J. E. Duboscq

Improved measurement of absolute branching fraction of D{sub s}{sup +}{yields}{tau}{sup +}{nu}{sub {tau}}

We have studied the leptonic decay D{sub s}{sup +}{yields}{tau}{sup +}{nu}{sub {tau}}, via the decay channel {tau}{sup +}{yields}e{sup +}{nu}{sub e}{nu}{sub {tau}}, using a sample of tagged D{sub s}{sup +} decays collected near the D{sub s}*{sup {+-}}D{sub s}{sup {+-}} peak production energy in e{sup +}e{sup -} collisions with the CLEO-c detector. We obtain B(D{sub s}{sup +}{yields}{tau}{sup +}{nu}{sub {tau}})=(5.30{+-}0.47{+-}0.22)% and determine the decay constant f{sub D{sub s}}=(252.5{+-}11.1{+-}5.2) MeV, where the first uncertainties are statistical and the second are systematic.

First model-independent determination of the relative strong phase between D{sup 0} and D{sup 0}{yields}K{sub S}{sup 0}{pi}{sup +}{pi}{sup -} and its impact on the CKM angle {gamma}/{phi}{sub 3} measurement

We exploit the quantum coherence between pair-produced D 0 and D 0 in Ψ(3770) decays to make a first determination of the relative strong phase differences between D 0 → K 0 S π + π - and D 0 → K 0 S π + π - which are of great importance in determining the Cabibbo-Kobayashi-Maskawa angle γ/Φ 3 in B - → D 0 (D 0 )K - decays. Using 818 pb -1 of e + e - collision data collected with the CLEO-c detector at E cm = 3.77 GeV, we employ a binned Dalitz-plot analysis of K 0 S π + π - and K 0 L π + π - decays recoiling against flavor-tagged, CP-tagged, and K 0 S π + π - -tagged events to determine these strong phase differences.

Measurement of B(D{sub s}{sup +}{yields}l{sup +}{nu}) and the decay constant f{sub D{sub s}{sup +}} from 600 pb{sup -1} of e{sup +}e{sup -} annihilation data near 4170 MeV

We examine e{sup +}e{sup -}{yields}D{sub s}{sup -}D{sub s}*{sup +} and D{sub s}*{sup -}D{sub s}{sup +} interactions at 4170 MeV using the CLEO-c detector in order to measure the decay constant f{sub D{sub s}{sup +}} with good precision. Previously our measurements were substantially higher than the most precise lattice based QCD calculation of (241{+-}3) MeV. Here we use the D{sub s}{sup +}{yields}l{sup +}{nu} channel, where the l{sup +} designates either a {mu}{sup +} or a {tau}{sup +}, when the {tau}{sup +}{yields}{pi}{sup +}{nu}. Analyzing both modes independently, we determine B(D{sub s}{sup +}{yields}{mu}{sup +}{nu})=(0.565{+-}0.045{+-}0.017)%, and B(D{sub s}{sup +}{yields}{tau}{sup +}{nu})=(6.42{+-}0.81{+-}0.18)%. We also analyze them simultaneously to find an effective value of B{sup eff}(D{sub s}{sup +}{yields}{mu}{sup +}{nu})=(0.591{+-}0.037{+-}0.018)% and f{sub D{sub s}{sup +}}=(263.3{+-}8.2{+-}3.9) MeV. Combining with the CLEO-c value determined independently using D{sub s}{sup +}{yields}{tau}{sup +}{nu}, {tau}{sup +}{yields}e{sup +}{nu}{nu} decays, we extract f{sub D{sub s}{sup +}}=(259.5{+-}6.6{+-}3.1) MeV. Combining with our previous determination of B(D{sup +}{yields}{mu}{sup +}{nu}), we extract the ratio f{sub D{sub s}{sup +}}/f{sub D{sup +}}=1.26{+-}0.06{+-}0.02. No evidence is found for a CP asymmetry between {gamma}(D{sub s}{sup +}{yields}{mu}{sup +}{nu}) and {gamma}(D{sub s}{sup -}{yields}{mu}{sup -}{nu}); specifically the fractional difference in rates is measured to be (4.8{+-}6.1)%. Finally, we find B(D{sub s}{sup +}{yields}e{sup +}{nu})<1.2x10{sup -4} at 90% confidencemorexa0» level.«xa0less

New measurement of exclusive decays of the {chi}{sub c0} and {chi}{sub c2} to two-meson final states

