arXiv subjects
Publications and source records attributed to A. K. Likhoded.
The exclusive photon-photon production of the $K$-meson pairs has been analyzed within the partonic model of QCD for the kinematical conditions of BELLE experiment. The cross section dependences on partonic masses, charges, and a shape of $K$-meson wave function have been studied for the process under discussion.
We confirm the results of previous works that the internal motion of quarks inside charmonium mesons increases the cross section of the process $e^+e^-\to $J/ψη_c$. We also show, that this effect increases the widths of the scalar meson decay into two vector ones and state that the decays $χ_{b0,2}\to2J/ψ$ can be used to detect these scalar mesons at Tevatron and LHC colliders.
In this paper the production of excited vector and pseudoscalar charmonium mesons in $\epem$ annihilation is analyzed in the framework of light cone. In particular the cross sections $\epem \to ψ(2S)η_c(1S), ψ(1S)η_c(2S),ψ(2S)η_c(2S)$ have been calculated. It is shown, that contrary to NRQCD the cross sections calculated in the framework of light cone agree with experimental data.
Charge asymmetries for the charm meson production ($D^{*+}$--$D^{*-}$, $D^{*0}$--$\bar D^{*0}$ and $D^+_s$--$\bar D^-_s$) have been estimated for the COMPASS kinematic conditions in the framework of perturbative recombination model. Mass corrections have been taken into account in the calculations. The large asymmetry for $D^+_s$--$\bar D^-_s$ production has been predicted.
The experimental data of BELLE Collaboration on the exclusive charmed meson pair production in the process of monophotonic $e^+e^-$-annihilation ($e^+e^-\to γ^* \to D\bar D$) has been studied. It has been shown that these data is described satisfactorily in the frame work of constituent quark model. Our studies have demonstrated that the central production process $e^+e^-\to e^+e^-γγ\to e^+e^-D\bar D +X$ and the process of monophotonic $e^+e^-$-annihilation yield comparable numbers of the charmed meson pairs.
The B_c photoproduction at HERA has been considered in the frame work of the pQCD. The estimated value of the total production cross section of Bc+, Bc*+, Bc- and Bc*- mesons is about 5 pb. Higher excitations yield about 30% to the total cross section. Thus for integrated HERA luminosity 1 fb-1 about 7000 Bc mesons will be produced.
BELLE Collaboration data for $J/ψ$ inclusive production in the processes $e^+e^-\to J/ψ+gg$ and $e^+e^-\to J/ψ+c\bar c$ have been discussed. These data have been compared with the predictions of two pQCD methods: the former method use the information about the $J/ψ$ wave function, the latter one do not use such information and is based on the quark-hadron duality hypothesis. Both these calculation methods lead to essential discrepancy between the theoretic predictions and the experimental data. The production cross section dependence on effective gluon mass has been investigated for the process $e^+e^-\to J/ψ+gg$. The production cross section of doubly charmed baryons $Ξ^{*}_{cc}$ has been estimated.
In the framework of the constituent quark model the exclusive pair production of the charmed mesons in the photon-photon interaction is calculated. The comparison of these predictions with the ones of the heavy quark effective theory is performed. It is shown, that the light valence quark of D-meson plays the essential role not only in the hadronization process, but also in the production of the heavy c-quark. Moreover, it is shown, that because of the strong interaction between the initial photon field and the light quark charge the similar situation is kept even in the limit (m_{Q}\to \infty), whence it is concluded, that the application of the heavy quark effective theory in the case of the photon-photon interaction is not valid because it does not take into account one of the dominant mechanisms of the heavy meson production.
We discuss the motivations and perspectives for the studies of the mesons of the (bc) family at LHCb. The description of production and decays at LHC energies is given in details. The event yields, detection efficiencies, and background conditions for several Bc decay modes at LHCb are estimated.
In the framework of scalar-vector dominance we calculate the hadronic matrix elements of scalar and tensor effective quark currents induced by virtual leptoquark interactions. Combined bounds on the product of couplings and leptoquark masses are obtained from experimental data.
We speculate on a possible interpretation of events selected by the SELEX collaboration and stress an insufficient evidence for the observation of doubly charmed baryon.
We evaluate the masses of baryons composed of two heavy quarks and a strange quark with account for spin-dependent splittings in the framework of potential model with the KKO potential motivated by QCD with a three-loop beta-function for the effective charge consistent with both the perturbative limit at short distances and linear confinement term at long distances between the quarks. The factorization of dynamics is supposed and explored in the nonrelativistic Schroedinger equation for the motion in the system of two heavy quarks constituting the doubly heavy diquark and the strange quark interaction with the diquark. The limits of approach, its justification and uncertainties are discussed. Excited quasistable states are classified by the quantum numbers of heavy diquark composed by the heavy quarks of the same flavor.
In the framework of perturbative QCD and a model for the production of charmed hadrons the structure function $F^c_2$ is calculated and compared with the experimental data of H1 and ZEUS Collaborations. We show that the spectator mechanism of the $D^*$-meson production independent of a hadronic remnant is valid at $p_T>10$ GeV, only. We find that the evolution of $F^c_2(x,Q^2)$ versus the virtuality $Q^2$ can be neglected in the kinematic region of HERA.
This report provides a comprehensive overview of the prospects for B physics at the Tevatron. The work was carried out during a series of workshops starting in September 1999. There were four working groups: 1) CP Violation, 2) Rare and Semileptonic Decays, 3) Mixing and Lifetimes, 4) Production, Fragmentation and Spectroscopy. The report also includes introductory chapters on theoretical and experimental tools emphasizing aspects of B physics specific to hadron colliders, as well as overviews of the CDF, D0, and BTeV detectors, and a Summary.
We consider a general scheme for calculating the leptonic constant of heavy quarkonium QQ-bar in the framework of nonrelativistic quantum chromodynamics, NRQCD, operating as the effective theory of nonrelativistic heavy quarks. We explore the approach of static potential in QCD, which takes into account both the evolution of effective charge in the three-loop approximation and the linearly raising potential term, which provides the quark confinement. The leptonic constants of bb-bar and cc-bar systems are evaluated by making use of two-loop anomalous dimension for the current of nonrelativistic quarks, where the factor for the normalization of matrix element is introduced in order to preserve the renormalization group invariance of estimates.
The cross section of the $D^*$-meson diffractive photoproduction at the HERA collider has been calculated in the framework of perturbatively motivated model for the different kinematic regions. The camparison between the different Pomeron models has been performed.
We consider general physical characteristics of doubly heavy baryons: the spectroscopy in the framework of potential approach and sum rules of QCD, mechanisms of production in various interactions on the basis of fragmentation model with account of preasymptotic corrections caused by higher twists over the transverse momentum of baryon, inclusive decays and lifetimes in the operator product expansion over the inverse powers of heavy quark masses as well as the exclusive decays in the sum rules of QCD. We generalize the methods developed in the effective theory of heavy quarks towards the description of systems with two heavy quarks and a single light quark. The calculations are presented for the masses, decay widths and yields of baryons with two heavy quarks in the running and planned experimental facilities. We discuss the prospects of search for the baryons and possibilities of experimental observation. The most bright physical effects concerning these baryons as well as their position in the system for the theoretical description of heavy quark dynamics are considered.
We present the calculation of the inclusive $x_F$-distributions of charmed hadrons, produced in high-energy $Σ^-$-beam. The 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. We predict the additional asymmetry in the production of charmed hadrons due to the different distributions of the valence s and d quarks in $Σ^-$-beam.