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Register a new userCharged Higgs contribution to $bar{B}_s rightarrow phi pi^0 $ and $bar{B}_s rightarrow phi rho^0 $
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Gaber Faisel
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We study the decay modes $bar{B}_sto phi pi^0$ and $bar{B}_sto phi rho^0$ within the frameworks of two-Higgs doublet models type-II and typ-III. We adopt in our study Soft Collinear Effective Theory as a framework for the calculation of the amplitudes. We derive the contributions of the charged Higgs mediation to the weak effective Hamiltonian governing the decay processes in both models. Moreover we analyze the effect of the charged Higgs mediation on the Wilson coefficients of the electrowek penguins and on the branching ratios of $bar{B}_sto phi pi^0$ and $bar{B}_sto phi rho^0$ decays. We show that wthin two-Higgs doublet models type-II and type-III the Wilson coefficients corresponding to the electroweak penguins can be enhanced due to the contributions from the charged Higgs mediation leading into enhancement in the branching ratios of $ bar{B}_sto phi pi^0$ and $bar{B}_sto phi rho^0 $ decays. We find that, within two-Higgs doublet models type-II, the enhancement in the branching ratio of $bar{B}_sto phi pi^0$ can not exceed $18%$ with respect to the SM predictions. For the branching ratio of $bar{B}_sto phi rho^0$, we find that the charged Higgs contribution in this case is small where the branching ratio of $bar{B}_sto phi rho^0$ can be enhanced or reduced by about $4% $ with respect to the SM predictions. For the case of the two-Higgs doublet models type-III we show that the branching ratio of $bar{B}_sto phi pi^0$ can be enhanced by about a factor $2$ of its value within two-Higgs doublet models type-II. However no sizable enhancement with respect to the SM predictions can be obtained for both $bar{B}_sto phi pi^0$ and $bar{B}_sto phi rho^0$ decays.
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The decay modes $bar{B}_s rightarrow pi^0(rho^0 ),eta^{()} $ are dominated by electroweak penguins that are small in the standard model. In this work we investigate the contributions to these penguins from a model with an additional $U(1)$ gauge symmetry and show there effects on the branching ratios of $bar{B}_s rightarrow pi^0(rho^0 ),eta^{()} $. In a scenario of the model, where $Z^prime$ couplings to the left-handed quarks vanish, we show that the maximum enhancement occurs in the branching ratio of $bar B^0_sto ,pi^0,eta$ where it can reach $6$ times the SM prediction. On the other hand, in a scenario of the model where $Z^prime$ couplings to both left-handed and right-handed quarks do not vanish, we find that $Z^prime$ contributions can enhance the branching ratio of $B^0_sto,rho^0,eta$ up to one order of magnitude comparing to the SM prediction for several sets of the parameter space where both $ Delta M_{B_s}$ and $S_{psiphi}$ constraints are satisfied. This kind of enhancement occurs for a rather fine-tuned point where $ Delta M_{B_s}$ constraint on $mid S_{SM} (B_s) + S_{Z} (B_s)mid $ is fulfilled by overcompensating the SM via $S_{Z} (B_s) simeq -2 S_{SM} (B_s)$.
We perform a quantitative analysis of the $bbbar{b}bar{b}$ tetraquark decays into hidden- and open-bottom mesons and calculate, for the first time, the $bbbar{b}bar{b}$ tetraquark total decay width. On the basis of our results, we propose the $bbbar{b}bar{b} to B^{+} B^{-} (B^0 bar{B}^0) (B_s^0 bar{B}_s^0) to l^{+} l^{-}+text{X}$ decays as the most suitable channels to observe the $bbbar{b}bar{b}$ tetraquark states, since the calculated two-lepton cross section upper limit, $simeq 39 $ fb, is so large as to be potentially detectable with the 2018 LHCb sensitivity, paving the way to the observation of the $bbbar{b}bar{b}$ tetraquark in the future LHCb upgrade. The $4mu$ signal for the ground state, $J^{PC}=0^{++}$, is likely to be too small even for the upgraded LHCb, but it may not be hopeless for the $J^{PC}=2^{++}$ fully-bottom state.
