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Ablikim, M., Achasov, M. N., Ahmed, S., Albrecht, M., Amoroso, A., An, F. F., . . . Zou, J. H. (2018). Measurement of the matrix elements for the decays eta' -> eta pi(+) pi(-) and eta' -> eta pi(0)pi(0). Physical Review D: covering particles, fields, gravitation, and cosmology, 97(1), Article ID 012003.
Open this publication in new window or tab >>Measurement of the matrix elements for the decays eta' -> eta pi(+) pi(-) and eta' -> eta pi(0)pi(0)
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2018 (English)In: Physical Review D: covering particles, fields, gravitation, and cosmology, ISSN 2470-0010, E-ISSN 2470-0029, Vol. 97, no 1, article id 012003Article in journal (Refereed) Published
Abstract [en]

Based on a sample of 1.31 x 10(9) J/psi events collected with the BESIII detector, the matrix elements for the decays eta' -> eta pi(+) pi(-) and eta' -> eta pi(0)pi(0) are determined using 351,016 eta' -> (eta -> gamma gamma)pi' pi(-) and 56,249 eta' -> (eta -> gamma gamma)pi(0) pi(0) events with background levels less than 1%. Two commonly used representations are used to describe the Dalitz plot density. We find that an assumption of a linear amplitude does not describe the data well. A small deviation of the obtained matrix elements between eta' -> eta pi(+) pi(-) and eta' -> eta pi(0)pi(0) is probably caused by the mass difference between charged and neutral pions or radiative corrections. No cusp structure in eta' -> eta pi(0)pi(0) is observed.

Place, publisher, year, edition, pages
AMER PHYSICAL SOC, 2018
National Category
Subatomic Physics
Identifiers
urn:nbn:se:uu:diva-341574 (URN)10.1103/PhysRevD.97.012003 (DOI)000419711200002 ()
Available from: 2018-02-15 Created: 2018-02-15 Last updated: 2018-02-15Bibliographically approved
Ablikim, M., Achasov, M. N., Ahmed, S., Ai, X. C., Albayrak, O., Albrecht, M., . . . Zou, J. H. (2017). Amplitude analysis of the chi(c1) -> eta pi(+)pi(-) decays. Physical Review D: covering particles, fields, gravitation, and cosmology, 95(3), Article ID 032002.
Open this publication in new window or tab >>Amplitude analysis of the chi(c1) -> eta pi(+)pi(-) decays
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2017 (English)In: Physical Review D: covering particles, fields, gravitation, and cosmology, ISSN 2470-0010, E-ISSN 2470-0029, Vol. 95, no 3, article id 032002Article in journal (Refereed) Published
Abstract [en]

Using 448.0 x 10(6) psi(3686) events collected with the BESIII detector, an amplitude analysis is performed for psi(3686) -> gamma chi(c1), chi(c1) ->eta pi(+)pi(-) decays. The most dominant two- body structure observed is a(0)(980)(+/-) pi(-/+); a(0)(980)(+/-) -> eta pi(+/-.) line shape is modeled using a dispersion relation, and a significant nonzero a(0) (980) coupling to the eta'pi channel is measured. We observe chi(c1) -> a(2)(1700)pi production for the first time, with a significance larger than 17 sigma. The production of mesons with exotic quantum numbers, J(PC) = 1(-+), is investigated, and upper limits for the branching fractions chi(c1) -> pi(1)(1400)(+/-)pi(-/+) , chi(c1) -> pi(1)(1600)(+/-)pi(-/+) and chi(c1) -> pi 1(2015)(+/-)pi(-/+) with subsequent pi(1)(X)(+/-) -> eta pi(+/-) decay, are determined.

Place, publisher, year, edition, pages
AMER PHYSICAL SOC, 2017
National Category
Subatomic Physics
Identifiers
urn:nbn:se:uu:diva-319566 (URN)10.1103/PhysRevD.95.032002 (DOI)000393744600002 ()
Available from: 2017-04-06 Created: 2017-04-06 Last updated: 2017-11-29Bibliographically approved
Ablikim, M., Achasov, M. N., Ai, X. C., Albayrak, O., Albrecht, M., Ambrose, D. J., . . . Zou, J. H. (2017). Amplitude Analysis of the Decays eta ' -> pi(+)pi(-)pi(0) and eta' -> pi(0)pi(0)pi(0). Physical Review Letters, 118(1), Article ID 012001.
Open this publication in new window or tab >>Amplitude Analysis of the Decays eta ' -> pi(+)pi(-)pi(0) and eta' -> pi(0)pi(0)pi(0)
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2017 (English)In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 118, no 1, article id 012001Article in journal (Refereed) Published
Abstract [en]

Based on a sample of 1.31 x 10(9) J/Psi events collected with the BESIII detector, an amplitude analysis of the isospin-violating decays eta' -> pi(+)pi(-)pi(0) and eta' -> pi(0)pi(0)pi(0) is performed. A significant P-wave contribution from eta' -> rho(+/-)eta(-/+) is observed for the first time in eta' -> pi(+)pi(-)pi(0). The branching fraction is determined to be B(eta' -> rho(+/-)pi(-/+)) = (7.44 +/- 0.60 +/- 1.26 +/- 1.84) x 10(-4), where the first uncertainty is statistical, the second systematic, and the third model dependent. In addition to the nonresonant S-wave component, there is a significant sigma meson component. The branching fractions of the combined S-wave components are determined to be B(eta' -> pi(+)pi(-)pi(0))(S) = (37.63 +/- 0.77 +/- 2.22 +/- 4.48) x 10(-4) and B(eta' -> pi(0)pi(0)pi(0)) = (35.22 +/- 0.82 +/- 2.54) x 10(-4), respectively. The latter one is consistent with previous BESIII measurements.

National Category
Subatomic Physics
Identifiers
urn:nbn:se:uu:diva-315823 (URN)10.1103/PhysRevLett.118.012001 (DOI)000391474000007 ()
Funder
German Research Foundation (DFG), Collaborative Research Center CRC-1044
Available from: 2017-02-22 Created: 2017-02-22 Last updated: 2017-11-29Bibliographically approved
Ablikim, M., Achasov, M. N., Ahmed, S., Ai, X. C., Albayrak, O., Albrecht, M., . . . Zou, J. H. (2017). Analysis of D+ -> (K)over-bar(0)e(+)nu(e) and D+ -> pi(0)e(+)nu(e) semileptonic decays. Physical Review D: covering particles, fields, gravitation, and cosmology, 96(1), Article ID 012002.
Open this publication in new window or tab >>Analysis of D+ -> (K)over-bar(0)e(+)nu(e) and D+ -> pi(0)e(+)nu(e) semileptonic decays