Showing papers by "G. Chiefari published in 2002"
01 Aug 2002-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: The Drift Chamber for the KLOE experiment at the Frascati φ-factory, DAΦNE, is described in this article, together with a description of the track reconstruction program and of the calibration procedures.
Abstract: The design and construction of the large Drift Chamber for the KLOE experiment at the Frascati φ-factory, DAΦNE, are described. The relevant aspects of the various elements of the detector are reviewed together with a description of the track reconstruction program and of the calibration procedures. The performance of the detector based on measurements with cosmic rays and with e+e− colliding beams during DAΦNE commissioning is presented.
262 citations
TL;DR: The authors measured the branching ratio of φ mesons with the KLOE detector using a sample of ∼5×10 7 φ decays and fit the two-pion mass spectrum to models to disentangle contributions from various sources.
133 citations
TL;DR: In this paper, the branching ratio of the Frascati φ -factory was measured with the KLOE detector using a sample of ∼5×10 7 φ mesons.
104 citations
TL;DR: In this article, single top production in e^+e^- annihilations is searched for in data collected by the L3 detector at centre-of-mass energies from 189 to 209 GeV, corresponding to a total integrated luminosity of 634 pb-1.
79 citations
TL;DR: In this paper, the ηπ + π − final state in two-photon collisions was studied with the L3 detector at LEP, at centre-of-mass energies from 183 to 209 −GeV with an integrated luminosity of 664.6 −1.
61 citations
TL;DR: In this article, the radiative decays φ→ηγ, φ →η′γ selecting π+π−γγγ final state in a sample of ∼5×107 φ-mesons produced at the Frascati φfactory DAΦNE were measured.
51 citations
TL;DR: In this paper, a search for chargino, neutralino, scalar lepton and scalar quark pair-production in e+e− collisions is performed, without assuming R-parity conservation in decays, in the case that only one of the coupling constants is non-negligible.
45 citations
TL;DR: In this article, the authors studied the process e+e−−→W+W−γ using the data collected by the L3 detector at LEP and obtained an integrated luminosity of 427.4 pb−1 at center-of-mass energies from 192 to 207 GeV.
38 citations
TL;DR: In this article, the structure of high energy hadronic events recorded by the L3 detector at s ⩾192 ǫGeV was studied and the distributions of several event shape variables were compared to resummed O(α s 2 ) QCD calculations.
32 citations
TL;DR: Bose-Einstein correlations in W-pair production at LEP were investigated in a data sample of 629 pb−1 collected by the L3 detector at s =189 −209 −GeV as mentioned in this paper.
24 citations
TL;DR: In this paper, double-tag events in two-photon collisions are studied using the L3 detector at LEP centre-of-mass energies from root(s)=189 GeV to 209 GeV.
TL;DR: In this paper, a Higgs particle produced in association with a Z boson and decaying into two photons is searched for in the data collected by the L3 experiment at LEP, but no signal is observed in 447.5 pb^-1 of data recorded at centre-of-mass energies up to 209 GeV.
TL;DR: In this paper, the KLOE detector at the DA Φ NE e + e − collider was used to measure the ratio R S π = 2.236±0.003 stat ± 0.015 syst.
TL;DR: Bose-Einstein correlations of both neutral and like-sign charged pion pairs are measured in a sample of 2 million hadronic Z decays collected with the L3 detector at LEP as discussed by the authors.
TL;DR: In this article, the cross section of the process e + e − → Z γ γ → q q ¯ γ − γ is measured with 215 pb−1 of data collected with the L3 detector during the final LEP run at centre-of-mass energies around 205 GeV and 207 GeV.
TL;DR: In this paper, a measurement of the branching ratio BR (K S →π ± e ∓ ν (ν)) performed using the KLOE detector is presented. But this measurement is limited to a sample of ∼5×10 6 K S -tagged events.
TL;DR: In this article, single W boson production in electron-positron collisions was studied with the L3 detector at centre-of-mass energies between 192 and 209 GeV.
TL;DR: In this paper, three-particle Bose-Einstein correlations in hadronic Z decay with the L3 detector at LEP were measured and compared by comparing two-and threeparticle correlations, and they found that the data are consistent with fully incoherent pion production.
TL;DR: In this paper, the L3 detector at LEP has been used to study the rare baryon pair production in two-photon collisions with an integrated luminosity of 844 pb-1.
