Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userMeasurement of the $D to K^-pi^+pi^+pi^-$ and $D to K^-pi^+pi^0$ coherence factors and average strong-phase differences in quantum-correlated ${Dbar{D}}$ decays
83
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
The decays $Dto K^-pi^+pi^+pi^-$ and $D to K^-pi^+pi^0$ are studied in a sample of quantum-correlated $Dbar{D}$ pairs produced through the process $e^+e^- to psi(3770) to Dbar{D}$, exploiting a data set collected by the BESIII experiment that corresponds to an integrated luminosity of 2.93 fb$^{-1}$. Here $D$ indicates a quantum superposition of a $D^0$ and a $bar{D}^0$ meson. By reconstructing one neutral charm meson in a signal decay, and the other in the same or a different final state, observables are measured that contain information on the coherence factors and average strong-phase differences of each of the signal modes. These parameters are critical inputs in the measurement of the angle $gamma$ of the Unitarity Triangle in $B^- to DK^-$ decays at the LHCb and Belle II experiments. The coherence factors are determined to be $R_{K3pi}=0.52^{+0.12}_{-0.10}$ and $R_{Kpipi^0}=0.78 pm 0.04$, with values for the average strong-phase differences that are $delta_D^{K3pi}=left(167^{+31}_{-19}right)^circ$ and $delta_D^{Kpipi^0}=left(196^{+14}_{-15}right)^circ$, where the uncertainties include both statistical and systematic contributions. The analysis is re-performed in four bins of the phase-space of the $D to K^-pi^+pi^+pi^-$ to yield results that will allow for a more sensitive measurement of $gamma$ with this mode, to which the BESIII inputs will contribute an uncertainty of around 6$^circ$.
rate research
Read More
Using a data sample corresponding to 13.7 fb^-1 collected with the CLEO II and II.V detectors, we report new branching fraction measurements for two Cabibbo-suppressed decay modes of the D^+ meson: Br(D^+ to pi^+ pi^0) = (1.3 +/- 0.2) x 10^-3 and Br(D^+ to bar{K}^0 K^+) = (5.2 +/- 0.6) x 10^-3 which are significant improvements over past measurements. The errors include statistical and systematical uncertainties as well as the uncertainty in the absolute D^+ branching fraction scale. We also set the first 90% confidence level upper limit on the branching fraction of the doubly Cabibbo-suppressed decay mode Br(D^+ to K^+ pi^0) < 4.2 x 10^-4.
Quantum-correlated $psi(3770) to Dbar{D}$ decays collected by the CLEO-c experiment are used to perform a first measurement of $F_+^{4pi}$, the fractional $CP$-even content of the self-conjugate decay $D to pi^+pi^-pi^+pi^-$, obtaining a value of $0.737 pm 0.028$. An important input to the measurement comes from the use of $D to K^0_{rm S}pi^+pi^-$ and $D to K^0_{rm L}pi^+pi^-$ decays to tag the signal mode. This same technique is applied to the channels $D topi^+pi^-pi^0$ and $D to K^+K^-pi^0$, yielding $F_+^{pipipi^0} = 1.014 pm 0.045 pm 0.022$ and $F_+^{KKpi^0} = 0.734 pm 0.106 pm 0.054$, where the first uncertainty is statistical and the second systematic. These measurements are consistent with those of an earlier analysis, based on $CP$-eigenstate tags, and can be combined to give values of $F_+^{pipipi^0} = 0.973 pm 0.017$ and $F_+^{KKpi^0} = 0.732 pm 0.055$. The results will enable the three modes to be included in a model-independent manner in measurements of the unitarity triangle angle $gamma$ using $B^mp to DK^mp$ decays, and in time-dependent studies of $CP$ violation and mixing in the $Dbar{D}$ system.
