Measurement of radiative widths of a2(1320) and π2(1670)

COMPASS Collaboration

doi:10.1140/epja/i2014-14079-8

Measurement of radiative widths of a₂(1320) and π₂(1670)

COMPASS Collaboration

Subatomic Physics

Research output: Contribution to journal › Article › Academic › peer-review

Abstract

The COMPASS Collaboration at CERN has investigated the reaction π̄γ → π̄π̄π⁺ embedded in the Primakoff reaction of 190 GeV pions scattering in the Coulomb field of a lead target, π̄Pb → π̄π̄π⁺ Pb. 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 a₂(1320) and π₂(1670) 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 a₂(1320) to be Γ₀(a₂(1320) → πγ) = (358 ± 6_stat ± 42_syst) keV. As the first measurement, Γ₀(π₂(1670) → πγ) = (181 ± 11_stat ± 27_syst)keV · (BR_f2π /BR/_f2π) is obtained for the radiative width of the π₂(1670), where in this analysis the branching ratio BRf_f2π^PDG = 0.56 has been used. We compare these values to previous measurements and theoretical predictions.

Original language	English
Article number	79
Number of pages	19
Journal	European physical journal. A, Hadrons and nuclei
Volume	50
Issue number	4
DOIs	https://doi.org/10.1140/epja/i2014-14079-8
Publication status	Published - Apr 2014

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Cite this

@article{faf8a1ca276e47b98a24ea18544e7b42,

title = "Measurement of radiative widths of a2(1320) and π2(1670)",

abstract = "The COMPASS Collaboration at CERN has investigated the reaction {\=π}γ → {\=π}{\=π}π+ embedded in the Primakoff reaction of 190 GeV pions scattering in the Coulomb field of a lead target, {\=π}Pb → {\=π}{\=π}π+ Pb. 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 a2(1320) and π2(1670) 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 a2(1320) to be Γ0(a2(1320) → πγ) = (358 ± 6stat ± 42syst) keV. As the first measurement, Γ0(π2(1670) → πγ) = (181 ± 11stat ± 27syst)keV · (BRf2π /BR/f2π) is obtained for the radiative width of the π2(1670), where in this analysis the branching ratio BRff2πPDG = 0.56 has been used. We compare these values to previous measurements and theoretical predictions.",

author = "C. Adolph and R. Akhunzyanov and Alexeev, {M. G.} and Alexeev, {G. D.} and A. Amoroso and V. Andrieux and V. Anosov and A. Austregesilo and B. Bade{\l}ek and F. Balestra and J. Barth and G. Baum and R. Beck and Y. Bedfer and A. Berlin and J. Bernhard and K. Bicker and J. Bieling and R. Birsa and J. Bisplinghoff and M. Bodlak and M. Boer and P. Bordalo and F. Bradamante and C. Braun and A. Bressan and M. B{\"u}chele and E. Burtin and L. Capozza and M. Chiosso and Chung, {S. U.} and A. Cicuttin and Crespo, {M. L.} and Q. Curiel and Torre, {S. Dalla} and Dasgupta, {S. S.} and S. Dasgupta and Denisov, {O. Y.} and Donskov, {S. V.} and N. Doshita and V. Duic and W. D{\"u}nnweber and M. Dziewiecki and A. Efremov and C. Elia and Eversheim, {P. D.} and W. Eyrich and M. Faessler and A. Ferrero and E. Rocco and {COMPASS Collaboration}",

year = "2014",

month = apr,

doi = "10.1140/epja/i2014-14079-8",

language = "English",

volume = "50",

journal = "European physical journal. A, Hadrons and nuclei",

issn = "1434-6001",

publisher = "Springer",

number = "4",

}

TY - JOUR

T1 - Measurement of radiative widths of a2(1320) and π2(1670)

AU - Adolph, C.

AU - Akhunzyanov, R.

AU - Alexeev, M. G.

AU - Alexeev, G. D.

AU - Amoroso, A.

AU - Andrieux, V.

AU - Anosov, V.

AU - Austregesilo, A.

AU - Badełek, B.

AU - Balestra, F.

AU - Barth, J.

AU - Baum, G.

AU - Beck, R.

AU - Bedfer, Y.

AU - Berlin, A.

AU - Bernhard, J.

AU - Bicker, K.

AU - Bieling, J.

AU - Birsa, R.

AU - Bisplinghoff, J.

AU - Bodlak, M.

AU - Boer, M.

AU - Bordalo, P.

AU - Bradamante, F.

AU - Braun, C.

AU - Bressan, A.

AU - Büchele, M.

AU - Burtin, E.

AU - Capozza, L.

AU - Chiosso, M.

AU - Chung, S. U.

AU - Cicuttin, A.

AU - Crespo, M. L.

AU - Curiel, Q.

AU - Torre, S. Dalla

AU - Dasgupta, S. S.

AU - Dasgupta, S.

AU - Denisov, O. Y.

AU - Donskov, S. V.

AU - Doshita, N.

AU - Duic, V.

AU - Dünnweber, W.

AU - Dziewiecki, M.

AU - Efremov, A.

AU - Elia, C.

AU - Eversheim, P. D.

AU - Eyrich, W.

AU - Faessler, M.

AU - Ferrero, A.

AU - Rocco, E.

AU - COMPASS Collaboration

PY - 2014/4

Y1 - 2014/4

N2 - The COMPASS Collaboration at CERN has investigated the reaction π̄γ → π̄π̄π+ embedded in the Primakoff reaction of 190 GeV pions scattering in the Coulomb field of a lead target, π̄Pb → π̄π̄π+ Pb. 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 a2(1320) and π2(1670) 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 a2(1320) to be Γ0(a2(1320) → πγ) = (358 ± 6stat ± 42syst) keV. As the first measurement, Γ0(π2(1670) → πγ) = (181 ± 11stat ± 27syst)keV · (BRf2π /BR/f2π) is obtained for the radiative width of the π2(1670), where in this analysis the branching ratio BRff2πPDG = 0.56 has been used. We compare these values to previous measurements and theoretical predictions.

AB - The COMPASS Collaboration at CERN has investigated the reaction π̄γ → π̄π̄π+ embedded in the Primakoff reaction of 190 GeV pions scattering in the Coulomb field of a lead target, π̄Pb → π̄π̄π+ Pb. 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 a2(1320) and π2(1670) 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 a2(1320) to be Γ0(a2(1320) → πγ) = (358 ± 6stat ± 42syst) keV. As the first measurement, Γ0(π2(1670) → πγ) = (181 ± 11stat ± 27syst)keV · (BRf2π /BR/f2π) is obtained for the radiative width of the π2(1670), where in this analysis the branching ratio BRff2πPDG = 0.56 has been used. We compare these values to previous measurements and theoretical predictions.

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U2 - 10.1140/epja/i2014-14079-8

DO - 10.1140/epja/i2014-14079-8

M3 - Article

AN - SCOPUS:84899636152

SN - 1434-6001

VL - 50

JO - European physical journal. A, Hadrons and nuclei

JF - European physical journal. A, Hadrons and nuclei

IS - 4

M1 - 79

ER -