Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userMeasurement of the branching fraction and time-dependent $CP$ asymmetry for $B^0to J/psipi^0$ decays
90
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
We measure the branching fraction and time-dependent $CP$-violating asymmetry for $B^0to J/psipi^0$ decays using a data sample of 711 ${rm fb^{-1}}$ collected on the $Upsilon(4S)$ resonance by the Belle experiment running at the KEKB $e^+e^-$ collider. The branching fraction is measured to be $mathcal{B}(B^0to J/psipi^0) = [1.62,pm 0.11~({rm stat}) pm0.07~({rm syst})]times 10^{-5}$, which is the most precise measurement to date. The measured $CP$ asymmetry parameters are $mathcal{S} = -0.59,pm 0.19~({rm stat}) pm 0.03~({rm syst})$ and $mathcal{A} = -0.15,pm 0.14~({rm stat}),^{+0.04}_{-0.03}~({rm syst})$. The mixing-induced $CP$ asymmetry ($mathcal{S}$) differs from the case of no $CP$ violation by 3.0 standard deviations, and the direct $CP$ asymmetry ($mathcal{A}$) is consistent with zero.
rate research
Read More
We present a measurement of the time-dependent $CP$ violation parameters in $B^0toetaK^0$ decays. The measurement is based on the full data sample containing $772times 10^6$ $Bbar{B}$ pairs collected at the $Upsilon(4S)$ resonance using the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. The measured values of the mixing-induced and direct $CP$ violation parameters are: begin{align} sin 2 phi^{rm eff}_1 &= +0.68pm 0.07 pm 0.03, onumber mathcal{A}_{etaK^0} &= +0.03pm 0.05pm 0.04, onumber end{align} where the first uncertainty is statistical and the second is systematic. The values obtained are the most accurate to date. Furthermore, these results are consistent with our previous measurements and with the world-average value of $sin 2phi_1$ measured in $B^0to J/psi K^0$ decays.}
The $B_s^0to J/psi K_S^0$ branching fraction is measured in a data sample corresponding to 0.41$fb^{-1}$ of integrated luminosity collected with the LHCb detector at the LHC. This channel is sensitive to the penguin contributions affecting the sin2$beta$ measurement from $B^0to J/psi K_S^0$ The time-integrated branching fraction is measured to be $BF(B_s^0to J/psi K_S^0)=(1.83pm0.28)times10^{-5}$. This is the most precise measurement to date.
The time-dependent CP asymmetry in B_s^0to J/psi K^+K^- decays is measured using $pp$ collision data at sqrt{s}=7TeV, corresponding to an integrated luminosity of 1.0fb^-1, collected with the LHCb detector. The decay time distribution is characterised by the decay widths Gamma_L and Gamma_H of the light and heavy mass eigenstates of the B_s^0--bar{B}_s^0 system and by a CP-violating phase phi_s. In a sample of 27,617 B_s^0to J/psi K^+K^- decays, where the dominant contribution comes from B_s^0to J/psiphi decays, these parameters are measured to be phi_s = 0.07 pm 0.09 (stat) pm 0.01 (syst) rad, Gamma_s equiv (Gamma_L+Gamma_H)/2 = 0.663 pm 0.005 (stat) pm 0.006 (syst) ps^-1, DeltaGamma_s equiv Gamma_L -Gamma_H = 0.100 pm 0.016 (stat) pm 0.003 (syst) & ps^-1, corresponding to the single most precise determination of phi_s, DeltaGamma_s and Gamma_s. The result of performing a combined analysis with B_s^{0} to J/psi pi^+pi^- decays gives phi_s = 0.01 pm 0.07 (stat) pm 0.01 (syst) rad, Gamma_s = 0.661 pm 0.004 (stat) pm 0.006 (syst) ps^-1, DeltaGamma_s = 0.106 pm 0.011 (stat) pm 0.007 (syst) & ps^-1. All measurements are in agreement with the Standard Model predictions.
We measure the branching fraction and $CP$ violation asymmetry in the decay $B^{0}to pi^{0}pi^{0}$, using a data sample of $752times 10^{6}$ $Bbar{B}$ pairs collected at the $Upsilon(4S)$ resonance with the Belle detector at the KEKB $e^{+}e^{-}$ collider. The obtained branching fraction and direct $CP$ asymmetry are $ mathcal{B}(Bto pi^{0}pi^{0}) = [1.31 pm 0.19~ text{(stat.)} pm 0.19~ text{(syst.)}] times 10^{-6}$ and $ A_{CP} = +0.14 pm 0.36~ text{(stat.)} pm 0.10~ text{(syst.)}, $ respectively. The signal significance, including the systematic uncertainty, is 6.4 standard deviations. We combine these results with Belles earlier measurements of $B^{0}to pi^{+} pi^{-}$ and $B^{pm} to pi^{pm} pi^{0}$ to exclude the $CP$-violating parameter $phi_{2}$ from the range $15.5^{circ} < phi_{2} < 75.0^{circ}$ at 95% confidence level.
The branching fraction and direct $C!P$ asymmetry of the decay $B^{+}rightarrow J/psi rho^{+}$ are measured using proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7 and 8 TeV, corresponding to a total integrated luminosity of 3$mbox{fb}^{-1}$. The following results are obtained: begin{align} mathcal{B}(B^{+}rightarrow J/psi rho^{+}) &= (3.81 ^{+0.25}_{-0.24} pm 0.35) times 10^{-5}, onumber mathcal{A}^{C!P} (B^{+}rightarrow J/psi rho^{+}) &= -0.045^{+0.056}_{-0.057} pm 0.008, onumber end{align} where the first uncertainties are statistical and the second systematic. Both measurements are the most precise to date.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
