[Jlab-seminars] Theory Center Seminar

[Mary Fox]

Theory Center Seminar
Monday, March 25, 2013
1:00 p.m. (coffee at 12:45 p.m.)
CEBAF Center, Room L102

Nathan Hall
University of Adelaide

*Interference Radiative Corrections to the Proton's Weak Charge *

Low energy precision experiments provide crucial tests of our 
understanding of the Standard Model of particle physics. QWEAK is one 
such experiment, aiming to measure the proton's weak charge, QWp, to 
within 4%. Unfortunately, the theoretical prediction of QWp has been 
difficult to pin down owing to disagreements over the precise nature of 
certain higher-order radiative corrections and this has left the 
interpretation of future results subject to unwanted ambiguity. In this 
presentation, we examine the radiative corrections arising specifically 
from gammaZ interference and show that in fact, by using recent 
electron-deuteron parity-violating asymmetries, together with 
well-determined parton distribution functions, we can dramatically 
reduce the uncertainties associated with these corrections. Having 
removed such concerns, we provide a new estimate of both the gammaZ 
interference contribution and the revised theoretical uncertainties 
associated with it.
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