The processes \(e^+e^-\to e^+e^-X\), with \(X\) being either the \(\eta\) meson or \(\pi^0\pi^0\), are studied at DA\(\Phi\)NE, with \(e^+e^-\) beams colliding at \(\sqrt{s}\simeq1\) GeV, below the ...\(\phi\) resonance peak. The data sample is from an integrated luminosity of 240 pb\(^{-1}\), collected by the KLOE experiment without tagging of the outgoing \(e^+e^-\). Preliminary results are presented on the observation of the \(\gamma\gamma\to\eta\) process, with both \(\eta\to\pi^+\pi^-\pi^0\) and \(\eta\to\pi^0\pi^0\pi^0\) channels, and the evidence for \(\gamma\gamma\to\pi^0\pi^0\) production at low \(\pi^0\pi^0\) invariant mass.
We present precise measurements of the eta and K0 masses using the processes phi to eta gamma, eta to gamma gamma and phi to Ks Kl, Ks to pi+ pi-. The K0 mass measurement, M_K=497.583 +/- 0.005 ...(stat) +/- 0.020 (syst) MeV, is in acceptable agreement with the previous measurements but is more accurate. We find m(eta) = 547.874 +/- 0.007 (stat) +/- 0.031 (syst) MeV. Our value is the most accurate to date and is in agreement with two recent measurements based on eta decays, but is inconsistent, by about 10 sigma, with a measurement of comparable precision based on eta production at threshold.
We report a preliminary measurement of the slope parameter \(\alpha\) for the \(\eta\to 3\piz\) 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 have studied, with the KLOE detector at the DA\(\Phi\)NE \(\Phi\)-Factory, the dynamics of the decay \(\eta\to\pi^+\pi^-\pi^0\) using data from the radiative \(\phi\to\eta\gamma\) decay for an ...integrated luminosity \(L = 450 \textrm{pb^{-1}}\). From a fit to the Dalitz plot density distribution we obtain a precise measurement of the slope parameters. This should allow to improve the knowledge of the decay amplitude which is sensitive to the u-d quark mass difference. We also present new best results on the C-violating asymmetries in the \(\eta\to\pi^+\pi^-\pi^0\) decay.
Charged kaon lifetime at KLOE Ambrosino, F; Antonelli, A; Antonelli, M ...
arXiv.org,
07/2007
Paper, Journal Article
Open access
Preliminary result on the charged kaon lifetime, obtained by the KLOE experiment operating at DA\(\Phi\)NE, the Frascati \(\phi\)-factory, is presented
IEEETrans.Nucl.Sci.51:975-979,2004 The OPERA neutrino oscillation experiment foresees the construction of two
magnetized iron spectrometers located after the lead-nuclear emulsion targets.
The magnet ...is made up of two vertical walls of rectangular cross section
connected by return yokes. The particle trajectories are measured by high
precision drift tubes located before and after the arms of the magnet.
Moreover, the magnet steel is instrumented with Resistive Plate Chambers that
ease pattern recognition and allow a calorimetric measurement of the hadronic
showers. In this paper we review the construction of the spectrometers. In
particular, we describe the results obtained from the magnet and RPC prototypes
and the installation of the final apparatus at the Gran Sasso laboratories. We
discuss the mechanical and magnetic properties of the steel and the techniques
employed to calibrate the field in the bulk of the magnet. Moreover, results of
the tests and issues concerning the mass production of the Resistive Plate
Chambers are reported. Finally, the expected physics performance of the
detector is described; estimates rely on numerical simulations and the outcome
of the tests described above.
Here we present KLOE results on the phi meson decays in pi0 pi0 gamma, pi+ pi- gamma and eta pi0 gamma, the measurement of the ratio Br(phi to eta' gamma)/Br(phi to eta gamma) with the estimate of ...the eta' gluonium content and the measurement of the eta mass.
We report the measurement of the ratio \(\Gamma(\eta \to \pi^+\pi^-\gamma)/\Gamma(\eta \to \pi^+\pi^-\pi^0)\) analyzing a large sample of \(\phi \to \eta \gamma\) decays recorded with the KLOE ...experiment at the DA\(\Phi\)NE \(e^+ e^-\) collider, corresponding to an integrated luminosity of 558 pb\(^{-1}\). The \(\eta \to \pi^+\pi^-\gamma\) process is supposed to proceed both via a resonant contribution, mediated by the \(\rho\) meson, and a non resonant direct term, connected to the box anomaly. The presence of the direct term affects the partial width value. Our result \(R_{\eta}=\Gamma(\eta \to \pi^+ \pi^- \gamma)/\Gamma(\eta \to \pi^+ \pi^- \pi^0)= 0.1838\pm 0.0005_{stat} \pm 0.0030_{syst}\) is in agreement with a recent CLEO measurement, which differs by more 3 \(\sigma\) from the average of previous results.
Neutral kaons provide one of the systems most sensitive to quantum mechanics and
CPT violation. Models predicting quantum mechanics violation, also related to
CPT violation, have been tested at the ...CPLEAR and KLOE experiments. In this report results of CPLEAR obtained by studying the time evolution of single and two entangled kaons are reviewed. New or improved limits on decoherence and
CPT violation parameters have been obtained by KLOE studying the quantum interference in the channel
ϕ
→
K
S
K
L
→
π
+
π
−
π
+
π
−
. No deviations from the expectations of quantum mechanics and
CPT symmetry have been observed.
