization is that the fragmentation function is independent of x, and the parton distribution function q i (x, Q 2 ) independent of z. Both parton distribution and fragmentation functions, however, depend on Q 2 through logarithmic Q 2 evolution [16]. The second part describes the dependence on the transverse momentum P t , assumed to be Gaussian, and the general dependence [17] of the cross section in the unpolarized case on the angle φ, the angle between the electron scattering plane and the pion production plane, with A and B, reflecting the interference terms σ LT and σ T T , respectively, being functions of x, Q 2 , z, P t .…”

Section: Towards a High-energy Description Of Semi-inclusive Pionmentioning

confidence: 99%

Semi-inclusive charged-pion electroproduction off protons and deuterons: Cross sections, ratios, and access to the quark-parton model at low energies

Asaturyan¹,

Ent²,

Mkrtchyan³

et al. 2012

Phys. Rev. C

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A large set of cross sections for semi-inclusive electroproduction of charged pions (π ± ) from both proton and deuteron targets was measured. The data are in the deep-inelastic scattering region with invariant mass squared W 2 > 4 GeV 2 (up to ≈ 7 GeV 2 ) and range in four-momentum transfer squared 2 < Q 2 < 4 (GeV/c) 2 , and cover a range in the Bjorken scaling variable 0.2 < x < 0.6. The fractional energy of the pions spans a range 0.3 < z < 1, with small transverse momenta with respect to the virtual-photon direction, P 2 t < 0.2 (GeV/c) 2 . The invariant mass that goes undetected, Mx or W ′ , is in the nucleon resonance region, W ′ < 2 GeV. The new data conclusively show the onset of quark-hadron duality in this process, and the relation of this phenomenon to the high-energy factorization ansatz of electron-quark scattering and subsequent quark → pion production mechanisms. The x, z and P 2 t dependences of several ratios (the ratios of favored-unfavored fragmentation functions, charged pion ratios, deuteron-hydrogen and aluminum-deuteron ratios for π + and π − ) have been studied. The ratios are found to be in good agreement with expectations based upon a high-energy quark-parton model description. We find the azimuthal dependences to be small, as compared to exclusive pion electroproduction, and consistent with theoretical expectations based on tree-level factorization in terms of transverse-momentum-dependent parton distribution and fragmentation functions. In the context of a simple model, the initial transverse momenta of d quarks are found to be slightly smaller than for u quarks, while the transverse momentum width of the favored fragmentation function is about the same as for the unfavored one, and both fragmentation widths are larger than the quark widths.

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Section: Towards a High-energy Description Of Semi-inclusive Pionmentioning

confidence: 99%

Semi-inclusive charged-pion electroproduction off protons and deuterons: Cross sections, ratios, and access to the quark-parton model at low energies

Asaturyan¹,

Ent²,

Mkrtchyan³

et al. 2012

Phys. Rev. C

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“…It is of kinematic origin and contributed by the phase space for collinear gluon radiation off the quark leg in the final state [49].…”

Section: Nll Resummed Cross Sectionmentioning

confidence: 99%

Resummation for polarized semi-inclusive deep-inelastic scattering at small transverse momentum

2006

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We study the transverse-momentum distribution of hadrons produced in semi-inclusive deep-inelastic scattering (SIDIS). We consider cross sections for various combinations of polarizations of the initial lepton and nucleon or the produced hadron, for which we perform the resummation of large double-logarithmic perturbative corrections arising at small transverse momentum. We present phenomenological results for the processes lp → lπX with longitudinally polarized leptons and protons. We discuss the impact of the perturbative resummation and of estimated non-perturbative contributions on the corresponding cross sections and their spin asymmetry. Our results should be relevant for ongoing studies in the COMPASS experiment at CERN, and for future experiments at the proposed eRHIC collider at BNL.

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“…Note that as in the unpolarized and longitudinally polarized cases [22,24] the violation of the GLR only occurs in the C 2 F part of the splitting function.…”

mentioning

confidence: 90%

“…In other words, we could choose a (non-MS) factorization scheme in which the time-like transversity splitting functions would be given by AC δP (S),(1) qq,± (x) , without any extra term, so that no breaking of the ACR would occur. This possibility was first demonstrated for the unpolarized [31] and longitudinally polarized [24] cases, which are more general in the sense that singlet mixing is present there. In the following, we do stay within the more conventional MS scheme, however.…”

mentioning

confidence: 96%

Next-to-leading order QCD evolution of transversity fragmentation functions

Stratmann

Vogelsang

2002

Phys. Rev. D

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Next-to-leading order evolution of polarized and unpolarized fragmentation functions

Cited by 80 publications

References 48 publications

Semi-inclusive charged-pion electroproduction off protons and deuterons: Cross sections, ratios, and access to the quark-parton model at low energies

Semi-inclusive charged-pion electroproduction off protons and deuterons: Cross sections, ratios, and access to the quark-parton model at low energies

Resummation for polarized semi-inclusive deep-inelastic scattering at small transverse momentum

Next-to-leading order QCD evolution of transversity fragmentation functions

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