arXiv subjects
Publications and source records attributed to A. K. Likhoded.
The inclusive production of light mesons in pp-scattering is considered in the framework of reggeon phenomenology with supercritical Pomeron. Available low-energy data can be explained with three reggeon particles taken into account. With the obtained results rapidity and pseudorapidity distributions for light-meson production at LHC energies are predicted.
The article is devoted to Bc->Bs+n pi, Bc->Bs*+n pi decays with n=1, 2, 3, 4. In the framework of factorization theorem the branching fractions of these processes can be written as convolution of hard part, describing Bc->Bs W, Bc->Bs* W vertices, and spectral functions, that correspond to transition of virtual $W$-boson into a final pi-meson system. These functions were obtained from the fit of experimental data on $τ$-lepton decay and electron-positron annihilation. Using different sets of Bc->Bs decay form-factors we present branching fractions and distributions over the invariant mass of the final pi-meson system.
The decays $η'\to3π^{0}$ and $π^{0}π^{+}π^{-}$ were consider in isobar model approach. Branching ratio and Dalitz-plot shape of the decay $η'\to3π^{0}$ can be explain by $a0$- and $σ$-meson contributions. The $σ$ meson term is needed for the Dalitz-plot distribution reconstruction. The branching ratio of the decay $η'\to π^{0}π^{+}π^{-}$ can be calculated in the same isobar framework. The prediction for the Dalitz-plot of this decay is shown which strongly dependents from model parameters.
Decays of ground state $B_{c}$-meson $B_{c}\to J/ψ+nπ$ are considered. Using existing parametrizations for $B_{c}\to J/ψ$ form-factors and $W^{*}\to nπ$ spectral functions we calculate branching fractions and transferred momentum distributions of $B_{c}\to J/ψ+nπ$ decays for $n=1,2,3,4$. Inclusive decays $B_{c}\to J/ψ+\bar{u}d$ and polarization asymmetries of final charmonium are also investigated. Presented in our article results can be used to study form-factors of $B_{c}\to J/ψ$ transitions, $π$-meson system spectral functions and give the opportunity to check the factorization theorem.
The decay $η'\toηπ^{0}π^{0}$ is studied in the framework of isobar model. It is shown, that good agreement with the experiment is achieved if $a_0$- and $σ$-meson contributions are taken into account. The contribution of $a_0$-meson is dominant, but $σ$-meson is necessary to reproduce the form of experimental Dalitz plot. Instead of usual Breit-Wigner form of $σ$-meson propagator we use parametrization of $ππ$-amplitude, that satisfies analiticity, crossing, unitarity and chirality constraints. This amplitude has a pole in complex plane, that corresponds to $σ$-meson and describe experimental data on $ππ$-scattering in $K_{e4}$ decay.
This paper is devoted to the study of the leading twist distribution amplitudes of P-wave nonrelativistic mesons. It is shown that at the leading order approximation in relative velocity of quark-antiquark pair inside the mesons these distribution amplitudes can be expressed through one universal function. As an example, the distribution amplitudes of the P-wave charmonia mesons are considered. Within QCD sum rules the model for the universal function of P-wave charmonia mesons is built. In addition, it is found the relations between the moments of the universal function and the nonrelativistic QCD matrix elements that control relativistic corrections to any amplitude involving P-wave charmonia. Our calculation shows that characteristic size of these corrections is of order of ~30 %.
This paper is devoted to consideration of the hard exclusive processes $e^+e^- \to VP$, where $V=ρ,ϕ; P=η,η'$. Experimental measurement of the cross section of the process $e^+ e^- \to ϕη$ at BaBar collaboration at large center mass energy $\sqrt s=10.6$ GeV and some low energy experimental data $\sqrt s \sim 2-4$ GeV give us the possibility to study the cross section in the broad energy region. As the result, we have determined the asymptotic behavior of the cross section of $e^+ e^- \to ϕη$ in the limit $s \to \infty$, which is in agreement with perturbative QCD prediction. Assuming that the same asymptotic behavior is valid for the other processes under consideration and using low energy experimental data we have predicted the cross sections of these processes at energies $\sqrt s=3.67,~10.6$ GeV. In addition, we have calculated the cross sections of these processes at the same energies within perturbative QCD. Our results are in agreement with available experimental data.
