I. Volobouev

We have measured the inclusive $b\ensuremath{\rightarrow}s\ensuremath{\gamma}$ branching ratio to be $(2.32\ifmmode\pm\else\textpm\fi{}0.57\ifmmode\pm\else\textpm\fi{}0.35)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$, where the first error is statistical and the second is systematic. Upper and lower limits on the branching ratio, each at 95% C.L., are $B(b\ensuremath{\rightarrow}s\ensuremath{\gamma})<4.2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$ and $B(b\ensuremath{\rightarrow}s\ensuremath{\gamma})>1.0\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$. These limits restrict the parameters of extensions of the standard model.

The Intermediate Silicon Layers (ISL) detector is currently being built as part of the CDF II detector upgrade project. The ISL detector will significantly improve tracking in the central region and, together with the Silicon Vertex detector, provide stand-alone 3D track information in the forward/backward regions. In this article, we present the quality of the production sensors manufactured by Hamamatsu Photonics, which account for roughly half of the silicon sensors used in the ISL detector.

We have fully reconstructed decays of both B0 and B- Mesons into final states containing either D, D*, D**, Psi, Psi', or Chi_{c1} mesons. This allows us to obtain new results on many physics topics including branching ratios, tests of the factorization hypothesis, color suppression, resonant substructure, and the B- - B0 mass difference.

We describe the design, construction and performance of a Ring Imaging Cherenkov Detector (RICH) constructed to identify charged particles in the CLEO experiment. Cherenkov radiation occurs in LiF crystals, both planar and ones with a novel “sawtooth”-shaped exit surface. Photons in the wavelength interval 135–165 nm are detected using multi-wire chambers filled with a mixture of methane gas and triethylamine vapor. Excellent π/K separation is demonstrated.

We briefly describe the design, construction and performance of the LiF-Tea RICH detector built to identify charged particles in the CLEO III experiment. Excellent pion/kaon separation is demonstrated.

Using data collected by the CLEO II detector, we have observed two states decaying to ${\ensuremath{\Lambda}}_{c}^{+}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$. Relative to the ${\ensuremath{\Lambda}}_{c}^{+}$, their mass splittings are measured to be $+307.5\ifmmode\pm\else\textpm\fi{}0.4\ifmmode\pm\else\textpm\fi{}1.0$ and $+342.2\ifmmode\pm\else\textpm\fi{}0.2\ifmmode\pm\else\textpm\fi{}0.5\mathrm{MeV}{/c}^{2}$, respectively; this represents the first measurement of the less massive state. These two states are consistent with being orbitally excited, isospin zero ${\ensuremath{\Lambda}}_{c}^{+}$ states.

Using a sample of $2.6\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $\ensuremath{\Upsilon}(4\mathrm{S})\ensuremath{\rightarrow}B\overline{B}$ events collected with the CLEO II detector at the Cornell Electron Storage Ring, we have measured the form factors for ${\overline{B}}^{0}\ensuremath{\rightarrow}{D}^{*+}{\ensuremath{\ell}}^{\ensuremath{-}}\overline{\ensuremath{\nu}}$. We perform a three-parameter fit with the joint distribution of four kinematic variables to obtain the form-factor ratios ${R}_{1}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1.18\ifmmode\pm\else\textpm\fi{}0.30\ifmmode\pm\else\textpm\fi{}0.12$ and ${R}_{2}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.71\ifmmode\pm\else\textpm\fi{}0.22\ifmmode\pm\else\textpm\fi{}0.07,$ and the form-factor slope ${\ensuremath{\rho}}_{{A}_{1}}^{2}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.91\ifmmode\pm\else\textpm\fi{}0.15\ifmmode\pm\else\textpm\fi{}0.06,$ which is closely related to the slope of the Isgur-Wise function. The form-factor ratios are consistent with predicted corrections to the heavy-quark symmetry limit ${R}_{1}{\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}R}_{2}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1$.

We present measurements of spectral moments extracted from the invariant mass distributions of the final states of hadronic τ decay products recorded in the CLEO detector. From a fit of theoretical predictions to the measurements of spectral moments and the total hadronic decay width of the τ, we determine the strong coupling constant and a set of non-perturbative QCD parameters. The strong coupling constant is measured to be αs(mτ) = 0.306 ± 0.024, which when extrapolated to the Z mass, yields αs(Mz) = 0.114 ± 0.003.

Using the CLEO detector at the Cornell Electron Storage Ring, we have made a measurement of $R\ensuremath{\equiv}\ensuremath{\sigma}{(e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}\mathrm{hadrons})/\ensuremath{\sigma}{(e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}})=3.56\ifmmode\pm\else\textpm\fi{}0.01\ifmmode\pm\else\textpm\fi{}0.07$ at $\sqrt{s}$=10.52 GeV. This implies a value for the strong coupling constant of ${\ensuremath{\alpha}}_{s}(10.52 \mathrm{GeV})=0.20\ifmmode\pm\else\textpm\fi{}0.01\ifmmode\pm\else\textpm\fi{}0.06$, or ${\ensuremath{\alpha}}_{s}{(M}_{Z})=0.13\ifmmode\pm\else\textpm\fi{}0.005\ifmmode\pm\else\textpm\fi{}0.03$.

Using data taken with the CLEO II detector at the Cornell Electron Storage Ring, we present the first full angular analysis in the color-suppressed modes B0→J/ψK*0 and B+→J/ψK*+. This leads to a complete determination of the decay amplitudes of these modes including the longitudinal polarization γL/γ=0.52±0.07±0.04 and the P wave component |P|2=0.16±0.08±0.04. In addition, we update the branching fractions for B→J/ψK and B→J/ψK∗.Received 24 February 1997DOI:https://doi.org/10.1103/PhysRevLett.79.4533©1997 American Physical Society

Using data recorded by the CLEO II detector at the Cornell Electron Storage Ring, we report the first observation of an excited charmed baryon decaying into ${\ensuremath{\Xi}}_{c}^{0}{\ensuremath{\pi}}^{+}$. The state has mass difference $M({\ensuremath{\Xi}}_{c}^{0}{\ensuremath{\pi}}^{+})\ensuremath{-}M({\ensuremath{\Xi}}_{c}^{0})$ of $174.3\ifmmode\pm\else\textpm\fi{}0.5\ifmmode\pm\else\textpm\fi{}1.0\mathrm{MeV}{/c}^{2}$, and a width of $<3.1\mathrm{MeV}{/c}^{2}$ (90% confidence level limit). We identify the new state as the ${\ensuremath{\Xi}}_{c}^{*+}$, the isospin partner of the recently discovered ${\ensuremath{\Xi}}_{c}^{*0}$.

