We present measurements of D{yields}K{sub S}{sup 0}{pi} and D{yields}K{sub L}{sup 0}{pi} branching fractions using 281 pb{sup -1} of {psi}(3770) data at the CLEO-c experiment. We find that B(D{sup ...0}{yields}K{sub S}{sup 0}{pi}{sup 0}) is larger than B(D{sup 0}{yields}K{sub L}{sup 0}{pi}{sup 0}), with an asymmetry of R(D{sup 0})=0.108{+-}0.025{+-}0.024. For B(D{sup +}{yields}K{sub S}{sup 0}{pi}{sup +}) and B(D{sup +}{yields}K{sub L}{sup 0}{pi}{sup +}), we observe no measurable difference; the asymmetry is R(D{sup +})=0.022{+-}0.016{+-}0.018. The D{sup 0} asymmetry is consistent with the value based on the U-spin prediction A(D{sup 0}{yields}K{sup 0}{pi}{sup 0})/A(D{sup 0}{yields}K{sup 0}{pi}{sup 0})=-tan{sup 2}{theta}{sub C}, where {theta}{sub C} is the Cabibbo angle.
Using a 281 pb{sup -1} data sample collected at the {psi}(3770) with the CLEO-c detector, we present the first absolute branching fraction measurement of the decay D{sup 0}{yields}K{sup -}{pi}{sup ...+}{pi}{sup -}e{sup +}{nu}{sub e} at a statistical significance of about 4.0 standard deviations. We find 10 candidates consistent with the decay D{sup 0}{yields}K{sup -}{pi}{sup +}{pi}{sup -}e{sup +}{nu}{sub e}. The probability that a background fluctuation accounts for this signal is less than 4.1x10{sup -5}. We find B(D{sup 0}{yields}K{sup -}{pi}{sup +}{pi}{sup -}e{sup +}{nu}{sub e})=2.8{sub -1.1}{sup +1.4}(stat){+-}0.3(syst)x10 = {sup -4}. By restricting the invariant mass of the hadronic system to be consistent with K{sub 1}(1270), we obtain the product of branching fractions B(D{sup 0}{yields}K{sub 1}{sup -}(1270)e{sup +}{nu}{sub e})xB(K{sub 1}{sup -}(1270){yields}K{sup -}{pi}{sup +}{pi}{sup -})=2.5{sub -1.0} = {sup +1.3}(stat){+-}0.2(syst)x10{sup -4}. Using B(K{sub 1}{sup -}(1270){yields}K{sup -}{pi}{sup +}{pi}{sup -})=(33{+-}3)%, we obtain B(D{sup 0}{yields}K{sub 1}{sup -}(1270)e{sup +}{nu}{sub e})=7.6{sub -3.0}{sup +4.1}(stat){+-}0.6(syst){+-}0.7 = x10{sup -4}. The last error accounts for the uncertainties in the measured K{sub 1}{sup -}(1270){yields}K{sup -}{pi}{sup +}{pi}{sup -} branching fractions.
We measure the decay constant f{sub D{sub s}{sup +}} using 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}. Using both measurements we find f{sub D{sub s}{sup +}}=274{+-}13{+-}7 MeV. Combining with our previous determination of f{sub D{sup +}}, we compute the ratio f{sub D{sub s}{sup +}}/f{sub D{sup +}}=1.23{+-}0.11{+-}0.04. We compare with theoretical estimates.
Observation of D+ --> etae + nue Shepherd, M R; Besson, D; Pedlar, T K ...
Physical review letters,
2009-Feb-27, 20090227, Letnik:
102, Številka:
8
Journal Article
Recenzirano
Using a 281 pb-1 data sample collected at the psi(3770) resonance with the CLEO-c detector at the Cornell Electron Storage Ring, we report the first observation of D+ --> etae + nue. We also set ...upper limits for D+ --> eta'e + nue and D + --> varphie + nue that are about 2 orders of magnitude more restrictive than those obtained by previous experiments.
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