Observation of the Semileptonic Decay D0→a0(980)−

Abstract

Using an e^{+}e^{-} collision data sample of 2.93 fb^{-1} collected at a center-of-mass energy of 3.773 GeV by the BESIII detector at BEPCII, we report the observation of D^{0}→a_{0}(980)^{-}e^{+}ν_{e} and evidence for D^{+}→a_{0}(980)^{0}e^{+}ν_{e} with significances of 6.4σ and 2.9σ, respectively. The absolute branching fractions are determined to be B(D^{0}→a_{0}(980)^{-}e^{+}ν_{e})×B(a_{0}(980)^{-}→ηπ^{-})=[1.33_{-0.29}^{+0.33}(stat)±0.09(syst)]×10^{-4} and B(D^{+}→a_{0}(980)^{0}e^{+}ν_{e})×B(a_{0}(980)^{0}→ηπ^{0})=[1.66_{-0.66}^{+0.81}(stat)±0.11(syst)]×10^{-4}. This is the first time the a_{0}(980) meson has been measured in a D^{0} semileptonic decay, which would open one more interesting page in the investigation of the nature of the puzzling a_{0}(980) states.

a0(980) physics in semileptonic D0Achasov1, Киселев2 2018Phys. Rev. D212190View full textAdd to dashboardCite

“…þ a 0− 0 e þ ν → π − ηe þ ν and D þ → dde þ ν → ½a 0 0 ð980Þ þ a 00 0 e þ ν → π 0 ηe þ ν decays is presented and does not contradict the data [30]. An experiment on higher statistics could check this prediction.…”

“…3(a) that the Ref. [30] curve lies below the data in the interval m ≡ M ηπ ¼ 1.1-1.3 GeV (though within large errors). It may be a manifestation of a sizable a 0 0 contribution.…”

“…The first measurement of D 0 → dūe þ ν → ½a − 0 ð980Þ þ a 0− 0 e þ ν → π − ηe þ ν and D þ → dde þ ν → ½a 0 0 ð980Þ þ a 00 0 e þ ν → π 0 ηe þ ν decays [30] is an important step for the investigation of the nature of light scalar mesons.…”

“…In Ref. [30] fits take into account only the a 0 ð980Þ contribution, but one can see from Fig. 3(a) that the Ref.…”

Study of the isospin breaking decay Y(2175)→ϕf0(980)Cheng1, Li2, Wang3 et al. 2019Phys. Rev. D8030View full textAdd to dashboardCite

“…here, the minus sign is associated with the λ π 0 η vertex corresponding to the π 0 ↔ η transition [13,46,47]. m f 0 = (0.99 ± 0.02)GeV [44] Γ f 0 = 0.074GeV [48] m a 0 = (0.98 ± 0.02)GeV [44] Γ a 0 = (0.092 ± 0.008)GeV [44] m Y = (2.188 ± 0.010)GeV [44] Γ Y = (0.083 ± 0.012)GeV [44] m φ = 1019M eV [44] g a 0 ηπ 0 = 2.43GeV [1,49] g a 0 K + K − = (2.76 ± 0.46)GeV [50,51] g a 0 K 0K0 = (2.76 ± 0.46)GeV [50,51] g f 0 π + π − = 1.39GeV [1,49] g f 0 π 0 π 0 = 0.98GeV [1,49] [29] where Γ f 0 and Γ a 0 are the decay widths of f 0 (980) and a 0 0 (980), respectively. From Refs.…”