5,836 research outputs found
Omega_{ccc} production via fragmentation at LHC
In the framework of the leading order of perturbative QCD and the
nonrelativistic quark-diquark model of baryons we have obtained fragmentation
function for c-quark to split into Omega_{ccc} baryon. It is shown that at LHC
one can expect 3.5 10^3 events with Omega_{ccc} at p_t>5 GeV/c and -1<y<1 per
year.Comment: LaTex, 5 pages and 2 figures. Talk presented at XIV Workshop on High
Energy Physics and Quantum Field Theory, Moscow, May 27 - June 4, 199
Prompt meson production at the LHC in the NRQCD with -factorization
In the framework of the -factorization, the prompt production of
mesons at the LHC conditions is studied. Our consideration is based on
the off-shell amplitudes for hard partonic subprocesses and on the
nonrelativistic QCD (NRQCD) formalism for the formation of bound states. We try
two latest parametrizations for noncollinear, or transverse momentum dependent
(TMD) gluon densities derived from the Catani-Ciafaloni-Fiorani-Marchesini
(CCFM) equation. We use the values of the nonperturbative matrix elements
obtained from a combined fit of the and differential cross
sections. Finally, we show an universal set of parameters that provides a
reasonable simultaneous description for all of the available data on the prompt
and production at the LHC.Comment: 5 pages, 2 figures, 3 table
Prompt charmonia production and polarization at LHC in the NRQCD with -factorization. Part III: meson
In the framework of -factorization approach, the production and
polarization of prompt mesons at the LHC energies is studied. Our
consideration is based on the non-relativistic QCD formalism for bound states
and off-shell amplitudes for hard partonic subprocesses. Both the direct
production mechanism and feed-down contributions from and
decays are taken into account. The transverse momentum dependent (or
unintegrated) gluon densities in a proton were derived from
Ciafaloni-Catani-Fiorani-Marchesini evolution equation or, alternatively, were
chosen in accordance with Kimber-Martin-Ryskin prescription. The
non-perturbative color-octet matrix elements were first deduced from the fits
to the latest CMS data on transverse momentum distributions and then
applied to describe the ATLAS and LHCb data on production and
polarization at , and TeV. We perform an estimation of
polarization parameters , and which determine spin density matrix and demonstrate that
treating the soft gluon emission as a series of explicit color-electric dipole
transitions within NRQCD leads to unpolarized production at high
transverse momenta, that is in qualitative agreement with the LHC data.Comment: 23 pages, 14 figures. arXiv admin note: substantial text overlap with
arXiv:1508.0548
First estimates of the wave function from the data on the production cross section
In the framework of perturbative QCD and nonrelativistic bound state
formalism, we calculate the production of and mesons at the
conditions of the CDF and LHCb experiments. We derive first estimations for the
wave function from a comparison with the available data.Comment: 3 pages, 1 figur
Gravitationally Induced Particle Production and its Impact on the WIMP Abundance
A large set of independent astronomical observations have provided a strong
evidence for nonbaryonic dark matter in the Universe. One of the most
investigated candidates is an unknown long-lived Weakly Interacting Massive
Particle (WIMP) which was in thermal equilibrium with the primeval plasma. Here
we investigate the WIMP abundance based on the relativistic kinetic treatment
for gravitationally induced particle production recently proposed in the
literature (Lima \& Baranov, Phys. Rev. D {\bf 90}, 043515, 2014). The new
evolution equation is deduced and solved both numerically and also through a
semi-analytical approach. The predictions of the WIMP observables are discussed
and compared with the ones obtained in the standard approach.Comment: 15 pages, 4 figures, discussion added in section 4. Accepted for
publication in Phys. Lett.
Particle Event Generator: A Simple-in-Use System PEGASUS version 1.0
PEGASUS is a parton-level Monte-Carlo event generator designed to calculate
cross sections for a wide range of hard QCD processes at high energy and
collisions, which incorporates the dynamics of transverse momentum
dependent (TMD) parton distributions in a proton. Being supplemented with
off-shell production amplitudes for a number of partonic subprocesses and
provided with necessary TMD gluon density functions, it produces weighted or
unweighted event records which can be saved as a plain data file or a file in a
commonly used Les Houches Event format. A distinctive feature of PEGASUS is an
intuitive and extremely user friendly interface, allowing one to easily
implement various kinematical cuts into the calculations. Results can be also
presented "on the fly" with built-in tool \textsc{pegasus plotter}. A short
theoretical basis is presented and detailed program description is given.Comment: 24 pages, 8 figure
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