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Register a new userStrong Phase and $D^0-D^0bar$ mixing at BES-III
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Most recently, both BaBar and Belle experiments found evidences of neutral $D$ mixing. In this paper, we discuss the constraints on the strong phase difference in $D^0 to Kpi$ decay from the measurements of the mixing parameters, $y^prime$, $y_{CP}$ and $x$ at the $B$ factories. The sensitivity of the measurement of the mixing parameter $y$ is estimated in BES-III experiment at $psi(3770)$ peak. We also make an estimate on the measurements of the mixing rate $R_M$. Finally, the sensitivity of the strong phase difference at BES-III are obtained by using data near the $Dbar{D}$ threshold with CP tag technique at BES-III experiment.
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We have searched for mixing in the D0-D0bar system by measuring the decay-time distribution of D0->K+pi- decays. The analysis uses 90 fb^{-1} of data collected by the Belle detector at the KEKB e+e- collider. We fit the decay-time distribution for the mixing parameters x and y and also for the parameter R_D, which is the ratio of the rate for the doubly-Cabibbo-suppressed decay D0->K+pi- to that for the Cabibbo-favored decay D0->K-pi+. We do these fits both assuming CP conservation and allowing for CP violation. We use a frequentist method to obtain a 95% C.L. region in the x^2 - y plane. Assuming no mixing, we measure R_D = (0.381 pm 0.017 +0.008 -0.016) %.
First observations and measurements of the branching fractions of the $bar{B}_s^0to D^+D^-$, $bar{B}_s^0to D_s^+D^-$ and $bar{B}_s^0to D^0bar{D}^0$ decays are presented using 1.0 fb$^{-1}$ of data collected by the LHCb experiment. These branching fractions are normalized to those of $bar{B}^0to D^+D^-$, $B^0to D_s^+D^-$ and $B^-to D^0D_s^-$, respectively. An excess of events consistent with the decay $bar{B}^0to D^0bar{D}^0$ is also seen, and its branching fraction is measured relative to that of $B^-to D^0D_s^-$. Improved measurements of the branching fractions ${cal{B}}(bar{B}_s^0to D_s^+D_s^-)$ and ${cal{B}}(B^-to D^0D_s^-)$ are reported, each relative to ${cal{B}}(B^0to D_s^+D^-)$. The ratios of branching fractions are {-0.2in} {center} {align*} {{cal{B}}(bar{B}_s^0to D^+D^-)over {cal{B}}(bar{B}^0to D^+D^-)} &= 1.08pm 0.20pm0.10, {{cal{B}}(bar{B}_s^0to D_s^+D^-)over {cal{B}}(B^0to D_s^+D^-)} &= 0.050pm 0.008pm0.004, {{cal{B}}(bar{B}_s^0to D^0bar{D}^0)over {cal{B}}(B^-to D^0D_s^-)} &= 0.019pm 0.003pm0.003, {{cal{B}}(bar{B}^0to D^0bar{D}^0)over {cal{B}}(B^-to D^0D_s^-)} &= 0.0014pm 0.0006pm0.0002,{{cal{B}}(bar{B}_s^0to D_s^+D_s^-)over {cal{B}}(B^0to D_s^+D^-)} &= 0.56pm 0.03pm0.04, {{cal{B}}(B^-to D^0D_s^-)over {cal{B}}(B^0to D_s^+D^-)} &= 1.22pm 0.02pm0.07, {align*} {center} oindent where the uncertainties are statistical and systematic, respectively.
We review basic phenomenology on $D^0$ mixing/CP violation and recent experimental results on them. $D^0$ mixing is established by combining results from multiple experiments but no CP violation in the charm sector has been seen. $D^0$ mixing from a single experiment will clarify the size of the mixing, and observation of CP violation in charm decays at the present level of experimental sensitivity would be clear signal of new physics beyond the standard model.
We present an observation and rate measurement of the decay D0 -> K+pi-pi0 produced in 9/fb of e+e- collisions near the Upsilon(4S) resonance. The signal is inconsistent with an upward fluctuation of the background by 4.9 standard deviations. We measured the rate of D0 -> K+pi-pi0 normalized to the rate of D0bar -> K+pi-pi0 to be 0.0043 +0.0011 -0.0010 (stat) +/- 0.0007 (syst). This decay can be produced by doubly-Cabibbo-suppressed decays or by the D0 evolving into a D0bar through mixing, followed by a Cabibbo-favored decay to K+pi-pi0. We also found the CP asymmetry A=(8 +25 -22)% to be consistent with zero.
This physics book provides detailed discussions on important topics in $tau$-charm physics that will be explored during the next few years at bes3 . Both theoretical and experimental issues are covered, including extensive reviews of recent theoretical developments and experimental techniques. Among the subjects covered are: innovations in Partial Wave Analysis (PWA), theoretical and experimental techniques for Dalitz-plot analyses, analysis tools to extract absolute branching fractions and measurements of decay constants, form factors, and CP-violation and DzDzb-oscillation parameters. Programs of QCD studies and near-threshold tau-lepton physics measurements are also discussed.
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