| 1. |
- Maciula, Rafal, et al.
(author)
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Central exclusive quark-antiquark dijet and standard model Higgs boson production in proton-(anti)proton collisions
- 2011
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In: Physical Review D. Particles and fields. - 0556-2821 .- 1089-4918. ; 83:11
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Journal article (peer-reviewed)abstract
- We consider the central exclusive production of q (q) over bar pairs and Higgs boson in proton-proton collisions at LHC. The amplitude for the process is derived within the k(perpendicular to)-factorization approach and considered in different kinematical asymptotics, in particular, in the important high quark transverse momenta and massless quark limits. Quark helicity and spin-projection amplitudes in two different frames are shown in extenso. Rapidity distributions, quark jet p(perpendicular to) distributions, invariant q (q) over bar mass distributions, angular azimuthal correlations between outgoing protons and jets are presented. Irreducible b (b) over bar background to the central exclusive Higgs boson production is analyzed in detail, in particular, how to impose cuts to maximize signal-to-background ratio.
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| 2. |
- Maciula, Rafal, et al.
(author)
-
Exclusive b(b)over-bar pair production and irreducible background to the exclusive Higgs boson production
- 2010
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In: Physical Review D - Particles, Fields, Gravitation and Cosmology. - 1550-7998. ; 82:11, s. 114011-
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Journal article (peer-reviewed)abstract
- We calculated the cross section for the exclusive double-diffractive b (b) over bar production in pp -> p(b (b) over bar )p reaction at LHC. Large cross sections are obtained (3-10 nb). This process constitutes the irreducible background to the exclusive Higgs production and is of particular importance in the upcoming Higgs boson searches. The distribution in invariant mass of the b (b) over bar pair is calculated and compared with the corresponding contribution from the Higgs decay. The contribution from the exclusive production of Z(0) and its decay as well as the contribution from the gamma gamma -> b (b) over bar subprocess are also presented for the first time. The influence of cuts on the signal-to-background ratio is discussed.
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| 3. |
- Maciula, Rafal, et al.
(author)
-
New contributions to central exclusive production of dijets in proton-(anti)proton collisions
- 2011
-
In: Physical Review D (Particles, Fields, Gravitation and Cosmology). - 1550-2368. ; 84:11
-
Journal article (peer-reviewed)abstract
- We consider central exclusive production of gg dijets in proton-proton (proton-antiproton) collisions at LHC and Tevatron for different intermediate and final gluon polarizations. The amplitude for the process is derived within the k(perpendicular to)-factorization approach (with both the standard QCD and the Lipatov's effective three-gluon vertices) and is considered in various kinematical asymptotia, in particular, in the important limit of high-p(perpendicular to) jets. Compared to earlier works we include emissions of gluons from different gluonic t-channel lines as well as emission of quark-antiquark dijets. Rapidity distributions, gluon jet p(perpendicular to) distributions and invariant dijet mass distributions 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. The second mechanism requires a special treatment. We propose two different approaches. Including special kinematics and using properties of off-diagonal gluons at small x and xi, we arrive to correlations in two-dimensional distributions in rapidity of one and second jet. We find that the second contribution is much smaller than that known from the literature. The digluon production constitutes an important background to exclusive Higgs production.
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