1,215 research outputs found
Moments of Wigner function and Renyi entropies at freeze-out
Relation between Renyi entropies and moments of the Wigner function,
representing the quantum mechanical description of the M-particle
semi-inclusive distribution at freeze-out, is investigated. It is shown that in
the limit of infinite volume of the system, the classical and quantum
descriptions are equivalent. Finite volume corrections are derived and shown to
be small for systems encountered in relativistic heavy ion collisions.Comment: 15 pages, one figur
Bose-Einstein correlations: a study of an invariance group
A group of transformations changing the phases of the single particle density
matrix, but leaving unchanged the predictions for identical particles
concerning the momentum distributions, momentum correlations etc., is
identified. Its implications for the determinations of the interaction region
from studies of Bose-Einstein correlations are discussed.Comment: 15 pages LateX + one figure ep
Sensitivity to the Standard Model Higgs Boson in Exclusive Double Diffraction
We use a Monte Carlo implementation of recently developed models of double
diffraction to assess the sensitivity of the LHC experiments to Standard Model
Higgs bosons produced in exclusive double diffraction. The signal is difficult
to extract, due to experimental limitations related to the first level trigger,
and to contamination by inclusive double diffractive background. Assuming the
above difficulties can be overcome, the expected signal-to-background ratio is
presented as a function of the experimental resolution on the missing mass.
Injecting a missing mass resolution of 2 GeV, a signal-to-background ratio of
about 0.5 is obtained; a resolution of 1 GeV brings a signal to background
ratio of 1. This result is lower than previous estimates, and the discrepancy
is explained.Comment: Revised versio
Replica analysis of a preferential urn model
We analyse a preferential urn model with randomness using the replica method.
The preferential urn model is a stochastic model based on the concept "the rich
get richer." The replica analysis clarifies that the preferential urn model
with randomness shows a fat-tailed occupation distribution. The analytical
treatments and results would be useful for various research fields such as
complex networks, stochastic models, and econophysics.Comment: 6 pages, 2 figure
Phase Structure of Dynamical Triangulation Models in Three Dimensions
The dynamical triangulation model of three-dimensional quantum gravity is
shown to have a line of transitions in an expanded phase diagram which includes
a coupling mu to the order of the vertices. Monte Carlo renormalization group
and finite size scaling techniques are used to locate and characterize this
line. Our results indicate that for mu < mu1 ~ -1.0 the model is always in a
crumpled phase independent of the value of the curvature coupling. For mu < 0
the results are in agreement with an approximate mean field treatment. We find
evidence that this line corresponds to first order transitions extending to
positive mu. However, the behavior appears to change for mu > mu2 ~ 2-4. The
simplest scenario that is consistent with the data is the existence of a
critical end point
DPEMC : A Monte-Carlo for Double Diffraction
We extend the POMWIG Monte Carlo generator developed by B.Cox and J.Forshaw,
to include new models of central production through inclusive and exclusive
Double Pomeron Exchange in proton-proton collisions. Double photon Exchange
processes are described as well, both in proton-proton and heavy-ion
collisions. In all contexts, various models have been implemented, allowing for
comparisons and uncertainty evaluation and enabling detailed experimental
simulations.Comment: Revised versio
Diffractive Production at the Tevatron and the LHC
We present predictions for the diffractive production of mesons in the
central rapidity region usually covered by collider detectors. The predicted
cross sections are based on the Bialas-Landshoff formalism for both exclusive
and inclusive production and makes use of the DPEMC Monte-Carlo simulation
adapted with kinematics appropriate for small-mass diffractive production. We
compare generator-level results with a CDF measurement for exclusive
production, and study background and other scenarios including the contribution
of inclusive production. The results agree with the Tevatron data and
are extrapolated, highlighting the exclusive \chic production at LHC
energies. A possible new measurement at the Tevatron using the D{\O}forward
detectors is investigated, taking advantage of the dominance of exclusive
production for high enough diffractive mass fraction.Comment: 9 pages, 2 figures, added akcnowledgment
Higgs boson production via Double Pomeron Exchange at the LHC
We study Higgs boson production via Double Pomeron Exchange allowing for the
presence of Pomeron remnants. We estimate the number of events produced at the
LHC collider, as a function of the Higgs boson mass and its decay channel. The
model which successfully describes the high mass dijet spectrum observed at
Tevatron (run I) is used to predict rates of events with tagged protons for the
acceptance range of the CMS/Totem experiments. Sizeable cross-sections and
encouraging event selection signals are found, demonstrating especially for
smaller Higgs boson masses the importance to study the diffractive channels.
Tagging of the Pomeron remnants can be exploited to achieve a good resolution
on the Higgs boson mass for inclusive diffractive events, by optimizing an
intermediary analysis between higher cross-sections of the fully {\it
inclusive} mode (all Pomeron remnants) and cleaner signals of the {\it
exclusive} mode (without Pomeron remnants).Comment: 6 pages, 4 eps.figure
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