We have measured the alpha parameter of the Omega- to Lambda K- decay using data collected with the HyperCP spectrometer during the 1997 fixed-target run at Fermilab. Analyzing a sample of 0.96 million Omega- to Lambda K^-, Lambda to p pi- decays, we obtain alpha_Omega*alpha_Lambda = [1.33+/-0.33(stat)+/-0.52(syst)] x 10^{-2}. With the accepted value of alpha_Lambda, alpha_Omega is found to be [2.07+/-0.51(stat)+/-0.81(syst)] x 10^{-2}.
The alpha decay parameter in the process Omega-minus -> Lambda + K-minus has been measured from a sample of 4.50 million unpolarized Omega-minus decays recorded by the HyperCP (E871) experiment at Fermilab and found to be [1.78 +/- 0.19(stat) +/- 0.16(syst)]{times}10^{-2}. This is the first unambiguous evidence for a nonzero alpha decay parameter, and hence parity violation, in the Omega-minus -> Lambda + K-minus decay.
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 preliminary measurement of the slope parameter $alpha$ for the $etato 3piz$ decay carried out with KLOE at DA$Phi$NE; where $alpha$ is the parameter describing the energy dependence of the square of the matrix element for this decay. By fitting the event density in the Dalitz plot with a collected statistic of 420 pb$^{-1}$ we determine $alpha = -0.027 pm 0.004 (stat) ^{+0.004}_{-0.006} (syst)$. This result is consistent with current chiral perturbation theory calculations within the unitary approach.
A new measurement of the neutrino asymmetry parameter B in neutron decay, the angular correlation between neutron spin and anti-neutrino momentum, is presented. The result, B=0.9802(50), agrees with the Standard Model expectation and earlier measurements, and permits improved tests on ``new physics in neutron decay.
Analyzing $(448.1pm2.9)times10^6$ $psi(3686)$ events collected with the BESIII detector at the BEPCII collider, the $psi(3686)to omega K_{S}^{0}K_{S}^{0}$ decay is observed for the first time. The branching fraction for this decay is determined to be $mathcal{B}_{psi(3686)to omega K_{S}^{0}K^{0}_{S}}$=$(7.04pm0.39pm0.36)$$times10^{-5}$, where the first uncertainty is statistical and the second is systematic.
HyperCP Collaboration: Y. C. Chen
,R. A. Burnstein
,A. Chakravorty
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(2005)
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"Measurement of the Alpha Asymmetry Parameter for the Omega- to Lambda K- Decay"
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Kam Biu Luk
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