Late Notice- MIT's NPPC for 3/15

[Sheela Hulsoor <hulsoor lns mit edu>]

BAPC Late Notice

Monday, March 15th
@4:15PM (refreshments at 4PM)
MIT
Nuclear and Particle Physics Colloquium (NPPC)
Kolker Room , 26-414

MARC VANDERHAEGHEN
William and Mary, and Jefferson Lab

Two-photon Exchange Physics in Elastic Electron-proton
Scattering

"In recent years precision polarization measurements of elastic
electron-proton scattering at large momentum transfers have yielded a
ratio for the proton's electron to magnetic form factors which is at
variance with the traditional Rosenbluth method, using unpolarized
measurements. In this talk, we link this difference to two-photon
exchange processes in elastic electron-proton scattering. This two-photon
exchange correction at large momentum transfer is estimated through the
scattering off a parton in the proton, and the process is related to the
generalized parton distributions which also enter in other wide angle
scattering processes. We shall show that these two-photon exchange
corrections are able to quantitatively resolve the discrepancy between
Rosenbluth and polarization data. Furthermore, a prospect will be given
how to directly access this two-photon physics by using single spin
asymmetries."


Visit
http://www.lns.mit.edu/seminars/nppc.html
to view the Spring 2004 schedule