371 research outputs found
c-quark decay modes in B_c-meson
We discuss the possibility for observing mesons in decay channels with
in final state.Comment: 6 pages, 1 table; refrences adde
Possible nature of
We discuss exotic states X(3872) and , observed recently in
experiment Belle. The QCD-string based explanation is suggested.Comment: 5 pages, 6 figure
Simultaneous production of charmonium and bottomonium mesons at LHC
Inclusive production of pair in proton-proton interation at
LHCb is considered. This process is forbidden at leading order of perturbation
theory, so such channels as double parton scattering, pair
production with subsequent radiative decays of -wave quarkonia,
contributions of color-octet states, and NLO corrections are studied in
details. For all these channels we present theoretical predictions of total
cross sections at LHCb and distributions over different kinematical variables.
According to presented in the paper results, double parton interaction gives
main contribution to the cross section of the considered reaction.Comment: minor changes, some references adde
Affine Transformations of Loop Nests for Parallel Execution and Distribution of Data over Processors
The paper is devoted to the problem of mapping affine loop nests onto
distributed memory parallel computers. A method to find affine transformations
of loop nests for parallel execution and distribution of data over processors
is presented. The method tends to minimize the number of communications between
processors and to improve locality of data within one processor. A problem of
determination of data exchange sequence is investigated. Conditions to
determine the ability to arrange broadcast is presented.Comment: 9 page
Production of and with real gluon emission at LHC
In the present work we study production of and in LHC. The first process is forbidden at the leading order in gluon
fusion due to the -parity conservation, and the first non-vanishing
contribution is given by the process with additional emission of real gluon.
Considering the direct production of , where the leading order
is allowed, we have found that the contribution from the higher order process
with real gluon emission is comparable and even more significant than the
leading order. Moreover, account of this higher order effect dramatically
changes kinematical distributions. Through the present paper we study in
details different channels of paired production: direct
production, feed-down from channel, double
parton scattering. We also try to find kinematical distributions that are most
suitable to separate these different channels.Comment: minor changes, some references adde
Hadronic Production of -mesons at LHC
Hadronic production of -wave charmonium states in hadronic
interaction is considered. Using experimental results of CDF and LHCb
collaborations we show, that contributions of color-singlet components are
dominant. As for color-octet mechanism, we show, that contributions from
-wave states can also be observed, while -wave states can be neglected.
The best experimental observables that give information about relative
importance of color-singlet and color-octet components are the ratios
and .Comment: 14 pages, 6 figures, 2 table
Production of - and -mesons in high energy hadronic collisions
This paper is devoted to phenomenological study of -mesons
production in high energy hadronic collisions in the framework of NRQCD. We
analyze all available experimental data on -mesons production and
extract non-perturbative NRQCD matrix elements from fitting the data. We show,
that measured -spectrum of -mesons is mainly formed by color
singlet components, while ratio depends
strongly on color octet matrix elements; this ratio becomes a highly sensitive
tool to study contribution of different terms from the NRQCD expansion.
Obtained using NRQCD scaling rules predictions for -mesons cross
sections are also given.Comment: 10 pages, 7 figure
Analytical calculation of heavy quarkonia production processes in computer
This report is devoted to the analytical calculation of heavy quarkonia
production processes in modern experiments such as LHC, B-factories and
superB-factories in computer. Theoretical description of heavy quarkonia is
based on the factorization theorem. This theorem leads to special structure of
the production amplitudes which can be used to develop computer algorithm which
calculates these amplitudes automatically. This report is devoted to the
description of this algorithm. As an example of its application we present the
results of the calculation of double charmonia production in bottomonia decays
and inclusive the mesons production in pp-collisions.Comment: minor change
Charmed hadrons production in high-energy beam
We present the calculation of the inclusive x_F-distributions of charmed
hadrons, produced in high-energy -beam. Our calculation is based on
the modified mechanism of charmed quarks fragmentation as well as on the
mechanism of c-quark recombination with the valence quarks from initial
hadrons.Comment: 6 pages, 6 figures, LaTe
On Mechanism of Charmed c-Quarks Fragmentation in Hadronic Collisions
We propose a modification of the mechanism of charmed quarks fragmentation
into mesons in hadronic collisions. It is shown that the distinction in
valence quark distributions in the initial and mesons
leads to different inclusive spectra of and mesons produced in
and beams.Comment: 18 pages, LaTeX, epsfig, 5 figure
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