arXiv subjects
Publications and source records attributed to Maciej Skrzypek.
In this paper, we briefly present the Monte Carlo event generators BHLUMI and BHWIDE for small and large angle Bhabha scattering, respectively, and discuss possible ways of their improvements in order to satisfy precision needs of future electron-positron colliders.
In order to stimulate new engagement and trigger some concrete studies in areas where further work would be beneficial towards fully understanding the physics potential of an $e^+e^-$ Higgs / Top / Electroweak factory, we propose to define a set of focus topics. The general reasoning and the proposed topics are described in this document.
High energy, high luminosity, future lepton colliders, circular or linear, may possibly give us hint about fundamental laws of Nature governing at very short distances and very short time intervals, the same which have brought our Universe to live. Currently considered projects are on one hand linear electron-positron colliders, which offer higher energy and lower beam intensities and on the other hand circular electron-positron colliders, limited in energy but offering tremendous interaction rates. On the far future horizon, muon circular colliders are the only viable projects which can explore $>10$TeV teritory of the lepton colliders. Experiments in all these future colliders will require theoretical calculations, mainly of Standard Model processes (including QED), at the precision level one or even two orders better than available today. After briefly characterization of theory puzzles in the fundamental interactions we shall overview main challenges in the precision calculations of the Standard Model effects, which have to be removed from data, in order to reveal traces of new unexpected phenomena.
Motivated by the regime of QCD explored nowadays at LHC, where both the total energy of collision and momenta transfers are high, we investigate evolution equations of high energy factorization. In order to study such effects like parton saturation in final states one is inevitably led to investigate how to combine physics of the BK and CCFM evolution equations. In this paper we obtain a new exclusive form of the BK equation which suggests a possible form of the nonlinear extension of the CCFM equation.
We show for a first time ever a prototype of a fully exclusive QCD NLO parton shower for the initial state (albeit for a limited set of diagrams). It is based on the rigorous theorems of the collinear factorisation, however the standard DGLAP evolution kernels are replaced by their exclusive versions. Contrary to the standard DGLAP approach, the constructed parton shower provides fully exclusive events, i.e. four-momenta of all emitted partons. At the inclusive level it is identical to the MS-bar scheme of the DGLAP evolution.
We present an analytic calculation of electron and tau O(alpha^3) loop effects on the muon anomalous magnetic moment. Computation of such three-loop diagrams with three mass scales is possible using asymptotic and eikonal expansions. An evaluation of a new type of eikonal integrals is presented in some detail.