Associative production of $Υ$ and open charm at LHC
The yield of $Υ$ associated with open charm has been estimated with different approaches. The crucial differences between SPS and DPS predictions are discussed.
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arXiv subjects
A. K. Likhoded
Publications and source records attributed to A. K. Likhoded.
Simultaneous production of charmonium and bottomonium mesons at LHC
Inclusive production of $ΥJ/ψ$ 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, $χ_bχ_c$ pair production with subsequent radiative decays of $P$-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.
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Production of $η_Q$ meson at LHC
The paper is devoted to theoretical consideration of inclusive $η_{c,b}$ meson production at LHC. It is shown that existing experimental data on $η_c$ meson production at LHCb detector can be described in the framework of NRQCD formalism and color-singlet component with phenomenological value of matrix element $|R(0)|^2$ gives main contribution. Using this model we present theoretical prediction for integrated cross sections and transverse momentum distributions for inclusive $η_c$ production at other LHC detectors. The case of $η_b$ meson production at LHC is also considered.
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Production of $χ_c$- and $χ_b$-mesons in high energy hadronic collisions
This paper is devoted to phenomenological study of $χ_{c,b}$-mesons production in high energy hadronic collisions in the framework of NRQCD. We analyze all available experimental data on $χ_c$-mesons production and extract non-perturbative NRQCD matrix elements from fitting the data. We show, that measured $p_T$-spectrum of $χ_c$-mesons is mainly formed by color singlet components, while $σ(χ_{c2})/σ(χ_{c1})$ 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 $χ_b$-mesons cross sections are also given.
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Radiative $B_c$ meson decays $B_c \to γu\bar{d}$
Inclusive radiative decays $B_c\toγu\bar{d}$ are considered. It is shown that photon emission allows one to bypass the chiral suppression and leads the increase of the branching fraction by about four orders of magnitude. The estimates of exclusive decay branching fractions of $B_c$ meson into different sets of $π$ mesons are also given.
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The relative yields of heavy hadrons as function of transverse momentum at LHC experiments
It is shown that the dependence of ratio $f_s/f_d$ could be understood within the fragmentation approach. However, the validity of fragmentation model is questionable at low $p_T$, and contributions of nonfragmentation mechanisms are possible. It is demonstrated, that the precise measurements of $p_T$ dependence of $f_s/f_d$, $f_{Λ_b}/f_{B}$ and analogous values as function of $p_T$ can essentially improve our understanding of heavy hadron production.At large $p_T$ a plateau is expected in $f_s/f_d$ distribution. Contrary, a plateau is not expected in $f_{B_c}/f_{B}$ distribution on $p_T$.
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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 $χ_{cJ}$ mesons production in pp-collisions.
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The observation possibility of $B_c$ excitations at LHC
It is shown that in the decays $B_c(2P)\to B_c^* γ^\mathrm{hard}$, $B_c(3P)\to B_c^* γ^\mathrm{hard}$ and $B_c(2S)\to B_c^* +π^+π^-$ followed by the decay $B_c^*\to B_c +γ^\mathrm{soft}$ the loss of the soft photon $γ^\mathrm{soft}$ do not wash out peaks from the initial excitations. The relative yields of $B_c^*$, 2P-wave, and 3P-wave states of $B_c$ meson at LHC are estimated as function of transverse energy of emitted photon $γ^\mathrm{hard}$. It is pointed out, that the decays $B_c(2S) \to B_c(B_c^*)+π^+π^-$ could provide a new information about a $σ$ resonance nature.
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Hadronic Production of $chi_c$-mesons at LHC
Hadronic production of $P$-wave charmonium states $χ_{cJ}$ 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 $P$-wave states can also be observed, while $S$-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 $χ_{c2}/χ_{c1}$ and $χ_{c0}/χ_{c1}$.
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$Υ$-meson pair production at LHC
Theoretical predictions for $pp\to 2 Υ+X$ cross section at $\sqrt{s}=8$ TeV for the LHCb and ATLAS kinematical conditions are obtained. A possibility to observe the new hypothetical particles containing two valence $b$-quarks and two valence $\bar{b}$-quarks is discussed.
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Production of $χ_{b}$-mesons at LHC
In the present paper, we discuss the $P$-wave bottomonium production within the both color octet and color singlet models in NLO at LHC energies. We calculate the production and the transverse momentum distributions of the $χ_{1,2b}$ states. We found, that the ratios of bottomonium and charmonium spin states are fundamentally complementary at different $p_T$ scales. We give predictions for the ratio of the $n=2$ and $n=1$ radial excitations production cross sections.
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Double charmonium production in exclusive bottomonia decays
This paper is devoted to the leading twist exclusive bottomonia decays with double charmonium in the final state. Using models of the twist-2 charmonia distribution amplitudes the widths of these decays are calculated within light cone formalism. In addition, the processes under consideration are studied within nonrelativistic QCD. In our analysis we have found that the production of some of the $P$-wave charmonia mesons with $L_z \neq 0$ is allowed already at the leading twist approximation. This means that the selection rules which predict the suppression of such decays are violated. The mechanism which lies behind this violation is discussed.
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Associated production of $J/ψ$-mesons and open charm and double open charm production at the LHC
Theoretical predictions of cross sections and properties of the $J/ψ$-meson production in association with an open charm hadron and formation of two open charm hadrons from two $c\bar{c}$ pairs in the LHC conditions are presented. Processes in both single and in double parton scattering mechanisms are included into consideration. Special attention is paid to the kinematic limits of the LHCb detector for which comparison with the newest experimental data is carried out.
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Bc -> J/psi(Bs,Bs*)+ n pi Decays
The Bc -> J/psi(Bs,Bs*)+ n pi decay amplitudes are calculated in the frame work of factorization model, which allows to represent this processes as Bc decay into J/psi Bs+W* followed by the virtual W*-boson decay into the final set of pi mesons. The module for the generation of Bc meson decays into J/psi + n pi and Bs(*) + n pi (n <= 3) is implemented into the GAUSS program package of the LHCb Collaboration.
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Double J/psi-meson Production at LHC and 4c-tetraquark state
The article is devoted to double J/psi-meson production at LHC. Theoretical predictions for pp -> 2J/psi+X cross section at sqrt{s}=7 TeV for different kinematical restrictions are presented. Special attention is payed to possible contribution of novel particles -- tetraquarks build from four c-quarks. According to presented in our article estimates, it is quietly possible to observe at least one of these state (tensor meson) experimentally.
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Correlations in the associative production of Bc and D mesons at LHC
It is shown that the study of correlations in the associative production of Bc and D mesons at LHC allows to obtain the essential information about the Bc production mechanism.
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BC_NPI module for the analysis of Bc -> J/psi +n pi and Bc -> B_s +n pi decays within the EvtGen package
The module for the generation of $B_c$ meson decays into $J/ψ+ nπ$ and $B_s^{(*)} + nπ$ ($n\le 4$) is implemented into EvtGen program package. The decay amplitudes are calculated in the frame work of factorization model. Within this approach the decay can be represented as $B_c$ decay into $J/ψ(B_s)+W^*$ followed by the virtual $W^*$-boson decay into the final set of $π$-mesons. The described calculation technique allows to adopt the parameters of $W^*\to nπ$ transition from the analysis of $τ$ decay into $ν_τ+nπ$. Comparison with available theoretical predictions is performed.
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Associative production of B_c and D mesons at LHC
It is shown that the study of correlations in the associative production of B_c and D mesons at LHC allows to obtain the essential information about the B_c production mechanism.
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