427 research outputs found
Interactions of Heavy Hadrons using Regge Phenomenology and the Quark Gluon String Model
The search for stable heavy exotic hadrons is a promising way to observe new
physics processes at collider experiments. The discovery potential for such
particles can be enhanced or suppressed by their interactions with detector
material. This paper describes a model for the interactions in matter of stable
hadrons containing an exotic quark of charges or
using Regge phenomenology and the Quark Gluon String Model. The influence of
such interactions on searches at the LHC is also discussed
Vibrating the QCD string
The large distance behaviour of the adiabatic hybrid potentials is studied in
the framework of the QCD string model. The calculated spectra are shown to be
the result of interplay between potential-type longitudinal and string-type
transverse vibrations.Comment: LaTeX2e, 9 pages, 2 Postscript figures, final version to appear in
Yad.Fi
DTUJET--93 Sampling inelastic proton--proton and antiproton--proton collisions according to the two--component Dual Parton Model
A new version of a Monte Carlo Program for hadronic multi-particle production
is presented. It is based on the two-component Dual Parton Model which includes
the dual topological unitarization of soft and hard cross sections. The model
treats both soft (low ) and hard (minijet, large )
processes in a unified and consistent way. The unified description is important
at TeV-energies of hadron colliders, where the hard perturbative cross sections
of QCD become large and comparable to the total cross sections.Comment: 20 pages , PHYSZZX, SI-93-
Quark-Gluon String Model Description of Baryon Production in K^{\pm}N Interactions
The process of baryon production in K p collisions at high energies is
considered in the framework of the Quark-Gluon String Model. The contribution
of the string-junction mechanism to the strange baryon production is analysed.
The results of numerical calculations are in reasonable agreement with the data
on inclusive spectra of p, Lambda, bar{Lambda}, and on the bar{Lambda}/Lambda
asymmetry. The predictions for Xi and Omega baryons are presented.Comment: 19 pages, 7 figure
Triangular and Y-shaped hadrons in QCD
Gauge invariant extended configurations are considered for the three
fundamental (quarks) or adjoint (gluons) particles. For quarks it is shown that
the Y-shaped configuration is the only possible. For adjoint sources both the
Y-shaped and triangular configurations may realize. The corresponding static
potentials are calculated in the Method of Field Correlators and in the case of
baryon shown to be consistent with the lattice simulations. For adjoint sources
the potentials of Y-shaped and Delta-shaped configurations turn out to be close
to each other, which leads to almost degenerate masses of 3-- 3g glueballs and
odderon trajectories.Comment: 9 pages, 5 eps figures, latex2e, one reference adde
Baryon stopping and hyperon enhancement in the improved dual parton model
We present an improved version of the dual parton model which contains a new
realization of the diquark breaking mechanism of baryon stopping. We reproduce
in this way the net baryon yield in nuclear collisions. The model, which also
considers strings originating from diquark-antidiquark pairs in the nucleon
sea, reproduces the observed yields of p and Lambda and their antiparticles and
underestimates cascades by less than 50 %. However, Omega's are underestimated
by a factor five. Agreement with data is restored by final state interaction,
with an averaged cross-section as small as 0.14 mb. Hyperon yields increase
significantly faster than antihyperons, in agreement with experiment.Comment: 40 pages, 18 postscript figure
Feynman scaling violation on baryon spectra in pp collisions at LHC and cosmic ray energies
A significant asymmetry in baryon/antibaryon yields in the central region of
high energy collisions is observed when the initial state has non-zero baryon
charge. This asymmetry is connected with the possibility of baryon charge
diffusion in rapidity space. Such a diffusion should decrease the baryon charge
in the fragmentation region and translate into the corresponding decrease of
the multiplicity of leading baryons. As a result, a new mechanism for Feynman
scaling violation in the fragmentation region is obtained. Another numerically
more significant reason for the Feynman scaling violation comes from the fact
that the average number of cutted Pomerons increases with initial energy. We
present the quantitative predictions of the Quark-Gluon String Model (QGSM) for
the Feynman scaling violation at LHC energies and at even higher energies that
can be important for cosmic ray physics.Comment: 21 pages, 11 figures, and 1 table. arXiv admin note: substantial text
overlap with arXiv:1107.1615, arXiv:1007.320
Factorization and Scaling in Hadronic Diffraction
In standard Regge theory with a pomeron intercept a(0)=1+\epsilon, the
contribution of the tripe-pomeron amplitude to the t=0 differential cross
section for single diffraction dissociation has the form d\sigma/dM^2(t=0) \sim
s^{2\epsilon}/(M^2)^{1+\epsilon}. For \epsilon>0, this form, which is based on
factorization, does not scale with energy. From an analysis of p-p and p-pbar
data from fixed target to collider energies, we find that such scaling actually
holds, signaling a breakdown of factorization. Phenomenologically, this result
can be obtained from a scaling law in diffraction, which is embedded in the
hypothesis of pomeron flux renormalization introduced to unitarize the triple
pomeron amplitude.Comment: 39 pages, Latex, 16 figure
On recent puzzles in the production of heavy quarkonia
Recently, several surprising experimental observations in the production of
heavy quarkonium have been reported. In annihilation at
GeV, Belle Collaboration finds that mesons are
predominantly produced in association with an extra pair, with
, and the BaBar collaboration reports that the
produced 's have mostly longitudinal polarization. In
collisions at the Tevatron, the CDF Collaboration reported an excess of
and mesons at high over the perturbative
QCD predictions; non--perturbative approach of NRQCD can accomodate the
magnitude of the production cross section but not the observed experimentally
polarization of quarkonia. In this note we propose possible solutions to these
puzzles, and devise further experimental tests.Comment: 3 pages, 2 figure
On the role of the final state interactions in rare B-decays
The effects of final state interactions (FSI) in hadronic B-decays are
investigated. The model for FSI, based on Regge phenomenology of high-energy
hadronic interactions is proposed. It is shown that this model explains the
pattern of phases in matrix elements of and decays.
These phases play an important role for CP-violation in B-decays. The most
precise determination of the unitarity triangle angle from decays is performed. The relation between CP-asymmetries in decays is discussed. It is emphasized that the large distance FSI can
explain the structure of polarizations of the vector mesons in B-decays and
other puzzles like a very large branching ratio of the B-decay to
.Comment: 19 page
- …