874 research outputs found
ExHuME: A Monte Carlo Event Generator for Exclusive Diffraction
We have written the Exclusive Hadronic Monte Carlo Event (ExHuME) generator.
ExHuME implements the perturbative QCD calculation of Khoze, Martin and Ryskin
of the process pp-> p+X+p, where X is a centrally produced colour singlet
system.Comment: 11 pages, 3 figure
Hunting a light CP-violating Higgs via diffraction at the LHC
We study the central diffractive production of the (three neutral) Higgs
bosons, with a rapidity gap on either side, in an MSSM scenario with
CP-violation. We consider the bb-bar and tautau-bar decay for the light H_1
boson and the four b-jet final state for the heavy H_2 and H_3 bosons, and
discuss the corresponding backgrounds. A direct indication of the existence of
CP-violation can come from the observation of either an azimuthal asymmetry in
the angular distribution of the tagged forward protons (for the exclusive pp ->
p+H+p process) or of a sin(2phi) contribution in the azimuthal correlation
between the transverse energy flows in the proton fragmentation regions for the
process with the diffractive dissociation of both incoming protons (pp ->
X+H+Y). We emphasise the advantage of reactions with the rapidity gaps (that is
production by the pomeron-pomeron fusion) to probe CP parity and to determine
the quantum numbers of the produced central object.Comment: 11 pages, 3 figure
Diffractive gamma-gamma production at hadron colliders
We compute the cross section for exclusive double-diffractive gamma-gamma
production at the Tevatron, , and
the LHC. We evaluate both the gluon-gluon and quark-antiquark t-channel
exchange contributions to the process. The observation of exclusive gamma-gamma
production at the Tevatron will provide a check on the model predictions, and
offer an opportunity to confirm the expectations for exclusive
double-diffractive Higgs production at the LHC.Comment: 16 pages, 7 figure
Structure of the final states in Higgs production at Hadronic Colliders
We quantify the rate and the signal-to-background ratio for Higgs detection in double-diffractive events at the Tevatron and the LHC.
The signal is predicted to be very small at the Tevatron, but observable at the
LHC. We exemplify the diagnostic power of hadronic antenna pattern by
considering the topology of hadronic flow corresponding to Higgs
events.Comment: 4 pages, talk given at XXXI International Symposium on Multiparticle
Dynamics, Sept 1-7, 2001, Datong China. URL http://ismd31.ccnu.edu.cn
Rapidity Gap Higgs Signal at the Tevatron and the LHC
We quantify the rate and the signal-to-background ratio for Higgs --> b
anti-b detection in double-diffractive events at the Tevatron and the LHC. The
signal is predicted to be very small at the Tevatron, but observable at the
LHC. We show that the double-diffractive dijet production may serve as a unique
gluon factory. This process can be used also as a Pomeron-Pomeron luminosity
monitor.Comment: 12 pages, 1 figure, Late
Non-factorizable corrections and effective field theories
We analyze the structure of higher-order radiative corrections for processes
with unstable particles. By subsequently integrating out the various scales
that are induced by the presence of unstable particles we obtain a hierarchy of
effective field theories. In the effective field theory framework the
separation of physically different effects is achieved naturally. In
particular, we automatically obtain a separation of factorizable and
non-factorizable corrections to all orders in perturbation theory. At one loop
this treatment is equivalent to the double-pole approximation (DPA) but
generalizes to higher orders and, at least in principle, to beyond the DPA. It
is known that one-loop non-factorizable corrections to invariant mass
distributions are suppressed at high energy. We study the mechanism of this
suppression and obtain estimates of higher-order non-factorizable corrections
at high energy.Comment: 45 page
QCD Interconnection Studies at Linear Colliders
Heavy objects like the W, Z and t are short-lived compared with typical
hadronization times. When pairs of such particles are produced, the subsequent
hadronic decay systems may therefore become interconnected. We study such
potential effects at Linear Collider energies.Comment: 1+7 pages, 6 figure
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