M. Selen

Analysis of the decay D{sup 0}{yields}K{sub S}{sup 0}{pi}{sup 0}{pi}{sup 0}

We present the results of a Dalitz plot analysis of D{sup 0}{yields}K{sub S}{sup 0}{pi}{sup 0}{pi}{sup 0} using the CLEO-c data set of 818 pb{sup -1} of e{sup +}e{sup -} collisions accumulated at {radical}(s)=3.77 GeV. This corresponds to 3x10{sup 6} D{sup 0}D{sup 0} pairs from which we select 1259 tagged candidates with a background of 7.5{+-}0.9 percent. Several models have been explored, all of which include the K{sup *}(892), K{sub 2}{sup *}(1430), K{sup *}(1680), the f{sub 0}(980), and the {sigma}(500). We find that the combined {pi}{sup 0{pi}0} S-wave contribution to our preferred fit is (28.9{+-}6.3{+-}3.1)% of the total decay rate while D{sup 0}{yields}K{sup *}(892){sup 0}{pi}{sup 0} contributes (65.6{+-}5.3{+-}2.5)%. Using three tag modes and correcting for quantum correlations we measure the D{sup 0}{yields}K{sub S}{sup 0}{pi}{sup 0}{pi}{sup 0} branching fraction to be (1.058{+-}0.038{+-}0.073)%.

Search for D{sup 0}{yields}pe{sup +} and D{sup 0}{yields}pe{sup -}

We search for simultaneous baryon and lepton number violating decays of the D{sup 0} meson. Specifically, we use 281 pb{sup -1} of data taken on the {psi}(3770) resonance with the CLEO-c detector at the CESR collider to look for decays D{sup 0}{yields}pe{sup +}, D{sup 0}{yields}pe{sup +}, D{sup 0}{yields}pe{sup -}, and D{sup 0}{yields}pe{sup -}. We find no significant signals and set the following branching fraction upper limits: D{sup 0}{yields}pe{sup +}(D{sup 0}{yields}pe{sup +})<1.1x10{sup -5} and D{sup 0}{yields}pe{sup -}(D{sup 0}{yields}pe{sup -})<1.0x10{sup -5}, both at the 90% confidence level.

Determination of the D{sup 0}{yields}K{sup -}{pi}{sup +}{pi}{sup 0} and D{sup 0}{yields}K{sup -}{pi}{sup +}{pi}{sup +}{pi}{sup -} coherence factors and average strong-phase differences using quantum-correlated measurements

The first measurements of the coherence factors (R{sub K{pi}}{sub {pi}{sup 0}} and R{sub K3{pi}}) and the average strong-phase differences ({delta}{sub D}{sup K{pi}}{sup {pi}{sup 0}} and {delta}{sub D}{sup K3{pi}}) for D{sup 0}{yields}K{sup -}{pi}{sup +}{pi}{sup 0} and D{sup 0}{yields}K{sup -}{pi}{sup +}{pi}{sup +}{pi}{sup -} are presented. These parameters can be used to improve the determination of the unitarity triangle angle {gamma} in B{sup -}{yields}DK{sup -} decays, where D is a D{sup 0} or D{sup 0} meson decaying to the same final state. The measurements are made using quantum-correlated, fully reconstructed D{sup 0}D{sup 0} pairs produced in e{sup +}e{sup -} collisions at the {psi}(3770) resonance. The measured values are: R{sub K{pi}}{sub {pi}{sup 0}}=0.84{+-}0.07, {delta}{sub D}{sup K{pi}}{sup {pi}{sup 0}}=(227{sub -17}{sup +14}) deg., R{sub K3{pi}}=0.33{sub -0.23}{sup +0.20}, and {delta}{sub D}{sup K3{pi}}=(114{sub -23}{sup +26}) deg. These results indicate significant coherence in the decay D{sup 0}{yields}K{sup -}{pi}{sup +}{pi}{sup 0}, whereas lower coherence is observed in the decay D{sup 0}{yields}K{sup -}{pi}{sup +}{pi}{sup +}{pi}{sup -}. The analysis also results in a small improvement in the knowledge of other D-meson parameters, in particular, the strong-phase difference for D{sup 0}{yields}K{sup -}{pi}{sup +}, {delta}{sub D}{sup K{pi}}, and the mixing parameter y.

{chi}{sub cJ} decays to h{sup +}h{sup -}h{sup 0}

Using a sample of 3x10{sup 6} {psi}(2S) decays recorded by the CLEO detector, we study three-body decays of the {chi}{sub c0}, {chi}{sub c1}, and {chi}{sub c2} produced in radiative decays of the {psi}(2S). We consider the final states {pi}{sup +}{pi}{sup -}{eta}, K{sup +}K{sup -}{eta}, pp{eta}, {pi}{sup +}{pi}{sup -}{eta}{sup }, K{sup +}K{sup -}{pi}{sup 0}, pp{pi}{sup 0}, {pi}{sup +}K{sup -}K{sub S}{sup 0}, and K{sup +}p{lambda}, measuring branching fractions or placing upper limits. For {chi}{sub c1}{yields}{pi}{sup +}{pi}{sup -}{eta}, K{sup +}K{sup -}{pi}{sup 0}, and {pi}{sup +}K{sup -}K{sub S}{sup 0} our observed samples are large enough to indicate the largest contributions to the substructure.