The decay $overline{B}_s^0 rightarrow psi(2S) K^+ pi^-$ is observed using a data set corresponding to an integrated luminosity of $3.0fb^{-1}$ collected by the LHCb experiment in $pp$ collisions at centre-of-mass energies of 7 and 8 TeV. The branching fraction relative to the $B^0rightarrow psi(2S) K^+ pi^-$ decay mode is measured to be begin{equation} frac{{cal B}(overline{B}^0_s rightarrow psi(2S) K^+ pi^-)}{{cal B}(B^0 rightarrow psi(2S) K^+ pi^-)} = 5.38 pm 0.36 (stat) pm 0.22 (syst) pm 0.31 , (f_s/f_d) , %, onumber end{equation} where $f_s/f_d$ indicates the uncertainty due to the ratio of probabilities for a $b$ quark to hadronise into a $B_s^0$ or $B^0$ meson. Using an amplitude analysis, the fraction of decays proceeding via an intermediate $K^*(892)^0$ meson is measured to be $0.645 pm 0.049 (stat) pm 0.049 (syst)$ and its longitudinal polarisation fraction is $0.524 pm 0.056 (stat) pm 0.029 (syst)$. The relative branching fraction for this component is determined to be begin{equation} frac{{cal B}(overline{B}^0_s rightarrow psi(2S) K^*(892)^0)}{{cal B}(B^0 rightarrow psi(2S) K^*(892)^0)} = 5.58 pm 0.57 (stat) pm 0.40 (syst) pm 0.32 , (f_s/f_d) , %. onumber end{equation} In addition, the mass splitting between the $B_s^0$ and $B^0$ mesons is measured as begin{equation} M(B^0_s) - M(B^0) = 87.45 pm 0.44 (stat) pm 0.07 (syst) MeV/c^2. onumber end{equation}
The Dalitz plot distribution of $B^0 rightarrow bar{D}^0 K^+ pi^-$ decays is studied using a data sample corresponding to $3.0rm{fb}^{-1}$ of $pp$ collision data recorded by the LHCb experiment during 2011 and 2012. The data are described by an amplitude model that contains contributions from intermediate $K^*(892)^0$, $K^*(1410)^0$, $K^*_2(1430)^0$ and $D^*_2(2460)^-$ resonances. The model also contains components to describe broad structures, including the $K^*_0(1430)^0$ and $D^*_0(2400)^-$ resonances, in the $Kpi$ S-wave and the $Dpi$ S- and P-waves. The masses and widths of the $D^*_0(2400)^-$ and $D^*_2(2460)^-$ resonances are measured, as are the complex amplitudes and fit fractions for all components included in the amplitude model. The model obtained will be an integral part of a future determination of the angle $gamma$ of the CKM quark mixing matrix using $B^0 rightarrow D K^+ pi^-$ decays.
The first observation of the decay $B_s^0 rightarrow phi bar{K}^{*0}$ is reported. The analysis is based on a data sample corresponding to an integrated luminosity of 1.0 fb$^{-1}$ of $pp$ collisions at $sqrt{s} = 7 TeV$, collected with the LHCb detector. A yield of $30 pm 6$ $B_s^0 rightarrow (K^+K^-)(K^-pi^+)$ decays is found in the mass windows $1012.5 < M(K^+K^-) < 1026.5 MeV/c^2$ and $746 < M(K^-pi^+)< 1046 MeV/c^2$. The signal yield is found to be dominated by $B_s^0 rightarrow phi bar{K}^{*0}$ decays, and the corresponding branching fraction is measured to be ${cal B}(B_s^0 rightarrow phi bar{K}^{*0}) = (1.10 pm 0.24 (stat) pm 0.14 (syst) pm 0.08 (f_d/f_s)) times 10^{-6}$, where the uncertainties are statistical, systematic and from the ratio of fragmentation fractions $f_d/f_s$ which accounts for the different production rate of $B^0$ and $B_s^0$ mesons. The significance of $B_s^0 rightarrow phi bar{K}^{*0}$ signal is 6.1 standard deviations. The fraction of longitudinal polarization in $B_s^0 rightarrow phi bar{K}^{*0}$ decays is found to be $f_0 = 0.51 pm 0.15 (stat) pm 0.07 (syst)$.
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