Publications (14)46.86 Total impact
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Article: Erratum to: Precise measurement of Γ(K→eν(γ))/Γ(K→μν(γ)) and study of K→eνγ
European Physical Journal C 05/2012; 65(3):703-703. · 3.63 Impact Factor -
Article: A study of the radiative KL→π±e∓νγ decay and search for direct photon emission with the KLOE detector
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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 328pb-1 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)×10-5 for the branching ratio and 〈X〉=-2.3±1.3stat±1.4syst for the effective strength parameter describing direct emission.European Physical Journal C 04/2012; 55(4):539-546. · 3.63 Impact Factor -
Article: Precise measurement of Γ(KS→π+π-(γ))/Γ(KS→π0π0) with the KLOE detector at DAΦNE
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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±0.0021corr-stat±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 04/2012; 48(3):767-780. · 3.63 Impact Factor -
Article: Precision measurement of the KS meson lifetime with the KLOE detector
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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 04/2012; 71(3):1-6. · 3.63 Impact Factor -
Article: Precise measurement of Γ(K→eν(γ))/Γ(K→μν(γ)) and study of K→eνγ
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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 04/2012; 64(4):627-636. · 3.63 Impact Factor -
Article: Dalitz plot analysis of e+e-→π0π0γ events at with the KLOE detector
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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 non-resonant 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 04/2012; 49(2):473-488. · 3.63 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 φ-factory. 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 04/2012; 47(3):589-596. · 3.63 Impact Factor -
Article: Measurement of $\Gamma(\eta \to \pi^+\pi^-\gamma)/\Gamma(\eta \to \pi^+\pi^-\pi^0)$ with KLOE experiment
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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; -
Article: Precise measurement of B(K\to e\nu(\gamma))/B(K\to \mu\nu(\gamma)) and study of K\to e\nu\gamma
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ABSTRACT: We present a precise measurement of the ratio R_K=B(K\to e\nu(\gamma))/B(K\to \mu\nu(\gamma)) and a study of the radiative process $K\to e\nu\gamma$, performed with the KLOE detector. The results are based on data collected at the Frascati $e^+e^-$ collider DAFNE for an integrated luminosity of 2.2 fb$^{-1}$. We find R_K = (2.493\pm0.025\pm0.019)x10^{-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 $d\Gamma(K\to e\nu\gamma)/dE_\gamma$ for photon energies $10<E_\gamma<250$ MeV. Results are compared with predictions from theory.07/2009; -
Article: Search for the K_S -> e+e- decay with the KLOE detector
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ABSTRACT: We present the result of a direct search for the decay K_S -> e+e-, obtained with a sample of e+e- -> phi -> K_S K_L events produced at DAFNE, the Frascati phi-factory, for an integrated luminosity of 1.9 fb^-1. The search has been performed using a pure K_S beam tagged by the simultaneous detection of a K_L interaction in the calorimeter. Background rejection has been optimized by using both kinematic and particle identification cuts. We find BR(K_S -> e+e-) < 9x10^-9 at 90% CL, which improves by an order of magnitude on the previous best limit. Comment: 13 pages, 11 figures, submitted to Physics Letters BPhysics Letters B 11/2008; · 3.95 Impact Factor -
Article: Determination of η → π+π−π0 Dalitz plot slopes and asymmetries with the KLOE detector
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ABSTRACT: We have studied, with the KLOE detector at the DAΦNE Φ-Factory, 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 C-invariance in the η → π+π−π0 decay.Journal of High Energy Physics 05/2008; 2008(05):006. · 5.83 Impact Factor -
Article: |Vus| and lepton universality from kaon decays with the KLOE detector
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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. · 5.83 Impact Factor -
Article: Precise measurements of the η meson and the neutral kaon masses with the KLOE detector
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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. · 5.83 Impact Factor -
Article: Erratum to: Precise measurement of Γ(
http://dx.doi.org/10.1140/epjc/s10052-009-1217-6.
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Institutions
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2012
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Sapienza University of Rome
- Department of Physics
Roma, Latium, Italy
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