Cross sections for semi-inclusive electroproduction of charged pions (π±) from both proton and deuteron targets were measured for 0.2 < x < 0.5, 2 < Q2 < 4 GeV2, 0.3 < z < 1, and Pt 2 < 0.2 GeV2. For Pt < 0.1 GeV, we find the azimuthal dependence to be small, as expected theoretically. For both π+ and π-, the Pt 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 d quarks is larger than for u quarks and, contrary to expectations, the transverse momentum width of the favored fragmentation function is larger than the unfavored one.
|Original language||English (US)|
|Number of pages||6|
|Journal||Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics|
|State||Published - Jul 3 2008|
Bibliographical noteFunding Information:
The authors wish to thank H. Avakian, A. Afanasev, and M. Schlegel for useful discussions, and the Physics Letters referees for useful suggestions. This work is supported in part by research grants from the US Department of Energy and the US National Science Foundation. The Southeastern Universities Research Association operates the Thomas Jefferson National Accelerator Facility under the US Department of Energy contract DEAC05-84ER40150.