Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userMeasurement of CP violation in the $B_s^0rightarrowphiphi$ decay and search for the $B^0rightarrow phiphi$ decay
67
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
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.
rate research
Read More
A measurement of direct CP violation in the decay $B^{+} rightarrow K^{+} pi^{0}$ is reported using a data sample corresponding to an integrated luminosity of 5.4 $textrm{fb}^{-1}$, collected with the LHCb experiment at a center-of-mass energy of $sqrt{s}=13$ TeV. The CP asymmetry is measured to be $0.025 pm 0.015 pm 0.006 pm 0.003$, where the uncertainties are statistical, systematic, and due to an external input, respectively. This is the most precise measurement of the CP asymmetry in the decay $B^{+} rightarrow K^{+} pi^{0}$ and exceeds the precision on the current world average. This direct CP asymmetry is a key input to studies of a long-standing anomaly in $B$ meson decays, known as the $Kpi$-puzzle. The asymmetry is consistent with the previous measurements of this quantity, confirming and significantly enhancing the observed anomalous difference between the direct CP asymmetries of the $B^{0} rightarrow K^{+} pi^{-}$ and $B^{+} rightarrow K^{+} pi^{0}$ decays.
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 measure the decay $B_s^0rightarrow K^0overline{K}^0$ using data collected at the $Upsilon(5S)$ resonance with the Belle detector at the KEKB $e^+e^-$ collider. The data sample used corresponds to an integrated luminosity of 121.4 ${rm fb^{-1}}$. We measure a branching fraction $mathcal{B}(B_s^0rightarrow K^0overline{K}^0) = [19.6,^{+5.8}_{-5.1}({rm stat.}),pm1.0({rm sys.}),pm 2.0(N^{}_{B_s^0overline{B}_s^0})]times 10^{-6}$ with a significance of 5.1 standard deviations. This measurement constitutes the first observation of this decay.
The shape of the $B_s^0rightarrow D_s^{*-}mu^+ u_{mu}$ differential decay rate is obtained as a function of the hadron recoil using proton-proton collision data at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 1.7 fb$^{-1}$ collected by the LHCb detector. The $B_s^0rightarrow D_s^{*-}mu^+ u_{mu}$ decay is reconstructed through the decays $D_s^{*-}rightarrow D_s^{-}gamma$ and $D_s^{-}rightarrow K^-K^+pi^-$. The differential decay rate is fitted with the Caprini-Lellouch-Neubert (CLN) and Boyd-Grinstein-Lebed (BGL) parametrisations of the form factors, and the relevant quantities for both are extracted.
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 $(+0.08pm0.28pm0.14)%$.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
