Precision Calculation of Bhabha Scattering at LEP

For the small-angle Bhabha-scattering process, we consider the error budget for the calculation of the LEP/SLC luminosity in the Monte Carlo event generator BHLUMI 4.04, from the standpoint of new calculations of exact results for the respective O(alpha**2) photonic corrections in the context of the Yennie-Frautchi-Suura exponentiation. We find that an over-all precision tag for the currently available program BHLUMI 4.04 can be reduced from 0.11% to 0.061% at LEP1 and from 0.25% to 0.122% at LEP2. For the large-angle Bhabha process, we present the Monte Carlo program BHWIDE and compare its predictions with predictions of other Monte Carlo programs as well as semi-analytical calculations

The Femto-experiment for the LHC: The W-boson beams and their targets

The LHC has been designed as a collider of proton and ion beams. However, in its experimental program, which is focused mainly on studies of high energy transfer collisions of Standard Model point-like particles, protons and ions will play a backstage role. For the majority of the LHC experimentalists, their role will be confined to providing standardized, acceleration-process-stable envelopes for tunable-density and tunable-isospin bunches of Standard Model constituents: quarks and gluons. The inter-bunch environment of collisions of these Standard Model particles specific to hadronic colliders and absent in the leptonic ones, has always been considered as a burden - an annoying but unavoidable price to pay for increasing the collision-energy of point-like particles in the storage rings. In this paper we shall argue that such a burden can be converted into an important merit of the high-energy hadronic colliders - a corner-stone for a fermi-length-scale ``collision-experiment'' employing the bunches of spectator quarks and gluons as tunable ``femtoscopic'' targets for the beams of short-living electroweak bosons

Monte Carlo program KoralW 1.42 for all four-fermion final states in e+e−e^{+} e^{-} collisions

The Monte Carlo program KoralW version 1.42 is presented. It generates all four-fermion final states with multibranch dedicated Monte Carlo pre-samplers and complete, massive, Born matrix elements. The presamplers cover the entire phase space. Multiphoton bremsstrahlung is implemented in the ISR approximation within the YFS formulation with the O(alpha**3) leading-log matrix element. The anomalous WWV couplings are implemented in CC03 approximation. The standard decay libraries (JETSET, PHOTOS, TAUOLA) are interfaced. The semi-analytical CC03-type code KorWan for differential and total cross-sections is included