191 research outputs found
Photon pair production at flavour factories with per mille accuracy
We present a high-precision QED calculation, with 0.1% theoretical accuracy,
of two photon production in annihilation, as required by more and
more accurate luminosity monitoring at flavour factories. The accuracy of the
approach, which is based on the matching of exact next-to-leading order
corrections with a QED Parton Shower algorithm, is demonstrated through a
detailed analysis of the impact of the various sources of radiative corrections
to the experimentally relevant observables. The calculation is implemented in
the latest version of the event generator BabaYaga, available for precision
simulations of photon pair production at colliders of moderately high
energies.Comment: 11 pages, 5 figures, 1 tabl
Multi-photon corrections to W boson mass determination at hadron colliders
The impact of higher-order final-state photonic corrections on the precise
determination of the W-boson mass at the Tevatron and LHC colliders is
evaluated. The W-mass shift from a fit to the transverse mass distribution is
found to be about 10 MeV in the W --> mu nu channel and a few MeV in the W -->
e nu channel. The calculation, which is implemented in the Monte Carlo event
generator HORACE for data analysis, can contribute to reduce the uncertainty
associated to the W mass measurement at present and future hadron collider
experiments.Comment: 3 pages, 2 figures, to appear in the proceedings of International
Europhysics Conference on High-Energy Physics (EPS 2003), Aachen, Germany,
17-23 Jul 200
Precision electroweak calculation of the production of a high transverse-momentum lepton pair at hadron colliders
We present a detailed study of the production of a high transverse-momentum
lepton pair at hadron colliders, which includes the exact O(alpha) electroweak
corrections properly matched with leading logarithmic effects due to multiple
photon emission, as required by the experiments at the Fermilab Tevatron and
the CERN LHC. Numerical results for the relevant observables of single Z-boson
production at hadron colliders are presented. The impact of the radiative
corrections is discussed in detail. The presence in the proton of a photon
density is considered and the effects of the photon-induced partonic
subprocesses are analyzed. The calculation has been implemented in the new
version of the event generator HORACE, which is available for precision
simulations of the neutral and charged current Drell-Yan processes.Comment: October 2007, 22p
A new approach to evaluate the leading hadronic corrections to the muon g-2
We propose a novel approach to determine the leading hadronic corrections to
the muon g-2. It consists in a measurement of the effective electromagnetic
coupling in the space-like region extracted from Bhabha scattering data. We
argue that this new method may become feasible at flavor factories, resulting
in an alternative determination potentially competitive with the accuracy of
the present results obtained with the dispersive approach via time-like data.Comment: 7 pages, 3 figures. Version accepted for publication in Phys. Lett.
Full one-loop electroweak corrections to e+e- to 3 jets at linear colliders
We describe the impact of the full one-loop electroweak terms of O(alpha_s
alpha_EM^3) entering the electron-positron into three-jet cross-section from
sqrt(s)=M_Z to TeV scale energies. We include both factorisable and
non-factorisable virtual corrections and photon bremsstrahlung. Their
importance for the measurement of alpha_S from jet rates and shape variables is
explained qualitatively and illustrated quantitatively, also in presence of
b-tagging.Comment: 6 pages, to appear in the proceedings of the workshop "LC09 -- e+e-
Physics at the TeV scale and the Dark Matter Connection", 21-24 September
2009, Perugia (Italy). Minor corrections, references added
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