| 1. |
- Ablikim, M., et al.
(författare)
-
First direct measurement of the absolute branching fraction of Sigma(+) -> Lambda e(+)upsilon(e)
- 2023
-
Ingår i: Physical Review D. - : American Physical Society (APS). - 2470-0010 .- 2470-0029. ; 107:7
-
Tidskriftsartikel (refereegranskat)abstract
- The first direct measurement of the absolute branching fraction of Sigma(+) -> Lambda e(+)nu(e) is reported based on an e(+) e(-) annihilation sample of (10087 +/- 44) x 10(6) J/psi events collected with the BESIII detector at root s = 3.097 GeV. The branching fraction is determined to be B(Sigma(+)-> Lambda e(+)nu(e))=2.93 +/- 0.74 (stat) +/- 0.13(syst)] x 10(-5), which is the most precise measurement obtained in a single experiment to date and also the first result obtained at a collider experiment. Combining this result with the world average of B(Sigma(-)-> Lambda e(-) (nu) over bar (e). and the lifetimes of Sigma(+/-), the ratio, Gamma (Sigma(-) ->Lambda e(-) (nu) over bar (e) /Sigma(+) -> Lambda e(+) (nu) over bar (e), is determined to be 1.06 +/- 0.28, which is within 1.8 standard deviations of the value expected in the absence of second-class currents.
|
|
| 2. |
- Ablikim, M., et al.
(författare)
-
Measurement of cross sections for e(+) e(-) -> mu(+) mu(-) at center-of-mass energies from 3.80 to 4.60 GeV
- 2020
-
Ingår i: Physical Review D. - : American Physical Society (APS). - 2470-0010 .- 2470-0029. ; 102:11
-
Tidskriftsartikel (refereegranskat)abstract
- The observed cross sections for e(+)e(-) -> mu(+) mu(-) at energies from 3.8 to 4.6 GeVare measured using data samples taken with the BESIII detector operated at the BEPCII collider. We measure the muonic widths and determine the branching fractions of the charmonium states psi(4040), psi(4160), and psi(4415) decaying to mu(+)mu(-), as well as making a first determination of the phase of the amplitudes. In addition, we observe evidence for a structure in the dimuon cross section near 4.220 GeV/(c)2, which we denote as So4220+. Analyzing a coherent sum of amplitudes yields eight solutions, one of which gives a mass of M-S(4220) = 4216.7 +/- 8.9 +/- 4.1 MeV/c(2), a total width of Gamma(tot+)(S(4220)) = 47.2 +/- 22.8 +/- 10.5 MeV, and a muonic width of Gamma(mu mu)(S(4220))+ = 1.53 +/- 1.26 +/- 0.54 keV, where the first uncertainties are statistical and the second systematic. The eight solutions give the central values of the mass, total width, muonic width to be, respectively, in the range from 4212.8 to 4219.4 MeV/c(2), from 36.4 to 49.6 MeV, and from 1.09 to 1.53 keV. The statistical significance of the S(4220) signal is 3.9 sigma. Correcting the total dimuon cross section for radiative effects yields a statistical significance for this structure of 8.1 sigma.
|
|
| 3. |
- Ablikim, M., et al.
(författare)
-
Measurement of the absolute branching fraction for Lambda(+)(c) -> Lambda mu(+)nu(mu)
- 2017
-
Ingår i: Physics Letters B. - : ELSEVIER SCIENCE BV. - 0370-2693 .- 1873-2445. ; 767, s. 42-47
-
Tidskriftsartikel (refereegranskat)abstract
- We report the first measurement of the absolute branching fraction for Lambda(+)(c) -> Lambda mu(+)nu(mu).This measurement is based on a sample of e+e(-) annihilation data produced at a center-of-mass energy root s = 4.6 GeV, collected with the BESIII detector at the BEPCII storage rings. The sample corresponds to an integrated luminosity of 567 pb(-1). The branching fraction is determined to be B( Lambda(+)(c) -> Lambda mu(+)nu(mu)) = (3.49 +/- 0.46( stat) +/- 0.27( syst))%. In addition, we calculate the ratio B( Lambda(+)(c) -> Lambda mu(+)nu(mu))/B(Lambda(+)(c) -> Lambda e(+)nu(e) to be 0.96 +/- 0.16( stat) +/- 0.04( syst).
|
|
| 4. |
- Ablikim, M., et al.
