No Arabic abstract
We propose a new experiment at the AGS to search for the T-violating polarization of the muon normal to the decay plane of the K+ to mu+ pi0 nu decay. Motivated by the need for a stronger CP violation source to account for the baryon asymmetry of the Universe, the experiment aims to search for T-violation beyond the Standard Model. The experiment will be performed with in-flight decays from an intense 2 GeV/c separated K+ beam at the AGS. We expect to analyze 10**9 events to obtain the sensitivity of delta Pt = +- 0.00013 at 1 sigma, corresponding to the sensitivity of +-0.0007 to Im(xi), an improvement by 40 over the present limit.
We report a search for CP-violating asymmetry in B0 -> D*+- D-+ decays. The analysis employs two methods of B0 reconstruction: full and partial. In the full reconstruction method all daughter particles of the B0 are required to be detected; the partial reconstruction technique requires a fully reconstructed D- and only a slow pion from the D*+ -> D0 pi_slow+ decay. From a fit to the distribution of the time interval corresponding to the distance between two B meson decay points we calculate the CP-violating parameters and find the significance of nonzero CP asymmetry to be 2.7 standard deviations.
We search for CP violation in the decay $D^+rightarrow K^0_S K^+$ using a data sample with an integrated luminosity of 977 fb$^{-1}$ collected with the Belle detector at the KEKB $e^+e^-$ asymmetric-energy collider. No CP violation has been observed and the CP asymmetry in $D^+rightarrow K^0_S K^+$ decay is measured to be $(-0.25pm0.28pm0.14)%$, which is the most sensitive measurement to date. After subtracting CP violation due to $K^0-bar{K}^0$ mixing, the CP asymmetry in $D^+rightarrowbar{K}^0 K^+$ decay is found to be $(+0.08pm0.28pm0.14)%$.
A search for CP violation in the phase space of the decay $D^+topi^-pi^+pi^+$ is reported using $pp$ collision data, corresponding to an integrated luminosity of 1.0 fb$^{-1}$, collected by the LHCb experiment at a centre-of-mass energy of 7 TeV. The Dalitz plot distributions for $3.1times 10^6$ $D^+$ and $D^-$ candidates are compared with binned and unbinned model-independent techniques. No evidence for CP violation is found.
We search for $CP$ violation in the charged charm meson decay $D^{+}topi^{+}pi^{0}$, based on a data sample corresponding to an integrated luminosity of $rm 921~fb^{-1}$ collected by the Belle experiment at the KEKB $e^{+}e^{-}$ asymmetric-energy collider. The measured $CP$ violating asymmetry is $[+2.31pm1.24({rm stat})pm0.23({rm syst})]%$, which is consistent with the standard model prediction and has a significantly improved precision compared to previous results.
A measurement of the time-dependent CP-violating asymmetry in $B_s^0rightarrowphiphi$ decays is presented. Using a sample of proton-proton collision data corresponding to an integrated luminosity of $5.0$fb$^{-1}$ collected by the $mbox{LHCb}$ experiment at centre-of-mass energies $sqrt{s} = 7$ TeV in 2011, 8 TeV in 2012 and 13 TeV in 2015 and 2016, a signal yield of around 9000 $B_s^0rightarrowphiphi$ decays is obtained. The CP-violating phase $phi_s^{sbar{s}s}$ is measured to be $-0.073 pm 0.115$(stat)$pm 0.027$(syst) rad, under the assumption it is independent on the helicity of the $phiphi$ decay. In addition, the CP-violating phases of the transverse polarisations under the assumption of CP conservation of the longitudinal phase are measured. The helicity-independent direct CP-violation parameter is also measured, and is found to be $|lambda|=0.99 pm 0.05 $(stat)$ pm 0.01 $(syst). In addition, $T$-odd triple-product asymmetries are measured. The results obtained are consistent with the hypothesis of CP conservation in $brightarrowbar{s}sbar{s}$ transitions. Finally, a limit on the branching fraction of the $B^0rightarrow phiphi$ decay is determined to be $mathcal{B}(B^0rightarrow phiphi)<2.7times 10^{-8}$ at 90% confidence level.