[Theory-seminars] Theory seminar Monday Nov 26 1 p.m. F113

[Alexei Prokudin]

* *Dear all,
we will have a theory seminar on Monday Nov 26, at 1 p.m. in F113.

Speaker: Igor Akushevich (Duke University/Jefferson Lab)

* Title: Exact Calculation of Radiative Corrections in DVCS and SIDIS
*
Abstract:
The experimental precision achievable in modern experiments on 
ep-scattering allows for measuring the cross section and spin 
asymmetries in Bethe-Heitler (BH) and semi-inclusive deep inelastic 
scattering (SIDIS) processes with unprecedented accuracies. The QED 
radiative correction is one serious source of systematical uncertainties 
and therefore must be known with any predetermined accuracy. Several 
available calculations provide only leading logarithm accuracy (for BH), 
performed only for unpolarized target (for SIDIS), and/or have certain 
other limitations. In this report we present the results of exact 
calculation of RC for BH process for unpolarized target as well as for 
both longitudinally and transversely polarized targets. Details of the 
calculations of the three key components such as i) the calculation of 
the cross section of two-photon-emission process and analytic 
integration over additional kinematical variables, ii) extraction of 
infrared divergence using the dimensional regularization, and iii) 
calculation of loop effects with extraction and complete cancellation of 
the infrared divergence, are discussed. Also we present an approach for 
exact calculation of RC in semi-inclusive process. The general task of 
exactly calculated RC in semi-inclusive processes for arbitrary target 
polarization requires the calculation of the covariant SIDIS hadronic 
tensor, important intermediate quantity. Recent results for its 
calculation are presented and discussed.

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 Alexei Prokudin                    | Tel:     +1 (757) 269 5385
 JLab Theory Center                 | Fax:     +1 (757) 269 7002
 12000 Jefferson Avenue             | E-mail:  prokudin at jlab.org
 Newport News, VA 23606             | http://www.to.infn.it/~prokudin
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