Inverse bremsstrahlung contributions to Drell-Yan like processes

The contribution of the sub-process $\gamma q \to q' l_1\bar{l}_2$ in hadron-hadron interactions is considered. It is a part of one-loop electroweak radiative corrections for the Drell-Yan production of lepton pairs at hadron colliders. It is shown that this contribution should be taken into account aiming at the 1% accuracy of the Drell-Yan process theoretical description. Both the neutral and charged current cases are evaluated. Numerical results are presented for typical conditions of LHC experiments.Comment: 11 pages, 8 figure

One-loop corrections to the Drell-Yan process in SANC (I). The charged current case

Radiative corrections to the charged current Drell-Yan processes are revisited. Complete one-loop electroweak corrections are calculated within the automatic SANC system. Electroweak scheme dependence and the choice of the factorization scale are discussed. Comparisons with earlier calculations are presented.Comment: extended version submitted to EPJ

PHOTOS Monte Carlo for precision simulation of QED in decays - History and properties of the project

Because of properties of QED, the bremsstrahlung corrections to decays of particles or resonances can be calculated, with a good precision, separately from other effects. Thanks to the widespread use of event records such calculations can be embodied into a separate module of Monte Carlo simulation chains, as used in High Energy Experiments of today. The PHOTOS Monte Carlo program is used for this purpose since nearly 20 years now. In the following talk let us review the main ideas and constraints which shaped the program version of today and enabled it widespread use. We will concentrate specially on conflicting requirements originating from the properties of QED matrix elements on one side and degrading (evolving) with time standards of event record(s). These issues, quite common in other modular software applications, become more and more difficult to handle as precision requirements become higher.Comment: Prepared for XI International Workshop on Advanced Computing and Analysis Techniques in Physics Research, Amsterdam, the Netherlands, April 23 200

Electroweak Effects in Neutral Current Drell-Yan Processes within SANC System

The complete one-loop electroweak radiative corrections to the neutral current Drell-Yan process $pp \to \ell^+\ell^- X$ are presented for the case of longitudinal polarization of initial particles. The calculations are based on the SANC computer system. The paper contains a brief description of the SANC approach and a discussion of the sources of theoretical uncertainties in electroweak effects

PHOTOS Monte Carlo and its theoretical accuracy

Because of properties of QED, the bremsstrahlung corrections to decays of particles or resonances can be calculated, with a good precision, separately from other effects. Thanks to the widespread use of event records such calculations can be embodied into a separate module of Monte Carlo simulation chains, as used in High Energy Experiments of today. The PHOTOS Monte Carlo program is used for this purpose since nearly 20 years now. In the following talk let us review the main ideas and constraints which shaped the program version of today and enabled it widespread use. Finally, we will underline importance of aspects related to reliability of program results: event record contents and implementation of channel specific matrix elements.Comment: Presented by Z. Was, April 08 2008, International Workshop on e+e- collisions from Phi to Ps

PHOTOS Monte Carlo for precision simulation of QED in decays

Because of properties of QED, the bremsstrahlung corrections to decays of particles or resonances can be calculated, with a good precision, separately from other effects. Thanks to the widespread use of event records such calculations can be embodied into a separate module of Monte Carlo simulation chains, as used in High Energy Experiments of today. The PHOTOS Monte Carlo program is used for this purpose since nearly 20 years now. In the following talk let us review the main ideas and constraints which shaped the program version of today and enabled it widespread use. We will concentrate specially on conflicting requirements originating from the properties of QED matrix elements on one side and degrading (evolving) with time standards of event record(s). These issues, quite common in other modular software applications, become more and more difficult to handle as precision requirements become higher