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Search for the decay phi -> K0-K0bar-gamma with the KLOE experiment

2009-06-30T22:00:00Z

Search for the decay phi -> K0-K0bar-gamma with the KLOE experiment Ambrosino, F.; Antonelli, A.; Antonelli, M.; Archilli, F.; Beltrame, P.; Bencivenni, G.; Bertolucci, S.; Bini, C.; Bloise, C.; Bocchetta, Serena; Bossi, F.; Branchini, P.; Capon, G.; Capussela, T.; Ceradini, Filippo; Ciambrone, P.; De Lucia, E.; De Santis, A.; De Simone, P.; De Zorzi, G.; Denig, A.; Di Domenico, A.; Di Donato, C.; Di Micco, Biagio; Dreucci, M.; Felici, G.; Fiore, S.; Franzini, P.; Gatti, C.; Gauzzi, P.; Giovannella, S.; Graziani, E.; Lanfranchi, G.; Lee-Franzini, J.; Martini, M.; Massarotti, P.; Meola, S.; Miscetti, S.; Moulson, M.; Mueller, S.; Murtas, F.; Napolitano, M.; Nguyen, Federico; Palutan, M.; Pasqualucci, E.; Passeri, A.; Patera, V.; Santangelo, P.; Sciascia, B.; Spadaro, T.; Testa, M.; Tortora, L.; Valente, P.; Venanzoni, G.; Versaci, R.; Xu, G. 2009-07 Physics Letters B 679 10-14 We have searched for the decay phi -> K0-K0bar-gamma by detecting KS pairs plus a photon and with the KS-mesons decaying to pi+ pi-, in a sample of about 1.5 x 10^9 phi-decays collected by the KLOE experiment at DAFNE. The reaction proceeds through the intermediate states f0(980)-gamma, a0(980)-gamma. We find five events with 3.2 events expected from background processes. We obtain the upperlimit: BR(phi -> K0-Kobar-gamma < 1.9 x 10^(-8) at 90% CL.

Precise measurement of Gamma(K -> e nu(gamma))/Gamma(K -> mu nu(gamma))and study of K -> e nu gamma

2009-11-30T23:00:00Z

Precise measurement of Gamma(K -> e nu(gamma))/Gamma(K -> mu nu(gamma))and study of K -> e nu gamma Ambrosino, F.; Antonelli, A.; Antonelli, M.; Archilli, F.; Beltrame, P.; Bencivenni, G.; Bini, C.; Bloise, C.; Bocchetta, Serena; Bossi, F.; Branchini, P.; Capon, G.; Capriotti, D.; Capussela, T.; Ceradini, Filippo; Ciambrone, P.; De Lucia, E.; De Santis, A.; De Simone, P.; De Zorzi, G.; Denig, A.; Di Domenico, A.; Di Donato, C.; Di Micco, Biagio; Dreucci, M.; Felici, G.; Fiore, S.; Franzini, P.; Gatti, C.; Gauzzi, P.; Giovannella, S.; Graziani, E.; Jacewicz, M.; Kulikov, V.; Lanfranchi, G.; Lee-Franzini, J.; Martini, M.; Massarotti, P.; Meola, S.; Miscetti, S.; Moulson, M.; Mueller, S.; Murtas, F.; Napolitano, M.; Nguyen, Federico; Palutan, M.; Passeri, A.; Patera, V.; Santangelo, P.; Sciascia, B.; Sibidanov, A.; Spadaro, T.; Tortora, L.; Valente, P.; Venanzoni, G.; Versaci, R. 2009-12 European Physical Journal C 64 627-636 We present a precise measurement of the ratio R-K = Gamma(K -> enu(gamma))/Gamma(K -> mu nu(gamma)) and a study of the radiativeprocess K -> e nu gamma, performed with the KLOE detector. The resultsare based on data collected at the Frascati e(+)e(-) collider DA Phi NEfor an integrated luminosity of 2.2 fb(-1). We find R-K = (2.493 +/-0.025(stat) +/- 0.019(syst)) x 10(-5), in agreement with the StandardModel expectation. This result is used to improve constraints onparameters of the Minimal Supersymmetric Standard Model with leptonflavor violation. We also measured the differential decay rate dGamma(K -> e nu gamma)/dE(gamma) for photon energies 10 < E-gamma < 250MeV. Results are compared with predictions from theory.

