Semi-Inclusive Charged-Pion Electroproduction off Protons and Deuterons: Cross Sections, Ratios and Access to the Quark-Parton Model at Low Energies

Abstract

A large set of cross sections for semi-inclusive electroproduction of charged pions (${\pi }^{\pm }$) 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${}^2$ 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, $P_t^2<0.2$ (GeV/c)${}^2$. The invariant mass that goes undetected, $M_x$ 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 $P_t^2$ dependences of several ratios (the ratios of favored-unfavored fragmentation functions, charged pion ratios, deuteron-hydrogen and aluminum-deuteron ratios for ${\pi }^{+}$ and ${\pi }^{-}$) 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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Cited by in corpus (12)

• Investigations into the flavor dependence of partonic transverse momentum
• Precision Studies of QCD in the Low Energy Domain of the EIC
• Hadron Transverse Momentum Distributions in Muon Deep Inelastic Scattering at 160 GeV/$c$
• Transverse-momentum-dependent Multiplicities of Charged Hadrons in Muon-Deuteron Deep Inelastic Scattering
• Beam-Target Double Spin Asymmetry A_LT in Charged Pion Production from Deep Inelastic Scattering on a Transversely Polarized He-3 Target at 1.4<Q^2<2.7 GeV^2
• Transition between nuclear and quark-gluon descriptions of hadrons and light nuclei
• Multiplicities of charged pions and unidentified charged hadrons from deep-inelastic scattering of muons off an isoscalar target
• Effects of TMD evolution and partonic flavor on $e^{+}{e}^{-}$ annihilation into hadrons
• Azimuthal asymmetries in semi-inclusive DIS with polarized beam and/or target and their nuclear dependences
• Leading and higher twist contributions in semi-inclusive e+e- annihilation at high energies
• First measurement of unpolarized SIDIS cross section and cross section ratios from a ${}^3$He target
• Spin Orbit Correlations and the Structure of the Nucleon