We report results from a search for the decays ${\mathit{B}}^{0}$\ensuremath{\rightarrow}${\mathrm{\ensuremath{\pi}}}^{+}$${\mathrm{\ensuremath{\pi}}}^{\mathrm{\ensuremath{-}}}$, ${\mathit{B}}^{0}$\ensuremath{\rightarrow}${\mathit{K}}^{+}$${\mathrm{\ensuremath{\pi}}}^{\mathrm{\ensuremath{-}}}$, and ${\mathit{B}}^{0}$\ensuremath{\rightarrow}${\mathit{K}}^{+}$${\mathit{K}}^{\mathrm{\ensuremath{-}}}$. We find 90% confidence level upper limits on the branching fractions, ${\mathit{B}}_{\mathrm{\ensuremath{\pi}}\mathrm{\ensuremath{\pi}}}$2.9\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}5}$, ${\mathit{B}}_{\mathit{K}\mathrm{\ensuremath{\pi}}}$2.6\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}5}$, and ${\mathit{B}}_{\mathit{K}\mathit{K}}$0.7\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}5}$. While there is no statistically significant signal in the individual modes, the sum of ${\mathit{B}}_{\mathrm{\ensuremath{\pi}}\mathrm{\ensuremath{\pi}}}$ and ${\mathit{B}}_{\mathit{K}\mathrm{\ensuremath{\pi}}}$ exceeds zero with a significance of more than 4 standard deviations, indicating that we have observed charmless hadronic B decays.

We have searched for two-body charmless decays of B mesons to purely hadronic exclusive final states including $\omega$ or $\phi$ mesons using data collected with the CLEO II detector. With this sample of $6.6 \times 10^6$ B mesons we observe a signal for the $\omega K^+$ final state, and measure a branching fraction of B($B^+ \to \omega K^+$) = 1.5 +0.7 -0.6 +-0.2 $\times 10^{-5}$. We also observe some evidence for the $\phi K^*$ final state, and upper limits are given for 22 other decay modes. These results provide the opportunity for studies of theoretical models and physical parameters.

Using the CLEO-II detector, we have obtained evidence for a new meson decaying to $D^0 K^+$. Its mass is $2573.2^{+1.7}_{-1.6}\pm 0.8\pm 0.5$ {}~MeV/$c^2$ and its width is $16^{+5}_{-4}\pm 3$~MeV/$c^2$. Although we do not establish its spin and parity, the new meson is consistent with predictions for an $L=1$, $S=1$, $J_P=2^+$ charmed strange state.

A measurement of absolute integrated luminosity is presented using the CLEO II detector operating at the CESR e+e− storage ring. Independent analyses of three different final states (e+e−, γγ, and μ+μ−) at √s ⋍ 10 GeV normalize to the expected theoretical cross sections and correct for detection efficiencies. The resulting luminosities are measured with systematic errors of ±1.8%, ±1.6%, and ±2.2%, respectively, and are consistent with one another. The combined luminosity has a systematic error of ±1.0%.

The signals from high-Z scintillating crystals such as PbWO4 and BGO contain a significant Cherenkov component. We investigate methods to determine the contribution of Cherenkov light to the signals generated by high-energy electrons and pions (mips), both statistically and event-by-event. These methods are based on differences in the spectra, the time structure and/or the directionality of the two types of light. The electron signals, and their composition, are also analyzed as a function of the age (or depth) of the shower.

We have searched for the effective FCNC decays b->s l+l- using an inclusive method. We set upper limits on the branching ratios B(b->s e+e-) < 5.7 10^{-5}, B(b->s mu+mu-) < 5.8 10^{-5}, and B(b->s e+-mu-+) < 2.2 10^{-5} (at 90 %\ C.L.). Combining the di-electron and di-muon decay modes we find: B(b->s l+l-) < 4.2 10^{-5} (at 90 % C.L.).

The revision D of the SVX3 readout IC has been fabricated in the Honeywell radiation-hard 0.8 μm bulk CMOS process, for instrumenting 712,704 silicon strips in the upgrade to the Collider Detector at Fermilab. This final revision incorporates new features and changes to the original architecture that were added to meet the goal of dead-timeless operation. This paper describes the features central to dead-timeless operation, and presents test data for un-irradiated and irradiated SVX3D chips.

Using the CLEO II data sample, with an integrated luminosity of 1.8 fb−1 at and near the Υ(4S) resonance, we have observed a signal for D0→K+π−, which could be due to either D0D¯0 mixing or doubly Cabibbo suppressed decay, or a combination of the two. We find scrB(D0→K+π−)/scrB(D0→K−π+)=0.0077±0 .0025(stat) ±0.0025(syst).Received 2 December 1993DOI:https://doi.org/10.1103/PhysRevLett.72.1406©1994 American Physical Society

We report on the response of the combined CMS electromagnetic (EB) and hadronic barrel (HB) calorimeters to hadrons, electrons and muons in a wide momentum range from 1 to 350 GeV/c. To our knowledge, this is the widest range of momenta in which any calorimeter system is studied. These tests, carried out at the H2 beam-line at CERN, provide a wealth of information, especially at low energies. We analyze in detail the dierences in total calorimeter response to charged pions, kaons, protons and antiprotons and discuss the underlying phenomena. These data will play a crucial role in the thorough understanding of jets in CMS.

Lead tungstate crystals doped with small fractions of praesodynium or molybdenum have been tested in beams of high-energy electrons. The goal of these tests was to study the effects of such dopants on the capability to separate the signal components deriving from the Cherenkov and scintillation light generated by the beam particles. These studies were carried out in view of the possible application of such crystals in dual-readout calorimeters.

A search for the lepton-family-number-violating decays →e␥ and →␥ has been performed using CLEO II data.No evidence of a signal has been found and the corresponding upper limits are B(→e␥)Ͻ2.7ϫ10Ϫ6 and B(→␥)Ͻ3.0ϫ10Ϫ6 at 90% C.L. ͓S0556-2821͑97͒50207-4͔

Using data collected with the CLEO II detector at the Cornell Electron Storage Ring, we have studied the decays of leptons produced through e ϩ e Ϫ annihilation into final states containing K S 0 mesons, observed through their decays to ϩ Ϫ .We present branching fractions for decays to five final states: Ϫ →K 0 h Ϫ , Ϫ →K 0 h Ϫ 0 , Ϫ →K 0 K Ϫ , Ϫ →K 0 K Ϫ 0 , and Ϫ →K S 0 K S 0 h Ϫ , where K 0 h Ϫ denotes the sum of the processes involving K ¯0 Ϫ and K 0 K Ϫ particle combinations.Substructure and mass spectra in these final states are also addressed.

