[Jlab-seminars] Physics Seminar Announcement

[Luci Collins]

*Physics Seminar
**April 6, 2012
11:00 AM
CEBAF Center AUD.
Cookies and Coffee 10:45AM
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*Jin Huang
Los Alamos National Laboratory*

*"Clues to New Quark Behavior" *

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 Hall A 6 GeV Transversity Experiment, 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 
published in PRL. Related future experiments will also be discussed.



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