Measurement of the wrong-sign decays D0 -> K+ pi- pi0 and D0 -> K+ pi- pi+ pi-, and search for CP violation

TL;DR

This study measures the rates of wrong-sign D0 decays involving multiple pions, compares them to favored decays, and searches for CP violation using Belle experiment data, providing insights into charm mixing and CP symmetry.

Contribution

First measurement of wrong-sign D0 decay rates to K+ pi- pi0 and K+ pi- pi+ pi- with Belle data, and the most precise CP asymmetry limits for these modes to date.

Findings

Wrong-sign decay rate for K+ pi- pi0 is approximately 0.229%.

Wrong-sign decay rate for K+ pi- pi+ pi- is approximately 0.320%.

CP asymmetries are consistent with zero within uncertainties.

Abstract

Using 281 fb^-1 of data from the Belle experiment recorded at or near the Upsilon(4S) resonance, we have measured the rates of the ``wrong-sign'' decays D0 -> K+ pi- pi0 and D0 -> K+ pi- pi+ pi- relative to those of the Cabibbo-favored decays D0 -> K- pi+ pi0 and D0 -> K- pi+ pi+ pi-. These wrong-sign decays proceed via a doubly Cabibbo-suppressed amplitude or via D0-D0bar mixing; the latter has not yet been observed. We obtain R_WS(Kpipi0)=[0.229 +/-0.017(stat.) +0.013-0.009(sys.)]% and R_WS(K3pi)=[0.320 +/-0.019(stat.) +0.018-0.013(sys.)]%. The CP asymmetries are measured to be -0.006 +/- 0.053 and -0.018 +/- 0.044 for the K+ pi- pi0 and K+ pi- pi+ pi- final states, respectively.