Publications (16)54.75 Total impact
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ABSTRACT: 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.07/2011;  [Show abstract] [Hide abstract]
ABSTRACT: 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.07/2011;  [Show abstract] [Hide abstract]
ABSTRACT: We report the first observation of the rare eta>e+ee+e decay based on 1.7 fb^{1} collected by the KLOE experiment at the DAFNE phifactory. The selection of the e+ee+e final state is fully inclusive of radiation. We have identified 362 + 29 events resulting in a branching ratio of (2.4 + 0.2_stat+bckg + 0.1_syst) x 10^{5}.05/2011;  [Show abstract] [Hide abstract]
ABSTRACT: Using a large sample of pure, slow, short lived K 0 mesons collected with KLOE detector at DAΦNE, we have measured the K S lifetime. From a fit to the proper time distribution we find τ(K S )=(89.562±0.029stat±0.043syst)ps. This is the most precise measurement to date of the short lived K 0 meson lifetime, in good agreement with the world average derived from previous measurements. We observe no dependence of the lifetime on the direction of the K S in galactic coordinates.European Physical Journal C 01/2010; 71(3):16. · 5.25 Impact Factor  European Physical Journal C 01/2010; 65(3):703703. · 5.25 Impact Factor
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ABSTRACT: We present a precise measurement of the ratio R K =Γ(K→e ν(γ))/Γ(K→μ ν(γ)) and a study of the radiative process K→e ν γ, performed with the KLOE detector. The results are based on data collected at the Frascati e + e − collider DAΦNE for an integrated luminosity of 2.2fb−1. We find R K =(2.493±0.025stat±0.019syst)×10−5, in agreement with the Standard Model expectation. This result is used to improve constraints on parameters of the Minimal Supersymmetric Standard Model with lepton flavor violation. We also measured the differential decay rate dΓ(K→e ν γ)/dE γ for photon energies 10<E γ < 250MeV. Results are compared with predictions from theory. PACS13.20.EbEuropean Physical Journal C 01/2009; 64(4):627636. · 5.25 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We have studied, with the KLOE detector at the DAΦNE ΦFactory, the dynamics of the decay η → π+π−π0 using η mesons from the decay → ηγ for an integrated luminosity = 450 pb−1. From a fit to the Dalitz plot density distribution we obtain a precise measurement of the slope parameters. An alternative parametrization relates the π+π−π0 slopes to that for η → 3π0 showing the consistency of KLOE results for both channels. We also obtain the best confirmation of the Cinvariance in the η → π+π−π0 decay.Journal of High Energy Physics 05/2008; 2008(05):006. · 5.62 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: KLOE has measured most decay branching ratios of KS, KL and K±mesons. It has also measured the KL and the K± lifetime and determined the shape of the form factors involved in kaon semileptonic decays. We present in the following a description of the above measurements and a well organized compendium of all of our data, with particular attention to correlations. These data provide the basis for the determination of the CKM parameter Vus and a test of the unitarity of the quark flavor mixing matrix. We also test lepton universality and place bounds on new physics using measurements of Vus from Kℓ2 and Kℓ3 decays.Journal of High Energy Physics 04/2008; 2008(04):059. · 5.62 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We present a measurement of the ratio R=Γ(K0 e3γ;E* γ > 30MeV, θ* γ>20°)/Γ(K0 e3) and a first measurement of the direct emission contribution in semileptonic KL decays. The measurement was performed at the DA NE φ factory by selecting φ→KLKS decays with the KLOE detector. We use 328pb1 of data, corresponding to about 3.5 million K0 e3 events and about 9000 K0 e3γ radiative events. Our result is R=(924±23stat±16syst)×105 for the branching ratio and 〈X〉=2.3±1.3stat±1.4syst for the effective strength parameter describing direct emission.European Physical Journal C 01/2008; 55(4):539546. · 5.25 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We present precise measurements of the η and K0 masses using the processes →ηγ, η→γγ and → KS K L, KS→π+π−. The K0 mass measurement, MK = 497.583±0.005stat±0.020syst MeV, is in acceptable agreement