Using proton-proton collision data collected by the LHCb experiment at sqrt(s) = 7 TeV, corresponding to an integrated luminosity of 1.0 fb^{-1}, the ratio of branching fractions of the B0 -> D*- pi+ pi- pi+ decay relative to the B0 -> D*- pi+ decay is measured to be B(B0 -> D*- pi+ pi- pi+) / B(B0 -> D*- pi+) = 2.64 pm 0.04 (stat.) pm 0.13 (syst.). The Cabibbo-suppressed decay B0 -> D*- K+ pi- pi+ is observed for the first time and the measured ratio of branching fractions is B(B0 -> D*- K+ pi- pi+) / B(B0 -> D*- pi+ pi- pi+) = (6.47 pm 0.37 (stat.) pm 0.35 (syst.)) x 10^{-2}. A search for orbital excitations of charm mesons contributing to the B0 -> D*- pi+ pi- pi+ final state is also performed, and the first observation of the B0 -> Dbar_{1}(2420)^0 pi+ pi- decay is reported with the ratio of branching fractions B(B0 -> (Dbar_{1}(2420)^0 -> D*- pi+) pi- pi+) / B(B0 -> D*- pi+ pi- pi+) = (2.04 pm 0.42 (stat.) pm 0.22 (syst.)) x 10^{-2}, where the numerator represents a product of the branching fractions B(B0 -> Dbar_{1}(2420)^0 pi- pi+) and B(Dbar_{1}(2420)^0 -> D*- pi+).
Measurements of the coherence factors (R_Kpipi0 and R_K3pi) and the average strong-phase differences (delta^Kpipi0_D and delta^K3pi_D) for the decays D0-> K-pi+pi0 and D0->K-pi+pi+pi- are presented. These parameters are important inputs to the determination of the unitarity triangle angle gamma in B+/- -> DK+/- decays, where D designates a D0 or D0bar meson decaying to a common final state. The measurements are made using quantum correlated DDbar decays collected by the CLEO-c experiment at the psi(3770) resonance, and augment a previously published analysis by the inclusion of new events in which the signal decay is tagged by the mode D-> K0Spi+pi-. The measurements also benefit from improved knowledge of external inputs, namely the D0D0bar mixing parameters, r_D^Kpi and several D-meson branching fractions. The measured values are R_Kpipi0 = 0.82 +- 0.07, delta_D^Kpipi0 = (164+20-14) deg., R_K3pi = 0.32+0.20-0.28 and delta^K3pi_D = (225+21_-78) deg. Consideration is given to how these measurements can be improved further by using the larger quantum-correlated data set collected by BESIII.
Time-integrated $CP$ asymmetries in $D^0$ decays to the final states $K^- K^+$ and $pi^- pi^+$ are measured using proton-proton collisions corresponding to $3mathrm{,fb}^{-1}$ of integrated luminosity collected at centre-of-mass energies of $7mathrm{,Tekern -0.1em V}$ and $8mathrm{,Tekern -0.1em V}$. The $D^0$ mesons are produced in semileptonic $b$-hadron decays, where the charge of the accompanying muon is used to determine the initial flavour of the charm meson. The difference in $CP$ asymmetries between the two final states is measured to be begin{align} Delta A_{CP} = A_{CP}(K^-K^+)-A_{CP}(pi^-pi^+) = (+0.14 pm 0.16mathrm{,(stat)} pm 0.08mathrm{,(syst)})% . onumber end{align} A measurement of $A_{CP}(K^-K^+)$ is obtained assuming negligible $CP$ violation in charm mixing and in Cabibbo-favoured $D$ decays. It is found to be begin{align} A_{CP}(K^-K^+) = (-0.06 pm 0.15mathrm{,(stat)} pm 0.10mathrm{,(syst)}) % , onumber end{align} where the correlation coefficient between $Delta A_{CP}$ and $A_{CP}(K^-K^+)$ is $rho=0.28$. By combining these results, the $CP$ asymmetry in the $D^0rightarrowpi^-pi^+$ channel is $A_{CP}(pi^-pi^+)=(-0.20pm0.19mathrm{,(stat)}pm0.10mathrm{,(syst)})%$.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
