Measurement of \Gamma(\eta -> \pi^+\pi^-\gamma)/\Gamma(\eta -> \pi^+\pi^-\pi^0) with the KLOE Detector

The ratio R_{\eta}=\Gamma(\eta -> \pi^+\pi^-\gamma)/\Gamma(\eta -> \pi^+\pi^-\pi^0) has been measured by analyzing 22 million \phi \to \eta \gamma decays collected by the KLOE experiment at DA\PhiNE, corresponding to an integrated luminosity of 558 pb^{-1}. The \eta \to \pi^+\pi^-\gamma proceeds both via the \rho resonant contribution, and possibly a non-resonant direct term, connected to the box anomaly. Our result, R_{\eta}= 0.1856\pm 0.0005_{stat} \pm 0.0028_{syst}, points out a sizable contribution of the direct term to the total width. The di-pion invariant mass for the \eta -> \pi^+\pi^-\gamma decay could be described in a model-independent approach in terms of a single free parameter, \alpha. The determined value of the parameter \alpha is \alpha = (1.32 \pm 0.08_{stat} +0.10/-0.09_{syst}\pm 0.02_{theo}) GeV^{-2}Comment: Paper in press, accepted by PL

Test of CPT and Lorentz symmetry in entangled neutral kaons with the KLOE experiment

Neutral kaon pairs produced in Ï\u86 decays in anti-symmetric entangled state can be exploited to search for violation of CPT symmetry and Lorentz invariance. We present an analysis of the CP-violating process Ï\u86 â\u86\u92 KSKL â\u86\u92 Ï\u80 +Ï\u80 -Ï\u80 +Ï\u80 - based on 1.7 fb -1 of data collected by the KLOE experiment at the Frascati Ï\u86-factory DAΦNE. The data are used to perform a measurement of the CPT-violating parameters δaμ for neutral kaons in the context of the Standard Model Extension framework. The parameters measured in the reference frame of the fixed stars are:δa0=(-6.0±7.7stat±3.1syst)Ã\u9710-18 GeV,δaX=(0.9±1.5stat±0.6syst)Ã\u9710-18 GeV,δaY=(-2.0±1.5stat±0.5syst)Ã\u9710-18 GeV,δaZ=(3.1±1.7stat±0.5syst)Ã\u9710-18 GeV. These are presently the most precise measurements in the quark sector of the Standard Model Extension. © 2014 The Authors

Measurement of Gamma(eta -> pi(+)pi(-)gamma)/Gamma(eta -> pi(+)pi(-)pi(0)) with the KLOE detector

The ratio R-eta = Gamma(eta -> pi(+)pi(-)gamma)/Gamma(eta -> pi(+)pi(-)pi(0)) has been measured by analysing 22 million phi -> eta gamma decays collected by the KLOE experiment at DANE, corresponding to an integrated luminosity of 558 pb(-1). The eta -> pi(+)pi(-)gamma proceeds both via the rho resonant contribution, and possibly a non-resonant direct term, connected to the box anomaly. Our result, R-eta = 0.1856 +/- 0.0005(stat)+/- 0.0028(syst), points out a sizable contribution of the direct term to the total width. The di-pion invariant mass for the eta -> pi(+)pi(-)gamma decay could be described in a model-independent approach in terms of a(-) single free parameter, alpha. The determined value of the parameter alpha is alpha = (1.32 +/- 0.08(stat-0.09syst)(+0.10) +/- 0.02(theo)) GeV-2. 2012 Elsevier B.V. All rights reserved