1,366 research outputs found
New Showers with transverse-momentum-ordering
Two new showering routines are introduced, one for timelike final-state
showers and one for spacelike initial-state ones. They are both based on
emissions ordered in approximate transverse momenta that can easily be
translated to virtualities. Matrix-element corrections can then be imposed as
in the existing Pythia routines.Comment: LaTeX, 4 pages, submitted to the proceedings of the Workshop on
Physics at TeV Colliders, Les Houches, France, 26 May - 6 June 200
Multiple Interactions and Beam Remnants
Open issues on the structure of multiple interactions are outlined. An
improved model is summarized, with a new approach to correlated parton
densities in flavour, colour, longitudinal and transverse momenta, for both
hard-scattering partons and beam-remnant ones.Comment: LaTeX, 5 pages, submitted to the proceedings of the Workshop on
Physics at TeV Colliders, Les Houches, France, 26 May - 6 June 200
Measurement of D-meson production in pp collisions with ALICE at the LHC
The -differential cross section of D mesons in the rapidity
range was measured in pp collisions at = 2.76, 7 and 8
TeV. D mesons were reconstructed in their hadronic decay channels by means of
the invariant mass analysis. The D-meson production cross sections is compared
among different energies and to pQCD calculations. Also the prompt D meson are
studied as a function of the multiplicity of charged articles produced in
inelastic pp collisions at a centre-of-mass energy of = 7 TeV. The
measurements are compared with model calculations.Comment: 3 pages, 5 figures, XXII DAE-BRNS High Energy Physics Symposium 201
Measurement of charged jet cross sections and jet shapes in proton-proton collisions at sqrt(s) = 2.76 TeV with the ALICE detector at LHC
We present measurements of charged jet cross sections and jet shape
observables in leading jet in proton-proton (pp) collisions at sqrt(s) = 2.76
TeV with the ALICE detector at LHC. Jets are reconstructed at the midrapidity
from charged particle using sequential recombination anti-kT jet finding
algorithm for various R values. The results are compared to measurements from
HERWIG, PHOJET and different tunes of PYTHIA6 and earlier measurements at 7
TeV.Comment: Proceedings of XXII DAE-BRNS High Energy Physics Symposium 2016
conference, 12-16 December, 201
Improving jet distributions with effective field theory
We obtain perturbative expressions for jet distributions using soft-collinear
effective theory (SCET). By matching SCET onto QCD at high energy, tree level
matrix elements and higher order virtual corrections can be reproduced in SCET.
The resulting operators are then evolved to lower scales, with additional
operators being populated by required threshold matchings in the effective
theory. We show that the renormalization group evolution and threshold
matchings reproduce the Sudakov factors and splitting functions of QCD, and
that the effective theory naturally combines QCD matrix elements and parton
showers. The effective theory calculation is systematically improvable and any
higher order perturbative effects can be included by a well defined procedure.Comment: 4 pages, 1 figure; typos corrected and notation updated to match
hep-ph/060729
Production and rescattering of strange baryons at SPS energies in a transport model with hadron potentials
A mean-field potential version of the Ultra-relativistic Quantum Molecular
Dynamics (UrQMD) model is used to investigate the production of strange
baryons, especially the s and s, from heavy ion
collisions at SPS energies. It is found that, with the consideration of both
formed and pre-formed hadron potentials in UrQMD, the transverse mass and
longitudinal rapidity distributions of experimental data of both s and
s can be quantitatively explained fairly well. Our
investigation also shows that both the production mechanism and the
rescattering process of hadrons play important roles in the final yield of
strange baryons.Comment: 15 pages, 7 figure
Study of particle production from quark and gluon jets in proton-proton collisions
We investigate whether and how different fragmentation properties of quarks
and gluons affect identified particle spectra. We present a systematic study of
, and production in minimum bias (inelastic, non-diffractive),
two- and three-jet events at RHIC, Tevatron and LHC energies. Through the study
of two- and three-jet events and various jet-production channels we can
directly access the fragmentation properties of quark and gluon jets. We
present MC estimate for the contribution of quark and gluon jets to individual
particle species spectra, that can be compared to experimental results and test
our current knowledge of the physics behind particle production inside jets.Comment: 5 pages, 3 figures, presented at Hot Quarks 201
Studies of isolated photon production in simulated proton-proton collisions with ALICE-EMCal
The production of prompt photons at high transverse momentum in proton-proton
collisions (p-p) is a useful tool to study perturbative Quantum-Chromo-Dynamics
(pQCD). In particular, they yield valuable information about parton
distribution functions in the proton. The experimental measurement of prompt
photons is a difficult task due to the large background of decay photons from
neutral mesons, mainly pi0. We present a full simulation and reconstruction
study of prompt photons identification in p-p at sqrt(s) = 14 TeV in the ALICE
electromagnetic calorimeter EMCal, giving details on the methods developed to
separate them from decay photons with the help of shower-shape and isolation
cuts. We present Monte Carlo predictions for signal and background. The method
used to extract the final isolated corrected cross-section is presented and the
calculation of various experimental corrections is outlined.Comment: 4 pages, 6 figures. Proceedings Hot Quarks 2010 La-Londe-les-Maures
(France), JPG submitte
The Sources of b-Quarks at the Tevatron and their Correlations
The leading-log order QCD hard scattering Monte-Carlo models of HERWIG,
ISAJET, and PYTHIA are used to study the sources of b-quarks at the Tevatron.
The reactions responsible for producing b and bbar quarks are separated into
three categories; flavor creation, flavor excitation, and
parton-shower/fragmentation. Flavor creation corresponds to the production of a
b-bbar pair by gluon fusion or by annihilation of light quarks, while flavor
excitation corresponds to a b or bbar quark being knocked out of the
initial-state by a gluon or a light quark or antiquark. The third source occurs
when a b-bbar pair is produced within a parton shower or during the
fragmentation process of a gluon or a light quark or antiquark (includes gluon
splitting). The QCD Monte-Carlo models indicate that all three sources of
b-quarks are important at the Tevatron and when combined they qualitatively
describe the inclusive cross-section data. Correlations between the b and bbar
quark are very different for the three sources and can be used to isolate the
individual contributions.Comment: RevTex4, 14 pages, 20 figures, submitted to Phys. Rev.
Single Production of Fourth Family Sneutrino via RPV Couplings at Linear Colliders
The single production of fourth family sneutrino via
R-parity violating interactions in electron-positron collisions has been
investigated. We study the decays of into different flavor
dilepton via R-parity violation. It is shown that R-parity
violating couplings down to 0.001 will be
reachable at future linear colliders which would provide better accuracy
comparing to the indirect measurements as complementary to the LHC results.Comment: 11 pages, 6 figure
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