Search for the K-S -> e(+)e(-) decay with the KLOE detector

2008-12-31T23:00:00Z

Search for the K-S -> e(+)e(-) decay with the KLOE detector Ambrosino, F.; Antonelli, A.; Antonelli, M.; Archilli, F.; Beltrame, R.; Bencivenni, G.; Bertolucci, S.; Bini, C.; Bloise, C.; Bocchetta, Simona Serena; Bossi, F.; Branchini, P.; Campana, P.; Capon, G.; Capriotti, D.; Capussela, T.; Ceradini, Filippo; Ciambrone, P.; Crucianelli, F.; De Lucia, E.; De Santis, A.; De Simone, P.; De Zorzi, G.; Denig, A.; Di Domenico, A.; Di Donato, C.; Di Micco, Biagio; Dreucci, M.; Felici, G.; Ferrer, M. L.; Fiore, S.; Franzini, P.; Gatti, C.; Gauzzi, P.; Giovannella, S.; Graziani, E.; Kluge, W.; Kulikov, V.; Lanfranchi, G.; Lee-Franzini, J.; Leone, D.; Martini, M.; Massarotti, P.; Meola, S.; Miscetti, S.; Moulson, M.; Mueller, S.; Murtas, F.; Napolitano, M.; Nguyen, Federico; Palutan, M.; Pasqualucci, E.; Passeri, A.; Patera, V.; Perfetto, F.; Santangelo, P.; Sciascia, B.; Sciubba, A.; Sibidanov, A.; Spadaro, T.; Testa, M.; Tortora, L.; Valente, P.; Venanzoni, G.; Versaci, R. 2009 Physics Letters B 672 203-208 We present the result of a direct search for the decay K-S -> e(+)e(-),obtained with a sample of e(+)e(-) -> phi -> KSKL events produced at DAphi NE, the Frascati phi-factory, for an integrated luminosity of 1.9fb(-1). The search has been performed using a pure K-S beam tagged bythe simultaneous detection of a K-L interaction in the calorimeter.Background rejection has been optimized by using both kinematic andparticle identification cuts. We find BR(KS -> e(+)e(-)) < 9 x 10(-9)at 90% CL, which improves by an order of magnitude on the previous bestlimit, (C) 2009 Elsevier B.V, All rights reserved.

Study of the a0(980) meson via the radiative decay phi -> eta pi0 gamma with the KLOE detector

2009-08-31T22:00:00Z

Study of the a0(980) meson via the radiative decay phi -> eta pi0 gamma with the KLOE detector Ambrosino, Fabio; Bacci, Cesare; Bocchetta, Simona Serena; Ceradini, Filippo; Di Micco, Biagio; Nguyen, Federico 2009-09 Physics Letters B 681 5-13 We have studied the phi-> a0(980) gamma process with the KLOE detector at the Frascati phi-factory DAFNE by detecting the phi -> eta pi0 gamma decays in the final states with η -> gamma gamma and eta -> pi+ pi- pi0. We have measured the branching ratios for both final states: Br(phi -> eta pi0 gamma) = (7.01 ± 0.10 ± 0.20)×10−5 and (7.12 ± 0.13 ± 0.22)×10−5, respectively. We have also extracted the a0(980) mass and its couplings to eta-pi0, K+K−, and to the φ-meson from the fit of the eta-pi0 invariant mass distributions using different phenomenological models.

Scalar mesons with the KLOE experiment

2008-12-31T23:00:00Z

Scalar mesons with the KLOE experiment Ambrosino, Fabio; Bacci, Cesare; Bocchetta, Simona Serena; Ceradini, Filippo; Di Micco, Biagio; Nguyen, Federico 2009-01 Nuclear Physics B Proceedings Supplements 186 290-293 New results concerning the scalar mesons f0(980) produced in the φ → ππγ decays, and the a0(980) scalar mesons in the φ → a0(980)γ → ηπ0γ decays, are presented.

