| 1. |
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| 2. |
- Tabiri, S, et al.
(författare)
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- 2021
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swepub:Mat__t
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| 3. |
- Bravo, L, et al.
(författare)
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- 2021
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swepub:Mat__t
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| 4. |
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| 5. |
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| 6. |
- Singh, B., et al.
(författare)
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Feasibility study for the measurement of pi N transition distribution amplitudes at (P)over-barANDA in (P)over-barp -> J/psi pi(0)
- 2017
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Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 95:3
-
Tidskriftsartikel (refereegranskat)abstract
- The exclusive charmonium production process in (P) over barp annihilation with an associated pi 0 meson (p) over barp -> J/psi pi(0) is studied in the framework of QCD collinear factorization. The feasibility of measuring this reaction through the J/psi -> e(+) e(-) decay channel with the AntiProton ANnihilation at DArmstadt ((P) over bar ANDA) experiment is investigated. Simulations on signal reconstruction efficiency as well as the background rejection from various sources including the (P) over barp -> pi(+)pi(-)pi(0) and (p) over barp -> J/psi pi(0)pi(0) reactions are performed with PANDAROOT, the simulation and analysis software framework of the (P) over bar ANDA experiment. It is shown that the measurement can be done at (P) over bar ANDA with significant constraining power under the assumption of an integrated luminosity attainable in four to five months of data taking at the maximum design luminosity.
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| 7. |
- Singh, B., et al.
(författare)
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Study of doubly strange systems using stored antiprotons
- 2016
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Ingår i: Nuclear Physics A. - : Elsevier. - 0375-9474 .- 1873-1554. ; 954, s. 323-340
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Tidskriftsartikel (refereegranskat)abstract
- Bound nuclear systems with two units of strangeness are still poorly known despite their importance for many strong interaction phenomena. Stored antiprotons beams in the GeV range represent an unparalleled factory for various hyperon-antihyperon pairs. Their outstanding large production probability in antiproton collisions will open the floodgates for a series of new studies of systems which contain two or even more units of strangeness at the PANDA experiment at FAIR. For the first time, high resolution gamma-spectroscopy of doubly strange Lambda Lambda-hypernuclei will be performed, thus complementing measurements of ground state decays of Lambda Lambda-hypernuclei at J-PARC or possible decays of particle unstable hypernuclei in heavy ion reactions. High resolution spectroscopy of multistrange Xi(-) -atoms will be feasible and even the production of Omega(-) -atoms will be within reach. The latter might open the door to the vertical bar S vertical bar = 3 world in strangeness nuclear physics, by the study of the hadronic Omega(-) -nucleus interaction. For the first time it will be possible to study the behavior of Xi(+) in nuclear systems under well controlled conditions.
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| 8. |
- Collaboration, The PANDA, et al.
(författare)
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Feasibility studies of time-like proton electromagnetic form factors at PANDA at FAIR
- 2016
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Ingår i: European Physical Journal A. - : Springer Publishing Company. - 1434-6001 .- 1434-601X. ; 52:10
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Tidskriftsartikel (refereegranskat)abstract
- Simulation results for future measurements of electromagnetic proton form factors at P ¯ ANDA (FAIR) within the PandaRoot software framework are reported. The statistical precision with which the proton form factors can be determined is estimated. The signal channel p¯ p→ e+e- is studied on the basis of two different but consistent procedures. The suppression of the main background channel, i.e.p¯ p→ π+π-, is studied. Furthermore, the background versus signal efficiency, statistical and systematical uncertainties on the extracted proton form factors are evaluated using two different procedures. The results are consistent with those of a previous simulation study using an older, simplified framework. However, a slightly better precision is achieved in the PandaRoot study in a large range of momentum transfer, assuming the nominal beam conditions and detector performance.
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| 9. |
- Singh, B. P., et al.
(författare)
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Experimental access to Transition Distribution Amplitudes with the PANDA experiment at FAIR
- 2015
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Ingår i: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 51:8
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Tidskriftsartikel (refereegranskat)abstract
- Baryon-to-meson Transition Distribution Amplitudes (TDAs) encoding valuable new information on hadron structure appear as building blocks in the collinear factorized description for several types of hard exclusive reactions. In this paper, we address the possibility of accessing nucleon-to-pion (pi N) TDAs from (p) over barp -> e(+)e(-)pi(0) reaction with the future PANDA detector at the FAIR facility. At high center-of-mass energy and high invariant mass squared of the lepton pair q(2), the amplitude of the signal channel (p) over barp -> e(+)e(-)pi(0) admits a QCD factorized description in terms of pi N TDAs and nucleon Distribution Amplitudes (DAs) in the forward aid backward kinematic regimes. Assuming the validity of this factorized description, we perform feasibility studies for measuring (p) over barp -> e(+)e(-)pi(0) with the PANDA detector. Detailed simulations on signal reconstruction efficiency as well as on rejection of the most severe background channel, i.e. (p) over barp -> pi(+)pi(-)pi(0) were performed for the center-of-mass energy squared s = 5 GeV2 and s = 10 GeV2, in the kinematic regions 3.0 < q(2) < 4.3 GeV2 and 5 < q(2) < 9 GeV2, respectively, with a neutral pion scattered in the forward or backward cone vertical bar cos theta(pi 0)vertical bar > 0.5 in the proton-antiproton center-of-mass frame. Results of the simulation show that the particle identification capabilities of the PANDA detector will allow to achieve a background rejection factor of 5 . 10(7) (1 . 10(7)) at low (high) q(2) for s = 5 GeV2, and of 1 . 10(8) (6 . 10(6)) at low (high) q(2) for s = 10 GeV2, while keeping the signal reconstruction efficiency at around 40%. At both energies, a clean lepton signal can be reconstructed with the expected statistics corresponding to 2 of integrated luminosity. The cross sections obtained from the simulations are used to show that a test of QCD collinear factorization can be done at the lowest order by measuring scaling laws and angular distributions. The future measurement of the signal channel cross section with PANDA will provide a new test of the perturbative QCD description of a novel class of hard exclusive reactions and will open the possibility of experimentally accessing pi N TDAs.
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| 10. |
- Erni, W., et al.
