Study of the decayD0→K−K−K+π+

Physical Review Letters, 2009

Physical Review D, 2007

Physics Letters B, 1998

Using data from the FOCUS (E831) experiment at Fermilab, we present a new measurement for the Cabibbo-suppressed

Physical Review Letters, 2005

Physical Review Letters, 2005

Physics Letters B, 2003

Using data from the FOCUS (E831) experiment at Fermilab, we present a new measurement of the branching ratio for the Cabibbo-favored decay mode

Physical Review D, 1998

We present results of a search for D 0 − D 0 mixing and doubly-Cabibbosuppressed decays of the D 0 in Fermilab experiment E791, a fixed-target charm hadroproduction experiment. We look for evidence of mixing in the decay chain D * → πD → π(Kπ or Kπππ). If the charge of the pion from the D * decay is the same as the charge of the kaon from the D decay (a "wrong-sign" event), mixing may have occurred. Mixing can be distinguished from other sources of wrong-sign events (such as doubly-Cabibbosuppressed decays) by analyzing the distribution of decay times. We see no evidence of mixing. Allowing for CP violation in the interference between DCS and mixing amplitudes our fitted ratio for mixed to unmixed decay rates is r mix = (0.39 +0.36 −0.32 ± 0.16)%. This corresponds to a 90% CL upper limit of r mix < 0.85%. The sensitivity of this result is comparable to that of previous measurements, but the assumptions made in fitting the data are notably more general. We present results from many fits to our data under various assump-

Physical Review Letters, 2001

Using a large sample of photoproduced charm mesons from the FOCUS experiment at Fermilab (FNAL-E831), we observe the decay D 0 → K + π − with a signal yield of 149 ± 31 events compared to a similarly cut sample consisting of 36 760±195 D 0 → K − π + events. We use the observed ratio of D 0 → K + π − to D 0 → K − π + (0.404 ± 0.085 ± 0.025)% to obtain a relationship between the D 0 mixing and doubly Cabibbo suppressed decay parameters. 13.25.Ft, 12.15.Ff, 14.40.Lb Typeset using REVT E X

Physics Letters B, 1994

We report a measurement of the relative branching ratio of two Cabibbo-suppressed decay modes: D0 --> π-π+ and D0 --> K-K+. The data were accumulated in the 1990-1991 fixed target run of Fermilab high energy photoproduction experiment E687. The branching ratios of these modes relative to the Cabibbo-allowed decay D0 --> K-π+ are also presented. The relative branching ratios are measured to be Γ(D0 --> KK)/Γ(D0 --> ππ) = 2.53 +/- 0.46 +/- 0.19, Γ(D0 --> KK)/Γ(D0 --> Kπ) = 0.109 +/- 0.007 +/- 0.009, and Γ(D0 --> ππ)/Γ(D0 --> Kπ) = 0.043 +/- 0.007 +/- 0.003.

Physical Review Letters, 2003