2022 Impact factor 4.4
Particles and Fields

Eur. Phys. J. C 22, 55-79 (2001)
DOI: 10.1007/s1005201O0793

$\mathrm{\cal T}$-violation and $\mathrm{\cal CPT}$-invariance measurements in the CPLEAR experiment: a detailed description of the analysis of neutral-kaon decays to $\mathrm{e} \pi \nu$

The CPLEAR Collaboration1, A. Angelopoulos1, E. Aslanides2, G. Backenstoss3, P. Bargassa4, O. Behnke5, A. Benelli3, V. Bertin2, F. Blanc6, 4, P. Bloch7, P. Carlson8, M. Carroll9, E. Cawley9, M.B. Chertok10, M. Danielsson8, M. Dejardin11, J. Derre11, A. Ealet2, C. Eleftheriadis12, W. Fetscher5, M. Fidecaro7, A. Filipcic13, D. Francis10, J. Fry9, E. Gabathuler9, R. Gamet9, H.-J. Gerber5, A. Go7, A. Haselden9, P.J. Hayman9, F. Henry-Couannier2, R.W. Hollander14, K. Jon-And8, P.-R. Kettle4, P. Kokkas15, R. Kreuger14, R. Le Gac2, F. Leimgruber3, I. Mandic13, N. Manthos15, G. Marel11, M. Mikuz13, J. Miller10, F. Montanet2, A. Muller T. Nakada11, 4, B. Pagels5, I. Papadopoulos12, P. Pavlopoulos3, G. Polivka3, R. Rickenbach3, B.L. Roberts10, T. Ruf7, L. Sakeliou1, M. Schäfer5, L.A. Schaller6, T. Schietinger3, A. Schopper7, L. Tauscher3, C. Thibault16, F. Touchard2, C. Touramanis9, C.W.E. Van Eijk14, S. Vlachos3, P. Weber5, O. Wigger4, M. Wolter5, D. Zavrtanik13 and D. Zimmerman10

1  University of Athens, Greece
2  CPPM, IN2P3-CNRS et Université d'Aix-Marseille II, France
3  University of Basle, Switzerland
4  Paul Scherrer Institut (PSI), Switzerland
5  ETH-IPP Zürich, Switzerland
6  University of Fribourg, Switzerland
7  CERN, Geneva, Switzerland
8  Royal Institute of Technology, Stockholm, Sweden
9  University of Liverpool, UK
10  Boston University, USA
11  CEA, DSM/DAPNIA, CE-Saclay, France
12  University of Thessaloniki, Greece
13  J. Stefan Inst. and Phys. Dep., University of Ljubljana, Slovenia
14  Delft University of Technology, Netherlands
15  University of Ioannina, Greece
16  CSNSM, IN2P3-CNRS, Orsay, France

(Received: 24 July 2001 / Published online: 5 October 2001 - © Springer-Verlag / Società Italiana di Fisica 2001 )

A detailed description of the analysis of neutral kaons decaying to $\mathrm{e} \pi \nu$ is given, based on the complete set of data collected with the CPLEAR experiment. Using a novel approach involving initially strangeness-tagged K0 and $\mathrm{\overline{K}}{}^0$, time-dependent decay-rate asymmetries were measured. These asymmetries enabled $\mathrm{\cal T}$- and $\mathrm{\cal CPT}$-violation parameters to be measured in the context of a systematic study. The highlights of this study are the first direct observation of $\mathrm{\cal T}$ violation and the direct determination of the $\mathrm{\cal CPT}$ parameter $\mathrm{Re}(\delta)$ with an accuracy improved by two orders of magnitude with respect to the current value.

© Società Italiana di Fisica, Springer-Verlag 2001