Nuclear Physics Seminar

"New Investigation of Quark Orbital Motion in Nucleon"

Presented by Jin Huang, Brookhaven National Laboratory

Tuesday, December 20, 2011, 11:00 am — Small Seminar Room, Bldg. 510

New measurements of novel spin phenomena in deep inelastic electron-neutron scattering (DIS) provide the first experimental indication of a longitudinal quark polarization inside a transversely polarized nucleon. Such a polarization, known as transversal helicity, can only be observed if the quarks undergo orbital motion inside the nucleon. In the first measurement of its kind, transversal helicity was accessed at Jefferson Lab through the beam-target double spin asymmetry for charged pion electroproduction in DIS on a transversely polarized He-3 target. A state-of-the-arts polarized He-3 target was used as an effective polarized neutron target, which is sensitive to the d-quark distributions in the nucleon. Systematic uncertainties were minimized due to the frequent reversal of both the beam helicity and the target spin. This result was recently accepted by PRL for publication. Related future experiments will also be discussed.

Hosted by: Matthew Lamont

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