(författare)
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Technical design report for the PANDA (AntiProton Annihilations at Darmstadt) Straw Tube Tracker
- 2013
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Ingår i: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 49:2
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Tidskriftsartikel (refereegranskat)abstract
- This document describes the technical layout and the expected performance of the Straw Tube Tracker (STT), the main tracking detector of the PANDA target spectrometer. The STT encloses a Micro-Vertex-Detector (MVD) for the inner tracking and is followed in beam direction by a set of GEM stations. The tasks of the STT are the measurement of the particle momentum from the reconstructed trajectory and the measurement of the specific energy loss for a particle identification. Dedicated simulations with full analysis studies of certain proton-antiproton reactions, identified as being benchmark tests for the whole PANDA scientific program, have been performed to test the STT layout and performance. The results are presented, and the time lines to construct the STT are described.
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| 11. |
- Ablikim, M., et al.
(författare)
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Determination of the Spin and Parity of the Z(c)(3900)
- 2017
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Ingår i: Physical Review Letters. - : AMER PHYSICAL SOC. - 0031-9007 .- 1079-7114. ; 119:7
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Tidskriftsartikel (refereegranskat)abstract
- The spin and parity of the Z(c)(3900)(+/-) state are determined to be J(P) = 1(+) with a statistical significance larger than 7 sigma over other quantum numbers in a partial wave analysis of the process e(+)e(-) -> pi(+)pi(-) J/psi We use a data sample of 1.92 fb(-1) accumulated at root s = 4.23 and 4.26 GeV with the BESIII experiment. When parametrizing the Z(c)(3900)(+/-) with a Flatte-like formula, we determine its pole mass M-pole = (3881.2 +/- 4.2(stat) +/- 52.7(syst)) MeV/c(2) and pole width Gamma(pole) = (51.8 +/- 4.6(stat) +/- 36.0(syst)) MeV. We also measure cross sections for the process e(+)e(-) -> Z(c)(3900)(+)pi(-) + c.c. -> J/psi pi(+)pi(-) and determine an upper limit at the 90% confidence level for the process e(+)e(-) -> Z(c)(4020)(+)pi(-) + c.c. -> J/psi pi(+)pi(-).
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| 12. |
- Ablikim, M., et al.
(författare)
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Measurement of higher-order multipole amplitudes in psi(3686) -> gamma chi(c1,2) with chi(c1,2) -> gamma J/psi and search for the transition eta(c)(2S) -> gamma J/psi
- 2017
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Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 95:7
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Tidskriftsartikel (refereegranskat)abstract
- Using 106 x 10(6) psi(3686) events collected with the BESIII detector, we measure multipole amplitudes for the decay psi(3686) ->; gamma chi(c1,2) -> gamma gamma J/psi beyond the dominant electric-dipole amplitudes. The normalized magnetic-quadrupole (M2) amplitude for psi(3686) -> gamma chi(c1,2) -> gamma gamma J/psi and the normalized electric-dipole amplitudes for psi(3686) -> gamma chi(c2) -> gamma J/psi and determined. The M2 amplitudes for psi(3686) -> gamma chi(c1) and ; chi(c1,2) -> gamma J/psi are found to differ significantly from zero and are consistent with theoretical predictions. We also obtain the ratios of M2 contributions of psi(3686) and J/psi decays to;2,chi(c1,2,) b(2)(1/)b(2)(2) = 1.35 +/- 0.72 and a(2)(1/)a(2)(2) = 0.617 +/- 0.083,,which agree well with theoretical expectations. By considering the multipole contributions of chi(c1,2), we measure the product branching fractions for the cascade decays psi(3686) -> gamma chi(c 0,1,2) -> gamma gamma J/psi and search for the process eta(c)(2s) -> gamma J/psi through psi(3686) -> gamma eta(c)(2s).The product branching fraction for psi(3686) -> gamma chi(c0) -> gamma gamma J/psi is 3 sigma larger than published measurements, while those of psi(3686) -> gamma chi(c1,2) -> gamma gamma J/psi are consistent. No significant signal for the decay psi(3686) -> gamma eta(c) (2s) -> gamma gamma J/psi is observed, and the upper limit of the product branching fraction at the 90% confidence level is determined.
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| 13. |
- Ablikim, M., et al.
(författare)
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Observation of a Neutral Structure near the D(D)over-bar* Mass Threshold in e(+)e(-) -> (D(D)over-bar*)(0)pi(0) at root s=4.226 and 4.257 GeV
- 2015
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 115:22
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Tidskriftsartikel (refereegranskat)abstract
- A neutral structure in the D (D) over bar* system around the D (D) over bar* mass threshold is observed with a statistical significance greater than 10 sigma in the processes e(+)e(-) -> D+D*(-)pi(0) + c.c. and e(+)e(-) -> D-0(D) over bar*(0)pi(0) + c.c. at root s = 4.226 and 4.257 GeV in the BESIII experiment. The structure is denoted as Z(c)(3885)(0). Assuming the presence of a resonance, its pole mass and width are determined to be [3885.7(-5.7)(+4.3) (stat) +/- 8.4(syst)] MeV/c(2) and [35(-12)(+11) (stat) +/- 15(syst)] MeV, respectively. The Born cross sections are measured to be sigma[e(+)e(-) -> Z(c)(3885)(0)pi(0); Z(c)(3885)(0) -> D (D) over bar*] = [77 +/- 13(stat) +/- 17(syst)] pb at 4.226 GeV and [47 +/- 9(stat) +/- 10(syst)] pb at 4.257 GeV. The ratio of decay rates B[Z(c)(3885)(0) -> D+D*(-) + c.c.]/B[Z(c)(3885)(0) -> D-0(D) over bar*(0) + c.c.] is determined to be 0.96 +/- 0.18(stat) +/- 0.12(syst), consistent with no isospin violation in the process, Z(c)(3885)(0) -> D (D) over bar*.
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| 14. |
- Ablikim, M., et al.
(författare)
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Observation of J/psi -> p(p)over-bara(0)(980) at BESIII
- 2014
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Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 90:5, s. 052009-
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Tidskriftsartikel (refereegranskat)abstract
- Using 2.25 x 10(8) J/psi events collected with the BESIII detector at the BEPCII storage rings, we observe for the first time the process J/psi -> p (p) over bara(0)(980) -> pi(0)eta with a significance of 6.5 sigma (3.2 sigma including systematic uncertainties). The product branching fraction of J/psi -> p (p) over bara(0)(980) -> p (p) over bara(0)pi(0)eta is measured to be (6.8 +/- 1.2 +/- 1.3) x 10(-5), where the first error is statistical and the second is systematic. This measurement provides information on the a(0) production near threshold coupling to p (p) over bar and improves the understanding of the dynamics of J/psi decays to four-body processes.
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| 15. |
- Ablikim, M., et al.
