Measurement of the D → K−π+π+π− and D → K−π+π0 coherence factors and average strong-phase differences in quantum-correlated $$ D\overline{D} $$ decays

Abstract

The decays D → K−π+π+π− and D → K−π+π0 are studied in a sample of quantum-correlated $$ D\overline{D} $$ D D ¯ pairs produced through the process e+e− → ψ(3770) → $$ D\overline{D} $$ D D ¯ , exploiting a data set collected by the BESIII experiment that corresponds to an integrated luminosity of 2.93 fb−1. Here D indicates a quantum superposition of a D0 and a $$ {\overline{D}}^0 $$ D ¯ 0 meson. By reconstructing one neutral charm meson in a signal decay, and the other in the same or a different final state, observables are measured that contain information on the coherence factors and average strong-phase differences of each of the signal modes. These parameters are critical inputs in the measurement of the angle γ of the Unitarity Triangle in B− → DK− decays at the LHCb and Belle II experiments. The coherence factors are determined to be RK3π = $$ {0.52}_{-0.10}^{+0.12} $$ 0.52 − 0.10 + 0.12 and $$ {R}_{K{\pi \pi}^0} $$ R K ππ 0 = 0.78 ± 0.04, with values for the average strong-phase differences that are $$ {\delta}_D^{K3\pi }=\left({167}_{-19}^{+31}\right){}^{\circ} $$ δ D K 3 π = 167 − 19 + 31 ° and $$ {\delta}_D^{K{\pi \pi}^0}=\left({196}_{-15}^{+14}\right){}^{\circ} $$ δ D K ππ 0 = 196 − 15 + 14 ° , where the uncertainties include both statistical and systematic contributions. The analysis is re-performed in four bins of the phase-space of the D → K−π+π+π− to yield results that will allow for a more sensitive measurement of γ with this mode, to which the BESIII inputs will contribute an uncertainty of around 6°.

Measurements of the absolute branching fractions of hadronic $D$-meson decays involving kaons and pions

“…[24] and the parameters quoted from Refs. [25][26][27], we find the correction factors (f QC ) that account for the QC effect on the measured branching fractions to be 1.081 ± 0.007 stat and 0.956 ± 0.006 stat for D 0 → K 0 S π 0 π 0 π 0 and D 0 → K 0 S π + π − π 0 π 0 , respectively. Here, f QC multiplies the naively extracted branching fractions.…”

Charming synergies: the role of charm-threshold studies in the search for physics beyond the Standard Model

“…pact on -violation and oscillation studies at LHCb and Belle II to the analysis already discussed [7], and strongphase measurements have also been reported for the decays 0 → 0 + − [8] and 0 → ∓ ± [9]. In addition to quantum-correlated studies, the very clean environment of (3770) decays allows other interesting topics to be investigated.…”

Improved measurement of the strong-phase difference $$\delta _D^{K\pi }$$ in quantum-correlated $$D{\bar{D}}$$ decays

“…-The CP-eigenstate analysis is an update of a previous measurement [7], which it augments with additional decay modes to achieve increased sensitivity. Information on the CP-tagged yields for the majority of modes is taken from an earlier analysis [13], while the yields for the tagging modes reconstructed in isolation, required for normalisation purposes, are measured and presented here. Several new tags are added to the measurement, including decays that have K 0 L mesons in the final state.…”