Construction and performances of a high granularity calorimeter

2009-03-31T22:00:00Z

Construction and performances of a high granularity calorimeter Branchin, Paolo; Ceradini, Filippo; Corradi, Giovanni; Di Micco, Biagio; Loffredo, Salvatore; Passeri, Antonio 2009-04 IEEE Transactions on Nuclear Science 56 394-397 We describe the realization and performance of a prototype high granularity calorimeter built with lead and scintillating fibers. We describe the calorimeter construction and show cosmic ray and electron test beam results obtained with a custom-designed trigger.

Construction and tests of a fine granularity lead-scintillating fibers calorimeter

2008-12-31T23:00:00Z

Construction and tests of a fine granularity lead-scintillating fibers calorimeter Branchini, Paolo; Ceradini, Filippo; Corradi, Giovanni; Di Micco, Biagio; Passeri, Antonio 2009-01 Journal of Physics: Conference Series 160 1-8 We report the construction and the tests of a small prototype of the lead-scintillating fiber calorimeter of the KLOE experiment, instrumented with multianode photomultipliers to obtain a 16 times finer readout granularity. The prototype is 15 cm wide, 15 radiation lengths deep and is made of 200 layers of fibers 50 cm long. On one side it is read out with an array of 3×5 multianode photomultipliers Hamamatsu type R8900-M16, each segmented with 4×4 anodes, the read out granularity being 240 pixels of 11×11 mm2 corresponding to about 64 scintillating fibers each. These are interfaced to the 6×6 mm2 pixeled photocathode with truncated pyramid light guides made of Bicron BC-800 plastic to partially transmit the UV light. Each photomultiplier provides also an OR of the 16 last dynodes that is used for trigger. The response of the individual anodes, their relative gain and cross-talk has been measured with the light (440 nm) of a laser illuminating only few fibers on the side opposite to the readout. We finally present the first results of the calorimeter response to cosmic rays in autotrigger mode.

Calibration and performances of the KLOE calorimeter

2008-12-31T23:00:00Z

Calibration and performances of the KLOE calorimeter Ambrosino, F.; Antonelli, A.; Antonelli, M.; Archilli, F.; Bacci, Cesare; Beltrame, P.; Bencivenni, G.; Bertolucci, S.; Bini, C.; Bloise, C.; Bocchetta, Simona Serena; Bossi, F.; Branchini, Paolo; Campana, P.; Capon, G.; Capussela, T.; Ceradini, Filippo; Chi, S.; Chiefari, G.; Ciambrone, P.; Crucianelli, F.; De Lucia, E.; De Santis, A.; De Simone, P.; De Zorzi, G.; Denig, A.; Di Domenico, A.; Di Donato, C.; Di Micco, Biagio; Doria, A.; Dreucci, M.; Felici, G.; Ferrari, A.; Ferrer, M. L.; Fiore, S.; Forti, C.; Franzini, P.; Gatti, C.; Gauzzi, P.; Giovannella, S.; Gorini, E.; Graziani, E.; Kluge, W.; Kulikov, V.; Lacava, F.; Lanfranchi, G.; Lee-Franzini, J.; Leone, D.; Martini, M.; Massarotti, P.; Mei, W.; Meola, S.; Miscetti, S.; Moulson, M.; Mueller, S.; Murtas, F.; Napolitano, M.; Nguyen, Federico; Palutan, M.; Pasqualucci, E.; Passeri, Antonio; Patera, V.; Perfetto, F.; Primavera, M.; Santangelo, P.; Saracino, G.; Sciascia, B.; Sciubba, A.; Sibidanov, A.; Spadaro, T.; Testa, M.; Tortora, Ludovico; Valente, P.; Venanzoni, G.; Versaci, R.; Xu, G. 2009-01-01 Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment 598 239-243 The KLOE experiment uses a fine sampling lead-scintillating fibrecalorimeter to measure energy, time and position of neutral and charged particles. The overall detector consists of 88 modules organised in a barrel and two end-caps, for a total granularity of 2440 cells, read-out by photo-multipliers at both fibre ends. The chosen design of a high sampling fraction with the usage of thin lead layers and fast scintillating fibres allows to reach good efficiency for photonenergies down to few MeV, good energy resolution and excellent time resolution. The design, calibration and performances of the calorimeter on efficiency, time/position/energy resolution and particle identification is reviewed. The overall calorimeter impact on kaon tagging and on physics results is also presented.