The angular distributions of the decay Λ+c→Λe+νe have been studied using the CLEO II detector. By performing a three-dimensional maximum likelihood fit, the form factor ratio R=f2/f1 is determined to be −0.25±0.14±0.08. The decay asymmetry parameter of the Λc averaged over q2 is calculated to be αΛc=−0.82+0.09+0.06−0.06−0.03.Received 13 January 1995DOI:https://doi.org/10.1103/PhysRevLett.75.624©1995 American Physical Society

Using the CLEO II detector at CESR, we observe 500 $\Lambda l^+$ pairs consistent with the semileptonic decay $\Lambda_c \to \Lambda l^+ \nu_{l}$. We measure $\sigma (e^+ e^- \to \Lambda_c X) \dot {cal B}(\Lambda_c^+ \to \Lambda l \nu_{l}) =4.77 \pm 0.25 \pm 0.66 $pb. Combining with the charm semileptonic width and the lifetime of the $\Lambda_c$, we also obtain ${\cal B}(\Lambda_c \to p K^- \pi^+)$. We find no evidence for $\Lambda l^+ \nu_{l}$ final states in which there are additional $\Lambda_c^+$ decay products. We measure the decay asymmetry parameter of $\Lambda_c \to \Lambda l^+ \nu_{l}$ to be $\alpha_{\Lambda_c} =-0.89\pm{^{0.17}_{0.11}}\pm{^{0.09}_{0.06}}.

Using the CLEO II detector at CESR, we have observed two charmed states, where the higher mass state decays to D0π+ and to D∗0π+, while the lower mass state decays to D∗0π+, 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 L = 1 D1 (2420)+ and D2∗ (2460)+, 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 D2∗ (2460)+ to D∗0π+.

Branching ratios for the dominant Cabibbo-suppressed decays of the $\ensuremath{\tau}$ lepton have been measured by CLEO II in ${e}^{+}{e}^{\ensuremath{-}}$ annihilation at the Cornell Electron Storage Ring ($\sqrt{s}\ensuremath{\sim}10.6$ GeV) using kaons with momenta below 0.7 GeV/c. The inclusive branching ratio into one charged kaon is (1.60 \ifmmode\pm\else\textpm\fi{} 0.12 \ifmmode\pm\else\textpm\fi{} 0.19)%. For the exclusive decays, $B({\ensuremath{\tau}}^{\ensuremath{-}}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{\ensuremath{\nu}}_{\ensuremath{\tau}})=(0.66\ifmmode\pm\else\textpm\fi{}0.07\ifmmode\pm\else\textpm\fi{}0.09)%$, $B({\ensuremath{\tau}}^{\ensuremath{-}}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}{\ensuremath{\nu}}_{\ensuremath{\tau}})=(0.51\ifmmode\pm\else\textpm\fi{}0.10\ifmmode\pm\else\textpm\fi{}0.07)%$, and, based on three events, $B({\ensuremath{\tau}}^{\ensuremath{-}}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}2{\ensuremath{\pi}}^{0}{\ensuremath{\nu}}_{\ensuremath{\tau}})&lt;0.3%$ at the 90% confidence level. These represent significant improvements over previous results. $B({\ensuremath{\tau}}^{\ensuremath{-}}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}{\ensuremath{\nu}}_{\ensuremath{\tau}})$ is measured for the first time with exclusive ${\ensuremath{\pi}}^{0}$ reconstruction.

The branching fractions for $\ensuremath{\tau}\ensuremath{\rightarrow}e\ensuremath{\nu}{\ensuremath{\nu}}_{\ensuremath{\tau}},$ $\ensuremath{\mu}\ensuremath{\nu}{\ensuremath{\nu}}_{\ensuremath{\tau}},$ and $h{\ensuremath{\nu}}_{\ensuremath{\tau}}$ are measured using data collected with the CLEO detector at the CESR ${e}^{+}{e}^{\ensuremath{-}}$ collider: ${\mathcal{B}}_{e}$=0.1776$\ifmmode\pm\else\textpm\fi{}$0.0006$\ifmmode\pm\else\textpm\fi{}$0.0017, ${\mathcal{B}}_{\ensuremath{\mu}}$=0.1737$\ifmmode\pm\else\textpm\fi{}$0.0008$\ifmmode\pm\else\textpm\fi{}$0.0018, and ${\mathcal{B}}_{h}$=0.1152$\ifmmode\pm\else\textpm\fi{}$0.0005$\ifmmode\pm\else\textpm\fi{}$0.0012, where the first error is statistical, the second systematic, and $h$ refers to either a charged $\ensuremath{\pi}$ or $K$. Also measured is the $\ensuremath{\tau}$ mass, ${m}_{\ensuremath{\tau}}$=(1778.2$\ifmmode\pm\else\textpm\fi{}$1.4) MeV. Lepton universality is affirmed by the relative branching fractions $({\mathcal{B}}_{\ensuremath{\mu}}$/${\mathcal{B}}_{e}$=0.9777$\ifmmode\pm\else\textpm\fi{}$0.0063$\ifmmode\pm\else\textpm\fi{}$0.0087, ${\mathcal{B}}_{h}$/${\mathcal{B}}_{e}$=0.6484$\ifmmode\pm\else\textpm\fi{}$0.0041$\ifmmode\pm\else\textpm\fi{}$0.0060) and the charged-current gauge coupling-constant ratios ${(g}_{\ensuremath{\mu}}{/g}_{e}$=1.0026$\ifmmode\pm\else\textpm\fi{}$0.0055, ${g}_{\ensuremath{\tau}}{/g}_{\ensuremath{\mu}}$=0.9990$\ifmmode\pm\else\textpm\fi{}$0.0098). The $\ensuremath{\tau}$ mass result may be recast as a $\ensuremath{\tau}$ neutrino mass limit, ${m}_{{\ensuremath{\nu}}_{\ensuremath{\tau}}}&lt;$60 MeV at 95% C.L.