(författare)
-
Measurement of the form factors in the decay D+ → ωe+νe and search for the decay D+ → ϕe+νe
- 2015
-
Ingår i: Physical Review D. - : American Physical Society. - 1550-7998 .- 1550-2368. ; 92:7
-
Tidskriftsartikel (refereegranskat)abstract
- Using 2.92 fb−1 of electron-positron annihilation data collected at a center-of-mass energy of √s=3.773 GeV with the BESIII detector, we present an improved measurement of the branching fraction B(D+ → ωe+νe)=(1.63±0.11±0.08)×10−3. The parameters defining the corresponding hadronic form factor ratios at zero momentum transfer are determined for the first time; we measure them to be rV=1.24±0.09±0.06 and r2=1.06±0.15±0.05. The first and second uncertainties are statistical and systematic, respectively. We also search for the decay D+ → ϕe+νe. An improved upper limit B(D+ → ϕe+νe)<1.3×10−5 is set at 90% confidence level.
|
|
| 5. |
- Ablikim, M., et al.
(författare)
-
Observation of OZI-suppressed decays chi(cJ) -> omega phi
- 2019
-
Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 99:1
-
Tidskriftsartikel (refereegranskat)abstract
- Decays chi(cJ)(J = 0, 1, 2) -> omega phi are studied using (448.1 +/- 2.9) x 10(6)psi(3686) events collected with the BESIII detector in 2009 and 2012. In addition to the previously established chi(c0) -> omega phi, the first observation of chi(c1) -> omega phi is reported in this paper. The measured product branching fractions are B(psi(3686) -> gamma chi(c0)) x B(chi(c0) -> omega phi) = (13.83 +/- 0.70 +/- 1.01) x 10(-6) and B(psi(3686) -> gamma chi(c1)) x B(chi(c1) -> omega phi) = (2.67 +/- 0.31 +/- 0.27) x 10(-6), and the absolute branching fractions are B(chi(c0) -> omega phi) = (13.84 +/- 0.70 +/- 1.08) x 10(-5) and B(chi(c1) -> omega phi) = (2.80 +/- 0.32 +/- 0.30) x 10(-5). We also find strong evidence for chi(c2) -> omega phi with a statistical significance of 4.8 sigma, and the corresponding product and absolute branching fractions are measured to he B(psi(3686) -> gamma chi(c2)) x B(chi(c2) -> omega phi) = (0.91 +/- 0.23 +/- 0.12) x 10(-6) and B(chi(c2) -> omega phi) = (1.00 +/- 0.25 +/- 0.14) x 10(-5). Here, the first errors are statistical and the second ones systematic.
|
|
| 6. |
- Ablikim, M., et al.
(författare)
-
Observation of the Psi(1(3)D(2)) State in e(+)e(-) -> pi(+)pi(-)gamma chi(c1) at BESIII
- 2015
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 115:1
-
Tidskriftsartikel (refereegranskat)abstract
- We report the observation of the X(3823) state in the process e(+)e(-) -> pi(+)pi(-) X(3823) pi(+)pi(-)gamma chi(c1) with a statistical significance of 6.2 sigma, in data samples at center-of-mass energies root s = 4.230, 4.260, 4.360, 4.420, and 4.600 GeV collected with the BESIII detector at the BEPCII electron positron collider. The measured mass of the X(3823) state is (3821.7 +/- 1.3 +/- 0.7) MeV/c(2), where the first error is statistical and the second systematic, and the width is less than 16 MeV at the 90% confidence level. The products of the Born cross sections for e(+)e(-) -> pi(+)pi(-) X(3823) and the branching ratio B [X(3823) -> gamma X-c1c2] are also measured. These measurements are in good agreement with the assignment of the X(3823) state as the Psi(1(3)D(2)) charmonium state.
|
|
| 7. |
- Ablikim, M., et al.
