Precision measurement of the ratio BR(KS→π+π−e+e−)/BR(KL→π+π−πD0)

6533b7d2fe1ef96bd125ea07

RESEARCH PRODUCT

Precision measurement of the ratio BR(KS→π+π−e+e−)/BR(KL→π+π−πD0)

Lau Gatignon P. Cenci A. Maier P. Hristov Roberta Arcidiacono Roberta Arcidiacono R. Fantechi B. Panzer-steindel P. F. Dalpiaz Nadia Pastrone Jacqueline Batley I. Mannelli H. Dibon Wander Baldini M. Veltri L. Fiorini L. Fiorini S. Giudici G. Lamanna L. Masetti A. Peters A. Norton A. Norton Roland Winston P. Lubrano G. Kalmus P. Debu M. Sozzi A. Nappi M. Holder S. A. Wotton Ivan Mikulec Ivan Mikulec E. Iacopini P. Grafström Niels Doble Niels Doble E. Menichetti S. Goy Lopez R. Sacco C. Cheshkov Maulik R. Patel B. Vallage F. Petrucci M. Savrie Nicolo Cartiglia G.m. Pierazzini Cristina Biino G. Bocquet Yu. Potrebenikov P. Rubin P. Rubin P. Rubin Konrad Kleinknecht P. Marouelli M. De Beer J.b. Cheze Vladimir Kekelidze G. Neuhofer V. Kozhuharov V. Kozhuharov M. Valdata-nappi Manfred Jeitler D.c. Cundy D.c. Cundy G. Anzivino G. Gouge M. Behler V. Falaleev M. Ziolkowski M. Martini Evgueni Goudzovski W. Kubischta D. J. Munday E. Imbergamo G. Marel Rainer Wanke E. C. Swallow M. Slater M. Eppard M. Szleper A. Dabrowski M. C. Petrucci U. Moosbrugger M. Markytan M. Lenti A. Hirstius D. T. Madigozhin Cristina Lazzeroni E. Mazzucato C. Morales Morales U. Koch A. Winhart T. Fonseca Martin Mauro Piccini Mayda Velasco A. I. Zinchenko A. Gianoli C. Cerri E. Monnier H. D. Wahl H. D. Wahl B. Peyaud M. Calvetti Leander Litov P.l. Frabetti P.l. Frabetti Alan W. Walker N. A. Molokanova K. Eppard F. Marchetto A. Michetti F. Costantini A. Ceccucci L. Widhalm M. Scarpa Andrea Bizzeti W. Wislicki Marco Clemencic Marco Clemencic S. Stoynev M. Pepe G. Ruggiero A. Gonidec G. Collazuol

subject

Physics Nuclear and High Energy Physics Angular distribution 010308 nuclear & particles physics Branching fraction 0103 physical sciences Bremsstrahlung Pi Analytical chemistry CP violation 010306 general physics 01 natural sciences

description

Abstract The K S → π + π − e + e − decay mode was investigated using the data collected in 2002 by the NA48/1 Collaboration. With about 23 k K S → π + π − e + e − events and 59 k K L → π + π − π D 0 normalization decays, the K S → π + π − e + e − branching ratio relative to the K L → π + π − π D 0 one was determined to be BR ( K S → π + π − e + e − ) / BR ( K L → π + π − π D 0 ) = ( 3.28 ± 0.06 stat ± 0.04 syst ) × 10 − 2 . This result was used to set the upper limit | g E1 / g BR | 3.0 at 90% CL on the presence, in the decay amplitude, of an E1 direct emission ( g E1 ) term relative to the dominant inner bremsstrahlung ( g BR ) term. The CP-violating asymmetry A ϕ in the sin ϕ cos ϕ distribution of K S → π + π − e + e − events, where ϕ is the angle between the π + π − and the e + e − decay planes in the kaon centre of mass, was found to be A ϕ = ( − 0.4 ± 0.8 ) % , consistent with zero. These results are in good agreement with a description of the K S → π + π − e + e − decay amplitude dominated by the CP-even inner bremsstrahlung process.

year	journal	country	edition	language
2011-01-01	Physics Letters B

https://doi.org/10.1016/j.physletb.2010.10.008