129 research outputs found
Nucleon Compton Scattering with Two Space--Like Photons
We calculated two--photon exchange effects for elastic electron--proton
scattering at high momentum transfers. The corresponding nucleon Compton
amplitude is defined by two space--like virtual photons that appear to have
significant virtualities. We make predictions for a) a single--spin beam
asymmetry, and b) a single--spin target asymmetry or recoil proton polarization
caused by an unpolarized electron beam.Comment: 9 pages, 4 figures, requires ws-procs9x6 (enclosed), Talk presented
at the Workshop on Exclusive Processes at High Momentum Transfer, Jefferson
Lab, Newport News, VA, May 15-18, 200
Bhabha scattering at LEP1. Calorimeter event selection
Analitical calculations have been used to describe the calorimeter event
selection in small-angle electron-positron scattering at LEP1. The first-order
QED correction to the Born cross-section has been derived with leading log and
the next-to-leading log approximations. The second- and the third-order
corrections were computed with leading accuracy. The present analytical results
are illustated by Tabeles and compared with the corresponding results obtained
with the Monte Carlo generator BHLUMI.Comment: 26p., submitted to Journ. of Physics
Pair Production in Small-Angle Bhabha Scattering
Radiative corrections due to the production of virtual as well as real soft
and hard pairs in small-angle Bhabha scattering are calculated analytically.
Both the collinear and the semi-collinear kinematical regions of hard pair
production are considered. The calculation, within the leading and
next-to-leading logarithmic approximation, provides an accuracy of O(0.1%).
Numerical results show that the effects of pair production have to be taken
into account for a luminosity determination accurate to O(0.1%) at LEP.Comment: Latex. 20 page
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