(författare)
-
Precision measurement of the D*(0) decay branching fractions
- 2015
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368 .- 2470-0010. ; 91:3
-
Tidskriftsartikel (refereegranskat)abstract
- Using 482 pb(-1) of data taken at root s = 4.009 GeV, we measure the branching fractions of the decays of D*(0) into D-0 pi(0) and D-0 gamma to be B(D*(0) -> D-0 pi(0)) = (65.5 +/- 0.8 +/- 0.5)% and B(D*(0) -> D0 gamma) = (34.5 +/- 0.8 +/- 0.5)%, respectively, by assuming that the D*(0) decays only into these two modes. The ratio of the two branching fractions is B(D*(0) -> D-0 pi(0))/B(D*(0) -> D-0 gamma) = 1.90 +/- 0.07 +/- 0.05, which is independent of the assumption made above. The first uncertainties are statistical and the second ones systematic. The precision is improved by a factor of 3 compared to the present world average values.
|
|
| 8. |
- Ablikim, M., et al.
(författare)
-
Search for intermediate resonances and dark gauge bosons in J/ψ→γπ0η′
- 2020
-
Ingår i: Physical Review D. - : American Physical Society (APS). - 1550-7998 .- 1550-2368. ; 102:5
-
Tidskriftsartikel (refereegranskat)abstract
- We report on an analysis of the decay J/ψ→γπ0η′ using a sample of (1310.6±7.0)×106J/ψ events collected with the BESIII detector. We search for the CP-violating process ηc→π0η′ and a dark gauge boson U′ in J/ψ→U′η′,U′→γπ0,π0→γγ. No evidence of an ηc signal is observed in the π0η′ invariant-mass spectrum and the upper limit of the branching fraction is determined to be 5.6×10−5 at the 90% confidence level. We also find no evidence of U′ production and set upper limits at the 90% confidence level on the product branching fraction B(J/ψ→U′η′)×B(U′→π0γ) in the range between (0.8−6.5)×10−7 for 0.2≤mU′≤2.1 GeV/c2. In addition, we study the process J/ψ→ωη′ with ω→γπ0. The branching fraction of J/ψ→ωη′ is found to be (1.87±0.09±0.12)×10−4, where the first uncertainty is statistical and the second is systematic, with a precision that is improved by a factor of 1.4 over the previously published BESIII measurement.
|
|
| 9. |
- Ablikim, M., et al.
(författare)
-
Search for the rare decay D+ → D0e+νe
- 2017
-
Ingår i: Physical Review D. - 2470-0010 .- 2470-0029. ; 96:9
-
Tidskriftsartikel (refereegranskat)abstract
- Using a data set with an integrated luminosity of 2.93 fb(-1) collected at root s = 3.773 GeV with the BESIII detector operating at the BEPCII storage rings, we search for the rare decay D+ -> D(0)e(+)nu(e). No signal events are observed. We set the upper limit on the branching fraction for D+ -> D(0)e(+)nu(e) to be 1.0 x 10(-4) at the 90% confidence level.
|
|
| 10. |
- Ablikim, M., et al.
(författare)
-
Search for the rare decay eta ' -> pi(0)pi(0)pi(0)pi(0) at BESIII
- 2020
-
Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 101:3
-
Tidskriftsartikel (refereegranskat)abstract
- Using a sample of 1.31 x 10(9) J/psi events collected with the BESIII detector, we perform a search for the rare decay if eta' -> 4 pi(0) via J/psi -> gamma eta'. No significant eta' signal is observed in the 4 pi(0) invariant mass spectrum. With a Bayesian approach, the upper limit on the branching fraction is determined to be B(eta' -> 4 pi(0)) < 4.94 x 10(-5) at the 90% confidence level, which is a factor of 6 smaller than the previous experimental limit.
|
|
