arXiv subjects
Publications and source records attributed to M. Savci.
The strong coupling constant g_(Ko* K pi) of the scalar Ko* meson decay to (K pi) is calculated in light cone QCD sum rule. The predicted value of the coupling constant g_(Ko* K pi) is in a good agreement with the experimental result.
The radiative "B_c -> tau nu_tau gamma" decay is analyzed in the standard model. The branching ratio of this decay is calculated and the contributions of the Bremstrahlung and structure dependent parts are compared. It is shown that this decay can be detected at LHC.
We examine the possibility for precise determination of |V_{ts}| (and |V_{td}/V_{ts}|) from the exclusive decays, $B --> K \ell^+ \ell^-, B --> K^* \ell^+ \ell^-$ (and $B --> π\ell^+ \ell^-, B --> ρ\ell^+ \ell^-$). We show that the ratio |V_{ts}| can be extracted experimentally with a small theoretical uncertainty from hadronic form--factors, if we {\bf appropriately constrain} kinematical regions of $q^2$. We also give detailed analytical and numerical results on the differential decay width $dΓ(B --> K^* \ell^+ \ell^-)/dq^2$, and the ratios of integrated branching fractions, ${\cal B}(B --> ρ\ell^+ \ell^-)/{\cal B}(B --> K^* \ell^+ \ell^-)$. We estimate that one can determine the ratio |V_{ts}| from those decays within theoretical accuracy of $\sim 10%$.
The radiative B_c -> l nu gamma decay is investigated in the Standard Model in framework of the light cone QCD. The transition form factors and decay width are calculated. A comparison of light cone QCD and constituent quark model predictions on these quantities is presented.
We investigate the radiative B_c -> rho^+ gamma and B_c -> K^{*+} gamma decays in the standard model. The transition form factors are calculated in the framework of the light cone QCD sum rules method. We estimate the branching ratios of the B_c -> rho^+ gamma and B_c -> K^{*+} gamma decays.
The radiative B -> tau^+ tau^- gamma decay is investigated in the framework of the Standard Model. When only short (short and long together) distance contributions are taken into account, the Branching Ratio is found as 9.54x10^(-9) (1.52x10^(-8)), for the value of the cut delta = 0.01 imposed on the photon energy.
The decay width, forward-backward asymmetry and tau lepton longitudinal and transversal polarization for the exclusive (B -> K tau^+ tau^-) decay in a two Higgs doublet model are computed. It is shown that the forward-backward asymmetry and longitudinal polarization of the tau lepton are very effective tools for establishing new physics.
We investigate the pseudoscalar neutral Higgs-boson A^0 production in the polarized (gamma e) collisions with two different center of mass energies sqrt{s} = 500 GeV and sqrt{s} = 1 TeV. The cross-section of the process (gamma e -> e A^0) and the polarization asymmetry due the spin of the initial beams are calculated.
The decay width, forward-backward asymmetry and lepton longitudinal and transversal polarization for the exclusive K^* -> l^+ l^- decay in a two Higgs doublet model are computed. It is shown that all these quantities are very effective tools for establishing new physics.
We calculate the transition formfactors for the B -> K l(+) l(-) decay in the framework of the light cone QCD sum rules. The invariant dilepton mass distribution and the final lepton longitudinal polarization asymmetry are investigated. The comparison analysis of our results with traditional sum rules method predictions on the formfactors is performed.
The radiative dileptonic decays B_s(B_d) -> l^+ l^- gamma (l = e, mu) are investigated within the Standard Model . The transition formfactors are calculated in the framework of the light cone QCD sum rules method and it is found that the branching ratios are B(B_s -> e^+ e^- gamma) =2.35 x 10^(-9), B(B_s -> mu^+ mu^- gamma) =1.9 x 10^(-9), B(B_d -> e^+ e^- gamma) = 1.5 x 10^(-10) and B(B_d -> μ^+ μ^- gamma) = 1.2 x 10^(-10). A comparison of our results with the constituent quark model predictions on the branching ratios is presented.
The formfactors of B_1 -> pi and D_1 -> pi transitions, where B_1(D_1) is the 1^+ P-wave -> Q gamma_νγ_5q meson state, are calculated in the framework of the light cone QCD. Furthermore these formfactors are compared with the pole dominance model prediction using the values of the strong coupling constants g_{B_1 B^* pi} and g_{D_1 D^* pi}, and a good agreement between these two different descriptions is observed.
We investigate the transition formfactors for the B -> K^* l^+ l^- (l = mu, tau) decay in the light cone QCD. It is found that the light cone and 3-point QCD sum rules analyses for some of the formfactors for the decay B -> K^* l^+ l^- lead to absolutely different $q^2$ dependence. The invariant dilepton mass distributions for the B -> K^* mu^+ mu^- and B -> K^* tau^+ tau^- decays and final lepton longitudinal polarization asymmetry, which includes both short and long-distance contributions, are also calculated.
Using the light cone QCD Sum Rules Method, we study the rare B -> nu barnu gamma decay and and find that the branching ratios are, B(B_s -> nu barnu gamma) = 7.5 10^{-8}, B(B_d -> nu -> nu gamma) = 4.2 10^{-9}. A comparision of our results, on branching ratio, with constituent quark and pole dominance model predictions are presented.
We calculate the strong coupling constants g_(P^(**)P^(*)π), where P^(**)(D^(**), B^(**)) is the 1^+ p-wave state, in the framework of the light cone QCD sum rules, and using these values of g_(P^(**)P^(*) pi, we compute the hadronic decay widths for D^(**) -> D^* pi and B^(**) -> B^* pi.
To leading order in alpha_s, the leading and non-leading 1/m_b corrections to the excited g_B^(**) meson coupling g_B^(**)BPi is calculated in the framework of QCD spectral moment sum rules in the full theory. Our prediction is in good agreement=20 with the light-cone QCD sum rule result.