https://doi.org/10.1140/epja/i2014-14079-8
Regular Article - Experimental Physics
Measurement of radiative widths of a2(1320) and
(1670)
1
Universität Bielefeld, Fakultät für Physik, 33501, Bielefeld, Germany
2
Universität Bochum, Institut für Experimentalphysik, 44780, Bochum, Germany
3
Universität Bonn, Helmholtz-Institut für Strahlen- und Kernphysik, 53115, Bonn, Germany
4
Universität Bonn, Physikalisches Institut, 53115, Bonn, Germany
5
Institute of Scientific Instruments, AS CR, 61264, Brno, Czech Republic
6
Matrivani Institute of Experimental Research & Education, 700 030, Calcutta, India
7
Joint Institute for Nuclear Research, 141980, Dubna, Russia
8
Universität Erlangen-Nürnberg, Physikalisches Institut, 91054, Erlangen, Germany
9
Universität Freiburg, Physikalisches Institut, 79104, Freiburg, Germany
10
CERN, 1211, Geneva 23, Switzerland
11
Technical University in Liberec, 46117, Liberec, Czech Republic
12
LIP, 1000-149, Lisbon, Portugal
13
Universität Mainz, Institut für Kernphysik, 55099, Mainz, Germany
14
University of Miyazaki, 889-2192, Miyazaki, Japan
15
Lebedev Physical Institute, 119991, Moscow, Russia
16
Ludwig-Maximilians-Universität München, Department für Physik, 80799, Munich, Germany
17
Technische Universität München, Physik Department, 85748, Garching, Germany
18
Nagoya University, 464, Nagoya, Japan
19
Charles University in Prague, Faculty of Mathematics and Physics, 18000, Prague, Czech Republic
20
Czech Technical University in Prague, 16636, Prague, Czech Republic
21
State Scientific Center Institute for High Energy Physics of National Research Center “Kurchatov Institute”, 142281, Protvino, Russia
22
CEA IRFU/SPhN Saclay, 91191, Gif-sur-Yvette, France
23
Tel Aviv University, School of Physics and Astronomy, 69978, Tel Aviv, Israel
24
Trieste Section of INFN, 34127, Trieste, Italy
25
University of Trieste, Department of Physics, 34127, Trieste, Italy
26
Abdus Salam ICTP, 34151, Trieste, Italy
27
University of Turin, Department of Physics, 10125, Turin, Italy
28
Torino Section of INFN, 10125, Turin, Italy
29
University of Eastern Piedmont, 15100, Alessandria, Italy
30
National Centre for Nuclear Research, 00-681, Warsaw, Poland
31
University of Warsaw, Faculty of Physics, 00-681, Warsaw, Poland
32
Warsaw University of Technology, Institute of Radioelectronics, 00-665, Warsaw, Poland
33
Yamagata University, 992-8510, Yamagata, Japan
Received:
13
March
2014
Accepted:
24
March
2014
Published online:
25
April
2014
The COMPASS Collaboration at CERN has investigated the reaction embedded in the Primakoff reaction of 190 GeV pions scattering in the Coulomb field of a lead target,
. Exchange of quasi-real photons is selected by isolating the sharp Coulomb peak observed at momentum transfer below 0.001 (GeV/c)2. Using a partial-wave analysis the amplitudes and relative phases of the
and
mesons have been extracted, and the Coulomb and the diffractive contributions have been disentangled. Measuring absolute production cross sections we have determined the radiative width of the
to be
keV. As the first measurement,
is obtained for the radiative width of the
, where in this analysis the branching ratio
has been used. We compare these values to previous measurements and theoretical predictions.
© SIF, Springer-Verlag Berlin Heidelberg, 2014