Aniello Nappi

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The direct CP violation parameter Re( ′/ ) has been measured from the decay rates of neutral kaons into two pions using the NA48 detector at the CERN SPS. The 2001 running period was devoted to collecting additional data under varied conditions compared to earlier years (1997–1999). The new data yield the result: Re( ′/ )= (13.7 ± 3.1)× 10−4. Combining this(More)
The decay rate of KL → π0γγ has been measured with the NA48 detector at the CERN SPS. A total of 2558 KL → π0γγ candidates have been observed with a residual background of 3.2%. The branching ratio is determined to be (1.36 ± 0.03(stat) ± 0.03(syst) ± 0.03(norm)) × 10−6 and the vector coupling constant av = −0.46± 0.03(stat) ± 0.04(syst). This result(More)
The NA48 experiment at CERN has performed a new measurement of direct CP violation, based on data taken in 1997 0 0 q y Ž X . by simultaneously collecting K and K decays into p p and p p . The result for the CP violating parameter Re ́ r ́ L S Ž Ž . Ž .. y4 is 18.5"4.5 stat "5.8 syst =10 . q 1999 Elsevier Science B.V. All rights reserved. 1 Present(More)
Present address: Fachbereich Physik, Universit~it Siegen, D-5900 Siegen 21, Fed. Rep. Germany. 2 On leave from SLAC, Stanford, CA 94305, USA. 3 Work supported in part by the US Department of Energy contract DE-AC03-765F00515. 4 Present address: Scuola Normale Superiore e Sezione INFN, 1-56100 Pisa, Italy. 5 Present address: DVFLR, D-5000 Cologne, Fed. Rep.(More)
The semileptonic decay of the neutral K meson, K L → πeν (Ke3), was used to study the strangeness-changing weak interaction of hadrons. A sample of 5.6 million reconstructed events recorded by the NA48 experiment was used to measure the Dalitz plot density. Admitting all possible Lorentz-covariant couplings, the form factors for vector (f+(q )), scalar (fS)(More)
A measurement of the KS lifetime is presented using data recorded by the NA48 experiment at the CERN-SPS during 1998 and 1999. The KS lifetime is derived from the ratio of decay time distributions in simultaneous, collinear KS and KL beams, giving a result which is approximately independent of the detector acceptance and with reduced systematic errors. The(More)
Using the full data set of the NA48/2 experiment, the decay K± → π±e+e−γ is observed for the first time, selecting 120 candidates with 7.3 ± 1.7 estimated background events. With K± → π±π0 D as normalisation channel, the branching ratio is determined in a model-independent way to be Br(K± → π±e+e−γ, meeγ > 260 MeV/c2) = (1.19 ± 0.12stat ± 0.04syst) × 10−8.(More)