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
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.
We present a measurement of the slope parameter \(\alpha\) for the \(\eta\to 3\pi^{0}\) 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.
Investigation at a \(\phi\)--factory can shed light on several debated issues in particle physics. We discuss: i) recent theoretical development and experimental progress in kaon physics relevant for ...the Standard Model tests in the flavor sector, ii) the sensitivity we can reach in probing CPT and Quantum Mechanics from time evolution of entangled kaon states, iii) the interest for improving on the present measurements of non-leptonic and radiative decays of kaons and eta/eta\(^\prime\) mesons, iv) the contribution to understand the nature of light scalar mesons, and v) the opportunity to search for narrow di-lepton resonances suggested by recent models proposing a hidden dark-matter sector. We also report on the \(e^+ e^-\) physics in the continuum with the measurements of (multi)hadronic cross sections and the study of gamma gamma processes.
KLOE uses the radiative return to measure cross section
σ
(
e
+
e
−
→
π
+
π
−
γ
)
at the electron-positron collider DAΦNE. Divinding by a theoretical radiator function, we obtain the cross section
σ
...(
e
+
e
−
→
π
+
π
−
γ
)
for the mass range
0.35
<
s
π
<
0.95
GeV
2
. We calculate the hadronic contribution to the muon anomaly for the given mass range:
a
μ
=
388.7
±
0.8
s
t
a
t
±
3.5
s
y
s
t
±
3.5
t
h
.
We propose a new approach to the problem of the missing baryons. Building on the common assumption that the missing baryons are in the form of the warm hot intergalactic medium (WHIM), we also assume ...here that the galaxy luminosity density can be used as a tracer of the WHIM. This last assumption is supported by our discovery of a significant correlation between the WHIM density and the galaxy luminosity density in recent hydrodynamical simulations. We also found that the percentage of the gas mass in the WHIM phase is substantially higher (by a factor of ~1.6) within large-scale galactic filaments, i.e. ~70%, compared to the average in the full simulation volume of ~0.1 Gpc3. The relation between the WHIM overdensity and the galaxy luminosity overdensity within the galactic filaments is consistent with a linear one: δwhim = 0.7 ± 0.1 × δLD0.9±0.2. We then applied our procedure to the line of sight towards the blazar H2356-309 and found evidence of WHIM that corresponds to the Sculptor Wall (SW) (z ~ 0.03 and log NH = 19.9+ 0.1-0.3) and Pisces-Cetus (PC) superclusters (z ~ 0.06 and log NH = 19.7+ 0.2-0.3), in agreement with the redshifts and column densities of the X-ray absorbers identified recently. This agreement indicates that the galaxy luminosity density and galactic filaments are reliable signposts for the WHIM and that our method is robust for estimating WHIM density. The signal that we detected cannot originate in the halos of nearby galaxies because they cannot account for the high WHIM column densities that our method and X-ray analysis consistently find in the SW and PC superclusters.
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