20-27 July 2011
Alpes Congrès - Alpexpo
Europe/Paris timezone

Exclusive production of Higgs boson, $b \bar b$ and gluonic jets

21 Jul 2011, 17:30
15m
Bayard (Alpes Congrès - Alpexpo)

Bayard

Alpes Congrès - Alpexpo

Parallel session talk QCD QCD

Speaker

Prof. Antoni Szczurek (Rzeszow University and Institute of Nuclear Physics PAN)

Description

We discuss the central exclusive production of Higgs boson and $q\bar{q}$ pairs in proton-proton (proton-antiproton) collisions at LHC and Tevatron. The amplitude for both processes is derived within the $k_t$-factorization approach and discussed in different kinematical asymptotia. In particular, we consider important high-$p_t$ and massless quark limits for $q \bar q$ production. Rapidity distributions, quark jet $p_t$ distributions, invariant $q\bar{q}$ mass distributions, angular azimuthal correlations between outgoing protons and between ougoing jets are presented. Exclusive $b \bar b$ production constitutes an irreducible background for exclusive Higgs production The $b{\bar b}$ background is analyzed in detail, in particular we study how to impose cuts to maximize signal-to-background ratio and show some solutions. We consider also central exclusive production of $gg$ dijets. The amplitude for the process is derived within the $k_t$-factorization approach (with both the standard QCD and the Lipatov's effective 3-gluon verticies) and is considered in various kinematical asymptotia, in particular, in the important limit of high-$p_t$ jets. Compared to earlier works we include emissions of gluons from different gluonic $t$-channel lines. Rapidity distributions, gluon jet $p_t$ distributions, invariant dijet mass distributions, angular azimuthal correlations between outgoing protons and jets are presented. We explore the competition of the standard diagram with both jets emitted from a single $t$-channel gluon and the one with the emission from both $t$-channel gluons. We find that the latter contribution is much smaller than that known from the literature. It becomes comparable only when the jet rapidity difference is large or the gluon transverse momenta are very small. It can, therefore, give contributions to the central diffractive production of mesons. We compare our results with the Tevatron data for exclusive dijets. \item R. Maciu{\l}a, R.S. Pasechnik and A. Szczurek, "Exclusive double-diffractive production of open charm in proton-proton and proton-antiproton collisions", Phys. Lett. {\bf B685} (2010) 165. \item R. Maciu{\l}a, R. Pasechnik and A. Szczurek, ``Exclusive $b \bar b$ pair production and irreducible background to the exclusive Higgs boson production'', Phys. Rev. {\bf D82} (2010) 114011. \item R. Maciu{\}a, R. Pasechnik and A. Szczurek, ``Central exclusive quark-antiquark dijet and Standard Model Higgs boson production in proton-(anti)proton collisions, arXiv:1011.5842, to be published in Phys. Rev.D

Primary author

Prof. Antoni Szczurek (Rzeszow University and Institute of Nuclear Physics PAN)

Co-author

Dr Roman Pasechnik (Uppsala Un)

Presentation Materials