[Jlabsa_gs] **Reminder** Pizza Seminar - Wednesday, January 22, 2014 - A Message From Hari Areti

[Jodi Patient]

Jefferson Lab's Graduate Student and Post-Doc Association Wiki:
  https://gspda.jlab.org/wiki/index.php/Main_Page

         Please RSVP to:  patient at jlab.org by COB on January 21, 2014

                         Wednesday, January 22, 2014

                                   ***F113***

                                  12:00-1:00 pm


"An Outlook on Beam Normal Single Spin Asymmetry in Electron Nucleon Scattering"


                               Buddhini Waidyawansa

                              Postdoctoral Associate
                                  Jefferson Lab

                     

Abstract:  A beam normal single spin asymmetry, B_n, is generated by the scattering 
of transversely polarized electrons from unpolarized targets. This parity conserving 
observable provides direct access to the imaginary part of the two photon exchange 
amplitude. Because it can be calculated from the sum of the amplitudes for all on-shell 
intermediate states, a measurement provides an integral test of our understanding of 
the fundamental gamma + nucleon --> X  processes. In addition this observable is also 
of special interest to experiments making precision parity-violating asymmetry 
measurements because small amounts of residual transverse polarization in the beam can 
lead to percent-level corrections. However, B_n is highly suppressed hence is only 
accessible with apparatus designed to measure asymmetries at the few percent level. 
I will discuss the theoretical and experimental status of beam normal single spin 
asymmetry and their implications on the two-photon exchange theories.