Measurement of the Decay Asymmetry Parameters in Λc+→Λπ+\Lambda_c^+ \to \Lambda\pi^+ and Λc+→Σ+π0\Lambda_c^+ \to \Sigma^+\pi^0

We have measured the weak decay asymmetry parameters (\aLC ) for two \LC\ decay modes. Our measurements are \aLC = -0.94^{+0.21+0.12}_{-0.06-0.06} for the decay mode $\Lambda_c^+ \to \Lambda\pi^+$ and \aLC = -0.45\pm 0.31 \pm 0.06 for the decay mode $\Lambda_c \to \Sigma^+\pi^0$. By combining these measurements with the previously measured decay rates, we have extracted the parity-violating and parity-conserving amplitudes. These amplitudes are used to test models of nonleptonic charmed baryon decay.Comment: 11 pages including the figures. Uses REVTEX and psfig macros. Figures as uuencoded postscript. Also available as http://w4.lns.cornell.edu/public/CLNS/1995/CLNS95-1319.p

Production and Decay of D_1(2420)^0 and D_2^*(2460)^0

We have investigated $D^{+}\pi^{-}$ and $D^{*+}\pi^{-}$ final states and observed the two established $L=1$ charmed mesons, the $D_1(2420)^0$ with mass $2421^{+1+2}_{-2-2}$ MeV/c$^{2}$ and width $20^{+6+3}_{-5-3}$ MeV/c$^{2}$ and the $D_2^*(2460)^0$ with mass $2465 \pm 3 \pm 3$ MeV/c$^{2}$ and width $28^{+8+6}_{-7-6}$ MeV/c$^{2}$. Properties of these final states, including their decay angular distributions and spin-parity assignments, have been studied. We identify these two mesons as the $j_{light}=3/2$ doublet predicted by HQET. We also obtain constraints on {\footnotesize $\Gamma_S/(\Gamma_S + \Gamma_D)$} as a function of the cosine of the relative phase of the two amplitudes in the $D_1(2420)^0$ decay.Comment: 15 pages in REVTEX format. hardcopies with figures can be obtained by sending mail to: [email protected]

Measurement of the branching fraction for Υ(1S)→τ+τ−\Upsilon (1S) \to \tau^+ \tau^-

We have studied the leptonic decay of the $\Upsilon (1S)$ resonance into tau pairs using the CLEO II detector. A clean sample of tau pair events is identified via events containing two charged particles where exactly one of the particles is an identified electron. We find $B(\Upsilon(1S) \to \tau^+ \tau^-) = (2.61~\pm~0.12~{+0.09\atop{-0.13}})$. The result is consistent with expectations from lepton universality.Comment: 9 pages, RevTeX, two Postscript figures available upon request, CLNS 94/1297, CLEO 94-20 (submitted to Physics Letters B

A measurement of B(D+S → φl+ν) B(D+S → φπ+)

Using the CLEO II detector at CESR, we have measured the ratio of branching fractions B (D + S → φl + ν) B (D + S → φπ + ) = 0.54 ± 0.05 ± 0.04 . We use this measurement to obtain a model dependent estimate of B (D + S → φπ + )