An investigation of D{sup +}{yields}{tau}{sup +}{nu}

We test whether or not the {tau} lepton manifests the same couplings as the {mu} lepton by investigating the relative decay rates in purely leptonic D{sup +} meson decays. We use 281 pb{sup -1} of data accumulated at the {psi}(3770) resonance with the CLEO-c detector, to limit B(D{sup +}{yields}{tau}{sup +}{nu})<2.1x10{sup -3} at 90% confidence level (C.L.), thus allowing us to place the first upper limit on the ratio R={gamma}(D{sup +}{yields}{tau}{sup +}{nu})/{gamma}(D{sup +}{yields}{mu}{sup +}{nu}). The ratio of R to the standard model expectation of 2.65 then is <1.8 at 90% C.L., consistent with the prediction of lepton universality.We test whether or not the tau lepton manifests the same couplings as the mu lepton by investigating the relative decay rates in purely leptonic D+ meson decays. Specifically, we place the first upper limit on the ratio R=Gamma(D+ -> tau+ nu)/Gamma(D+ -> mu+ nu). We use 281 inverse pb of data accumulated at the psi(3770) resonance with the CLEO-c detector, to determine B(D+ -> tau+ nu) < 2.1 x 10^(-3) at 90% confidence level (C. L.). The ratio of R to the Standard Model expectation of 2.65 then is <1.8 at 90% C. L., consistent with the prediction of lepton universality.

Observation of the {sup 1}P{sub 1} state of charmonium

The spin-singlet P-wave state of charmonium, h{sub c}({sup 1}P{sub 1}), has been observed in the decay {psi}(2S){yields}{pi}{sup 0}h{sub c} followed by h{sub c}{yields}{gamma}{eta}{sub c}. Inclusive and exclusive analyses of the M(h{sub c}) spectrum have been performed. Two complementary inclusive analyses select either a range of energies for the photon emitted in h{sub c}{yields}{gamma}{eta}{sub c} or a range of values of M({eta}{sub c}). These analyses, consistent with one another within statistics, yield M(h{sub c})=[3524.9{+-}0.7 (stat){+-}0.4 (sys)] MeV/c{sup 2} and a product of the branching ratios B{sub {psi}}({psi}(2S){yields}{pi}{sup 0}h{sub c})xB{sub h}(h{sub c}{yields}{gamma}{eta}{sub c})=[3.5{+-}1.0 (stat){+-}0.7 (sys)]x10{sup -4}. When the {eta}{sub c} is reconstructed in seven exclusive decay modes, 17.5{+-}4.5 h{sub c} events are seen with an average mass M(h{sub c})=[3523.6{+-}0.9 (stat){+-}0.5 (sys)] MeV/c{sup 2}, and B{sub {psi}}B{sub h}=[5.3{+-}1.5 (stat){+-}1.0 (sys)]x10{sup -4}. If combined, the inclusive and exclusive data samples yield an overall mass M(h{sub c})=[3524.4{+-}0.6 (stat){+-}0.4 (sys)] MeV/c{sup 2} and product of branching ratios B{sub {psi}}B{sub h}=[4.0{+-}0.8 (stat){+-}0.7 (sys)]x10{sup -4}. The h{sub c} mass implies a P-wave hyperfine splitting {delta}M{sub HF}(1P){identical_to} -M(1{sup 1}P{sub 1})=[1.0{+-}0.6 (stat){+-}0.4 (sys)] MeV/c{sup 2}.

Photon transitions in {psi}(2S) decays to {chi}{sub cJ}(1P) and {eta}{sub c}(1S)

We have studied the inclusive photon spectrum in psi(2S) decays using the CLEO III detector. We present the most precise measurements of electric dipole (E1) photon transition rates for psi(2S)--> gamma chicJ(1P) (J=0,1,2). We also confirm the hindered magnetic dipole (M1) transition, psi(2S)-->gamma etac(1S). However, the direct M1 transition psi(2S)-->gamma etac(2S) observed by the Crystal Ball as a narrow peak at a photon energy of 91 MeV is not found in our data.

Search for [Formula Presented] violation in [Formula Presented] decay

We search for CP non-conservation in the decays of tau leptons produced via

Structure functions in the decay [formula presented]

e^+ e^-

Limit on the tau neutrino mass from [formula presented]

annihilation at