Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userBounds on the CP Asymmetry in $bto sgamma$ Decays
58
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
We have measured the CP asymmetry A_CP = [BF(b -> s gamma) - BF(bbar -> sbar gamma)]/ [BF(b -> s gamma) + BF(bbar -> sbar gamma)] to be A_CP = (-0.079 +/- 0.108 +/- 0.022)(1.0 +/- 0.030), implying that, at 90% confidence level, A_CP lies between -0.27 and +0.10. These limits rule out some extreme non-Standard Model predictions, but are consistent with most, as well as with the Standard Model.
rate research
Read More
Using the perturbative QCD amplitudes for $Bto pipi$ and $Bto Kpi$, we have performed an extensive study of the parameter space where the theoretical predictions for the branching ratios are consistent with recent experimental data. From this allowed range of parameter space, we predict the mixing induced CP asymmetry for $B to pi^+pi^-$ with about 11% uncertainty and the other CP asymmetries for $Bto pipi$, $Kpi$ with 40% ~ 47% uncertainty. These errors are expected to be reduced as we restrict the parameter space by studying other decay modes and by further improvements in the experimental data.
We measure the CP-violating asymmetries in decays to the D0 -> K+K- and D0 -> pi+pi- CP eigenstates using 540 fb^{-1} of data collected with the Belle detector at or near the Upsilon(4S) resonance. Cabibbo-favored D0 -> K-pi+ decays are used to correct for systematic detector effects. The results, A_{CP}^{KK} = (-0.43 +- 0.30 +- 0.11)% and A_{CP}^{pipi} = (+0.43 +- 0.52 +- 0.12)%, are consistent with no CP violation.
We describe a measurement of the direct CP asymmetry between inclusive b -> s gamma and bbar -> sbar gamma decays. This asymmetry is expected to be less than 0.01 in the Standard Model, but could be enhanced up to about 0.10 by new physics contributions. We use a sample of 89 million BB pairs recorded with the BaBar detector at PEP-II, from which we reconstruct a set of 12 exclusive b -> s gamma final states containing one charged or neutral kaon and one to three pions. We measure an asymmetry of A_CP(b -> s gamma) = 0.025 +/- 0.050(stat.) +/- 0.015(syst.), corresponding to an allowed range of -0.06 < A_CP(b -> s gamma) < +0.11 at 90% confidence level.
A measurement of the time-integrated $CP$ asymmetry in the Cabibbo-suppressed decay $D^0rightarrow K^-K^+$ is performed using pp collision data, corresponding to an integrated luminosity of 3fb$^{-1}$, collected with the LHCb detector at centre-of-mass energies of 7 and 8 TeV. The flavour of the charm meson at production is determined from the charge of the pion in $D^{*+}rightarrow D^0 pi^+$ and $D^{*-}rightarrow bar{D^0} pi^-$ decays. The time-integrated $CP$ asymmetry $A_{CP}(K^-K^+)$ is obtained assuming negligible $CP$ violation in charm mixing and in Cabibbo-favoured $D^0rightarrow K^-pi^+$, $D^+rightarrow K^-pi^+pi^+$ and $D^+rightarrow bar{K^0}pi^+$ decays used as calibration channels. It is found to be $A_{CP}(K^-K^+)=(0.14pm0.15(stat)pm0.10(syst))%$. A combination of this result with previous LHCb measurements yields $A_{CP}(K^-K^+)=(0.04pm0.12(stat)pm0.10(syst))%$, $A_{CP}(pi^-pi^+)=(0.07pm0.14(stat)pm0.11(syst))%$. These are the most precise measurements from a single experiment. The result for $A_{CP}(K^-K^+)$ is the most precise determination of a time-integrated $CP$ asymmetry in the charm sector to date, and neither measurement shows evidence of CP asymmetry.
A measurement of the CP asymmetry in B0 -> K*0 mu+ mu- decays is presented, based on 1.0fb-1 of pp collision data recorded by the LHCb experiment during 2011. The measurement is performed in six bins of invariant mass squared of the mu+ mu- pair, excluding the J/psi and psi(2S) resonance regions. Production and detection asymmetries are removed using the B0 -> J/Psi K*0 decay as a control mode. The integrated CP asymmetry is found to be -0.072 +- 0.040 (stat.) +- 0.005 (syst.), consistent with the Standard Model.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