Luminosity measurement with the CLEO II detector

complete author list: Crawford G.; Daubenmier C.; Fulton R.; Fujino D.; Gan K.; Honscheid K.; Kagan H.; Kass R.; Lee J.; Malchow R.; Skovpen Y.; Sung M.; White C.; Butler F.; Fu X.; Kalbfleisch G.; Ross W.; Skubic P.; Wood M.; Fast J.; McIlwain R.; Miao T.; Miller D.; Modesitt M.; Payne D.; Shibata E.; Shipsey I.; Wang P.; Battle M.; Ernst J.; Gibbons L.; Kwon Y.; Roberts S.; Thorndike E.; Wang C.; Dominick J.; Lambrecht M.; Sanghera S.; Shelkov V.; Skwarnicki T.; Stroynowski R.; Volobouev I.; Wei G.; Zadorozhny P.; Artuso M.; Goldberg M.; He D.; Horwitz N.; Kennett R.; Mountain R.; Moneti G.; Muheim F.; Mukhin Y.; Playfer S.; Rozen Y.; Stone S.; Thulasidas M.; Vasseur G.; Xing X.; Zhu G.; Bartelt J.; Csorna S.; Egyed Z.; Jain V.; Kinoshita K.; Edwards K.; Ogg M.; Bellerive A.; Britton D.; Hyatt E.; MacFarlane D.; Patel P.; Barish B.; Chadha M.; Chan S.; Cowen D.; Eigen G.; Miller J.; O'Grady C.; Urheim J.; Weinstein A.; Acosta D.; Athanas M.; Masek G.; Paar H.; Sivertz M.; Gronberg J.; Kutschke R.; Menary S.; Morrison R.; Nakanishi S.; Nelson H.; Nelson T.; Qiao C.; Richman J.; Ryd A.; Tajima H.; Sperka D.; Witherell M.; Procario M.; Balest R.; Cho K.; Daoudi M.; Ford W.; Johnson D.; Lingel K.; Lohner M.; Rankin P.; Smith J.; Alexander J.; Bebek C.; Berkelman K.; Bloom K.; Browder T.; Cassel D.; Cho H.; Coffman D.; Drell P.; Ehrlich R.; Gaiderev P.; Galik R.; Garcia-Sciveres M.; Geiser B.; Gittelman B.; Gray S.; Hartill D.; Heltsley B.; Jones C.; Jones S.; Kandaswamy J.; Katayama N.; Kim P.; Kreinick D.; Ludwig G.; Masui J.; Mevissen J.; Mistry N.; Ng C.; Nordberg E.; Patterson J.; Peterson D.; Riley D.; Salman S.; Sapper M.; Würthwein F.; Avery P.; Freyberger A.; Rodriguez J.; Stephens R.; Yang S.; Yelton J.; Cinabro D.; Henderson S.; Liu T.; Saulnier M.; Wilson R.; Yamamoto H.; Bergfeld T.; Eisenstein B.; Gollin G.; Ong B.; Palmer M.; Selen M.; Thaler J.; Sadoff A.; Ammar R.; Ball S.; Baringer P.; Bean A.; Besson D.; Coppage D.; Copty N.; Davis R.; Hancock N.; Kelly M.; Kotov S.; Kravchenko I.; Kwak N.; Lam H.; Kubota Y.; Lattery M.; Momayezi M.; Nelson J.; Patton S.; Perticone D.; Poling R.; Savinov V.; Schrenk S.; Wang R.; Alam M.; Kim I.; Nemati B.; O'Neill J.; Severini H.; Sun C.; Zoeller M.; Severini H.; Sun C.; Zoeller M.; Alam M.; Kim I.; Nemati B.; O'Neill J.; Poling R.; Savinov V.; Schrenk S.; Wang R.; Crawford G

Evidence for exclusive B decays to final states containing a charmed baryon

Using data collected in the region of the γ(4S) resonance with the CLEO-II detector, we report on the first observation of exclusive decays of the B meson to final states with a charmed baryon. We have made a preliminary measurement of the branching fraction B(B 0 → Γc + p π+π−) = (0.187 ± .059 ± 0.056 ± 0.045)%. In addition, we report upper limits for final states of the form B → Σ c + p (nπ) where (nπ) denotes up to four charged pions

Observation of B → ψπ decays

We have found the first evidence for the Cabibbo suppressed, color suppressed decay B<sup>−</sup> → ψπ<sup>−</sup> in a data sample of 4 million B decays obtained by the CLEO detector at the Cornell Electron Storage Ring (CESR). The branching ratio is found to be (4.3±2.3)% of the Cabibbo allowed B<sup>−</sup> → ψK<sup>−</sup> decay mode, which is consistent with theoretical expectations

Observation of D1 (2420)+ and D2∗(2460)+

Using the CLEO II detector at CESR, we have observed two charmed states, where the higher mass state decays to D0π+ and to , while the lower mass state decays to , but not to D0π+. The masses and widths were measured to be 2425±2±2 MeV/c2 and 26−7−4+8+4 MeV/c2 for the lower mass state, and 2463±3±3 MeV/c2 and 27−8−5+11+5 MeV/c2 for the higher mass state. Properties of these states, including their decay angular distributions and spin-parity assignments have been studied. The results of this analysis support the identification of these states as the charged , respectively. The isospin mass splittings between these states and their neutral partners have also been measured. This is the first full reconstruction of any decay mode of the D1 (2420)+ and the first observation of the decay of D~ (2460) + to D*°~ -+