170 research outputs found
Measuring Double Parton Distributions in Nucleons at Proton-Nucleus Colliders
We predict a strong enhancement of multijet production in proton-nucleus
collisions at collider energies, as compared to a naive expectation of a cross
section . The study of the process would allow to measure, for the
first time, the double parton distribution functions in a nucleon in a model
independent way and hence to study both the longitudinal and the transverse
correlations of partons.Comment: 12 pages, 2 figure
Production of -pairs at HERA-
The production of -pairs as a possible measure of the polarized gluon
distribution is studied for proton--nucleon collisions at
\sqrt{s} =40\;\mbox{GeV}^2 (HERA-). Possibilities of
reconstructing the helicity state of at least one of the 's are
critically reviewed. The observation of production asymmetries in the single
polarized mode of HERA- is found to be not feasible.Comment: 8 pages, LATeX, 3 figures availabe as .uu-fil
High- production as signals for Double Parton scattering at hadron colliders
We present an analysis of the \psi\psi production from double parton (DP)
sacttering and single parton (SP) scattering in the large p_T region via
color-octet gluon fragmentation. We find that at the Tevatron the DP \psi\psi
production is at the edge of the detectability at present, and at the LHC the
DP cross section will dominate over the SP cross section in the lower p_T(min)
region (i.e., p_T(min)<7GeV). We also conclude that the color-octet mechanism
is of crucial importance to the double j/psi production at high energy hadron
colliders.Comment: Revtex, 12 pages, 3 Postscript figure
Scale Factor in Double Parton Collisions and Parton Densities in Transverse Space
The scale factor , which characterizes double parton collisions
in high energy hadron interactions, is a direct manifestation of the
distribution of the interacting partons in transverse space, in such a way that
different distributions give rise to different values of in
different double parton collision processes. We work out the value of the scale
factor in a few reactions of interest, in a correlated model of the
multi-parton density of the proton recently proposed.Comment: 10 pages, 2 figure
Double parton distributions in the leading logarithm approximation of perturbative QCD
Recent CDF measurements of the inclusive cross section for a double parton
scattering attach a great importance to any theoretical calculations of
two-particle distribution functions. Using a parton interpretation of the
leading logarithm diagrams of perturbative QCD theory, generalized
Lipatov-Altarelli-Parisi-Dokshitzer equations for the two-parton distributions
are re-obtained. The solutions of these equations are not at all the product of
two single-parton distributions what is usually applied to the current analysis
as ansatz.Comment: 8 pages, LaTe
A double parton scattering background to Higgs boson production at the LHC
The experimental capability of recognizing the presence of b quarks in
complex hadronic final states has addressed the attention towards final states
with b\bar{b} pairs for observing the production of the Higgs boson at the LHC,
in the intermediate Higgs mass range.We point out that double parton scattering
processes are going to represent a sizeable background to the process.Comment: 9 pages, 2 figure
Signals for Double Parton Scattering at the Fermilab Tevatron
Four double-parton scattering processes are examined at the Fermilab Tevatron
energy. With optimized kinematical cuts and realistic parton level simulation
for both signals and backgrounds, we find large samples of four-jet and
three-jet+one-photon events with signal to background ratio being 20\%-30\%,
and much cleaner signals from two-jet+two-photon and two-jet+ final
states. The last channel may provide the first unambiguous observation of
multiple parton interactions, even with the existing data sample accumulated by
the Tevatron collider experiments.Comment: 7 pages, plain LaTeX, 2 tables, no figures. A compressed PS file is
available by anonymous ftp at
ftp://phenom.physics.wisc.edu/pub/preprints/1996/madph-96-945.ps.
Double parton scatterings in b-quark pairs production at the LHC
A sizable rate of events where two pairs of b-quarks are produced
contemporarily is foreseen at the CERN LHC, as a consequence of the large
parton luminosity. At very high energies both single and the double parton
scatterings contribute to the process, the latter mechanisms, although power
suppressed, giving the dominant contribution to the integrated cross section.Comment: 17 pages, 6 figure
Higher-Order QCD Corrections to Inclusive Particle Production in p anti-p Collisions
Inclusive single-particle production cross sections have been calculated
including higher-order QCD corrections. Transverse-momentum and rapidity
distributions are presented and the scale dependence is studied. The results
are compared with experimental data from the CERN S(p anti-p)S Collider and the
Fermilab Tevatron.Comment: 28 pages, [12 uuencoded PS figures, 3 available under request].
Preprint DESY 92-13
Multiparton interactions and production of minijets in high energy hadronic collisions
We discuss the inclusive cross section to produce two minijets with a large
separation in rapidity in high energy hadronic collisions. The contribution to
the inclusive cross section from the exchange of a BFKL Pomeron is compared
with the contribution from the exchange of two BFKL Pomerons, which is induced
by the unitarization of the semi-hard interaction. The effect of the multiple
exchange is studied both as a function of the azimuthal correlation and as a
function of the transverse momentum of the observed minijets.Comment: TeX file, 20 pages, 4 figures available on reques
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