We have observed five new decay modes of the charmed baryon ${\ensuremath{\Lambda}}_{c}^{+}$ using data collected with the CLEO II detector. Four decay modes, ${\ensuremath{\Lambda}}_{c}^{+}\ensuremath{\rightarrow}p{\overline{K}}^{0}\ensuremath{\eta}$, $\ensuremath{\Lambda}\ensuremath{\eta}{\ensuremath{\pi}}^{+}$, ${\ensuremath{\Sigma}}^{+}\ensuremath{\eta}$, and ${\ensuremath{\Sigma}}^{*+}\ensuremath{\eta}$, are first observations of final states with an $\ensuremath{\eta}$ meson, while the fifth mode, ${\ensuremath{\Lambda}}_{c}^{+}\ensuremath{\rightarrow}\ensuremath{\Lambda}{\overline{K}}^{0}{K}^{+}$, requires the creation of an $s\overline{s}$ quark pair. We measure the branching fractions of these modes relative to ${\ensuremath{\Lambda}}_{c}^{+}\ensuremath{\rightarrow}{\mathrm{pK}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$ to be $0.25\ifmmode\pm\else\textpm\fi{}0.04\ifmmode\pm\else\textpm\fi{}0.04$, $0.35\ifmmode\pm\else\textpm\fi{}0.05\ifmmode\pm\else\textpm\fi{}0.06$, $0.11\ifmmode\pm\else\textpm\fi{}0.03\ifmmode\pm\else\textpm\fi{}0.02$, $0.17\ifmmode\pm\else\textpm\fi{}0.04\ifmmode\pm\else\textpm\fi{}0.03$, and $0.12\ifmmode\pm\else\textpm\fi{}0.02\ifmmode\pm\else\textpm\fi{}0.02$, respectively.

We report new measurements of the differential and total branching ratios for inclusive B decay to D^0, D^+ and D^{*+} and the first measurement of the same quantities for inclusive B decay to $D^{*0}$. Here B is the mixture of B_d and B_u from $\Upsilon(4S)$ decay. Furthermore, since more than one charm particle (or antiparticle) of the same kind can be produced in B decay, here ``inclusive B branching ratio'' is used to mean the average number of charm particles and their antiparticles of a certain species produced in B decay. We obtain the following results (the first error is statistical, the second systematic of this analysis, the third is propagated from other measurements): ${\cal B}(B\to D^0 X) = (0.636\pm 0.014\pm 0.019\pm 0.018), {\cal B}(B\to D^+ X) = (0.235\pm 0.009\pm 0.009\pm 0.024), {\cal B}(B\to D^{*0} X) = (0.247\pm 0.012\pm 0.018\pm 0.018), {\cal B}(B\to D^{*+} X) = (0.239\pm 0.011\pm 0.014\pm 0.009)$. The following ratio of branching ratios is not affected by most of the systematic errors: ${\cal B}(B\to D^{*0} X)/{\cal B}(B\to D^{*+} X) = (1.03\pm 0.07\pm 0.09\pm 0.08).$ We also report the first measurement of the momentum-dependent $D^{*0}$ polarization and a new measurement of the $D^{*+}$ polarization in inclusive B decay. Using these measurements and other CLEO results and making some additional assumptions, we calculate the average number of c and $\bar c$ quarks produced in B decay to be $< n_c > = 1.10\pm 0.05$.

We have observed new channels for τ decays with an η in the final state. We study 3-prong tau decays, using the η→γγ and η→3π0 decay modes and 1-prong decays with two π0's using the η→γγ channel. The measured branching fractions are B(τ−→π−π−π+ηντ)=(3.4−0.5+0.6±0.6)×10−4 and B(τ−→π−2π0ηντ)=(1.4±0.6±0.3)×10−4. We observe clear evidence for f1→ηππ substructure and measure B(τ−→f1π−ντ)=(5.8−1.3+1.4±1.8)×10−4. We have also searched for η′(958) production and obtain 90% C.L. upper limits B(τ−→π−η′ντ)<7.4×10−5 and B(τ−→π−π0η′ντ)<8.0×10−5.Received 25 June 1997DOI:https://doi.org/10.1103/PhysRevLett.79.2406©1997 American Physical Society

Using data taken with the CLEO II detector at the Cornell Electron Storage Ring, we have determined the ratio of branching fractions: ${R}_{\ensuremath{\gamma}}\ensuremath{\equiv}\ensuremath{\Gamma}(\ensuremath{\Upsilon}(1S)\ensuremath{\rightarrow}\ensuremath{\gamma}\mathrm{gg})/\ensuremath{\Gamma}(\ensuremath{\Upsilon}(1S)\ensuremath{\rightarrow}\mathrm{ggg})=[2.75\ifmmode\pm\else\textpm\fi{}0.04(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.15(\mathrm{syst})]%$. From this ratio, we have determined the QCD scale parameter ${\ensuremath{\Lambda}}_{\overline{\mathrm{MS}}}$ (defined in the modified minimal subtraction scheme) to be ${\ensuremath{\Lambda}}_{\overline{\mathrm{MS}}}=233\ifmmode\pm\else\textpm\fi{}11\ifmmode\pm\else\textpm\fi{}59$ MeV, from which we determine a value for the strong coupling constant ${\ensuremath{\alpha}}_{s}{(M}_{\ensuremath{\Upsilon}(1S)})=0.163\ifmmode\pm\else\textpm\fi{}0.002\ifmmode\pm\else\textpm\fi{}0.014$, or ${\ensuremath{\alpha}}_{s}{(M}_{Z})=0.110\ifmmode\pm\else\textpm\fi{}0.001\ifmmode\pm\else\textpm\fi{}0.007$.

An angular analysis of B0-->J/psiK(*0) and B(0)(s)-->J/psistraight phi has been used to determine the decay amplitudes with parity-even longitudinal ( A0) and transverse ( A( parallel)) polarization and parity-odd transverse ( A( perpendicular)) polarization. The measurements are based on 190 B0 and 40 B(0)(s) candidates obtained from 89 pb(-1) of &pmacr;p collisions at the Fermilab Tevatron. The longitudinal decay amplitude dominates with |A0|(2) = 0.59+/-0. 06+/-0.01 for B0 and |A0|(2) = 0.61+/-0.14+/-0.02 for B(0)(s) decays. The parity-odd amplitude is found to be small with |A( perpendicular)|(2) = 0.13(+0.12)(-0.09)+/-0.06 for B0 and |A( perpendicular)|(2) = 0.23+/-0.19+/-0.04 for B(0)(s) decays.