Measurement of the branching ratio and search for a CP violating asymmetry in the η→π+π−e+e− (γ ) decay at KLOE

2009-05-17T22:00:00Z

Measurement of the branching ratio and search for a CP violating asymmetry in the η→π+π−e+e− (γ ) decay at KLOE Ambrosino, F.; Antonelli, A.; Antonelli, M.; Archilli, F.; Beltrame, P.; Bencivenni, G.; Bertolucci, S.; Bini, C.; Bloise, C.; Bocchetta, Simona; Bossi, F.; Branchini, Paolo; Capon, G.; Capussela, T.; Ceradini, Filippo; Ciambrone, P.; Crucianelli, F.; De Lucia, E.; De Santis, A.; De Simone, P.; De Zorzi, G.; Denig, A.; Di Domenico, A.; Di Donato, C.; Di Micco, Biagio; Dreucci, M.; Felici, G.; Fiore, S.; Franzini, P.; Gatti, C.; Gauzzi, P.; Giovannella, S.; Graziani, Enrico; Lanfranchi, G.; Lee-Franzini, J.; Leone, D.; Martini, M.; Massarotti, P.; Meola, S.; Miscetti, S.; Moulson, M.; Mueller, S.; Murtas, F.; Napolitano, M.; Nguyen, Federico; Palutan, M.; Pasqualucci, E.; Passeri, Antonio; Patera, V.; Perfetto, F.; Santangelo, P.; Sciascia, B.; Spadaro, T.; Testa, M.; Tortora, Ludovico; Valente, P.; Venanzoni, G.; Versaci, R.; Xu, G. 2009-05-18 Physics Letters B 675 283-288 We have studied the η→π+π−e+e− (γ ) decay using about 1.7 fb−1 collected by the KLOE experiment at the DA NE φ-factory. This corresponds to about 72 millions η mesons produced in φ radiative decays. We have measured the branching ratio, inclusive of radiative effects, with 4% accuracy: BR(η→ π+π−e+e− (γ )) = (26.8 ± 0.9Stat. ± 0.7Syst.) × 10−5. We have obtained the first measurement of the CPodd ππ–ee decay planes angular asymmetry, Aφ = (−0.6±2.5Stat. ±1.8Syst.)×10−2.

A global fit to determine the pseudoscalar mixing angle and the gluonium content of the eta ' meson

