12 research outputs found
Transverse momentum dependence of semi-inclusive pion production
Cross sections for semi-inclusive electroproduction of charged pions
() from both proton and deuteron targets were measured for
, GeV, , and GeV. For
GeV, we find the azimuthal dependence to be small, as expected
theoretically. For both and , the dependence from the
deuteron is found to be slightly weaker than from the proton. In the context of
a simple model, this implies that the initial transverse momenta width of
quarks is larger than for quarks and, contrary to expectations, the
transverse momentum width of the favored fragmentation function is larger than
the unfavored one.Comment: 15 pages, 4 figures. Fit form changed to include Cahn effect Minor
revisions. Added one new figur
The Onset of Quark-Hadron Duality in Pion Electroproduction
A large data set of charged-pion electroproduction from both hydrogen and
deuterium targets has been obtained spanning the low-energy residual-mass
region. These data conclusively show the onset of the quark-hadron duality
phenomenon, as predicted for high-energy hadron electroproduction. We construct
several ratios from these data to exhibit the relation of this phenomenon to
the high-energy factorization ansatz of electron-quark scattering and
subsequent quark-to- pion production mechanisms.Comment: 11 pages, 3 figures, accepted in Phys. Rev. Lett. Tables adde
Electroproduction of Eta Mesons in the S11(1535) Resonance Region at High Momentum Transfer
The differential cross-section for the process p(e,e'p)eta has been measured
at Q2 ~ 5.7 and 7.0 (GeV/c)2 for centre-of-mass energies from threshold to 1.8
GeV, encompassing the S11(1535) resonance, which dominates the channel. This is
the highest momentum transfer measurement of this exclusive process to date.
The helicity-conserving transition amplitude A_1/2, for the production of the
S11(1535) resonance, is extracted from the data. Within the limited Q2 now
measured, this quantity appears to begin scaling as 1/Q3 - a predicted, but not
definitive, signal of the dominance of perturbative QCD, at Q2 ~ 5 (GeV/c)2.Comment: LaTeX, 30 pages, 29 figures, uses longtable.sty, slashbox.sty,
ifthen.sty; (v2) corrected figure inclusions; (v3) changes in filenames for
prc and added Report-no; (v4) correction based on comments from referee
{small changes to abstract and conclusion, inserted figure 9, other small
changes to the text} (v5) very minor additions to improve clarit
Semi-inclusive charged-pion electroproduction off protons and deuterons: Cross sections, ratios, and access to the quark-parton model at low energies
Measurements of the separated longitudinal structure function FL from hydrogen and deuterium targets at low Q2
© 2018 American Physical Society. Structure functions, as measured in lepton-nucleon scattering, have proven to be very useful in studying the partonic dynamics within the nucleon. However, it is experimentally difficult to separately determine the longitudinal and transverse structure functions, and consequently there are substantially less data available in particular for the longitudinal structure function. Here, we present separated structure functions for hydrogen and deuterium at low four-momentum transfer squared, Q2\u3c1GeV2, and compare them with parton distribution parametrization and kT factorization approaches. While differences are found, the parametrizations generally agree with the data, even at the very low-Q2 scale of the data. The deuterium data show a smaller longitudinal structure function and a smaller ratio of longitudinal to transverse cross section, R, than the proton. This suggests either an unexpected difference in R for the proton and the neutron or a suppression of the gluonic distribution in nuclei
Measurements of the separated longitudinal structure function FL from hydrogen and deuterium targets at low Q2
Structure functions, as measured in lepton-nucleon scattering, have proven to be very useful in studying the partonic dynamics within the nucleon. However, it is experimentally difficult to separately determine the longitudinal and transverse structure functions, and consequently there are substantially less data available in particular for the longitudinal structure function. Here, we present separated structure functions for hydrogen and deuterium at low four-momentum transfer squared, Q2<1GeV2, and compare them with parton distribution parametrization and kT factorization approaches. While differences are found, the parametrizations generally agree with the data, even at the very low-Q2 scale of the data. The deuterium data show a smaller longitudinal structure function and a smaller ratio of longitudinal to transverse cross section, R, than the proton. This suggests either an unexpected difference in R for the proton and the neutron or a suppression of the gluonic distribution in nuclei