Electroproduction of Charged Pions in the Quark-Fragmentation Region

Drews, G.; Gebert, W.; Janata, F.; Joos, P.; Ladage, A.; Nagel, Hans-Hellmut; Preissner, H.; Söding, P.; Cohen, I.; Erickson, R.; Messing, F.; Nordberg, E.; Siemann, R.H.; Smith-Kintner, J.; Stein, P. C.; Sadoff, A. J.

doi:10.1103/physrevlett.41.1433

Cited by 28 publications

(11 citation statements)

References 16 publications

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“…The region extends to z ≥ 0.2 for W = 4.8 GeV (W ′ = 2.84 GeV) and to z ≥ 0.1 for W = 7.4 GeV (W ′ = 4.14 GeV). For z > 0.3, fragmentation functions have also been obtained from data [26] on ep → e ′ π ± X at an incident energy E = 11.5 GeV, with 3 < W < 4 GeV. All of these data are beyond the (W ′ > 2 GeV) nucleon resonance region as defined above, and seem indeed reasonably well understood in terms of a simple fragmentation description.…”

Section: B Factorizationmentioning

confidence: 97%

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: B Factorizationmentioning

confidence: 97%

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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“…In order to estimate the violation of factorization of the semi-inclusive cross-section with respect to its x nand zn-dependence due to the %-corrections (3.24), (3.26) we consider the process ep ~ e n + X and compare our estimates with the data of [15]. This experiment covers the kinematic range of 2< Q2 <6GeV 2 (( Q2 ) = 2.8 GeV 2) and0.1 < x n < 0.45.…”

Section: F•u (Xnzu Q2) = Z Ezq Xuqon (Xu Q2)d~" (Zumentioning

confidence: 99%

“…6. It is pointed out in [15] that this test is limited by the systematic error associated with the kaon and proton subtractions made in the analysis of this experiment. The curves shown in 3) are negligible.…”

Section: F•u (Xnzu Q2) = Z Ezq Xuqon (Xu Q2)d~" (Zumentioning

confidence: 99%

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Finite corrections to quark fragmentation functions in perturbative QCD

Baier

Fey

1979

Z. Phys. C - Particles and Fields

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Abstract. The finite corrections of order % in perturbative QCD to the cross-sections for semi-inclusive hadron production from deep inelastic leptonhadron scattering and electron-positron annihilation are calculated. We define the effective quark fragmentation functions via e § e---* hadron + X including the finite terms in order to estimate these corrections for the reactions lepton + hadron --* lepton + hadron + anything. Contrary to the leading term the next-to-leading order term does not factorize into parts depending on the target and the fragment, respectively. For the processes e § p --* e 4-~+ § X and v + p ~/~-+ rc • + X the finite corrections of order % turn out to be at most 20~ in the range of momenta covered by present experiments.

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“…In Fig. 7 also data from the electron induced reaction [29] and from neutrino-proton reactions [30], which should be compared to the predictions from our fragmentation functions (dashed curves), are plotted. They show that our parametrizations are consistent with the leptoproduction data.…”

Section: D~(zmentioning

confidence: 99%

Correlation with large transverse momentum photons and the gluon structure function

Baier

Engels

Petersson

1980

Z. Phys. C - Particles and Fields

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Abstract. The inclusive two-particle cross section for the production of large PT photons and opposite side charged hadrons in proton-proton collisions is examined in detail in the framework of QCD. The model, with the parametrization as in our previous work, agrees with the measured single photon spectra. Quantitative predictions are made for twoparticle distributions to be measured at the ISR. The contributions due to the photon bremsstrahlung and the effects coming from the intrinsic constituent motion are estimated. It is shown that indeed the direct subprocess gluon + quark -* photon + quark gives the dominant contribution in the experimentally relevant region of phase space, and that direct information about the gluon structure function can be obtained from such measurements.

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Electroproduction of Charged Pions in the Quark-Fragmentation Region

Cited by 28 publications

References 16 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

Finite corrections to quark fragmentation functions in perturbative QCD

Correlation with large transverse momentum photons and the gluon structure function

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