(författare)
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Observation of the Singly Cabibbo-Suppressed Decay D+ -> omega pi(+) and Evidence for D-0 -> omega pi(0)
- 2016
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 116:8
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Tidskriftsartikel (refereegranskat)abstract
- Based on 2.93 fb(-1) e(+)e(-) collision data taken at center-of-mass energy of 3.773 GeV by the BESIII detector, we report searches for the singly Cabibbo-suppressed decays D+ -> omega pi(+) and D-0 -> omega pi(0). A double tag technique is used to measure the absolute branching fractions B(D+ -> omega pi(+)) = (2.79 +/- 0.57 +/- 0.16) x 10(-4) and B(D-0 +/- omega pi(0)) = (1.17 +/- 0.34 +/- 0.07) x 10(-4), with statistical significances of 5.5 sigma and 4.1 sigma, where the first and second uncertainties are statistical and systematic, respectively.
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| 16. |
- Ablikim, M., et al.
(författare)
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Study of D+ -> K-pi(+)e(+)nu(e)
- 2016
-
Ingår i: PHYSICAL REVIEW D. - 2470-0010. ; 94:3
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Tidskriftsartikel (refereegranskat)abstract
- We present an analysis of the decay D+ -> K-pi(+)e(+)nu(e) based on data collected by the BESIII experiment at the psi(3770) resonance. Using a nearly background-free sample of 18262 events, we measure the branching fraction B(D+ -> K-pi+e+nu e) = (3.77 +/- 0.03 +/- 0.08)%. For 0.8 < m(K pi) < 1.0 GeV/c(2), the partial branching fraction is B(D+ -> K-pi+e+nu e)([0.8,1.0]) = (3.39 +/- 0.03 +/- 0.08)%. A partial wave analysis shows that the dominant (K) over bar* (892)degrees component is accompanied by an S-wave contribution accounting for (6.05 +/- 0.22 +/- 0.18)% of the total rate and that other components are negligible. The parameters of the (K) over bar* (892)degrees resonance and of the form factors based on the spectroscopic pole dominance predictions are also measured. We also present a measurement of the (K) over bar* (892)degrees helicity basis form factors in a model-independent way.
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| 17. |
- Ablikim, M., et al.
(författare)
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Study of decay dynamics and CP asymmetry in D+ -> K(L)(0)e(+)nu(e) decay
- 2015
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Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 92:11
-
Tidskriftsartikel (refereegranskat)abstract
- Using 2.92 fb(-1) of electron-positron annihilation data collected at root s = 3.773 GeV with the BESIII detector, we obtain the first measurements of the absolute branching fraction B(D+ -> K(L)(0)e(+)nu(e)) = (4.481 +/- 0.027(stat) +/- 0.103(sys))% and the CP asymmetry A(CP)(D+-> KL0e+nu e) = (-0.59 +/- 0.60(stat) +/- 1.48(sys))%. From the D+ -> K(L)(0)e(+)nu(e) differential decay rate distribution, the product of the hadronic form factor and the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element, f(+)(K)(0)vertical bar V-cs vertical bar, is determined to be 0.728 +/- 0.006(stat) +/- 0.011(sys). Using vertical bar V-cs vertical bar from the SM constrained fit with the measured f(+)(K)(0)vertical bar V-cs vertical bar, f(+)(K)(0) = 0.748 +/- 0.007(stat) +/- 0.012(sys) is obtained, and utilizing the unquenched Lattice QCD (LQCD) calculation for f(+)(K)(0), vertical bar V-cs vertical bar = 0.975 +/- 0.008(stat) +/- 0.015(sys) +/- 0.025(LQCD).
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| 18. |
- Ablikim, M., et al.
(författare)
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Study of e(+)e(-) -> p(p)over-bar in the vicinity of psi(3770)
- 2014
-
Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 735, s. 101-107
-
Tidskriftsartikel (refereegranskat)abstract
- Using 2917 pb(-1) of data accumulated at 3.773 GeV, 44.5 pb(-1) of data accumulated at 3.65 GeV and data accumulated during a psi(3770) line-shape scan with the BESIII detector, the reaction e(+)e(-) -> p (p) over bar is studied considering a possible interference between resonant and continuum amplitudes. The cross section of e(+)e(-) -> psi(3770) -> p (p) over bar, sigma(e(+)e(-)-> psi(3770) -> p (p) over bar), is found to have two solutions, determined to be (0.059(-0.020)(+0.070) +/- 0.012) pb with the phase angle phi = (255.8(-26.6)(+39.0) +/- 4.8). (< 0.166 pb at the 90% confidence level), or sigma(e(+)e(-) -> psi(3770) -> p<(p)over bar>) = (2.57(-0.13)(+0.12) +/- 0.12) pb with phi = (266.9(-6.3)(+6.1) +/- 0.9)degrees both of which agree with a destructive interference. Using the obtained cross section of psi(3770) -> p (p) over bar, the cross section of p (p) over bar -> psi(3770), which is useful information for the future PANDA experiment, is estimated to be either (9.8(-3.9)(+11.8)) nb (< 27.5 nb at 90% C.L.) or (425.6(-43.7)(+42.9)) nb. (C) 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license.
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| 19. |
- Ablikim, M., et al.
(författare)
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Amplitude analysis of the D+ -> K-S(0)pi + (0)(pi) Dalitz plot
- 2014
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Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 89:5, s. 052001-
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Tidskriftsartikel (refereegranskat)abstract
- We perform an analysis of the D+ -> K-S(0)pi + (0)(pi) Dalitz plot using a data set of 2.92 fb(-1) of e(+) e(-) collisions at the (3770) mass accumulated by the BESIII experiment, in which 166694 candidate events are selected with a background of 15.1%. The Dalitz plot is found to be well represented by a combination of six quasitwo- body decay channels [k(SP)(0)(+) (1450)(+,) ] plus a small nonresonant component. Using the fit fractions from this analysis, partial branching ratios are updated with higher precision than previous measurements.
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| 20. |
- Ablikim, M., et al.
(författare)
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Amplitude Analysis of the Decays eta ' -> pi(+)pi(-)pi(0) and eta' -> pi(0)pi(0)pi(0)
- 2017
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 118:1
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 21. |
- Ablikim, M., et al.