The hadronic performance of a Dual-Readout calorimeter consisting of a crystal em section and a hadronic section read out with two types of optical fibers is studied with 200 GeV p þ .The em fraction of hadronic showers developing in this calorimeter system is determined event by event from the relative amounts of Cherenkov light and scintillation light produced in the shower development.Data are presented for two types of crystals (PbWO 4 and BGO), each of which offers unique opportunities in this respect.The information obtained with this technique may lead to an important improvement in the hadronic calorimeter performance.

The top quark is the heaviest of the six quarks of the standard model (SM). Precise knowledge of its mass is important for imposing constraints on a number of physics processes, including interactions of the as yet unobserved Higgs boson. The Higgs boson is the only missing particle of the SM, central to the electroweak symmetry breaking mechanism and generation of particle masses. In this review, experimental measurements of the top quark mass accomplished at the Tevatron, a proton-antiproton collider located at the Fermi National Accelerator Laboratory, are described. Topologies of top quark events and the methods used to separate signal events from background sources are discussed. Data analysis techniques used to extract information about the top mass value are reviewed. The combination of several of the most precise measurements performed with the two Tevatron particle detectors, CDF and DØ, yields a value of M(t) = 173.2 ± 0.9 GeV/c(2).

A measurement of the cross section for the combined two-photon production of charged pion and kaon pairs is performed using 1.2~$\rm fb^{-1}$ of data collected by the CLEO~II detector at the Cornell Electron Storage Ring. The cross section is measured at invariant masses of the two-photon system between 1.5 and 5.0 GeV/$c^2$, and at scattering angles more than $53^\circ$ away from the $\gamma\gamma$ collision axis in the $\gamma\gamma$ center-of-mass frame. The large background of leptonic events is suppressed by utilizing the CsI calorimeter in conjunction with the muon chamber system. The reported cross section is compared with leading order QCD models as well as previous experiments. In particular, although the functional dependence of the measured cross section disagrees with leading order QCD at small values of the two-photon invariant mass, the data show a transition to perturbative behavior at an invariant mass of approximately 2.5 GeV/$c^2$. hardcopies with figures can be obtained by writing to to: Pam Morehouse preprint secretary Newman Lab Cornell University Ithaca, NY 14853 or by sending mail to: preprints@lns62.lns.cornell.edu

We have searched for direct production of scalar top quarks at the Collider Detector at Fermilab in 88 pb-1 of p anti-p collisions at s**(1/2) = 1.8 TeV. We assume the scalar top quark decays into either a bottom quark and a chargino or a bottom quark, a lepton, and a scalar neutrino. The event signature for both decay scenarios is a lepton, missing transverse energy, and at least two b-quark jets. For a chargino mass of 90 GeV/c2 and scalar neutrino masses of at least 40 GeV/c2, we find no evidence for scalar top production and present upper limits on the production cross section in both decay scenarios.

We have searched for ${B}^{0}$ decays to two charged leptons and set 90% confidence level upper limits on the branching fractions: $B({B}^{0}\ensuremath{\rightarrow}{e}^{+}{e}^{\ensuremath{-}})&lt;5.9\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$, $B({B}^{0}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}})&lt;5.9\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$, $B({B}^{0}\ensuremath{\rightarrow}{e}^{\ifmmode\pm\else\textpm\fi{}}{\ensuremath{\mu}}^{\ensuremath{\mp}})&lt;5.9\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$, $B({B}^{0}\ensuremath{\rightarrow}{e}^{\ifmmode\pm\else\textpm\fi{}}{\ensuremath{\tau}}^{\ensuremath{\mp}})&lt;5.3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$, and $B({B}^{0}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{\ifmmode\pm\else\textpm\fi{}}{\ensuremath{\tau}}^{\ensuremath{\mp}})&lt;8.3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$.

Beam tests of a hybrid dual-readout calorimeter are described. The electromagnetic section of this instrument consists of 100 BGO crystals and the hadronic section is made of copper in which two types of optical fibers are embedded. The electromagnetic fraction of hadronic showers developing in this calorimeter system is estimated event by event from the relative amounts of Cherenkov light and scintillation light produced in the shower development. The benefits and limitations of this detector system for the detection of showers induced by single hadrons and by multiparticle jets are investigated. Effects of side leakage on the detector performance are also studied.

We present a systematic study of lead tungstate crystals doped with a small fraction of molybdenum, varying between 0.1% and 5%. These crystals were exposed to a beam of 50 GeV electrons and the signals were unraveled into scintillation and Cherenkov contributions, using the time structure of the signals and/or different types of transmission filters. These studies were carried out in view of the possible application of such crystals in dual-readout calorimeters.

Using data collected in the region of the Υ(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 measured the branching fractions B(B−→Λ+c¯pπ−)=(0.62+0.23−0.20±0.11±0.10)×10−3 and B(¯B0→Λ+c¯pπ+π−)=(1.33+0.46−0.42±0.31±0.21)×10−3, where the first error is statistical, the second is systematic, and the third is due to uncertainty in the Λ+c branching fractions. In addition, we report upper limits for final states of the form ¯B→Λ+c¯p(nπ) and Λ+c¯p(nπ)π0, where (nπ) denotes up to four charged pions.Received 12 July 1996DOI:https://doi.org/10.1103/PhysRevLett.79.3125©1997 American Physical Society

We have measured the weak decay asymmetry parameters (αΛc) for two Λc+ decay modes. Our measurements are αΛc = −0.94−0.06−0.06+0.21+0.12 for the decay mode Λc+ → Λπ+ and αΛc = −0.45 ±0.31 ±0.06 for the decay mode Λc → Σ+ π0. 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.

This Letter describes a direct measurement of the W boson total decay width, gamma(W), using the Collider Detector at Fermilab. The measurement uses an integrated luminosity of 90 pb(-1), collected during the 1994-1995 run of the Fermilab Tevatron p&pmacr; collider. The width is determined by normalizing predicted signal and background distributions to 49 844 W-->enu candidates and 21 806 W-->&mgr;nu candidates in the transverse-mass region M(T)<200 GeV and then fitting the predicted shape to the 438 electron events and 196 muon events in the high- M(T) region, 100<M(T)<200 GeV. The result is gamma(W) = 2.04+/-0.11(stat)+/-0.09(syst) GeV.

