Search for hadronic transitionχcJ→ηcπ+π−and observation ofχ

Abstract

Hadronic transitions of χ cJ → η c π + π − (J = 0, 1, 2) are searched for using a sample of 1.06 × 10 8 ψ(3686) events collected with the BESIII detector at the BEPCII storage ring. The η c is reconstructed with K 0 S K ± π ∓ and K + K − π 0 final states. No signals are observed in any of the three χ cJ states in either η c decay mode. At the 90% confidence level, the upper limits are determined to be B(χ c0 → η c π + π − ) < 0.07%, B(χ c1 → η c π + π − ) < 0.32%, and B(χ c2 → η c π + π − ) < 0.54%. The upper limit of B(χ c1 → η c π + π − ) is lower than the existing theoretical prediction by almost an order of magnitude. The branching fractions of χ cJ → K 0 S K ± π ∓ π + π − , K + K − π + π − π 0 , ωK + K − and φπ + π − π 0 (J = 0, 1, 2) are measured for the first time.

Observation of e+e−→ϕχc1 and ϕχ

“…The systematic uncertainty from photon reconstruction is determined to be 1.0% for each photon by studying the control sample of J/ψ → ρ 0 π 0 decays [53]. Since it is difficult to find an appropriate control sample to estimate the systematic uncertainty related to the kinematic fit and the vertex fit, we correct the chargedtrack helix parameters of the MC simulated events [54] to obtain a better match with the data sample. The difference between the efficiency with and without the correction is taken as the uncertainty associated with the kinematic fit.…”

Measurement of the absolute branching fraction of Ds0*(2317)±→Ablikim1, Ачасов2, Ahmed3 et al. 2018Phys. Rev. DSelf Cite15120View full textAdd to dashboardCite

“…To study this difference, we correct the helix parameters of the charged tracks in MC simulation [29]; the difference in χ 2 distribution between data and MC simulation becomes negligibly small according to other studies [30]. We take half of the difference in the ratio of detection efficiencies ϵ sig and ϵ tot between MC simulations with and without this correction as systematic uncertainty (3.1%).…”

Observation of a Neutral Structure near theDD¯*Mass Threshold ine+Ablikim1, Ачасов2, Ai3 et al. 2015Phys. Rev. Lett.Self Cite803390View full textAdd to dashboardCite

“…The uncertainty in π 0 reconstruction is 1% [31]. The systematic bias of the KF is estimated by using the track-parameter-correction method [33]. The correction factors for helix track parameters are determined from the control sample…”