97 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
Hadronic Cross Sections in Electron-Positron Annihilation with Tagged Photon
Events with tagged photons in the process of electron-positron annihilation
into hadrons are considered. The initial state radiation is suggested to scan
the hadronic cross section with the energy. QED radiative corrections are taken
into account. The results for the total and exclusive cross sections are given
in an analytic form. Some numerical estimates are presented.Comment: 12 pages, 2PS figures, the final journal versio
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