14 research outputs found
On the energy dependence of the D^+/D^- production asymmetry
In this paper we discuss the origin of the asymmetry present in D meson
production and its energy dependence. In particular, we have applied the meson
cloud model to calculate the asymmetries in D^-/D^+ meson production in high
energy p-p collisions and find a good agreement with recent LHCb data. Although
small, this non-vanishing asymmetry may shed light on the role played by the
charm meson cloud of the proton.Comment: 8 pages, 8 figures. arXiv admin note: text overlap with
arXiv:hep-ph/000927
Tetraquark Production in Double Parton Scattering
We develop a model to study tetraquark production in hadronic collisions. We
focus on double parton scattering and formulate a version of the color
evaporation model for the production of the and of the
tetraquark, a state composed by the quarks. We find that
the production cross section grows rapidly with the collision energy
and make predictions for the forthcoming higher energy data of the LHC.Comment: 13 pages, 3 figures. Corrections in the text and reference
Non-linear QCD dynamics in two-photon interactions at high energies
Perturbative QCD predicts that the growth of the gluon density at high
energies should saturate, forming a Color Glass Condensate (CGC), which is
described in mean field approximation by the Balitsky-Kovchegov (BK) equation.
In this paper we study the interactions at high energies and
estimate the main observables which will be probed at future linear colliders
using the color dipole picture. We discuss in detail the dipole - dipole cross
section and propose a new relation between this quantity and the dipole
scattering amplitude. The total ,
cross-sections and the real photon structure function are
calculated using the recent solution of the BK equation with running coupling
constant and the predictions are compared with those obtained using
phenomenological models for the dipole-dipole cross section and scattering
amplitude. We demonstrate that these models are able to describe the LEP data
at high energies, but predict a very different behavior for the observables at
higher energies. Therefore we conclude that the study of
interactions can be useful to constrain the QCD dynamics.Comment: 11 pages, 5 figures. Version to be published in European Physical
Journal
A new estimator method for GARCH models
The GARCH (p, q) model is a very interesting stochastic process with widespread applications and a central role in empirical finance. The Markovian GARCH (1, 1) model has only 3 control parameters and a much discussed question is how to estimate them when a series of some financial asset is given. Besides the maximum likelihood estimator technique, there is another method which uses the variance, the kurtosis and the autocorrelation time to determine them. We propose here to use the standardized 6th moment. The set of parameters obtained in this way produces a very good probability density function and a much better time autocorrelation function. This is true for both studied indexes: NYSE Composite and FTSE 100. The probability of return to the origin is investigated at different time horizons for both Gaussian and Laplacian GARCH models. In spite of the fact that these models show almost identical performances with respect to the final probability density function and to the time autocorrelation function, their scaling properties are, however, very different. The Laplacian GARCH model gives a better scaling exponent for the NYSE time series, whereas the Gaussian dynamics fits better the FTSE scaling exponent. Copyright EDP Sciences/Società Italiana di Fisica/Springer-Verlag 200789.65.Gh Economics; econophysics, financial markets, business and management, 05.45.Tp Time series analysis, 89.75.-k Complex systems,
Tetraquark Production in Hadronic Collisions
We develop a formalism to study the tetraquark production in hadronic collisions. We focus on double parton scattering and formulate a version of the color evaporation model for the production of the T4c tetraquark, a state composed by the quarks. We find that the production cross section grows rapidly with the collision energy and the T4c might be observable at LHC energies