Abstract The contributions of neutrons to hadronic signals from the DREAM calorimeter are measured by analyzing the time structure of these signals. This contribution is characterized by an exponential tail in the pulse shape, with a time constant of ∼ 20 ns . The relative contribution of neutrons to the signals is measured event by event. It is shown that this information can be used to improve the hadronic calorimeter performance.

Using the CLEO II detector we measure $\frac{\mathcal{B}({D}_{s}^{+}\ensuremath{\rightarrow}\ensuremath{\eta}{e}^{+}\ensuremath{\nu})}{\mathcal{B}({D}_{s}^{+}\ensuremath{\rightarrow}\ensuremath{\varphi}{e}^{+}\ensuremath{\nu})}=1.24\ifmmode\pm\else\textpm\fi{}0.12\ifmmode\pm\else\textpm\fi{}0.15$, $\frac{\mathcal{B}({D}_{s}^{+}\ensuremath{\rightarrow}{\ensuremath{\eta}}^{\ensuremath{'}}{e}^{+}\ensuremath{\nu})}{\mathcal{B}({D}_{s}^{+}\ensuremath{\rightarrow}\ensuremath{\varphi}{e}^{+}\ensuremath{\nu})}=0.43\ifmmode\pm\else\textpm\fi{}0.11\ifmmode\pm\else\textpm\fi{}0.07$, and $\frac{\mathcal{B}({D}_{s}^{+}\ensuremath{\rightarrow}{\ensuremath{\eta}}^{\ensuremath{'}}{e}^{+}\ensuremath{\nu})}{\mathcal{B}({D}_{s}^{+}\ensuremath{\rightarrow}\ensuremath{\eta}{e}^{+}\ensuremath{\nu})}=0.35\ifmmode\pm\else\textpm\fi{}0.09\ifmmode\pm\else\textpm\fi{}0.07$. We find the ratio of vector to pseudoscalar final states, $\frac{\mathcal{B}({D}_{s}^{+}\ensuremath{\rightarrow}\ensuremath{\varphi}{e}^{+}\ensuremath{\nu})}{\mathcal{B}({D}_{s}^{+}\ensuremath{\rightarrow}(\ensuremath{\eta}+{\ensuremath{\eta}}^{\ensuremath{'}}){e}^{+}\ensuremath{\nu})}=0.60\ifmmode\pm\else\textpm\fi{}0.06\ifmmode\pm\else\textpm\fi{}0.06$, which is similar to the ratio found in nonstrange $D$ decays.

Using data collected with the CLEO II detector at the Cornell Electron Storage Ring, we determine the ratio R(chrg) for the mean charged multiplicity observed in Upsilon(1S)->gggamma events, to the mean charged multiplicity observed in e+e- -> qqbar gamma events. We find R(chrg)=1.04+/-0.02+/-0.05 for jet-jet masses less than 7 GeV.

The CLEO II detector is used to search for the production of χc2 states in two-photon interactions. We use the signature χc2→γJ/ψ→γl+l− with l=e,μ. Using 1.49 fb−1 of data taken with beam energies near 5.29 GeV, the two-photon width of the χc2 is determined to be Γ(χc2→γγ)=1.08±0.30(stat)±0.26(syst) keV, in agreement with predictions from perturbative QCD.Received 22 February 1994DOI:https://doi.org/10.1103/PhysRevD.50.4265©1994 American Physical Society

Using 3.0 ${\mathrm{fb}}^{\mathrm{\ensuremath{-}}1}$ of data collected with the CLEO-II detector, we study the Cabibbo-suppressed decay ${\mathit{D}}^{0}$\ensuremath{\rightarrow}${\mathrm{\ensuremath{\pi}}}^{\mathrm{\ensuremath{-}}}$${\mathit{e}}^{+}$${\ensuremath{\nu}}_{\mathit{e}}$. The ratio of the branching fractions B(${\mathit{D}}^{0}$\ensuremath{\rightarrow}${\mathrm{\ensuremath{\pi}}}^{\mathrm{\ensuremath{-}}}$${\mathit{e}}^{+}$${\ensuremath{\nu}}_{\mathit{e}}$)/B(${\mathit{D}}^{0}$\ensuremath{\rightarrow}${\mathit{K}}^{\mathrm{\ensuremath{-}}}$${\mathit{e}}^{+}$${\ensuremath{\nu}}_{\mathit{e}}$) is measured to be (10.3\ifmmode\pm\else\textpm\fi{}3.9\ifmmode\pm\else\textpm\fi{}1.3)%, corresponding to an upper limit of 15.6% at the 90% confidence level.

We search for the radiative leptonic tau decays τ→ee+e−ντνe and τ→μe+e−ντνμ using 3.60fb−1 of data collected by the CLEO-II experiment at the Cornell Electron Storage Ring. We present a first observation of the τ→ee+e−ντνe process. For this channel we measure the branching fraction B(τ→ee+e−ντνe)=(2.7+1.5+0.4+0.1−1.1−0.4−0.3)×10−5. An upper limit is established for the second channel: B(τ→μe+e−ντνμ)<3.2×10−5 at 90% C.L. Both results are consistent with the rates expected from standard model predictions.Received 22 November 1995DOI:https://doi.org/10.1103/PhysRevLett.76.2637©1996 American Physical Society

Using the CLEO II detector operating at the e+e− Cornell Electron Storage Ring (CESR), we present evidence for new decay modes of the Ξc+ into Ξ0π+, Ξ0π+π0, and Ξ0π+π−π+. The branching ratios of these decay modes, relative to Ξc+→Ξ−π+π+, have been measured to be 0.55±0.13±0.09, 2.34±0.57±0.37, and 1.74±0.42±0.27, respectively.

The CLEO-III Detector upgrade for charged particle identification is discussed. The RICH design uses solid LiF crystal radiators coupled with multi-wire chamber photon detectors, using TEA as the photosensor, and low-noise Viking readout electronics. Results from our beam test at Fermilab are presented.

The signals from lead tungstate crystals are studied as a function of temperature. Over the range from 13 to 45∘C, the total light output decreases by about a factor of two. This effect only concerns the scintillation component, so that the relative contribution of Cherenkov light to the signals increases with the same factor. The decay time of the scintillation component is observed to decrease as well.

We use data collected by the CLEO II detector at the Cornell Electron Storage Ring (CESR) to search for ${B}^{+}\ensuremath{\rightarrow}{h}^{+}{h}^{\ensuremath{-}}{h}^{+}$ (nonresonant) decays, where ${h}^{\ifmmode\pm\else\textpm\fi{}}$ can be either ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}{,K}^{\ifmmode\pm\else\textpm\fi{}}$, or $p(\overline{p})$. We see no evidence for signals and set upper limits on the branching fractions in the range $(2.8--8.9)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$. If observed, these decays may display CP violating asymmetries.