with the previous measurements but is more accurate. We find mη = 547.874±0.007stat±0.029syst MeV. Our value is the most accurate to date and is in agreement with two recent measurements based on η decays, but is inconsistent, by about 10σ, with a measurement of comparable precision based on η production at threshold.Journal of High Energy Physics 12/2007; 2007(12):073. · 5.62 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: This paper is devoted to the measurement of the fully inclusive absolute branching ratios of the charged kaon semileptonic decays, $K^{\pm}\to\pi^0e^\pm\nu(\gamma)$ and $K^\pm \to \pi^0\mu^\pm\nu(\gamma)$. The measurements have been done using a tag technique, employing the twobody decays, $K^\pm \to \mu^\pm\nu$ and $K^\pm \to \pi^\pm\pi^0$, and using a sample of about 410 pb$^{1}$ collected during the 2001 and 2002 data taking of the KLOE experiment at Daphne, the Frascati $\phi$factory. The results obtained are BR(K$^\pm_{e3}$) = $0.04965 (38)_{Stat} (37)_{Syst}$ and BR(K$^\pm_{\mu3}$) = $0.03233 (29)_{Stat} (26)_{Syst}$.07/2007;  [Show abstract] [Hide abstract]
ABSTRACT: We have studied the Dalitz plot of the e+e→π0π0γ events (Nπ0π0γ∼65000) collected at Ös @ Mf\sqrt{s} \simeq{M}_{\phi} with the KLOE detector. In the dipion invariant mass (Mππ) region below 700MeV, the process under study is dominated by the nonresonant process e+e→ωπ0 with ω→π0γ whereas, for higher Mππ values, the radiative φ decay to the f0(980) is the dominant mechanism. Different theoretical models are used to fit the Dalitz plot, taking also into account a possible contribution of the σ(600). For each model, we extract the f0(980) mass and its coupling to ππ, KK̄ and to the φ.European Physical Journal C 10/2006; 49(2):473488. · 5.25 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: Using a sample of over 400 million φ→KSKL decays produced during the years 2001 and 2002 at the DAΦNE e+e collider, the ratio RS π=Γ(KS→π+π(γ))/Γ(KS→π0π0) has been measured with the KLOE detector. The result is RS π=2.2555±0.0012stat±0.0021corrstat±0.0050syst, which is in good agreement with the previously published result based on the KLOE data sample from the year 2000. The average of the KLOE results is RS π=2.2549±0.0054, reducing the total error by a factor of three, to 0.25%.European Physical Journal C 02/2006; 48(3):767780. · 5.25 Impact Factor 
Article: Measurement of the DAΦNE luminosity with the KLOE detector using large angle Bhabha scattering
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ABSTRACT: We describe the method of measuring the integrated luminosity of the e+e collider DAΦNE, the Frascati φfactory. The measurement is done with the KLOE detector selecting large angle Bhabha scattering events and normalizing them to the effective cross section. The e+e→e+e(γ) cross section is calculated using different event generators which account for the O(a)\mathcal{O}(\alpha) radiative initial and final state corrections, and the φ resonance contribution. The accuracy of the measurement is 0.6%, where 0.3% comes from systematic errors related to the event counting and 0.5% from theoretical evaluations of the cross section.European Physical Journal C 01/2006; 47(3):589596. · 5.25 Impact Factor  http://dx.doi.org/10.1140/epjc/s1005200912176.
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ABSTRACT: The neutral kaon system offers a unique possibility to perform fundamental tests of CPT invariance, as well as of the basic principles of quantum mechanics. The most recent limits obtained by the KLOE experiment at the DAΦNE e + e − collider on several kinds of possible CPT violation and decoherence mechanisms, which in some cases might be justified in a quantum gravity framework, are reviewed. No deviation from the expectations of quantum mechanics and CPT symmetry is observed, while the precision of the measurements, in some cases, reaches the interesting Planck scale region. Finally, prospects for this kind of experimental studies at KLOE2 are presented. Keywords CPT symmetryDecoherenceNeutral kaonsFoundations of Physics 40(7):852866. · 1.17 Impact Factor
Publication Stats
39  Citations  
54.75  Total Impact Points  
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Institutions

2006

Sapienza University of Rome
 Department of Physics
Roma, Latium, Italy