(författare)
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Amplitude analysis of the pi(0)pi(0) system produced in radiative J/psi decays
- 2015
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 92:5
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Tidskriftsartikel (refereegranskat)abstract
- An amplitude analysis of the pi(0)pi(0) system produced in radiative J/psi decays is presented. In particular, a piecewise function that describes the dynamics of the pi(0)pi(0) system is determined as a function of M pi(0)pi(0) from an analysis of the (1.311 +/- 0.011) x 10(9) J/psi decays collected by the BESIII detector. The goal of this analysis is to provide a description of the scalar and tensor components of the pi(0)pi(0) system while making minimal assumptions about the properties or number of poles in the amplitude. Such a model-independent description allows one to integrate these results with other related results from complementary reactions in the development of phenomenological models, which can then be used to directly fit experimental data to obtain parameters of interest. The branching fraction of J/psi -> pi(0)pi(0) is determined to be (1.15 +/- 0.05) x 10(-3), where the uncertainty is systematic only and the statistical uncertainty is negligible.
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| 22. |
- Ablikim, M., et al.
(författare)
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Confirmation of a charged charmoniumlike state Z(c)(3885)(-/+) in e(+)e(-) -> pi(+/-) (D(D)over-bar*)(-/+) with double D tag
- 2015
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 92:9
-
Tidskriftsartikel (refereegranskat)abstract
- We present a study of the process e(+)e(-) -> pi(+/-) (D (D) over bar*)(-/+) using data samples of 1092 pb(-1) at root s = 4.23 GeV and 826 pb(-1) at root s = 4.26 GeV collected with the BESIII detector at the BEPCII storage ring. With full reconstruction of the D meson pair and the bachelor pi(+) in the final state, we confirm the existence of the charged structure Z(c) (3885)(-/+) in the (D (D) over bar*)(-/+) system in the two isospin processes e(+)e(-) -> pi(+DD)-D-0*(-) and e(+)e(-) -> pi+D-D*(0). By performing a simultaneous fit, the statistical significance of Zc(3885)(-/+) signal is determined to be greater than 10 sigma, and its pole mass and width are measured to be M-pole = (3881.7 +/- 1.6(stat) +/- 1.6(syst)) MeV/c(2) and Gamma(pole) = (26.6 +/- 2.0(stat) +/- 2.1(syst)) MeV, respectively. The Born cross section times the (D (D) over bar*)(-/+) branching fraction (sigma(e(+)e(-) -> pi(+/-)Z(c)(3885)(-/+)) x Br(Z(c)(3885)(-/+) -> (D (D) over bar*)(-/+) )) is measured to be (141.6 +/- 7.9(stat) +/- 12.3(syst)) pb at root s = 4.23 GeV and (108.4 +/- 6.9(stat) +/- 8.8(syst)) pb at root s = 4.26 GeV. The polar angular distribution of the pi(+) - Z(c)(3885)(-/+) system is consistent with the expectation of a quantum number assignment of J(P) = 1(+) for Z(c)(3885)(-/+).
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| 23. |
- Ablikim, M., et al.
(författare)
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Evidence for e(+)e(-)->gamma chi c1,2 at center-of-mass energies from 4.009 to 4.360 GeV
- 2015
-
Ingår i: Chinese Physics C. - : IOP Publishing. - 1674-1137 .- 2058-6132. ; 39:4
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Tidskriftsartikel (refereegranskat)abstract
- Using data samples collected at center-of-mass energies of root s=4.009, 4.230, 4.260, and 4.360 GeV with the BESIII detector operating at the BEPCII collider, we perform a search for the process e(+)e(-)->gamma chi(cJ) (J=0, 1, 2) and find evidence for e(+)e(-)->gamma chi(c1) and e(+)e(-)->gamma chi(c2) with statistical significances of 3.0 sigma and 3.4 sigma, respectively. The Born cross sections sigma(B)(e(+)e(-)->gamma chi(cJ)), as well as their upper limits at the 90% confidence level (C.L.) are determined at each center-of-mass energy.
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| 24. |
- Ablikim, M., et al.
(författare)
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Improved measurement of the absolute branching fraction of D+ -> (K)over-bar(0)mu(+)nu(mu)
- 2016
-
Ingår i: European Physical Journal C. - : SPRINGER. - 1434-6044 .- 1434-6052. ; 76:7
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Tidskriftsartikel (refereegranskat)abstract
- By analyzing 2.93 fb(-1) of data collected at root s = 3.773 GeV with the BESIII detector, we measure the absolute branching fraction B(D+ -> (K) over bar (0) (+)(mu)nu(mu)) = (8.72 +/- 0.07(stat). +/- 0.18(sys).) %, which is consistent with previous measurements within uncertainties but with significantly improved precision. Combining the Particle Data Group values of B(D-0 -> K- mu(+)nu(mu)), B(D+-> (K) over bar (0)e(+)nu(e)), and the lifetimes of the D-0 and D+ mesons with the value of B(D+ -> (K) over bar (0)mu(+)nu(mu)) measured in this work, we determine the following ratios of partial widths: Gamma (D-0 -> (K) over bar (-)mu(+)nu(mu))/Gamma (D+ -> (K) over bar (0)mu+nu(mu)) = 0.963 +/- 0.044 and Gamma (D+ -> (K) over bar (0) mu+nu(mu))/Gamma(D+ -> (K) over bar (0)e+nu(e)) = 0.988 +/- 0.033.
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| 25. |
- Ablikim, M., et al.
(författare)
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Improved measurements of branching fractions for eta(c) -> phi phi and omega phi
- 2017
-
Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 95:9
-
Tidskriftsartikel (refereegranskat)abstract
- Using (223.7 +/- 1.4) x 10(6) J / Psi events accumulated with the BESIII detector, we study eta(c) decays to phi phi and omega phi final states. The branching fraction of n(c) -> phi phi is measured to be Br(eta(c) -> phi phi) = (2.5 +/- 0(-0.7)(+0.3) +/- 0.6) X 10(-3,) where the first uncertainty is statistical, the second is systematic, and the third is from the uncertainty of Br(J / Psi -> gamma eta(C)). No significant signal for the double Okubo-Zweig-Iizuka suppressed decay of eta(c) -> omega phi is observed, and the upper limit on the branching fraction is determined to be Br(eta(c) -> omega phi) < 2.5 x 10(-4) at the 90% confidence level.
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| 26. |
- Ablikim, M., et al.
(författare)
-
Measurement of chi(cJ) decaying into eta ' K+K-
- 2014
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 89:7, s. 074030-
-
Tidskriftsartikel (refereegranskat)abstract
- Using (106.41 +/- 0.86) x 10(6) Psi(3686) events collected with the BESIII detector at BEPCII, we study for the first time the decay chi(cJ) -> eta'K+K- (J = 1, 2), where eta' -> gamma rho(0) and eta' -> eta pi(+)pi(-). A partial wave analysis in the covariant tensor amplitude formalism is performed for the decay chi(c1) -> eta'K+K-. Intermediate processes chi(c1) -> eta'f(2)'(1525) chi(c1) -> K-0*(1430)K-+/-(-/+) (K-0*(1430)(+/-) -> eta'K-+/-) are observed with statistical significances larger than 5 sigma, and their branching fractions are measured.
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| 27. |
- Ablikim, M., et al.
(författare)
-
Measurement of the branching fraction for psi(3686) -> omega K+K-
- 2014
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 89:11, s. 112006-
-
Tidskriftsartikel (refereegranskat)abstract
- With 1.06 x 10(8) psi(3686) events collected with the BESIII detector, the branching fraction of psi(3686) -> omega K+K- is measured to be (1.54 +/- 0.04 +/- 0.11) x 10(-4). This is the most precise result to date, due to the largest psi(3686) sample, improved signal reconstruction efficiency, good simulation of the detector performance, and a more accurate knowledge of the continuum contribution. Using the branching fraction of J/psi -> omega K+K-, the ratio B(psi(3868) -> K+K-)/B(J/psi -> K+K-) is determined to be (18.4 +/- 3.7)%. This constitutes a significantly improved test of the 12% rule, with the uncertainty now dominated by the J/psi branching fraction.
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| 28. |
- Ablikim, M., et al.
(författare)
-
Measurement of the Ds<(+)-> l(+)ve branching fractions and the decay constant fDs
- 2016
-
Ingår i: PHYSICAL REVIEW D. - 2470-0010. ; 94:7
-
Tidskriftsartikel (refereegranskat)abstract
- Using 482 pb(-1) of e(+) e(-) collision data collected at a center-of-mass energy of root s = 4.009 GeV with the BESIII detector, we measure the branching fractions of the decays D-s(+) -> u(+)v(u) and D-s(+) -> tau(+)v(tau). By constraining the ratio of decay rates of Ds(+) to tau(+)v(u) and to u(+)v(u) to the Standard Model prediction, the branching fractions are determined to be B(D-s(+) -> u(+)v(u) = (0.495 +/- 0.067 +/- 0.026)% and B(D-s(+) -> tau(+)v(tau) = (4.83 +/- 0.65 +/- 0.26)% Using these branching fractions, we obtain a value for the decay constant f(Ds+) of (241.0 +/- 16.3 +/- 6.5) MeV, where the first error is statistical and the second systematic.
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| 29. |
- Ablikim, M., et al.
(författare)
-
Measurement of the leptonic decay width of J/psi using initial state radiation
- 2016
-
Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 761, s. 98-103
-
Tidskriftsartikel (refereegranskat)abstract
- Using a data set of 2.93 fb(-1) taken at a center-of-mass energy of root s = 3.773 GeV with the BESIII detector at the BEPCII collider, we measure the process e(+) e(-) -> J/psi gamma -> mu(+)mu(-)gamma and determine the product of the branching fraction and the electronic width B-mu mu . Gamma(ee) = (333.4 +/- 2.5(stat) +/- 4.4(sys)) eV. Using the earlier-published BESIII result for B-mu mu = (5.973 +/- 0.007(stat) +/- 0.037(sys))%, we derive the J/psi electronic width Gamma(ee) = (5.58 +/- 0.05(stat) +/- 0.08(sys)) keV. (C) 2016 The Author(s). Published by Elsevier B.V.
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| 30. |
- Ablikim, M., et al.
(författare)
-
Measurement of y(CP) in D-0-(D)over-bar(0) oscillation using quantum correlations in e(+)e(-) -> D-0(D)over-bar(0) at root s=3.773 GeV
- 2015
-
Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 744, s. 339-346
-
Tidskriftsartikel (refereegranskat)abstract
- We report a measurement of the parameter y(CP) in D-0-(D) over bar (0) oscillations performed by taking advantage of quantum coherence between pairs of D-0(D) over bar (0) mesons produced in e(+)e(-) annihilations near threshold. In this work, doubly-tagged D-0(D) over bar (0) events, where one D decays to a CP eigenstate and the other D decays in a semileptonic mode, are reconstructed using a data sample of 2.92 fb(-1) collected with the BESIII detector at the center-of-mass energy of root s = 3.773 GeV. We obtain y(CP) = (-2.0 +/- 1.3 +/- 0.7)%, where the first uncertainty is statistical and the second is systematic. This result is compatible with the current world average.
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| 31. |
- Ablikim, M., et al.
(författare)
-
Observation of e(+)e(-) -> pi(0)pi(0)h(c) and a Neutral Charmoniumlike Structure Z(c)(4020)(0)
- 2014
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 113:21, s. 212002-
-
Tidskriftsartikel (refereegranskat)abstract
- Using data collected with the BESIII detector operating at the Beijing Electron Positron Collider at center-of-mass energies of root s = 4.23, 4.26, and 4.36 GeV, we observe e(+)e(-) -> pi(0)pi(0)h(c) for the first time. The Born cross sections are measured and found to be about half of those of e(+)e(-) -> pi(+)pi(-)h(c) within less than 2 sigma. In the pi(0)h(c) mass spectrum, a structure at 4.02 GeV/c(2) is found. It is most likely to be the neutral isospin partner of the Z(c)(4020)(+/-) observed in the process of e(+)e(-) -> pi(+)pi(-)h(c) being found. A fit to the pi(0)h(c) invariant mass spectrum, with the width of the Z(c)(4020)(0) fixed to that of its charged isospin partner and possible interferences with non-Z(c)(4020)(0) amplitudes neglected, gives a mass of (4023.9 +/- 2.2 +/- 3.8) MeV/c(2) for the Z(c)(4020)(0), where the first error is statistical and the second systematic.
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| 32. |
- Ablikim, M., et al.
(författare)
-
Observation of eta' -> pi(+) pi(-) pi(+) pi(-) and eta' -> pi(+) pi(-) pi(0) pi(0)
- 2014
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 112:25, s. 251801-
-
Tidskriftsartikel (refereegranskat)abstract
- Using a sample of 1.3 x 10(9) J/psi events collected with the BESIII detector, we report the first observation of eta' -> pi(+) pi(-) pi(+) pi(-) and eta' -> pi(+) pi(-) pi(0) pi(0). The measured branching fractions are B(eta' -> pi(+) pi(-) pi(+) pi(-)) = [8.53 +/- 0.69(stat.) +/- 0.64(syst.)] x 10(-5) and B(eta' -> pi(+) pi(-) pi(0) pi(0)) = [1.82 +/- 0.35(stat.) +/- 0.18(syst.)] x 10(-4), which are consistent with theoretical predictions based on a combination of chiral perturbation theory and vector-meson dominance.