The CLEOII detector at the Cornell e+ e- storage ring CESR has been used to search for the two-photon production of the $f_J(2220)$ decaying into pi+ pi-. No evidence for a signal is found in data corresponding to an integrated luminosity of 4.77/fb and a 95% CL upper limit on $\Gamma_{two-photon} * BR{pi+ pi-}$ of 2.5 eV is set. If this result is combined with the BES Collaboration's measurement of $f_J(2220) -> pi+ pi-$ in radiative $J/\psi$ decay, a 95% CL lower limit on the stickiness of the $f_J(2220)$ of 73 is obtained. If the recent CLEO result for $\Gamma_{two-photon} * BR{\K_S K_S}$ is combined with the present result, the stickiness of the $f_J(2220)$ is found to be larger than 102 at the 95% CL. These results for the stickiness (the ratio of the probabilities for two-gluon coupling and two-photon coupling) provide further support for a substantial neutral parton content in the $f_J(2220)$.

Using data collected with the CLEO II detector at the Cornell Electron Storage Ring, we present new measurements of the branching fractions for ${D}^{+}\ensuremath{\rightarrow}{K}_{S}{K}^{+}$ and ${D}^{+}\ensuremath{\rightarrow}{K}_{S}{\ensuremath{\pi}}^{+}$. These results are combined with other CLEO measurements to extract the ratios of isospin amplitudes and phase shifts for $D\ensuremath{\rightarrow}\mathrm{KK}$ and $D\ensuremath{\rightarrow}K\ensuremath{\pi}$.

Using $3.1{\mathrm{fb}}^{\mathrm{\ensuremath{-}}1}$ of data accumulated at the $\ensuremath{\Upsilon}(4S)$ by the CLEO-II detector, corresponding to $3.3\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ pairs, we have searched for the color-suppressed $B$ hadronic decay processes ${B}^{0}\ensuremath{\rightarrow}{D}^{0}{(D}^{*0}){\mathrm{X}}^{0},$ where ${\mathrm{X}}^{0}$ is a light neutral meson ${\ensuremath{\pi}}^{0},$ ${\ensuremath{\rho}}^{0},$ \ensuremath{\eta}, ${\ensuremath{\eta}}^{\ensuremath{'}}$ or \ensuremath{\omega}. The ${D}^{*0}$ mesons are reconstructed in ${D}^{*0}\ensuremath{\rightarrow}{D}^{0}{\ensuremath{\pi}}^{0}$ and the ${D}^{0}$ mesons in ${D}^{0}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+},$ ${K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{0}$ and ${K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ decay modes. No obvious signal is observed. We set 90% C.L. upper limits on these modes, varying from $1.2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$ for ${B}^{0}\ensuremath{\rightarrow}{D}^{0}{\ensuremath{\pi}}^{0}$ to $1.9\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$ for ${B}^{0}\ensuremath{\rightarrow}{D}^{*0}{\ensuremath{\eta}}^{\ensuremath{'}}.$

We have observed the previously unseen decay modes Λπ+π0, Σ0π+π0 and Σ0π−π+π+ of the charmed baryon Λc+, as well as Λc+→Σ0π+ observed previously by ARGUS. The branching ratios for these four decay modes relative to Λc+→pK−π+ are measured to be 0.73 ±0.09± 0.16, 0.36 ±0.09±0.10, 0.21±0.05±0.05, and 0.21±0.02 ±0.04, respectively. Using the recent CLEO measurement of the branching ratio for Λc+→pK− π+, these modes account for 6% of Λc+ decays.

Using the CLEO detector at the Cornell e ϩ e Ϫ storage ring CESR we study the two-photon production of ⌳⌳ ¯, making the first observation of ␥␥→⌳⌳ ¯.We present the cross section for ␥␥→⌳⌳ ¯as a function of the ␥␥ center of mass energy and compare it to that predicted by the quark-diquark model.͓S0556-2821͑97͒50217-7͔

This article surveys the procedures used for deriving detector transfer functions and normalizing probability densities for the statistical analysis technique known as the "matrix element method" in the context of high energy physics (HEP) data analysis. Common misconceptions about transfer functions and efficiencies are pointed out and clarified.

We have studied the Cabibbo suppressed and color suppressed two-body decays B to ψϱ (ψω or ψa1). Using a data sample of 5.12 million B decays collected with the CLEO II detector we find the 90% confidence level upper limits for branching fractions of B0 → ψϱ0 and B0 → ψω to be 2.5 · 10−4 and 2.7 · 10−4, respectively. We also update the branching fraction B− → ψπ− to be (5.6 ± 2.7) · 10−5.

A limit on the mass of the tau neutrino is derived from 4.5 million tau pairs produced in an integrated luminosity of 5.0 fb^{-1} of electron-positron annihilation to tau pairs at center of mass energies near 10.6 GeV. The measurement technique involves a two-dimensional extended likelihood analysis, including the dependence of the end-point population on the neutrino mass, and allows for the first time an explicit background contribution. We use the decays of the tau to five charged pions and a neutrino as well as the decay to three charged pions, two neutral pions and a neutrino to obtain an upper limit of 30 MeV/c^2 at 95% C.L.

Using a data sample with integrated luminosity of about 3.9 fb^{-1} collected in e+ e- annihilation with the CLEO-II detector at the Cornell Electron Storage Ring, we have measured the branching ratios for the decay modes Ds -> (eta, eta') pi and Ds -> (eta, eta') rho relative to Ds -> phi pi. These decay modes are among the most common hadronic decays of the Ds's and can be related by factorization to the semileptonic decays Ds -> (eta,eta') l nu. The results obtained are compared with previous CLEO results and with the branching ratios measured for the related semileptonic decays. We also report results on the Cabibbo-suppressed decays of the D+ to the same final states.

Using the CLEO II detector we have performed the first search for $CP$ violation in tau lepton decay. CP violation in lepton decay does not occur in the minimal standard model but can occur in extensions such as the multi-Higgs doublet model. It appears as a characteristic difference between the $\tau^+$ and $\tau^-$ decay angular distributions for the semi-leptonic decay modes such as $\tau^- \to K^0 \pi^- \nu$. We define an observable asymmetry to exploit this and find no evidence for any CP violation.