Using a sample of 2.59x10{sup 7} {psi}(2S) decays collected by the CLEO-c detector, we present results of a study of {chi}{sub c0} and {chi}{sub c2} decays into two-meson final states. We present the worlds most precise measurements of the {chi}{sub cJ,(J=0,2)}{yields}{pi}{sup +}{pi}{sup -}, {pi}{sup 0}{pi}{sup 0}, K{sup +}K{sup -}, K{sub S}{sup 0}K{sub S}{sup 0}, {eta}{eta}, and {eta}{sup }{eta}{sup } branching fractions, and a search for {chi}{sub c} decays into {eta}{eta}{sup }. These results shed light on the mechanism of charmonium decays into pseudoscalar mesons.

Dalitz plot analysis of the D{sup +}{yields}K{sup -}{pi}{sup +}{pi}{sup +} decay

We perform a Dalitz plot analysis of D{sup +}{yields}K{sup -}{pi}{sup +}{pi}{sup +} decay with the CLEO-c data set of 572 pb{sup -1} of e{sup +}e{sup -} collisions accumulated at the {psi}(3770). This corresponds to 1.6x10{sup 6} D{sup +}D{sup -} pairs from which we select 140 793 candidate events with a small background of 1.1%. We compare our results with previous measurements using the isobar model. We modify the isobar model with an improved description of some of the contributing resonances and get better agreement with our data. We also consider a quasi-model-independent approach and measure the magnitude and phase of the contributing K{pi} S wave in the range of invariant masses from the threshold to the maximum in this decay. This gives an improved description of our data over the isobar model. Finally we allow for an isospin-two {pi}{sup +}{pi}{sup +} S wave contribution and find that adding this to both the isobar model and the quasi-model-independent approach gives the best description of our data.

Determination of the D{sup 0}{yields}K{sup +}{pi}{sup -} relative strong phase using quantum-correlated measurements in e{sup +}e{sup -}{yields}D{sup 0}D{sup 0} at CLEO

We exploit the quantum coherence between pair-produced D{sup 0} and D{sup 0} in {psi}(3770) decays to study charm mixing, which is characterized by the parameters x and y, and to make a first determination of the relative strong phase {delta} between doubly Cabibbo-suppressed D{sup 0}{yields}K{sup +}{pi}{sup -} and Cabibbo-favored D{sup 0}{yields}K{sup +}{pi}{sup -}. We analyze a sample of 1.0x10{sup 6} D{sup 0}D{sup 0} pairs from 281 pb{sup -1} of e{sup +}e{sup -} collision data collected with the CLEO-c detector at E{sub cm}=3.77 GeV. By combining CLEO-c measurements with branching fraction input and time-integrated measurements of R{sub M}{identical_to}(x{sup 2}+y{sup 2})/2 and R{sub WS}{identical_to}{gamma}(D{sup 0}{yields}K{sup +}{pi}{sup -})/{gamma}(D{sup 0}{yields}K{sup +}{pi}{sup -}) from other experiments, we find cos{delta}=1.03{sub -0.17}{sup +0.31}{+-}0.06, where the uncertainties are statistical and systematic, respectively. In addition, by further including external measurements of charm mixing parameters, we obtain an alternate measurement of cos{delta}=1.10{+-}0.35{+-}0.07, as well as xsin{delta}=(4.4{sub -1.8}{sup +2.7}{+-}2.9)x10{sup -3} and {delta}=(22{sub -12-11}{sup +11+9}) deg.

Measurement of upper limits for {upsilon}{yields}{gamma}+R decays

We report on a study of exclusive radiative decays {upsilon}(nS){yields}{gamma}+R (n=1, 2, 3), with R a narrow resonant hadronic state decaying into four or more charged particles (plus possible neutrals). Using data collected from the CLEO III detector at the Cornell Electron Storage Ring, we present upper limits of order 10{sup -4} for such bottomonium two-body decays as a function of the mass M{sub R} recoiling opposite the photon.

Measuring B(D{sup +}{yields}{mu}{sup +}{nu}) and the pseudoscalar decay constant f{sub D{sup +}}

In 60 inverse-pb of data taken on the psi(3770) resonance with the CLEO-c detector, we find 8 D+ -> mu+ nu decay candidates that are mostly signal, containing only 1 estimated background. Using this statistically compelling sample, we measure a value of B(D+ -> mu+ nu) = (3.5 +/- 1.4 +/- 0.6) x10^(-4), and determine fD+=(202 +/- 41 +/-17) MeV.