TL;DR: In this paper, a search for the lightest CP-even and neutral CP-odd Higgs bosons of the minimal supersymmetric standard model is performed using 216.6 poly(n)pb−1 of data collected with the L3 detector at LEP at center-of-mass energies between 203 and 209.
TL;DR: In this paper, the authors studied the process e+ e- -> n gamma with n = 2 at centre-of-mass energies ranging from −1 to 208 GeV, and the total and differential cross sections were found to be in agreement with the QED expectations.
TL;DR: In this article, the authors measured differential cross sections as a function of the particle transverse momentum and pseudo-rapidity and compared the results to Monte Carlo predictions and to NLO QCD calculations.
TL;DR: In this paper, the L3 detector at LEP was used to study D^{*+-} production in two-photon collisions, using 683 pb^{-1} of data collected at centre-of-mass energies from 183 to 208 GeV.
01 Feb 2002-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this article, the main goal of the KLOE experiment at the Frascati DAΦNE φ − factory is the study CP violation in kaon decays, and the tracking device of the experiment is a drift chamber whose dimensions, 4m of diameter and 3.3m length, provide a large acceptance volume for the decay products of low momentum K L ( λ L = 3.4 m ).
Abstract: The main goal of the KLOE experiment at the Frascati DAΦNE φ − factory is the study CP violation in kaon decays. The tracking device of the experiment is a drift chamber whose dimensions, 4 m of diameter and 3.3 m length, provide a large acceptance volume for the decay products of low momentum K L ( λ L =3.4 m ). A complete stereo geometry with 12.582 cells arranged in 58 layers guarantees a high and uniform efficiency in the reconstruction of the charged K L decays. Very light materials have been chosen both for the drift medium, a helium-based gas mixture, and for the mechanical structure, made of carbon fiber, to minimize multiple scattering and conversion of low-energy photons. The design requirements, the adopted solutions together with the calibration procedure and the tracking performances of the drift chamber are discussed.
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TL;DR: In this paper, the invariant mass spectrum of the two pion system was analyzed using the radiative return method in the fixed energy environment of the hadronic system and the results showed that at energies below 1 GeV, the dominant hadronic process is the dominating process.
Abstract: In the fixed energy environment of the $e^{+}e^{-}$ collider DA$\Phi$NE, KLOE can measure the cross section of the process $e^{+}e^{-} \to hadrons$ as a function of the hadronic system energy using the radiative return method. At energies below 1 GeV, $e^{+}e^{-} \to \rho \to \pi^{+}\pi^{-}$ is the dominating hadronic process. We report here on the status of the analysis of the process $e^{+}e^{-} \to \pi^{+}\pi^{-}\gamma$. Some preliminary results on the invariant mass spectrum of the two pion system, obtained from the analysis of 22.6 pb$^{-1}$, are presented.
TL;DR: The KLOE detector as mentioned in this paper was designed and built with the primary goal of measuring Re(?' /?), the CP violation parameter in the kaon system, with a sensitivity of about one part in ten thousands.
Abstract: The KLOE detector is operational since spring '99 at DA?NE, the Frascati e+e- collider, a -factory running at 1.02 GeV c.m. energy. This detector has been designed and built with the primary goal of measuring Re(?' / ?), the CP violation parameter in the kaon system, with a sensitivity of about one part in ten thousands. Apart from CP studies in the kaon system, KLOE has a rich scientific program that can be exploited with an integrated luminosity not far from the one which has already been collected, namely the study of decays into scalar and pseudoscalar mesons, the measurement of the hadronic cross-section up to 1 GeV, rare kaon decays, decays into three pions. Since the detector installation there have been three periods of stable data taking and a total amount of ~200 pb-1 has been collected by end of 2001, corresponding to ~6.7 ? 108 mesons and to ~8.7 ? 106 ? mesons, being BR( ? ??) = (1.297?0.033) ? 10-2. We present the results obtained, for a data sample of 17 pb-1 collected in the year 2000, for ? ?? and ? ?'?: the ratio of these two BR's has been measured to be (5.3 ? 0.5 ? 0.4) ? 10-3, leading to a very accurate determination of the mixing angle in the flavor basis P = (40+7.5-1.5)? and to the most accurate determination of BR( ? ?'?) to date; (6.8 ? 0.6 ? 0.5) ? 10-5. From the ratio BR( ? ?'?)/BR( ? ?0?) we have extracted the value BR( ? ?0?) = (1.377 ? 0.007 ? 0.05) ? 10-3.
01 Jan 2002