The production of Jψ mesons in Z0 decays is studied using 3.6 million hadronic events recorded by the OPAL detector at LEP. The inclusive Z0 to Jψ and b-quark to Jψ branching ratios are measured from the total yield of Jψ mesons, identified from their decays into lepton pairs. The Jψ momentum distribution is used to study the fragmentation of b-quarks. The production rate of ψ′ mesons, identified from their decays into a Jψ and a π+π− pair, is measured as well. The following results are obtained: ${Br(Z^{0}⌝ghtarrow {⤪ J}/ i X)=(3.9pm 0.2pm 0.3)cdot 10^{-3} {⤪ and} ↦op Br(Z^0⌝ghtarrow i ^⌕ime X)=(1.6pm 0.3pm 0.2)cdot 10^{-3}, }$ where the first error is statistical and the second systematic. Finally the Jψ sample is used to reconstruct exclusive b-hadron decays and calculate the corresponding b-hadron branching ratios and masses.
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A preliminary analysis of exclusive $\btou$ decays to the final states $\pi~\pm\ell\nu$, $\pi~0\ell\nu$, $\rho~\pm\ell\nu$, $\rho~0\ell\nu$\ and $\omega\ell\nu$ based on $2.2\e{6}$ $\bbar$ decays collected at CLEO is presented. We have measured the first exclusive $\btou$ branching fraction $\bbpi=[1.19\pm0.41\pm0.21\pm0.19]\e{-4}$ ($[1.70\pm0.51\pm0.31\pm0.27]\e{-4}$), with the ISGW (WSB) model used for efficiency determination. A 90\% C.L. upper limit on $\bbrho$ similar to the previous CLEO limit is obtained. The ratio $\gamrho/\gampi<3.4$ at the 90\% confidence level for both the ISGW and WSB models. This ratio provides some discrimination between form factor models.
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The statistical and systematic uncertainties have been combined in quadrature.. 90% CL.
Both ISGW and WSB models, 90% CL. The statistical and systematic uncertainties have been combined in quadrature.
Using data recorded by the CLEO-II detector at CESR, we report the first observation of a narrow state decaying into $\Xi_c~+\pi~-$. The state has mass difference $M(\Xi_c~+\pi~-)-M(\Xi_c~+)$ of $178.2\pm0.5\pm1.0$ $\rm{MeV/c~2}$, and a width of $<5.5$ $\rm{MeV/c~2}$ (90\% confidence level limit). The most likely explanation of this new state is that it is the $J=\32$ spin excitation of the $\Xi_c~0$ charmed baryon.
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Charged hadronic four-body decays of D 0 mesons have been studied in the E687 photoproduction experiment at Fermilab. Branching ratios relative to the D 0 → K − π + π + π − decay mode for the Cabibbo-suppressed decays D 0 → π − π + π − π + , D 0 → K − K + π − π + have been measured and the first evidence of the D 0 → K − K + K − π + decay mode is reported. An analysis of the D 0 → K − K + π − π + resonance structure is also presented.
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NUCLEUS IS P, C, AL, CU.
NUCLEUS IS P, C, AL, CU.
NUCLEUS IS P, C, AL, CU.
Narrow states observable through the emission of monoenergetic charged pions have been searched for in p p annihilation at rest in a gaseous hydrogen target where annihilation from atomic angular momentum L = 1 states dominates. No structure is observed. The 5σ upper limit for the production of narrow states in the mass range 1100–1670 MeV is 2 × 10 −3 of all annihilations.
X means a narrow state.
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