Precision measurements of K{sup {+-}} {yields} {pi}{sup {+-}}{pi}{sup 0}{gamma} decay at NA48/2 and search for CP violation

Journal Article · Mon Oct 24 04:00:00 EDT 2011 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.3647142· OSTI ID:21608395

Bizzeti, Andrea ^[1]

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1. Dipartimento di Fisica, Universita di Modena e Reggio Emilia, via G. Campi 213/A, I-41100 Modena (Italy)

The direct emission (DE) and interference (INT) terms of the radiative decay K{sup {+-}} {yields} {pi}{sup {+-}}{pi}{sup 0}{gamma} have been measured by the NA48/2 experiment at CERN SPS. About 6 10{sup 5} K{sup {+-}} {yields} {pi}{sup {+-}}{pi}{sup 0}{gamma} decays have been selected from data collected during 2003 and 2004. The relative amounts of DE and INT with respect to the dominant Inner Bremsstrahlung (IB) contribution have been measured in the range 0<T{sub {pi}}{sup *}<80 MeV, where T{sub {pi}}{sup *} is the kinetic energy of the charged pion in the kaon rest frame, obtaining: Frac(DE) = (3.32 {+-}0.15{sub stat}{+-}0.14{sub syst})10{sup -2}, Frac(INT) = (-2.35 {+-}0.35{sub stat}{+-}0.39{sub syst}) 10{sup -2}. This is the first observation of an interference term in K{sup {+-}} {yields} {pi}{sup {+-}}{pi}{sup 0}{gamma} decays. From this measurement the DE normalized electric and magnetic amplitudes are derived: X{sub E} = (-24 {+-}6) GeV{sup -4}, X{sub M} = (254 {+-} 9) GeV{sup -4}.In addition, the CP violating asymmetry in the K{sup +} and K- branching ratios for this channel has been determined to be less than 1.5 10{sup -3} at 90% confidence level.

• OSTI ID: 21608395
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 1374; ISSN 0094-243X; ISSN APCPCS
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ACCELERATORS
ASYMMETRY
BOSONS
BRANCHING RATIO
BREMSSTRAHLUNG
CERN SPS SYNCHROTRON
CHIRAL SYMMETRY
CP INVARIANCE
CYCLIC ACCELERATORS
DECAY
DIMENSIONLESS NUMBERS
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
HADRONS
INTERNAL BREMSSTRAHLUNG
INVARIANCE PRINCIPLES
KAONS
KAONS MINUS
KAONS PLUS
MASSLESS PARTICLES
MEASURING INSTRUMENTS
MESONS
MULTIPARTICLE SPECTROMETERS
PARTICLE DECAY
PARTICLE IDENTIFICATION
PHOTONS
PIONS
PIONS MINUS
PIONS NEUTRAL
PIONS PLUS
PSEUDOSCALAR MESONS
RADIATIONS
RADIATIVE DECAY
SPECTROMETERS
STRANGE MESONS
STRANGE PARTICLES
SYMMETRY
SYNCHROTRONS