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Wolke, Magnus
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Publications (10 of 199) Show all publications
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., Albrecht, M., Amoroso, A., An, F. F., . . . Zou, J. H. (2018). Measurements of the branching fractions for the semileptonic decays D-s(+) -> phi e(+)v(e), phi mu(+)v(mu), eta mu(+)v(mu) and eta 'mu(+)v(mu). Physical Review D: covering particles, fields, gravitation, and cosmology, 97(1), Article ID 012006.
Open this publication in new window or tab >>Measurements of the branching fractions for the semileptonic decays D-s(+) -> phi e(+)v(e), phi mu(+)v(mu), eta mu(+)v(mu) and eta 'mu(+)v(mu)
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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 012006Article in journal (Refereed) Published
Abstract [en]

By analyzing 482 pb(-1) of e(+) e(-) collision data collected at the center-of-mass energy root s = 4.009 GeV with the BESIII detector, we measure the branching fractions for the semi-leptonic decays D-s(+) -> phi e(+)v(e), phi mu(+)v(mu), eta mu(+)v(mu) and eta'mu(+)v(mu) to be B(D-s(+) -> phi e(+)v(e)) = (2.26 +/- 0.45 +/- 0.09)%, B(D-s(+) -> phi mu+v(mu)) = (1.94 +/- 0.53 +/- 0.09)%, B(D-s(+) -> eta mu(+)v(mu)) = (2.42 +/- 0.46 +/- 011)% and B(D-s(+) -> eta'mu(+)v(mu)) = (1.06 +/- 0.54 +/- 0.07)%, where the first and second uncertainties are statistical and systematic, respectively. The branching fractions for the three semi-muonic decays D-s(+) -> phi mu(+)v(mu), eta mu(+)v(mu) and eta'mu(+)v(mu) are determined for the first time and that of D-s(+) -> phi e(+)v(e) is consistent with the world average value within uncertainties.

Place, publisher, year, edition, pages
American Physical Society, 2018
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:uu:diva-346892 (URN)10.1103/PhysRevD.97.012006 (DOI)000423434300001 ()
Funder
Swedish Research Council
Available from: 2018-04-05 Created: 2018-04-05 Last updated: 2018-04-05Bibliographically approved
Ablikim, M., Achasov, M. N., Ahmed, S., Ai, X. C., Albayrak, O., Albrecht, M., . . . Zou, J. H. (2018). Observation of a cross-section enhancement near mass threshold in e(+)e(-) -> Lambda(Lambda)over-bar. Physical Review D: covering particles, fields, gravitation, and cosmology, 97(3), Article ID 032013.
Open this publication in new window or tab >>Observation of a cross-section enhancement near mass threshold in e(+)e(-) -> Lambda(Lambda)over-bar
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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 3, article id 032013Article in journal (Refereed) Published
Abstract [en]

The process e(+)e(-) -> Lambda(Lambda) over bar is studied using data samples at root s = 2.2324, 2.400, 2.800 and 3.080 GeV collected with the BESIII detector operating at the BEPCII collider. The Born cross section is measured at root s = 2.2324 GeV, which is 1.0 MeVabove the Lambda(Lambda) over bar mass threshold, to be 305 +/- 45(-36)(+66) pb, where the first uncertainty is statistical and the second systematic. The cross section near threshold is larger than that expected from theory, which predicts the cross section to vanish at threshold. The Born cross sections at root s = 2.400, 2.800 and 3.080 GeV are measured and found to be consistent with previous experimental results, but with improved precision. Finally, the corresponding effective electromagnetic form factors of Lambda are deduced.

Place, publisher, year, edition, pages
AMER PHYSICAL SOC, 2018
National Category
Subatomic Physics
Identifiers
urn:nbn:se:uu:diva-348979 (URN)10.1103/PhysRevD.97.032013 (DOI)000426322600001 ()
Funder
Swedish Research CouncilGerman Research Foundation (DFG), CRC 1044German Research Foundation (DFG), FOR 2359
Available from: 2018-04-26 Created: 2018-04-26 Last updated: 2018-04-26Bibliographically approved
Ablikim, M., Achasov, M. N., Ahmed, S., Albrecht, M., Amoroso, A., An, F. F., . . . Zou, J. H. (2018). Observation of e(+)e(-) -> phi chi(c1) and phi chi(c2) at root s=4.600 GeV. Physical Review D: covering particles, fields, gravitation, and cosmology, 97(3), Article ID 032008.
Open this publication in new window or tab >>Observation of e(+)e(-) -> phi chi(c1) and phi chi(c2) at root s=4.600 GeV