uu.seUppsala University Publications
Change search
Link to record
Permanent link

Direct link
BETA
Alternative names
Publications (10 of 262) 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)
Show others...
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
Adlarson, P., Augustyniak, W., Bardan, W., Bashkanov, M., Bass, S. D., Bergmann, F. S., . . . Zurek, M. (2018). Spin Dependence of eta Meson Production in Proton-Proton Collisions Close to Threshold. Physical Review Letters, 120(2), Article ID 022002.
Open this publication in new window or tab >>Spin Dependence of eta Meson Production in Proton-Proton Collisions Close to Threshold
Show others...
2018 (English)In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 120, no 2, article id 022002Article in journal (Refereed) Published
Abstract [en]

Taking advantage of the high acceptance and axial symmetry of the WASA-at-COSY detector, and the high polarization degree of the proton beam of COSY, the reaction →pp→ppη has been measured close to threshold to explore the analyzing power Ay. The angular distribution of Ay is determined with the precision improved by more than 1 order of magnitude with respect to previous results, allowing a first accurate comparison with theoretical predictions. The determined analyzing power is consistent with zero for an excess energy of Q=15  MeV, signaling s-wave production with no evidence for higher partial waves. At Q=72  MeV the data reveal strong interference of Ps and Pp partial waves and cancellation of (Pp)2 and Ss∗Sd contributions. These results rule out the presently available theoretical predictions for the production mechanism of the η meson.

National Category
Subatomic Physics
Identifiers
urn:nbn:se:uu:diva-341490 (URN)10.1103/PhysRevLett.120.022002 (DOI)000419478800004 ()
Available from: 2018-02-21 Created: 2018-02-21 Last updated: 2018-02-21Bibliographically approved
Ablikim, M., Achasov, M. N., Ahmed, S., Ai, X. C., Albayrak, O., Albrecht, M., . . . Zou, J. H. (2017). Amplitude analysis of D0 -> K -π+π+π-. Physical Review D: covering particles, fields, gravitation, and cosmology, 95(7), Article ID 072010.
Open this publication in new window or tab >>Amplitude analysis of D0 -> K -π+π+π-
Show others...
2017 (English)In: Physical Review D: covering particles, fields, gravitation, and cosmology, ISSN 2470-0010, E-ISSN 2470-0029, Vol. 95, no 7, article id 072010Article in journal (Refereed) Published
Abstract [en]

We present an amplitude analysis of the decay D-0 -> K- pi(+)pi(+)pi(-) based on a data sample of 2.93 fb(-1) acquired by the BESIII detector at the psi(3770) resonance. With a nearly background free sample of about 16000 events, we investigate the substructure of the decay and determine the relative fractions and the phases among the different intermediate processes. Our amplitude model includes the two-body decays D-0 -> (K) over bar*(0)rho(0), D-0 -> K- a(1)(+) (1260) and D-0 -> K-1(-)(1270)pi(+), the three-body decays D-0 -> K-1(-)*(0)pi(+)pi(-) and D-0 -> K- pi(+)rho(0), as well as the four-body nonresonant decay D-0 -> K- pi(+)pi(+)pi(-). The dominant intermediate process is D-0 -> K(-)a(1)(+)(1260)accounting for a fit fraction of 54.6%.

Keyword
Helicity-coupling amplitudes, Tensor formalism, Mesons, Decays
National Category
Subatomic Physics
Identifiers
urn:nbn:se:uu:diva-322816 (URN)10.1103/PhysRevD.95.072010 (DOI)000399946100003 ()
Note

title in WoS: Amplitude analysis of D-0 -> K- pi(+) pi(+) pi(-)

Available from: 2017-09-13 Created: 2017-09-13 Last updated: 2018-01-11
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
Show others...
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)