M. D. Sokoloff

Dalitz plot analysis ofD→Kππdecays

Decays of the [ital D][sup 0] meson to [ital K][sup [minus]][pi][sup +][pi][sup 0] and [ital [bar K]][sup 0][pi][sup +][pi][sup [minus]] and of the [ital D][sup +] to [ital K][sup [minus]][pi][sup +][pi][sup +] have been analyzed for resonant substructure. We present results on the amplitudes and phases of each decay mode and compare the results with other measurements. We confirm the highly nonresonant nature of the [ital D][sup +] to [ital K][sup [minus]][pi][sup +][pi][sup +] decays. There is general agreement with theoretical models for the branching ratios measured.

Measurement of the decaysD0→π−π+andD0→K−K+

Using data from Fermilab photoproduction experiment E691, we measure the ratio of branching fractions between the Cabibbo-suppressed modes {ital B}({ital D}{sup 0}{r arrow}{ital K}{sup {minus}}{ital K+})/{ital B}({ital D}{sup 0}{r arrow}{pi}{sup {minus}}{pi}{sup +}) to be 1.95{plus minus}0.34{plus minus}0.22. We also report branching fractions for the modes {ital D}{sup 0}{r arrow}{ital K}{sup {minus}}{ital K+} and {ital D}{sup 0}{r arrow}{pi}{sup {minus}}{pi}{sup +} relative to the Cabibbo-allowed decay {ital D}{sup 0}{r arrow}{ital K}{sup {minus}}{pi}{sup +}. Furthermore, we place an upper limit of 0.45 at the 90% C.L. on the {ital CP}-violating asymmetry in {ital D}{sup 0}{r arrow}{ital K}{sup {minus}}{ital K+} vs {ital {bar D}} {sup 0}{r arrow}{ital K}{sup {minus}}{ital K+} decays.

Measurement of the form factors in the decayD+→K¯*0e+νe

We have measured the three form factors governing the decay {ital D}{sup +}{r arrow}{ital {bar K}} {sup *0}{ital e}{sup +}{nu}{sub {ital e}}, observed in Fermilab photoproduction experiment E691, using the complete decay distribution of the data. The results are {ital A}{sub 1}(0)=0.46{plus minus}0.05{plus minus}0.05, {ital A}{sub 2}(0)=0.0{plus minus}0.2{plus minus}0.1, and {ital V}(0)=0.9{plus minus}0.3{plus minus}0.1 for the two axial-vector and the vector form factors, respectively. The {ital {bar K}} {sup *0} mesons have a ratio of longitudinal to transverse polarization of 1.8{sub {minus}0.4}{sup +0.6}{plus minus}0.3. These results are significantly different from values predicted by a number of different models.

Study of the semileptonic decay modeD0→K−e+νe

We present an analysis of the exclusive semileptonic decay mode D/sup 0/ ..-->.. K/sup -/e/sup +/nu/sub e/. We have measured the ratio of decay rates GAMMA(D/sup 0/ ..-->.. K/sup -/e/sup +/nu/sub e/)/GAMMA(D/sup 0/ ..-->.. K/sup -/..pi../sup +/). After correcting for the reconstruction efficiencies and subtracting the contribution from other decay modes we have found the ratio to be equal to 0.77 +- 0.12(stat) +- 0.13(syst).