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.
We present a measurement of the slope parameter $alpha$ for the $etato 3pi^{0}$ decay, with the KLOE experiment at the DA$Phi$NE $phi$-factory, based on a background free sample of $sim$ 17 millions $eta$ mesons produced in $phi$ radiative decays. By fitting the event density in the Dalitz plot we determine $alpha = -0.0301 pm 0.0035,stat;_{-0.0035}^{+0.0022},syst,$. The result is in agreement with recent measurements from hadro- and photo-production experiments.
The dynamics of the $etato 3pi^0$ decay have been studied with the Crystal Ball multiphoton spectrometer and the TAPS calorimeter. Bremsstrahlung photons produced by the 1.5-GeV electron beam of the Mainz microtron MAMI-C and tagged by the Glasgow photon spectrometer were used for $eta$-meson production. The analysis of $3 times 10^6$ $gamma p to eta p to 3pi^0 p to 6gamma p$ events yields the value $alpha=-0.032pm0.003$ for the $etato 3pi^0$ slope parameter, which agrees with the majority of recent experimental results and has the smallest uncertainty. The $pi^0pi^0$ invariant-mass spectrum was investigated for the occurrence of a cusplike structure in the vicinity of the $pi^+pi^-$ threshold. The observed effect is small and does not affect our measured value for the slope parameter.
A precise measurement of the Dalitz plot parameter, alpha, for the eta->3pi^0 decay is presented. The experiment was performed with the Crystal Ball and TAPS large acceptance photon detectors at the tagged photon beam facility of the MAMI-B electron accelerator in Mainz. High statistics of 1.8*10^6 eta->3pi^0 events were obtained, giving the result alpha = -0.032 +/- 0.002(stat) +/- 0.002(syst).
The largest, at the moment, statistics of 7x10^6 eta->3pi^0 decays, based on 6.2x10^7 eta mesons produced in the gamma p -> eta p reaction, has been accumulated by the A2 Collaboration at the Mainz Microtron, MAMI. It allowed a detailed study of the eta->3pi^0 dynamics beyond its conventional parametrization with just the quadratic slope parameter alpha and enabled, for the first time, a measurement of the second-order term and a better understanding of the cusp structure in the neutral decay. The present data are also compared to recent theoretical calculations that predict a nonlinear dependence along the quadratic distance from the Dalitz-plot center.
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}.
KLOE collaboration: F. Ambrosino
,A. Antonelli
,M. Antonelli
.
(2007)
.
"Measurement of the slope parameter alpha for the etato 3pi^0 decay at KLOE"
.
Francesco Perfetto
هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا