Refine
Document Type
- Article (102) (remove)
Language
- English (102)
Has Fulltext
- yes (102)
Is part of the Bibliography
- no (102)
Keywords
- BESIII (10)
- e +-e β Experiments (10)
- Branching fraction (7)
- Lepton colliders (4)
- Particle and Resonance Production (4)
- Quarkonium (4)
- Charm Physics (3)
- Charmed mesons (3)
- Electroweak interaction (3)
- Exotics (3)
Institute
- Physik (101)
Precision measurements of DβΊβ β πeβΊβ’πβ and DβΊβ β πβ²β’eβΊβ’πβ
(2023)
Precision measurements of the semileptonic decays π·+π βπβ’π+β’ππ and π·+π βπβ²β’π+β’ππ are performed with 7.33ββfbβ1 of π+β’πβ collision data collected at center-of-mass energies between 4.128 and 4.226 GeV with the BESIII detector. The branching fractions obtained are β¬β‘(π·+π βπβ’π+β’ππ) = (2.255Β±0.03β’9statΒ±0.05β’1syst)% and β¬β‘(π·+π βπβ²β’π+β’ππ)=(0.810Β±0.03β’8statΒ±0.02β’4syst)%. Combining these results with the β¬β‘(π·+βπβ’π+β’ππ) and β¬β‘(π·+βπβ²β’π+β’ππ) obtained from previous BESIII measurements, the πβπβ² mixing angle in the quark flavor basis is determined to be πP=(40.0Β±2.0statΒ±0.6syst)Β°. Moreover, from the fits to the partial decay rates of π·+π βπβ’π+β’ππ and π·+π βπβ²β’π+β’ππ, the products of the hadronic transition form factors ππ(β²)+β‘(0) and the modulus of the πβπ Cabibbo-Kobayashi-Maskawa matrix element |ππβ’π | are determined by using different hadronic transition form factor parametrizations. Based on the two-parameter series expansion, the products ππ+β‘(0)β’|ππβ’π | = 0.4519Β±0.007β’1statΒ±0.006β’5syst and ππβ²+β‘(0)β’|ππβ’π | = 0.525Β±0.02β’4statΒ±0.00β’9syst are extracted. All results determined in this work supersede those measured in the previous BESIII analyses based on the 3.19ββfbβ1 subsample of data at 4.178 GeV.
A partial-wave analysis of the decay π½/πβπΎ+β’πΎββ’π0 has been made using (223.7Β±1.4)Γ106ββπ½/π events collected with the BESIII detector in 2009. The analysis, which is performed within the isobar-model approach, reveals contributions from πΎ*2β’(1430)Β±, πΎ*2β’(1980)Β± and πΎ*4β’(2045)Β± decaying to πΎΒ±β’π0. The two latter states are observed in π½/π decays for the first time. Two resonance signals decaying to πΎ+β’πΎβ are also observed. These contributions cannot be reliably identified and their possible interpretations are discussed. The measured branching fraction π΅β‘(π½/πβπΎ+β’πΎββ’π0) of (2.88Β±0.01Β±0.12)Γ10β3 is more precise than previous results. Branching fractions for the reported contributions are presented as well. The results of the partial-wave analysis differ significantly from those previously obtained by BESII and BABAR.
Using a sample of (10.09Β±0.04)Γ109 J/Ο events collected with the BESIII detector, a partial wave analysis of J/ΟβΞ³Ξ·β²Ξ·β² is performed.The masses and widths of the observed resonances and their branching fractions are reported. The main contribution is from J/ΟβΞ³f0(2020) with f0(2020)βΞ·β²Ξ·β², which is found with a significance of greater than 25Ο. The product branching fraction B(J/Ο β Ξ³f0(2020))β
B(f0(2020) β Ξ·β²Ξ·β² is measured to be (2.63Β±0.06(stat.) + 0.31β0.46(syst.))Γ10β4.
By analyzing (448.1Β±2.9)Γ106ββπβ‘(3686) events collected with the BESIII detector operating at the BEPCII collider, the decays of ππβ’π½βΞβ’
Β―Ξβ’π (π½=0, 1, and 2) are observed for the first time with statistical significances of 13.9β’π, 6.7β’π, and 8.2β’π, respectively. The product branching fractions of πβ‘(3686)βπΎβ’ππβ’π½ and ππβ’π½βΞβ’Β―Ξβ’π are measured. Dividing by the world averages of the branching fractions of πβ‘(3686)βπΎβ’ππβ’π½, the branching fractions of ππβ’π½βΞβ’Β―Ξβ’π decays are determined to be (2.31Β±0.30Β±0.21)Γ10β4, (5.86Β±1.38Β±0.68)Γ10β5, and (1.05Β±0.21Β±0.15)Γ10β4 for π½=0, 1 and 2, respectively, where the first uncertainties are statistical and the second systematic.
Using a sample of (448.1Β±2.9)Γ106βπβ‘(3686) decays collected with the BESIII detector at BEPCII, we report an observation of Ξβ transverse polarization with a significance of 7.3β’π in the decay πβ‘(3686)βΞββ’ Β―Ξ+ (ΞββΞβ’πβ, Β―Ξ+βΒ―Ξβ’π+, Ξβπβ’πβ, Β―ΞβΒ―πβ’π+). The relative phase of the electric and magnetic form factors is determined to be Ξβ’Ξ¦=(0.667Β±0.111Β±0.058)ββrad. This is the first measurement of the relative phase for a πβ‘(3686) decay into a pair of Ξββ’Β―Ξ+ hyperons. The Ξβ decay parameters (πΌΞβ, πΞβ) and their conjugates (πΌΒ―Ξ+, πΒ―Ξ+), the angular-distribution parameter πΌπ, and the strong-phase difference πΏπβπΏπ for Ξβ’πβ scattering are measured to be consistent with previous BESIII results.
Using (1310.6Β±7.0)Γ106 π½/π events acquired with the BESIII detector at the BEPCII storage rings, the decay πβ²βπ+β’πββ’π+β’πβ is observed for the first time with a significance of 8β’π via the process π½/πβπΎβ’πβ². We measure the branching fraction of πβ²βπ+β’πββ’π+β’πβ to be β¬β‘(πβ²βπ+β’πββ’π+β’πβ)=(1.97Β±0.33β’(stat)Β±0.19β’(syst))Γ10β5, where the first and second uncertainties are statistical and systematic, respectively
The hadronic decay ππβ‘(2β’π)β3β’(π+β’πβ) is observed with a statistical significance of 9.3 standard deviations using (448.1Β±2.9)Γ106ββπβ‘(3686) events collected by the BESIII detector at the BEPCII collider. The measured mass and width of ππβ‘(2β’π) are (3643.4Β±2.3β(stat)Β±4.4β(syst))ββMeV/π2 and (19.8Β±3.9β(stat)Β±3.1β(syst))ββMeV, respectively, which are consistent with the world average values within two standard deviations. The product branching fraction β¬β‘[πβ‘(3686)βπΎβ’ππβ‘(2β’π)]Γβ¬β‘[ππβ‘(2β’π)β3β’(π+β’πβ)] is measured to be (9.2Β±1.0β(stat)Β±1.2β(syst))Γ10β6. Using β¬β‘[πβ‘(3686)βπΎβ’ππβ‘(2β’π)]=(7.β’0+3.4β2.5)Γ10β4, we obtain β¬β‘[ππβ‘(2β’π)β3β’(π+β’πβ)]=(1.31Β±0.15β(stat)Β±0.17β(syst) (+0.64β0.47)β(extr))Γ10β2, where the third uncertainty is from β¬β‘[πβ‘(3686)βπΎβ’ππβ‘(2β’π)]. We also measure the ππβ’π½β3β’(π+β’πβ) (π½=0, 1, 2) decays via πβ²βπΎβ’ππβ’π½ transitions. The branching fractions are β¬β‘[ππβ’0β3β’(π+β’πβ)]=(2.080Β±0.006β(stat)Β±0.068β(syst))Γ10β2, β¬β‘[ππβ’1β3β’(π+β’πβ)]=(1.092Β±0.004β(stat)Β±0.035β(syst))Γ10β2, and β¬β‘[ππβ’2β3β’(π+β’πβ)]=(1.565Β±0.005β(stat)Β±0.048β(syst))Γ10β2.
The cross sections of e+eββK+KβJ/Ο at center-of-mass energies from 4.127 to 4.600~GeV are measured based on 15.6 fbβ1 data collected with the BESIII detector operating at the BEPCII storage ring. Two resonant structures are observed in the line shape of the cross sections. The mass and width of the first structure are measured to be (4225.3Β±2.3Β±21.5) MeV and (72.9Β±6.1Β±30.8)~MeV, respectively. They are consistent with those of the established Y(4230). The second structure is observed for the first time with a statistical significance greater than 8Ο, denoted as Y(4500). Its mass and width are determined to be (4484.7Β±13.3Β±24.1) MeV and (111.1Β±30.1Β±15.2) MeV, respectively. The first presented uncertainties are statistical and the second ones are systematic. The product of the electronic partial width with the decay branching fraction Ξ(Y(4230)βe+eβ)B(Y(4230)βK+KβJ/Ο) is reported.
We report the first observation of the semimuonic decay π·+βπβ’π+β’ππ using an π+β’πβ collision data sample corresponding to an integrated luminosity of 2.93ββfbβ1 collected with the BESIII detector at a center-of-mass energy of 3.773 GeV. The absolute branching fraction of the π·+βπβ’π+β’ππ decay is measured to be β¬π·+βπβ’π+β’ππ=(17.7Β±1.β’8statΒ±1.β’1syst)Γ10β4. Its ratio with the world average value of the branching fraction of the π·+βπβ’π+β’ππ decay probes lepton flavor universality and it is determined to be β¬π·+βπβ’π+β’ππ/β¬PDG π·+βπβ’π+β’ππ=1.05Β±0.14, in agreement with the standard model expectation within one standard deviation.
Using 2.93ββfbβ1 of π+β’πβ collision data collected at a center-of-mass energy of 3.773 GeV with the BESIII detector, the first observation of the doubly Cabibbo-suppressed decay π·+βπΎ+β’π+β’πββ’π0 is reported. After removing decays that contain narrow intermediate resonances, including π·+βπΎ+β’π, π·+βπΎ+β’π, and π·+βπΎ+β’π, the branching fraction of the decay π·+βπΎ+β’π+β’πββ’π0 is measured to be (1.13Β±0.0β’8statΒ±0.0β’3syst)Γ10β3. The ratio of branching fractions of π·+βπΎ+β’π+β’πββ’π0 over π·+βπΎββ’π+β’π+β’π0 is found to be (1.81Β±0.15)%, which corresponds to (6.28Β±0.52)β’tan4β‘ππΆ, where ππΆ is the Cabibbo mixing angle. This ratio is significantly larger than the corresponding ratios for other doubly Cabibbo-suppressed decays. The asymmetry of the branching fractions of charge-conjugated decays π·Β±βπΎΒ±β’πΒ±β’πββ’π0 is also determined, and no evidence for πΆβ’π violation is found. In addition, the first evidence for the π·+βπΎ+β’π decay, with a statistical significance of 3.3β’π, is presented and the branching fraction is measured to be β¬β‘(π·+βπΎ+β’π) = (5.β’7+2.5β2.1statΒ±0.β’2syst)Γ10β5.