A measurement of the transverse polarization of Lambda-hyperons produced in inelastic pN-reactions at 450 GeV proton energy

A study of the polarization of Λ hyperons produced in inelastic pN reactions induced by the 450 GeV proton beam from the CERN SPS has been performed with the NA48 detector. The Λ hyperons were detected at a fixed angle of 4.2 mrad in the momentum range from 50 GeV/c to 200 GeV/c. The polarization changes from −0.053 ± 0.034 to −0.298 ± 0.074 for a transverse momentum range of the Λ between 0.28 GeV/c and 0.86 GeV/c. The antiΛ polarization is consistent with zero

Investigation of K(L,S) -> pi+ pi- e+ e- decays

The KL → π+ π− e+ e− and KS → π+ π− e+ e− decay modes have been studied in detail using the NA48 detector at the CERN SPS. Based on the data collected during the 1998 and 1999 run periods, a sample of 1162 KL → π+ π− e+ e− candidates has been observed with an expected background level of 36.9 events, yielding the branching ratio measurement BR(KL → π+ π− e+ e−) = (3.08 ± 0.20) × 10^−7 . The distribution of events in the sinφ cosφ variable, where φ is the angle between the π+ π− and the e+ e− decay planes in the kaon centre of mass, is found to exhibit a large CP-violating asymmetry with the value Aφ = (14.2 ± 3.6)%. For the KS → π+ π− e+ e− decay channel, 621 candidates have been identified in the 1999 data sample with an estimated background contribution of 0.7 event. The corresponding branching ratio has been determined to be BR(KS → π+ π− e+ e−) = (4.71 ± 0.32) × 10^−5 . The combined value of this measurement with the published 1998 result is BR(KS → π+ π− e+ e−) = (4.69 ± 0.30) × 10^−5 . No asymmetry is observed in this decay mode. Our results are in good agreement with theoretical predictions based on a phenomenological description of radiative kaon decays. The form factor parameters a1/a2 and gM1 in the KL → π+ π− e+ e− direct emission process as well as the value of the K0 charge radius have been extracted from the data

Oekologisch vertraegliche Mobilitaet in Stadtregionen

SIGLEAvailable from TIB Hannover: F95B2343+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Measurement of Kμ30K^{0}_{\mu3} form factors

22 pages 7 figuresThis paper reports on a new high precision measurement of the form factors of the K_{L}\to \pi^{\pm} \mu^{\mp} \nu_{\mu} decay. The data sample of about 2.3$\times 10^{6}$ events was recorded in 1999 by the NA48 experiment at CERN. Studying the Dalitz plot density we measured a linear, $\lambda^{'}_{+} = (20.5\pm 2.2_{stat} \pm 2.4_{syst})\times 10^{-3}$, and a quadratic, $\lambda^{''}_{+} = (2.6\pm 0.9_{stat} \pm 1.0_{syst})\times 10^{-3}$ term in the power expansion of the vector form factor. No evidence was found for a second order term for the scalar form factor; the linear slope was determined to be $\lambda_{0} = (9.5\pm 1.1_{stat} \pm 0.8_{syst})\times 10^{-3}$. Using a linear fit our results were: $\lambda_{+} = (26.7\pm 0.6_{stat} \pm 0.8_{syst} )\times 10^{-3}$ and, $\lambda_{0} = (11.7\pm 0.7_{stat} \pm 1.0_{syst})\times 10^{-3}$. A pole fit of the form factors yields: $m_V = (905 \pm 9_{stat} \pm 17_{syst})$ MeV/c$^2$ and $m_S = (1400 \pm 46_{stat} \pm 53_{syst})$ MeV/c$^2$

The beam and detector for the NA48 neutral kaon CP violation experiment at CERN

The beam and detector, used for the NA48 experiment, devoted to the measurement of Re (ε{lunate}′ / ε{lunate}), and for the NA48/1 experiment on rare KS and neutral hyperon decays, are described. © 2007 Elsevier B.V. All rights reserved