Precision measurement of theD*0decay branching fractions

Abstract

We study the decays of the J/ψ and ψ ′ mesons to π + π − π 0 using data samples at both resonances collected with the BES III detector in 2009. We measure the corresponding branching fractions with unprecedented precision and provide mass spectra and Dalitz plots. The branching fraction for J/ψ −→ π + π − π 0 is determined to be (2.137 ± 0.004 (stat.) +0.058 −0.056 (syst.) +0.027 −0.026 (norm.)) × 10 −2 , and the branching fraction for ψ ′ −→ π + π − π 0 is measured as (2.14 ± 0.03 (stat.) +0.08 −0.07 (syst.) +0.09 −0.08 (norm.)) × 10 −4 .The J/ψ decay is found to be dominated by an intermediate ρ( 770) state, whereas the ψ ′ decay is dominated by di-pion masses around 2.2 GeV/c 2 , leading to strikingly different Dalitz distributions.

QCD calculations of radiative heavy meson decays with subleading power corrections

“…However, implementing an approximation to avoid the double Borel transformation with respect to the variables p 2 and (p + q) 2 [14] yields contamination of the obtained sum rules due to the "non-diagonal" transitions of the ground state to excited states. The resulting prediction for the branching fraction of D * 0 → D 0 γ turned out to be larger than that for the strong decay process D * 0 → D 0 π 0 [14], in contradiction with the experimental measurements from the CLEO [15,16], BaBar [17], and BES III [18] Collaborations. Subsequently, the radiative charm-meson decay form factors were computed from the three-point QCDSR approach 1 , including the power suppressed corrections from the higher-dimension operators up to the four-quark condensate [20], yielding the theoretical predictions in reasonable agreement with the experimental results [15][16][17][18].…”

“…The resulting prediction for the branching fraction of D * 0 → D 0 γ turned out to be larger than that for the strong decay process D * 0 → D 0 π 0 [14], in contradiction with the experimental measurements from the CLEO [15,16], BaBar [17], and BES III [18] Collaborations. Subsequently, the radiative charm-meson decay form factors were computed from the three-point QCDSR approach 1 , including the power suppressed corrections from the higher-dimension operators up to the four-quark condensate [20], yielding the theoretical predictions in reasonable agreement with the experimental results [15][16][17][18]. As demonstrated in [20], the numerically dominant contribution to the tree-level sum rules for the radiative D * + (s) → D + (s) γ form factors arises from the dimension-3 quark condensate correction instead of the leading power perturbative effect, due to the strong cancellation for the photon radiation off the charm and the anti-down (anti-strange) quarks, which also justifies the high suppression of the D * + (s) D + (s) γ coupling compared with the magnetic moment for the counterpart neutral D * 0 -meson.…”

Combined analysis of charm-quark fragmentation-fraction measurements

“…Compared to those, the present analysis extends to a larger set of measurements, in particular the final measurement in PHP by the ZEUS experiment at HERA [15], the pp measurements from LHCb [19,20], ALICE [21][22][23], ATLAS [24] and the Λ + c measurements from the BABAR experiment [8]. It uses the up-to-date branching-ratio values [25,29,30], treats correlations of branching-ratio uncertainties and recent theory predictions with reduced uncertainties [31,32] as input.…”

Combined analysis of charm-quark fragmentation-fraction measurements

“…[25]. The B(D * 0 → D 0 π 0 ) was calculated from the two most precise measurements [29,30] [25] 3 0 .70 ± 0.50, BELLE [7] D * + → D 0 π + 67.70 ± 0.50 [25] 6 8 .13 ± 1.40, ALEPH [11] 67.70 ± 0.50, ALICE [21][22][23] 55.00 ± 4.00, ARGUS [3][4][5] 67.70 ± 0.50, ATLAS [24] 67.70 ± 0.50, BELLE [7] 67.60 ± 0.50, H1 [18] 67.70 ± 0.50, ZEUS [14][15][16]33] 67.70 ± 0.50, LHCb [20] 68.30 ± 1.40, OPAL [9,10] D * 0 → D 0 100.00 [29,30] [6,8] D + → K − π + π + 9.46 ± 0.24 [25] 9 .13 ± 0.19, ALICE [21][22][23] 7.70 ± 1.00, ARGUS [3][4][5] 9.13 ± 0.19, ATLAS [24] 9.20 ± 0.60, BELLE [7] 9.00 ± 0.60, H1 [18] 9.51 ± 0.34, ZEUS [16,33] 9.20 ± 0.60, ZEUS [14] 9.13 ± 0.19, ZEUS [15] 9.13 ± 0.19, LHCb [19,20] D + → K 0 π + 1.53 ± 0.06 [25] D 0 → K − π + 3.93 ± 0.04 [25] 3 .85 ± 0.09, ALEPH [11] 3.87 ± 0.05, ALICE …”

“…Compared to those, the present analysis extends to a larger set of measurements, in particular the final measurement in PHP by the ZEUS experiment at HERA [15], the pp measurements from LHCb [19,20], ALICE [21][22][23], ATLAS [24] and the + c measurements from the BABAR experiment [8]. It uses the up-to-date branching-ratio values [25,29,30], treats correlations of branching-ratio uncertainties and recent theory predictions with reduced uncertainties [31,32] as input.…”