Wiesiek Placzek

BHWIDE 1.00: O(α) YFS exponentiated Monte Carlo for Bhabha scattering at wide angles for LEP1/SLC and LEP2☆

Abstract We present O (α) YFS exponentiated results for wide angle Bhabha scattering at LEP/SLC energies using a new Monte Carlo event generator BHWIDE 1.xx. Our calculations include two options for the pure weak corrections, as presented in Beenakker et al. and in Bohm et al. From comparison with the results of Beenakker et al., Montagna et al. and Cacciari et al., we conclude that the total precision of our BHWIDE results is 0.3% (0.5%) in the LEP1/SLC regime within ±100 MeV ( +2.75 −2.5 GeV ) of the Z peak. For LEP2, the corresponding precision is currently estimated at 1.5%; the latter could be improved if the data in LEP2 so require. Both precision tags represent clear improvements over what is currently available in the literature.

Monte Carlo program KORALW 1.02 for W-pair production at LEP2NLC energies with Yennie-Frautschi-Suura exponentiation

Abstract The Monte Carlo program KORALW version 1.02 for W-pair production is presented. Its main features are: multiple initial state photonic radiation with finite transverse photon momenta generated according to the Yennie-Frautschi-Suura Monte Carlo technique and massive kinematics for all final particles. Matrix element features second-order leading-logarithmic initial-state QED corrections. The dedicated semi-analytical program KORWAN, with structure-function based leading-logarithmic initial-state photonic radiation up to third order, is also included in the distribution package.

Initial state QED corrections to W-pair production at LEP2/NLC — Monte Carlo versus semi-analytical approach☆

Abstract We present a comparison of the Monte Carlo code KORALW with the SemiANalytical code KORWAN for W-pair production. We focus on the technical precision, total cross section and some differential distributions. We find the technical precision of KORALW in the LEP2 energy range to be of order 10−4 or better. We show that within the 0.1% precision level the O (α2) photonic corrections are not necessary in the YFS framework, at least for the total cross section. A detailed description of the semi-analytical formalism implemented in the KORWAN routine is also given.

Upgrade of the Monte Carlo program BHLUMI for Bhabha scattering at low angles to version 4.04

Abstract The new version of the Monte Carlo program for small-angle Bhabha scattering BHLUMI with an overall precision of 0.11% is presented. The main improvements are in the matrix element of the main multi-photon sub-generator based on the Yennie—Frautschi—Suura exponentiation, where the missing second-order terms in the leading-logarithmic (LL) approximation are supplemented and the contribution from the Z resonance is improved. In the LUMLOG sub-generator based on the LL approximation, we implement collinear photon emission in the final state and we also add a down-graded third-order LL matrix element, which has exactly the same incomplete third-order LL contribution as the multi-photon BHLUMI. The new LUMLOG is therefore capable of calculating the missing third-order LL part in the cross sections obtained from the main multi-photon event generator, for arbitrary event selection. The first-order event generator OLDBIS remains unchanged.

Multiphoton radiation in leptonic W -boson decays

Abstract.We present the calculation of multiphoton radiation effects in leptonic W-boson decays in the framework of the Yennie-Frautschi-Suura exclusive exponentiation. This calculation is implemented in the Monte Carlo event generator WINHAC for single W-boson production in hadronic collisions at the parton level. Some numerical results obtained with the help of this program are also presented.

Gauge-invariant YFS exponentiation of (un)stable Z -pair production at and beyond CERN LEP 2 energies

We present the theoretical basis and sample Monte Carlo data for the YFS exponentiated calculation of

The present theoretical error on the Bhabha scattering cross section in the luminometry region at LEP

{e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}\mathrm{ZZ}\ensuremath{\rightarrow}{f}_{1}{\overline{f}}_{1}+{\overline{f}}_{2}{f}_{2}

Precision calculation of the γ-Z interference effect in the SLC/LEP luminosity process☆

at and beyond CERN LEP 2 energies, where the left-handed part of

Exact O(α) gauge invariant YFS exponentiated Monte Carlo for (un)stable W+W− production at and beyond LEP2 energies1

{f}_{i}

Event generators for Bhabha scattering

is a component of an