474 research outputs found
Towards a Precise Parton Luminosity Determination at the CERN LHC
A new approach to determine the LHC luminosity is investigated. Instead of
employing the proton-proton luminosity measurement, we suggest to measure
directly the parton-parton luminosity. It is shown that the electron and muon
pseudorapidity distributions, originating from the decay of W+, W- and Z0
bosons produced at 14 TeV pp collisions (LHC), constrain the x distributions of
sea and valence quarks and antiquarks in the range from about 3 x 10**-4 to
about 10**-1 at a Q**2 of about 10**4 GeV**2. Furthermore, it is demonstrated
that, once the quark and antiquark structure functions are constrained from the
W+,W- and Z0 production dynamics, other quark-antiquark related scattering
processes at the LHC like q-qbar --> W+W- can be predicted accurately. Thus,
the lepton pseudorapidity distributions provide the key to a precise parton
luminosity monitor at the LHC, with accuracies of about +-1% compared to the so
far considered goal of +-5%.Comment: plain tex, 14 pages, 5 figure
Hadronic production and the Gottfried Sum Rule
The difference in production rate between and at hadron colliders
is very sensitive to the the difference between up- and down-quark
distributions in the proton. This sensitivity allows for a variety of useful
measurements. We consider the difference in the sea
distributions and the difference in the
polarized parton distribution functions. In both cases we construct an
asymmetry to reduce systematic uncertainties. Although we discuss measurements
at the Tevatron and future hadron colliders, we find that the Brookhaven
Relativistic Heavy Ion Collider (RHIC) is the most appropriate hadron collider
for these measurements.Comment: 19 pages (20 figures available from the authors), MAD/PH/74
Enhancing the top signal at Tevatron using Neural Nets
We show that Neural Nets can be useful for top analysis at Tevatron. The main
features of and background events on a mixed sample are projected in
a single output, which controls the efficiency and purity of the
signal.Comment: 11 pages, 6 figures (not included and available from the authors),
Latex, UB-ECM-PF 94/1
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
An update on vector boson pair production at hadron colliders
We present numerical results (including full one-loop QCD corrections) for
the processes p p-bar and pp -> W+ W-, W+/- Z/gamma* and Z/gamma* Z/gamma*
followed by the decay of the massive vector bosons into leptons. In addition to
their intrinsic importance as tests of the standard model, these processes are
also backgrounds to conjectured non-standard model processes. Because of the
small cross sections at the Tevatron, full experimental control of these
backgrounds will be hard to achieve. This accentuates the need for up-to-date
theoretical information. A comparison is made with earlier work and cross
section results are presented for p p-bar collisions at sqrt{s}=2 TeV and pp
collisions at sqrt{s}=14 TeV. Practical examples of the use of our calculations
are presented.Comment: 18 pages, 5 embedded figures, included extra reference [7
Large Jets at Hadron Colliders at Order : A Look Inside
Results from the study of hadronic jets in hadron-hadron collisions at order
in perturbation theory are presented. The focus is on various
features of the internal structure of jets. The numerical results of the
calculation are compared with data where possible and exhibit reasonable
agreement.Comment: 7 pages, 1 table and 2 figures (appended as postscript files), Late
Transverse Momentum Distributions for Heavy Quark Pairs
We study the transverse momentum distribution for a of heavy quarks
produced in hadron-hadron interactions. Predictions for the large transverse
momentum region are based on exact order QCD perturbation theory.
For the small transverse momentum region, we use techniques for all orders
resummation of leading logarithmic contributions associated with initial state
soft gluon radiation. The combination provides the transverse momentum
distribution of heavy quark pairs for all transverse momenta. Explicit results
are presented for pair production at the Fermilab Tevatron collider
and for pair production at fixed target energies.Comment: LaTeX (27 pages text, 8 figures not included, but available on
request
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