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| 33. |
- Ablikim, M., et al.
(författare)
-
Observation of h(c) Radiative Decay h(c) -> gamma eta ' and Evidence for h(c) -> gamma eta
- 2016
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 116:25
-
Tidskriftsartikel (refereegranskat)abstract
- A search for radiative decays of the P-wave spin singlet charmonium resonance h(c) is performed based on 4.48 x 10(8) psi' events collected with the BESIII detector operating at the BEPCII storage ring. Events of the reaction channels h(c) -> gamma eta' and gamma eta are observed with a statistical significance of 8.4 sigma and 4.0 sigma, respectively, for the first time. The branching fractions of h(c) -> gamma eta' and h(c) -> gamma eta' are measured to be B(h(c) -> gamma eta') = (1.52 +/- 0.27 +/- 0.29) x 10(-3) and B(h(c) -> gamma eta) = (4.7 +/- 1.5 +/- 1.4) x 10(-4), respectively, where the first errors are statistical and the second are systematic uncertainties.
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| 34. |
- Ablikim, M., et al.
(författare)
-
Observation of Ψ(3686) → e+e-ΧcJ and ΧcJ → e+e-J/Ψ
- 2017
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 118:22
-
Tidskriftsartikel (refereegranskat)abstract
- Using 4.479 x 10(8) psi(3686) events collected with the BESIII detector, we search for the decays psi(3686) -> e(+)e(-)chi(cJ) and chi(cJ) -> e(+)e(-)J/psi, where J = 0, 1, 2. The decays psi(3686) -> e(+)e(-)chi(cJ) and chi(cJ) -> e(+)e(-)J/psi are observed for the first time. The measured branching fractions are B(psi(3686) -> e(+)e(-)chi(cJ)) = (11.7 +/- 2.5 +/- 1.0) x 10(-4), (8.6 +/- 0.3 +/- 0.6) x 10(-4), (6.9 +/- 0.5 +/- 0.6) x 10(-4) for J = 0, 1, 2, and B(chi(cJ) -> e(+)e(-)J/psi) = (1.51 +/- 0.30 +/- 0.13)x10(-4), (3.73 +/- 0.09 +/- 0.25)x10(-3), (2.48 +/- 0.08 +/- 0.16)x10(-3) for J = 0, 1, 2, respectively. The ratios of the branching fractions B(psi(3686) -> e(+)e(-)chi(cJ))/B(psi(3686) -> gamma chi(cJ)) and B(chi(cJ) -> e(+)e(-)J/psi)/B(chi(cJ) -> gamma J/psi) are also reported. Also, the alpha values of helicity angular distributions of the e(+)e(-) pair are determined for psi(3686) -> e(+)e(-)chi(c1,2) and chi(c1,2) -> e(+)e(-)J/psi.
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| 35. |
- Ablikim, M., et al.
(författare)
-
Precision measurement of the mass of the tau lepton
- 2014
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 90:1
-
Tidskriftsartikel (refereegranskat)abstract
- An energy scan near the tau pair production threshold has been performed using the BESIII detector. About 24 pb(-1) of data, distributed over four scan points, were collected. This analysis is based on t pair decays to ee, e mu, eh, h, hh, e.,. and p. final states, where h denotes a charged p or K. The mass of the t lepton is measured from a maximum likelihood fit to the t pair production cross- section data to be m(tau) = 1776.91 +/- 0.12_0.10 - 0.13 _ MeV/c(2), which is currently the most precise value in a single measurement.
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| 36. |
- Ablikim, M., et al.
(författare)
-
Search for C-parity violation in J/psi -> gamma gamma and gamma phi
- 2014
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 90:9, s. 092002-
-
Tidskriftsartikel (refereegranskat)abstract
- Using 1.06 x 10(8) psi(3686) events recorded in e(+)e(-) collisions at root s = 3.686 GeV with the BESIII at the BEPCII collider, we present searches for C-parity violation in J/psi -> gamma gamma and gamma phi decays via psi(3686) -> J/psi pi(+)pi(-). No significant signals are observed in either channel. Upper limits on the branching fractions are set to be B(J/psi -> gamma gamma) < 2.7 x 10(-7) and B(J/psi -> gamma phi) < 1.4 x 10(-6) at the 90% confidence level. The former is one order of magnitude more stringent than the previous upper limit, and the latter represents the first limit on this decay channel.
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| 37. |
- Ablikim, M., et al.
(författare)
-
Search for the radiative transitions Psi(3770) -> gamma eta(c) and gamma eta(c) (2S)
- 2014
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 89:11, s. 112005-
-
Tidskriftsartikel (refereegranskat)abstract
- By using a 2.92 fb-1 data sample taken at pffisffiffi 3.773 GeV with the BESIII detector operating at the BEPCII collider, we search for the radiative transitions.d3770c and cd2S through the hadronic decays cdcd2S. K0 SK p. No significant excess of signal events above background is observed. We set upper limits at a 90% confidence level for the product branching fractions to be Bdd3770cxBd.c. K0 SK k p < 1.6x10-5 and Bd.d3770cd2SxBd.cd2S. K0 SK p<5.6x10-6. Combining our result with world-average values of Bd.cd.cd2S. K0 SK p, we find the branching fractions Bd.d3770c< 6.8 x 10-4 and Bd.d3770cd2S< 2.0 x 10-3 at a 90% confidence level.
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| 38. |
- Ablikim, M., et al.
(författare)
-
Search for the rare decays J/y -> D-s(-) rho(+) and J/psi -> <(D)over bar(0)<(K)over bar*(0)
- 2014
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 89:7, s. 071101-
-
Tidskriftsartikel (refereegranskat)abstract
- A search for the rare decays of J/psi -> D-S(-) rho(+) + c.c. and J/psi -> <(D)over bar(0)<(K)over bar*(0) + c.c. is performed with a data sample of 225.3-million J/psi events collected with the Beijing Spectrometer III detector. No evident signal is observed. Upper limits on the branching fractions are determined to be beta(J/psi -> D-S(-)rho(+) + c.c.) < 1.3 x 10(-5) and beta(J/psi -> <(D)over bar(0)<(K)over bar*(0) + c.c.) < 2.5 x 10(-6) at the 90% confidence level.
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| 39. |
- Ablikim, M., et al.
