Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userMeasurement of the charm-mixing parameter $y_{CP}$ in $D^{0}to K^{0}_{S}omega$ decays at Belle
68
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
We report the first measurement of the charm-mixing parameter $y_{CP}$ in $D^{0}$ decays to the $CP$-odd final state $K^{0}_{S}omega$. The study uses the full Belle $e^{+}e^-$ annihilation data sample of $976rm~ fb^{-1}$ taken at or near the $Upsilon(4S)$ centre-of-mass energy. We find $y_{CP} = (0.96 pm 0.91 pm 0.61 {}^{+0.17}_{-0.00})%$, where the first uncertainty is statistical, the second is systematic due to event selection and background, and the last is due to possible presence of $CP$-even decays in the data sample.
rate research
Read More
A measurement of the charm-mixing parameter $y_{CP}$ using $D^0 to K^+ K^-$, $D^0 to pi^+ pi^-$, and $D^0 to K^- pi^+$ decays is reported. The $D^0$ mesons are required to originate from semimuonic decays of $B^-$ and $overline{B}^0$ mesons. These decays are partially reconstructed in a data set of proton-proton collisions at center-of-mass energies of 7 and 8 TeV collected with the LHCb experiment and corresponding to an integrated luminosity of 3 fb$^{-1}$. The $y_{CP}$ parameter is measured to be $(0.57 pm 0.13(rm{stat.}) pm 0.09(rm{syst.}))%$, in agreement with, and as precise as, the current world-average value.
We report a measurement of the time-integrated $CP$ asymmetry in the neutral charm meson decay $D^0 to K^0_S K^0_S$ using 921~fb$^{-1}$ data collected at the $Upsilon(4S)$ and $Upsilon(5S)$ resonances with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. The observed asymmetry is $$ A_{CP}(D^0 to K^0_S K^0_S) = (-0.02 pm 1.53 pm 0.17) %, $$ where the first uncertainty is statistical and the second systematic. This latter uncertainty is dominated by the error of the normalisation channel. The result is consistent with Standard Model expectations and improves the uncertainty with respect to previous measurement of this quantity by more than a factor of three.
We report a measurement of the parameter $y_{CP}$ in $ensuremath{D^0}xspace-ensuremath{overline{D}^{0}}xspace$ oscillations performed by taking advantage of quantum coherence between pairs of $ensuremath{D^0}xspace ensuremath{overline{D}^{0}}xspace$ mesons produced in $e^+e^-$ annihilations near threshold. In this work, doubly-tagged $ensuremath{D^0}xspace ensuremath{overline{D}^{0}}xspace$ events, where one $D$ decays to a $CP$ eigenstate and the other $D$ decays in a semileptonic mode, are reconstructed using a data sample of 2.92,fb$^{-1}$ collected with the BESIII detector at the center-of-mass energy of $sqrt{s}$ = 3.773,GeV. We obtain $y_{CP} = (-2.0pm1.3pm0.7)%$, where the first uncertainty is statistical and the second is systematic. This result is compatible with the current world average.
We measure the branching fractions and $CP$ asymmetries for the singly Cabibbo-suppressed decays $D^{0}topi^{+}pi^{-}eta$, $D^{0}to K^{+}K^{-}eta$, and $D^{0}tophieta$, using 980 fb$^{-1}$ of data from the Belle experiment at the KEKB $e^+e^-$ collider. We obtain begin{eqnarray} mathcal{B}(D^{0}topi^{+}pi^{-}eta) & = & [1.22pm 0.02,({rm stat})pm 0.02,({rm syst})pm 0.03,(mathcal{B}_{rm ref})]times 10^{-3},, onumber mathcal{B}(D^{0}to K^{+}K^{-}eta) & = & [1.80,^{+0.07}_{-0.06},({rm stat})pm 0.04,({rm syst})pm 0.05,(mathcal{B}_{rm ref})]times 10^{-4},, onumber mathcal{B}(D^{0}tophieta) & = & [1.84pm 0.09,({rm stat})pm 0.06,({rm syst})pm 0.05,(mathcal{B}_{rm ref})]times 10^{-4},, onumber end{eqnarray} where the third uncertainty ($mathcal{B}_{rm ref}$) is from the uncertainty in the branching fraction of the reference mode $D^{0}to K^{-}pi^{+}eta$. The color-suppressed decay $D^{0}tophieta$ is observed for the first time, with very high significance. The results for the $CP$ asymmetries are begin{eqnarray} A_{CP}(D^{0}topi^{+}pi^{-}eta) & = & [0.9pm 1.2,({rm stat})pm 0.5,({rm syst})]%,, onumber A_{CP}(D^{0}to K^{+}K^{-}eta) & = & [-1.4pm 3.3,({rm stat})pm 1.1,({rm syst})]%,, onumber A_{CP}(D^{0}tophieta)&= & [-1.9pm 4.4,({rm stat})pm 0.6,({rm syst})]%,. onumber end{eqnarray} The results for $D^{0}topi^{+}pi^{-}eta$ are a significant improvement over previous results. The branching fraction and $A_{CP}$ results for $D^{0}to K^{+}K^{-}eta$, and the $A_{CP}$ result for $D^{0}tophieta$, are the first such measurements. No evidence for $CP$ violation is found in any of these decays.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
