Measurement of the doubly Cabibbo-suppressed decay D+ -> K+pi(+)pi(-)pi(0) with semileptonic tags

Abstract

We propose a new semileptonic tag method to study the doubly Cabibbo-suppressed D decay in ψ(3770)→DD¯ reaction. Utilizing the dataset corresponding to an integrated luminosity of 2.93 fb-1 at a center-of-mass energy of 3.773 GeV collected by the BESIII detector, we determine the branching fraction for D+→K+π+π-π0 to be (1.03±0.12stat±0.06syst)×10-3, in which the contributions from narrow intermediate resonances, D+→K+η, D+→K+ω, and D+→K+φ have been excluded. Combining the world average of the branching fraction of D+→K-π+π+π0, we determine B(D+→K+π+π-π0)/B(D+→K-π+π+π0)=(1.65±0.21)%, corresponding to (5.73±0.73)tan4θc, where θc is the Cabibbo mixing angle. These results are consistent with our previous measurement with hadronic tags but are significantly larger than other doubly Cabibbo-suppressed decays in the charm sector. © 2021 authors. Published by the American Physical Society.