(författare)
-
Search for the Y(4140) via e(+)e(-) -> gamma phi J/psi at root s=4.23, 4.26 and 4.36 GeV
- 2015
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 91:3
-
Tidskriftsartikel (refereegranskat)abstract
- Using data samples collected at center-of-mass energies root s = 4.23, 4.26, and 4.36 GeV with the BESIII detector operating at the BEPCII storage ring, we search for the production of the charmoniumlike state Y(4140) through a radiative transition followed by its decay to phi J/psi. No significant signal is observed and upper limits on sigma[e(+)e(-) -> gamma Y(4140)] . B(Y(4140) -> phi J/psi at the 90% confidence level are estimated as 0.35, 0.28, and 0.33 pb at root s = 4.23, 4.26, and 4.36 GeV, respectively.
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| 40. |
- Ablikim, M., et al.
(författare)
-
Searches for isospin-violating transitions chi(c0,2) -> pi(0)eta(c)
- 2015
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 91:11
-
Tidskriftsartikel (refereegranskat)abstract
- We present the first upper-limit measurement of the branching fractions of the isospin-violating transitions chi(c0,2) -> pi(0)eta(c). The measurements are performed using 106 x 10(6) psi(3686) events accumulated with the BESIII detector at the BEPCII e(+)e(-) collider at a center-of-mass energy corresponding to the psi(3686) mass. We obtained upper limits on the branching fractions at a 90% confidence level of B(chi(c0) -> pi(0)eta(c)) < 1.6 x 10(-3) and B(chi(c2) -> pi(0)eta(c)) < 3.2 x 10(-3).
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| 41. |
- Ablikim, M., et al.
(författare)
-
Study of chi(cJ) decaying into phi K*(892)(K)over-bar
- 2015
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 91:11
-
Tidskriftsartikel (refereegranskat)abstract
- Using a data sample of 106 million psi(3686) events collected with the BESIII detector operated at the BEPCII storage ring, we study for the first time the decays chi(cJ) -> phi(KSK +/-)-K-0 pi(-/+) and chi(cJ) -> phi K+K-pi(0) in the E1 radiative transition psi(3686) -> gamma chi(cJ). The decays are dominated by the three-body decay chi(cJ) -> phi K*(892)(K) over bar. We measure branching fractions for this reaction via the neutral and charged K*(892) and find them consistent with each other within the expectation of isospin symmetry. In the K (K) over bar pi invariant mass distribution, a structure near the K*(892)(K) over bar mass threshold is observed, and the corresponding mass and width are measured to be 1412 +/- 4(stat) +/- 8(sys) MeV/c(2) and Gamma = 84 +/- 12(stat) +/- 40(sys) MeV, respectively. The observed state favors an assignment to the h(1)(1380), considering its possible J(PC) and comparing its mass, width and decay mode to those reported in the Particle Data Group.
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| 42. |
- Ablikim, M., et al.
(författare)
-
Study of e(+)e(-) -> p(p)over-bar pi(0) in the vicinity of the psi(3770)
- 2014
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 90:3, s. 032007-
-
Tidskriftsartikel (refereegranskat)abstract
- The process e(+)e(-) -> p (p) over bar pi(0) has been studied by analyzing data collected at root s = 3.773 GeV, root s = 3.650 GeV, and during a psi(3770) line shape scan with the BESIII detector at the BEPCII collider. The Born cross section of p (p) over bar pi(0) in the vicinity of the psi(3770) is measured, and the Born cross section of psi(3770) -> p (p) over bar pi(0) is extracted considering interference between resonant and continuum production amplitudes. Two solutions with the same probability and a significance of 1.5 sigma are found. The solutions for the Born cross section of psi(3770) -> p (p) over bar pi(0) are 33.8 +/- 1.8 +/- 2.1 pb and 0.06(-0.04-0.01)(+0.10+0.01) pb (< 0.22 pb at a 90% confidence level). Using the estimated cross section and a constant decay amplitude approximation, the cross section sigma(p<(p)over bar> -> psi(3770)pi(0)) is calculated for the kinematic situation of the planned (p) over bar ANDA experiment. The maximum cross section corresponding to the two solutions is expected to be less than 0.79 nb at 90% confidence level and 122 +/- 10 nb at a center-of-mass energy of 5.26 GeV.
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| 43. |
- Ablikim, M., et al.
(författare)
-
Study of J/psi -> eta phi pi(+)pi(-) at BESIII
- 2015
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 91:5
-
Tidskriftsartikel (refereegranskat)abstract
- invariant mass spectrum of phi f(0)(980) with a statistical significance of greater than 10 sigma. The corresponding mass and width are determined to be M = 2200 +/- 6(stat) +/- 5(syst) MeV/c(2) and Gamma = 104 +/- 15(stat) +/- 15(syst) MeV, respectively, and the product branching fraction is measured to be B(J/psi ->eta Y(2175), Y(2175)->phi f(0)(980), f(0)(980)->pi(+)pi(-)) = (1.20 +/- 0.14(stat)+/- 0.37(syst))x10(-4). The results are consistent within errors with those of previous experiments. We also measure the branching fraction of J/psi ->phi f(1)(1285) with f(1)(1285)->eta pi(+)pi(-) and set upper limits on the branching fractions for J/psi ->phi eta(1405)/phi X(1835)/phi X(1870) with eta(1405)/X(1835)/X(1870)->eta pi(+)pi(-) at the 90% confidence level.
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| 44. |
- Ablikim, M., et al.
(författare)
-
Amplitude analysis of the π$^0$π$^0$ system produced in radiative J/ψ decays
- 2016
-
Ingår i: PHYSICAL REVIEW D. - 2470-0010. ; 93:3
-
Tidskriftsartikel (refereegranskat)abstract
- An amplitude analysis of the π0π0 system produced in radiative J/ψ decays is presented. In particular, a piecewise function that describes the dynamics of the π0π0 system is determined as a function of Mπ0π0 from an analysis of the (1.311±0.011)×109 J/ψ decays collected by the BESIII detector. The goal of this analysis is to provide a description of the scalar and tensor components of the π0π0 system while making minimal assumptions about the properties or number of poles in the amplitude. Such a model-independent description allows one to integrate these results with other related results from complementary reactions in the development of phenomenological models, which can then be used to directly fit experimental data to obtain parameters of interest. The branching fraction of J/ψ→γπ0π0 is determined to be (1.15±0.05)×10-3, where the uncertainty is systematic only and the statistical uncertainty is negligible.
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| 45. |
- Ablikim, M., et al.