The new polarization program SPASCHARM is being prepared in Protvino. The program has two stages. The first stage is dedicated to single-spin asymmetries in the production of miscellaneous light resonances with the use of 34 GeV $π^-$-beam. Inclusive and exclusive reactions will be studied simultaneously. The second stage is dedicated to single-spin and double-spin asymmetries in charmonium production with the use of 70 GeV polarized proton beam which will allow us to understand charmonium hadronic production mechanism and make gluon polarization $Δg(x)$ extraction at large $x$.
We discuss exotic states X(3872) and $Z^+(4430)$, observed recently in experiment Belle. The QCD-string based explanation is suggested.
We discuss the possibility for observing $B_c$ mesons in decay channels with $B_s$ in final state.
The production of the charmonium states in hadronic experiments is considered in NLO at the strong coupling constant. It is shown, that such an approach solves some significant problems, arising when only leading order processes are considered. In particular, in such a consideration distributions over the transverse momentum of the final charmonium can be obtained. There appears also a natural explanation to the existence of $χ_{c1}$-meson in final state, that is observed experimentally and cannot be produced in leading order processes.
This paper is devoted to the study of leading twist light cone wave function of $η_c$ meson. The moments of this wave function have been calculated within three approaches: potential models, nonrelativistic QCD and QCD sum rules. Using the results obtained within these approaches the model for the light cone wave function of leading twist has been proposed. Being scale dependent light cone wave function has very interesting properties at scales $μ> m_c$: improvement of the accuracy of the model, appearance of relativistic tail and violation of nonrelativistic QCD velocity scaling rules. The last two properties are the properties of real leading twist light cone wave function of $η_c$ meson.
This paper is devoted to the study of the process $\epem\to J/ψX(3940)$ in the framework of light cone formalism. In our calculation two hypotheses about the structure of X(3940) meson are considered: X(3940) is $3^1$S$_0$ state and X(3940) is one of $2^3$P states. The former hypothesis leads to a good agreements with the cross section measured at the experiment. As to the latter one, it is proposed a mechanism that allows one to understand the suppression of 2P mesons production in hard processes.
In this paper we show that heavy quarckonium states, similar to light mesons, form Regge trajectories in $(n,M^2)$ and $(M^2,J)$ planes and the slope of these trajectories is independent on the quantum numbers of the mesons. This fact can be useful for the prediction of the masses of heavy quarkonia and the determination of the quantum numbers of the newly discovered states.
In the framework of quark-hadron duality, the cross section values of charmonium and doubly charmed baryon production in $e^+e^-$-annihilations have been estimated at interaction energy $\sqrt{s}=10.6$ GeV. It has been shown that the approach under discussion allows to resolve some contradictions between the experimental data and pQCD predictions.
In this paper we have analyzed the production of pair charmonium mesons in the reactions $e^+ e^- \to J/ Ψχ_{c0}, e^+ e^-\to Ψ(2S) χ_{c0}$ at energy $\sqrt s = 10.6$GeV in the framework of the light cone formalism. In comparison with NRQCD the numerical results for the cross sections are in better agreement with experiment.
In this article we consider the three-particle decays $χ_{b0,2}\to J/ψc\bar c\to J/ψD\bar D+X$. We present the analytical formulae for the differential widths of these decays, the numerical values of their integrated widths and check the duality relation that connects the decays $χ_{b0,2}\toψc\bar c$ with the two-particle decays $χ_{b0,2}\to J/ψ(c\bar c)$. We also study the possibility of observing the $χ_{b0,2}\to J/ψDD+X$ mode at Tevatron and LHC colliders.
A possibility to accelerate a high intensity polarized proton beam up to 70 GeV at the IHEP accelerator, extract it from the main ring and deliver to several experimental setups is being studied now. We propose to study a wealth of single- and double-spin observables in various reactions using longitudinally and transverserly polarized proton beams at U70. The proposed measurements can be done at the existing detectors as well as require to create a few new experimental setups at U70.