26-30 March 2012
University of Bonn
Europe/Berlin timezone

Diffractive pQCD mechanisms of exclusive production of $b \bar b$ dijets and $W^+ W^-$ pairs in proton-proton collisions

27 Mar 2012, 17:30
20m
Lecture Hall, Institute for Applied Physics (University of Bonn)

Lecture Hall, Institute for Applied Physics

University of Bonn

Diffraction and vector mesons Diffraction and vector mesons

Speaker

Prof. Antoni Szczurek (Institute of Nuclear Physics Krakow (Poland))

Description

We discuss central exclusive production of $W^+W^-$ pairs in proton-proton collisions at LHC. Several observables related to this process are calculated. Predictions for the total cross section and differential distributions in rapidity and transverse momentum of $W^{\pm}$ and $WW$ invariant mass are presented. We show results for different polarization states of the final $W^{\pm}$ bosons. We discuss both $\gamma \gamma \to W^+ W^-$ mechanism as well as a new mechanism of exclusive diffractive production. The amplitude for the latter process is calculated in the Durham model used recently to estimate cross section for exclusive production of Higgs boson, gluon-gluon, $b \bar b$ dijets as well as for pairs of photons. Some results for those processes will be discussed briefly and compared to the CDF collaboration data. The amplitude for the $p p \to p p W^+ W^-$ process is expressed in terms of off-diagonal unintegrated gluon distribution functions. We compare the two (QED and QCD) types of contributions. The phase space integrated diffractive contribution when separated is only a small fraction of fb compared to 115.4 fb of the $\gamma \gamma$ contribution. The $\gamma \gamma$ contribution dominates at small four-momentum transfers squared in the proton lines as well as in a broad range of $W^+ W^-$ invariant masses. This opens a possibility of searches for anomalous four-boson $\gamma \gamma W^+ W^-$ coupling due to new physics beyond Standard Model. The example are Higgsless models. The presentation will be based mostly on our recent study. I will also show some published results on exclusive production of Higgs and dijets.

Primary author

Prof. Antoni Szczurek (Institute of Nuclear Physics Krakow (Poland))

Presentation Materials