SANCnews: Top decays in QCD and EW sectors

In this paper we present the results of the implementation of the decay t → bf ₁ $ \bar f $ \bar f ′₁ into the SANC system (f ₁ is a massless fermion). The new aspect of the work is the combination of QCD and EW corrections. All calculations are done at the one-loop level in the Standard Model. We give a detailed account of the new procedure — the forming of a class of J _{AW, WA} functions. These functions are related to the procedure of extraction of infrared and mass-shell singular divergences. The emphasis of this paper is on the presentation of numerical results for various approaches: complete one-loop calculations and different versions of pole approximations.     

Update of the MCSANC Monte Carlo integrator,v. 1.20

New features of the MCSANC v.1.20 program, a Monte Carlo tool for calculation of the next-to-leading order electroweak and QCD corrections to various Standard Model processes, have been presented. The extensions concern implementation of Drell–Yan-like processes and include a systematic treatment of the photon-induced contribution in proton–proton collisions and electroweak corrections beyond the NLO approximation. There are also technical improvements such as calculation of the forward–backward asymmetry for the neutral current Drell–Yan process. The updated code is suitable for studies of the effects due to EW and QCD radiative corrections to Drell–Yan (and several other) processes at the LHC and for forthcoming high-energy proton–proton colliders.     

Second Harmonic Generation in Thin Zinc Sulfide Films

Optical second harmonic generation, mechanical stresses, and structure are investigated in thin polycrystalline zinc sulfide films. The resulting data indicate that there is no correlation between the mechanical stresses and the quadratic optical nonlinearity. In view of the X-ray diffraction results, the nature of the nonlinearity is explained using the model of a nanotextured film consisting of crystallites with the sphalerite or wurtzite structure. It is shown that this model allows satisfactory agreement between calculations and experiment.     

SANC integrator in the progress: QCD and EW contributions

Modules and packages for the one-loop calculations at the partonic level represent the first level of SANC output computer product. The next level represents Monte Carlo integrator mcsanc, realizing fully differential hadron level calculations (convolution with PDF) for the HEP processes at LHC. In this paper we describe the implementation into the framework mcsanc first set of processes: DY NC, DY CC, $f_1 \bar f'_1 \to HW^ \pm (Z)$ and single top production. Both EW and QCD NLO corrections are taken into account. A comparison of SANC results with those existing in the world literature is given.     

Fragmentation functions from semi-inclusive DIS pion production and implications for the polarized parton densities

By combining recent HERMES data on semi-inclusive DIS (SIDIS) -production with the singlet fragmentation function , which is well determined from data, we are able to extract, for the first time, the flavoured fragmentation functions , and without making any assumptions about favoured and unfavoured transitions. Whereas and are very well determined, the accuracy of is limited by the uncertainty in evolving from the pole down to the SIDIS scale of a few . We discuss how the precision on could be improved. Knowledge of the will permit the extraction of the polarized parton densities from future polarized SIDIS asymmetry measurements. We study the precision that can be expected in such an extraction. Received: 6 August 2001 / Revised version: 3 October 2001 / Published online: 12 November 2001     

Electroweak radiative corrections to deep inelastic scattering at HERA

Analytic results are presented on electroweak radiative corrections for neutral-current deepinelastic electron proton scattering at HERA energies. Single photon bremsstrahlung is included without cuts.