2009-07-30T22:00:00Z

A global fit to determine the pseudoscalar mixing angle and the gluonium content of the eta ' meson Ambrosino, F.; Antonelli, A.; Antonelli, M.; Archilli, F.; Beltrame, P.; Bencivenni, G.; Bertolucci, S.; Bini, C.; Bloise, C.; Bocchetta, Simona; Bossi, F.; Branchini, Paolo; Capon, G.; Capussela, T.; Ceradini, Filippo; Ciambrone, P.; De Lucia, E.; De Santis, A.; De Simone, P.; De Zorzi, G.; Denig, A.; Di Domenico, A.; Di Donato, C.; Di Micco, Biagio; Dreucci, M.; Felici, G.; Fiore, S.; Franzini, P.; Gatti, C.; Gauzzi, P.; Giovannella, S.; Graziani, Enrico; Jacewicz, M.; Lanfranchi, G.; Lee-Franzini, J.; Martini, M.; Massarotti, P.; Meola, S.; Miscetti, S.; Moulson, M.; Mueller, S.; Murtas, F.; Napolitano, M.; Nguyen, Federico; Palutan, M.; Pasqualucci, E.; Passeri, Antonio; Patera, V.; Santangelo, P.; Sciascia, B.; Spadaro, T.; Testa, M.; Tortora, Ludovico; Valente, P.; Venanzoni, G.; Versaci, R.; Xu, G. 2009-07-31 Journal of High Energy Physics 7 105 We update the values of the eta-eta' mixing angle and of the eta' gluonium content by fitting our measurement R-phi = BR(phi -> etagamma)/BR(phi -> eta gamma) together with several vector meson radiative decays to pseudoscalars (V -> P gamma), pseudoscalar mesons radiative decays to vectors (P -> V gamma) and the eta' -> gamma gamma,pi(0) -> gamma gamma widths. From the fit we extract a gluonium fraction of Z(G)(2) = 0.12 +/- 0.04, the pseudoscalar mixing angle psi(P) = (40.4 +/- 0.6) degrees and the phi - omega mixing angle psi(V)= (3.32 +/- 0.09)degrees. Z(G)(2) and psi(P) are fairly consistent with those previously published. We also evaluate the impact on the eta' gluonium content determination of future experimental improvements of the eta' branching ratios and decay width.

Measurement of sigma(e+ e- -> pi+ pi- gamma) and the di-pion contribution to the muon anomaly with the KLOE detector

2008-12-31T23:00:00Z

Measurement of sigma(e+ e- -> pi+ pi- gamma) and the di-pion contribution to the muon anomaly with the KLOE detector Ambrosino, F.; Antonelli, A.; Antonelli, M.; Archilli, F.; Bacci, Cesare; Beltrame, P.; Bencivenni, G.; Bertolucci, S.; Bini, C.; Bloise, C.; Bocchetta, S.; Bossi, F.; Branchini, P.; Campana, P.; Capon, G.; Capussela, T.; Ceradini, Filippo; Chi, S.; Chiefari, G.; Ciambrone, P.; Crucianelli, F.; De Lucia, E.; De Santis, A.; De Simone, P.; De Zorzi, G.; Denig, A.; Di Domenico, A.; Di Donato, C.; Di Falco, S.; Di Micco, Biagio; Doria, A.; Dreucci, M.; Felici, G.; Ferrari, A.; Ferrer, M. L.; Fiore, S.; Forti, C.; Franzini, P.; Gatti, C.; Gauzzi, P.; Giovannella, S.; Gorini, E.; Graziani, E.; Incagli, M.; Kluge, W.; Kulikov, V.; Lacava, F.; Lanfranchi, G.; Lee-Franzini, J.; Leone, D.; Martemianov, M.; Martini, M.; Massarotti, P.; Mei, W.; Meola, S.; Miscetti, S.; Moulson, M.; Mueller, S.; Murtas, F.; Napolitanoe, M.; Nguyen, Federico; Palutan, M.; Pasqualucci, E.; Passeri, A.; Patera, V.; Perfetto, F.; Primavera, M.; Santangelo, P.; Saracino, G.; Sciascia, B.; Sciubba, A.; Sibidanov, A.; Spadaro, T.; Testa, M.; Tortora, L.; Valente, P.; Valeriani, B.; Venanzoni, G.; Versaci, R.; Xu, G. 2009-01 PHYSICS LETTERS B 670 285-291 We have measured the cross section sigma(e+ e- -> pi+ pi- gamma) at DAFNE, the Frascati phi-factory, using events with initial state radiation photons emitted at small angle andinclusive of final state radiation. We present the analysis of a newdata set corresponding to an integrated luminosity of 240 pb(-1). Wehave achieved a reduced systematic uncertainty with respect topreviously published KLOE results. From the cross section we obtain thepion form factor and the contribution to the muon magnetic anomaly fromtwo-pion states in the mass range 0.592 < M pi pi < 0.975 GeV. For the latter we find Delta(pi pi)_a(mu) = (387.2 +/- 0.5(stat) +/- 2.4(exp)+/- 2.3(th)) x 10^(-10).