(författare)
-
An improved limit for Gamma(ee) of X(3872) and Gamma(ee) measurement of psi(3686)
- 2015
-
Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 749, s. 414-420
-
Tidskriftsartikel (refereegranskat)abstract
- Using the data sets taken at center-of-mass energies above 4 GeV by the BESIII detector at the BEPCII storage ring, we search for the reaction e(+)e(-) -> gamma(ISR) X(3872) -> gamma(ISR)pi(+)pi(-) J/psi via the Initial State Radiation technique. The production of a resonance with quantum numbers J(PC) = 1(++) such as the X(3872) via single photon e(+)e(-) annihilation is forbidden, but is allowed by a next-to-leading order box diagram. We do not observe a significant signal of X(3872), and therefore give an upper limit for the electronic width times the branching fraction Gamma B-X(3872)(ee)(X(3872) -> pi(+)pi(-) J/psi) < 0.13 eVat the 90% confidence level. This measurement improves upon existing limits by a factor of 46. Using the same final state, we also measure the electronic width of the psi(3686) to be Gamma(psi)(ee)(3686) ee = 2213 +/- 18(stat) +/- 99(sys) eV.
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| 46. |
- Ablikim, M., et al.
(författare)
-
Dark photon search in the mass range between 1.5 and 3.4 GeV/c
- 2017
-
Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 774, s. 252-257
-
Tidskriftsartikel (refereegranskat)abstract
- Using a data set of 2.93 fb taken at a center-of-mass energy root s = 3.773 GeV with the BESIII detector at the BEPCII collider, we perform a search for an extra U(1) gauge boson, also denoted as a dark photon. We examine the initial state radiation reactions e(+)e(-) -> e(+)e(-) gamma(ISR) and e(+)e(-) -> mu(+)mu(-) gamma(ISR) for this search, where the dark photon would appear as an enhancement in the invariant mass distribution of the leptonic pairs. We observe no obvious enhancement in the mass range between 1.5 and 3.4 GeV/c(2) and set a 90% confidence level upper limit on the mixing strength of the dark photon and the Standard Model photon. We obtain a competitive limit in the tested mass range.
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| 47. |
- Ablikim, M., et al.
(författare)
-
Measurement of B(psi(3770) -> gamma chi(c1)) and search for psi(3770) -> gamma chi(c2)
- 2015
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 91:9
-
Tidskriftsartikel (refereegranskat)abstract
- We report a measurement of the branching fraction for psi(3770) -> gamma chi(c1) and search for the transition psi(3770) -> gamma chi(c2) based on 2.92 fb(-1) of e(+)e(-) data accumulated at root s = 3.773 GeV with the BESIII detector at the BEPCII collider. We measure B(psi(3770) -> gamma chi(c1)) = (2.48 +/- 0.15 +/- 0.23) x 10(-3), which is the most precise measurement to date. The upper limit on the branching fraction of psi(3770) -> gamma chi(c2) at a 90% confidence level is B(psi(3770) -> gamma chi(c2)) < 0.64 x 10(-3). The corresponding partial widths are Gamma(psi(3770) -> gamma chi(c1)) = (67.5 +/- 4.1 +/- 6.7)keV and Gamma(psi(3770) -> gamma chi(c2)) < 17.4 keV.
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| 48. |
- Ablikim, M., et al.
(författare)
-
Measurement of the absolute branching fraction of D+ → K̅0 e+νe via K̅0 → π 0 π 0
- 2016
-
Ingår i: Chinese Physics C. - : IOP Publishing. - 1674-1137 .- 2058-6132. ; 40:11
-
Tidskriftsartikel (refereegranskat)abstract
- By analyzing 2.93 fb(-1) data collected at the center-of-mass energy root s = 3.773 GeV with the BESIII detector, we measure the absolute branching fraction of the semileptonic decay D+ -> (K) over bar (0)e(+)nu(e) to be B(D (+) -> (K) over bar (0)e(+)nu(e)) = (8.59 +/- 0.14 +/- 0.21)% using (K) over bar (0) -> K-S(0) -> pi(0) pi(0), where the first uncertainty is statistical and the second systematic. Our result is consistent with previous measurements within uncertainties..
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| 49. |
- Ablikim, M., et al.
(författare)
-
Measurement of the branching fractions of D-s(+) -> eta ' X and D-s(+) -> eta 'rho(+) in e(+)e(-) -> Ds+Ds-
- 2015
-
Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 750, s. 466-474
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Tidskriftsartikel (refereegranskat)abstract
- We study D-s(+) decays to final states involving the eta' with a 482 pb(-1) data sample collected at root s = 4.009 GeV with the BESIII detector at the BEPCII collider. We measure the branching fractions B(D-s(+) -> eta'X) = (8.8 +/- 1.8 +/- 0.5)% and B(D-s(+) > eta'rho(+)) = (5.8 +/- 1.4 +/- 0.4)% where the first uncertainty is statistical and the second is systematic. In addition, we estimate an upper limit on the non-resonant branching ratio B(D-s(+) -> eta'pi(+)pi(0)) < 5.1% at the 90% confidence level. Our results are consistent with CLEO's recent measurements and help to resolve the disagreement between the theoretical prediction and CLEO's previous measurement of B(D-s(+) -> eta'rho(+)).
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- Ablikim, M., et al.
(författare)
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Measurement of the $D\to K^-\pi^+$ strong phase difference in $\psi(3770)\to D^0\overline{D}{}^0$
- 2014
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Ingår i: PHYSICS LETTERS B. - : Elsevier BV. - 0370-2693. ; 734
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Tidskriftsartikel (refereegranskat)abstract
- We study $D^0\overline{D}{}^0$ pairs produced in $e^+e^-$ collisions at $\sqrt{s}=3.773$ GeV using a data sample of 2.92 fb$^{-1}$ collected with the BESIII detector. We measure the asymmetry $\mathcal{A}^{CP}_{K\pi}$ of the branching fractions of $D \to K^-\pi^+$ in $CP$-odd and $CP$-even eigenstates to be $(12.7\pm1.3\pm0.7)\times10^{-2}$. $\mathcal{A}^{CP}_{K\pi}$ can be used to extract the strong phase difference $\delta_{K\pi}$ between the doubly Cabibbo-suppressed process $\overline{D}{}^{0}\to K^-\pi^+$ and the Cabibbo-favored process $D^0\to K^- \pi^+$. Using world-average values of external parameters, we obtain $\cos\delta_{K\pi} = 1.02\pm0.11\pm0.06\pm0.01$. Here, the first and second uncertainties are statistical and systematic, respectively, while the third uncertainty arises from the external parameters. This is the most precise measurement of $\delta_{K\pi}$ to date.
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