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Register a new userAnnihilation Contributions and CP Asymmetries in $B^+ to pi^+ K^0, K^+ K^0$ and $B^0to K^0 bar K^0$
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Recently the branching ratios for $B^+to K^+bar K^0$ and $B^0 to K^0 bar K^0$ have been measured. Data indicate that the annihilation amplitudes in these decays are not zero. A non-zero annihilation amplitude plays an important role in CP violation for $B^+to pi^+ K^0, K^+ bar K^0$. Using the measured branching ratios for these decays, we show that there is an absolute bound of 5% for the size of CP asymmetry in $B^+to pi^+ K^0$ from a relation between the amplitudes of these decays. The size of CP asymmetry in $B^+ to K^+bar K^0$ can, however, be as large as 90%. Future experimental data will test these predictions.
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We consider the K^0 - bar K^0 and B^0 - bar B^0 mixings in the MSSM with the two-Higgs-doublet scalar sector featuring explicit CP violation, and the Yukawa sector of type II. In the case of strong mixing between CP-odd and CP-even states the existence of light charged Higgs is allowed in the model. The mass splitting Delta m_{LS} and the amount of indirect CP violation epsilon are calculated. In the limit of effective low-energy approximation the nonstandard effects are shown to be negligibly small in Delta m_{LS} and epsilon for the K^0-mesons, being almost independent on the charged Higgs boson mass. However, for the B_d^0 - bar B_d^0 and B_s^0 - bar B_s^0 systems the effects of nonstandard physics are shown to be larger, limiting the MSSM parameter space.
A search for $C$P and $P$ violation using triple-product asymmetries is performed with $Lambda^{0}_{b}to pK^{-}pi^{+}pi^{-}$, $Lambda^{0}_{b}to pK^{-}K^{+}K^{-}$ and $Xi^{0}_{b}to pK^{-}K^{-}pi^{+}$ decays. The data sample corresponds to integrated luminosities of 1.0fb$^{-1}$ and 2.0fb$^{-1}$, recorded with the LHCb detector at centre-of-mass energies of 7TeV and 8TeV, respectively. The $CP$- and $P$-violating asymmetries are measured both integrating over all phase space and in specific phase-space regions. No significant deviation from $CP$ or $P$ symmetry is found. The first observation of $Lambda^{0}_{b}to pK^{-}chi_{c0}(1P)(topi^{+}pi^{-}, K^{+}K^{-})$ decay is also reported.
We study the decay processes of $bar{B}^0 to J/psi bar{K}^{*0} K^0$ and $bar{B}^0 to J/psi f_1(1285)$ to analyse the $f_1(1285)$ resonance. By the calculation within chiral unitary approach where $f_1(1285)$ resonance is dynamically generated from the $K^*bar{K}-c.c.$ interaction, we find that the $bar{K}^{*0} K^0$ invariant mass distribution has a clear broad peak. Such broad peak has been understood as the signal of the $f_1(1285)$. Finally, we obtain a theoretical result $R_t=Gamma_{bar{B}^0 to J/psi bar{K}^{*0} K^0}/Gamma_{bar{B}^0 to J/psi f_1(1285)}$ which is expected to be compared with the experimental data.
We report measurements of CP violation parameters in $B^0 to K^0 pi^0$ decays based on a data sample of $657 times 10^6 Bbar{B}$ pairs collected with the Belle detector at the KEKB $e^+ e^-$ asymmetric-energy collider. We use $B^0 to K^0_S pi^0$ decays for both mixing-induced and direct $CP$ violating asymmetry measurements and $B^0 to K^0_L pi^0$ decays for the direct CP violation measurement. The CP violation parameters obtained are $sin 2 phi_1^{rm eff} = +0.67 pm 0.31{(stat)} pm 0.08 {(syst)}$ and $mathcal{A}_{K^0 pi^0} = +0.14 pm 0.13{(stat)} pm 0.06 {(syst)}$. The branching fraction of $B^0 to K^0 pi^0$ decay is measured to be $mathcal{B}(B^0 to K^0 pi^0) = (8.7pm0.5 (rm{stat.})pm0.6 (rm{syst.}))times 10^{-6}$. The observed $mathcal{A}_{K^0 pi^0}$ value differs by 1.9 standard deviations from the value expected from an isospin sum rule.
An angular analysis of the decay $B_s^0 rightarrow K^{*0}bar{K}{}^{*0}$ is performed using $pp$ collisions corresponding to an integrated luminosity of $1.0$ ${fb}^{-1}$ collected by the LHCb experiment at a centre-of-mass energy $sqrt{s} = 7$ TeV. A combined angular and mass analysis separates six helicity amplitudes and allows the measurement of the longitudinal polarisation fraction $f_L = 0.201 pm 0.057 {(stat.)} pm 0.040{(syst.)}$ for the $B_s^0 rightarrow K^*(892)^0 bar{K}{}^*(892)^0$ decay. A large scalar contribution from the $K^{*}_{0}(1430)$ and $K^{*}_{0}(800)$ resonances is found, allowing the determination of additional $CP$ asymmetries. Triple product and direct $CP$ asymmetries are determined to be compatible with the Standard Model expectations. The branching fraction $mathcal{B}(B_s^0 rightarrow K^*(892)^0 bar{K}{}^*(892)^0)$ is measured to be $(10.8 pm 2.1 { rm (stat.)} pm 1.4 { rm (syst.)} pm 0.6 (f_d/f_s) ) times 10^{-6}$.
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