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+).

We have measured the spectral shape Michel parameters $\ensuremath{\rho}$ and $\ensuremath{\eta}$ using leptonic decays of the $\ensuremath{\tau}$, recorded by the CLEO II detector. Assuming $e\ensuremath{-}\ensuremath{\mu}$ universality in the vectorlike couplings, we find ${\ensuremath{\rho}}_{e\ensuremath{\mu}}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.735\ifmmode\pm\else\textpm\fi{}0.013\ifmmode\pm\else\textpm\fi{}0.008$ and ${\ensuremath{\eta}}_{e\ensuremath{\mu}}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}\ensuremath{-}0.015\ifmmode\pm\else\textpm\fi{}0.061\ifmmode\pm\else\textpm\fi{}0.062$, where the first error is statistical and the second systematic. We also present measurements for the parameters for $e$ and $\ensuremath{\mu}$ final states separately.

A measurement of the spin alignment of charged D^* mesons produced in continuum e^+ e^- \to c \bar{c} events at \sqrt{s}=10.5 GeV is presented. This study using 4.72 fb^{-1} of CLEO II data shows that there is little evidence of any D^* spin alignment.

We present new measurements of photon energies and branching fractions for the radiative transitions Υ(2S)→γχb(J=0,1,2)(1P). The masses of the χb states are determined from the measured radiative photon energies. The ratio of mass splittings between the χb substates, r≡(MJ=2−MJ=1)/(MJ=1−MJ=0), with M the χb mass, provides information on the nature of the b¯b confining potential. We find r(1P)=0.542±0.022±0.024. This value is somewhat lower than the previous world average, but more consistent with the theoretical expectation that r(1P)<r(2P); i.e., that this mass splitting ratio is smaller for the χb(1P) states than for the χb(2P) states.Received 12 March 1998DOI:https://doi.org/10.1103/PhysRevD.59.032003©1999 American Physical Society

The decay ${\ensuremath{\tau}}^{\ensuremath{-}}\ensuremath{\rightarrow}2{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}3{\ensuremath{\pi}}^{0}{\ensuremath{\nu}}_{\ensuremath{\tau}}$ has been studied with the CLEO II detector at the Cornell Electron Storage Ring. The branching fraction is measured to be $(2.85\ifmmode\pm\else\textpm\fi{}0.56\ifmmode\pm\else\textpm\fi{}0.51)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$. The result is in good agreement with the isospin expectation but somewhat below the conserved-vector-current prediction. We have searched for resonance substructure in the decay. Within the statistical precision, the decay is saturated by the channels ${\ensuremath{\tau}}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{-}}2{\ensuremath{\pi}}^{0}\ensuremath{\omega}{\ensuremath{\nu}}_{\ensuremath{\tau}}$, $2{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}\ensuremath{\eta}{\ensuremath{\nu}}_{\ensuremath{\tau}}$, and ${\ensuremath{\pi}}^{\ensuremath{-}}2{\ensuremath{\pi}}^{0}\ensuremath{\eta}{\ensuremath{\nu}}_{\ensuremath{\tau}}$. This is the first observation of this \ensuremath{\omega} decay mode and the branching fraction is measured to be $({1.89}_{\ensuremath{-}0.67}^{+0.74}\ifmmode\pm\else\textpm\fi{}0.40)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$.

The CLEO III Ring Imaging Cherenkov detector uses LiF radiators to generate Cherenkov photons which are then detected by proportional wire chambers using a mixture of CH4 and TEA gases. The first two photon detector modules which were constructed, were taken to the Fermilab and tested in a beam dump that provided high-momentum muons. We report on results using both plane and “sawtooth”–shaped radiators. Specifically, we discuss the number of photoelectrons observed per ring and the angular resolution. The particle separation ability is shown to be sufficient for the physics of CLEO III.

This article introduces a new jet reconstruction method for particle physics. Event energy flow analysis is performed in two stages. Pattern recognition stage is applied first, utilizing multiresolution filtering techniques in the Fourier domain. Jet energy determination follows, conditional upon the choice of signal topology. The resulting algorithm is global, efficient, collinear and infrared safe, and allows the user to identify and avoid the event topology bifurcation points when energy reconstruction is performed. The performance of the new approach is better than that of commonly used jet algorithms such as kT, anti-kT, and seedless cone. An open source implementation is available at http://projects.hepforge.org/fftjet/.

We have searched for the decay of the lepton into seven charged particles and zero or one 0 .The data used in the search were collected with the CLEO II detector at the Cornell Electron Storage Ring ͑CESR͒ and correspond to an integrated luminosity of 4.61 fb Ϫ1 .No evidence for a signal is found.Assuming all the charged particles are pions, we set an upper limit on the branching fraction B" Ϫ →4 Ϫ 3 ϩ ( 0 ) …Ͻ2.4ϫ10 Ϫ6 at the 90% confidence level.This limit represents a significant improvement over the previous limit.͓S0556-2821͑97͒50221-9͔

We have searched for the decays $B\ensuremath{\rightarrow}\ensuremath{\mu}{\overline{\ensuremath{\nu}}}_{\ensuremath{\mu}}\ensuremath{\gamma}$ and $B\ensuremath{\rightarrow}e{\overline{\ensuremath{\nu}}}_{e}\ensuremath{\gamma}$ in a sample of $2.7\ifmmode\times\else\texttimes\fi{}{10}^{6}$ charged $B$ decays collected with the CLEO II detector. In the muon channel, we observe no candidates in the signal region and set an upper limit on the branching fraction of $\mathcal{B}(B\ensuremath{\rightarrow}\ensuremath{\mu}{\overline{\ensuremath{\nu}}}_{\ensuremath{\mu}}\ensuremath{\gamma})&lt;5.2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$ at the 90% confidence level. In the electron channel, we observe five candidates in the signal region and set an upper limit on the branching fraction of $\mathcal{B}(B\ensuremath{\rightarrow}e{\overline{\ensuremath{\nu}}}_{e}\ensuremath{\gamma})&lt;2.0\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$ at the 90% confidence level.

We have searched for the decay $\stackrel{\ensuremath{\rightarrow}}{B}{D}_{s1}^{+}(2536)X$ and measured an upper limit for the inclusive branching fraction of $\mathcal{B}(\stackrel{\ensuremath{\rightarrow}}{B}{D}_{s1}^{+}X)&lt;0.96%$ at the 90% confidence level. This limit is small compared with the total expected $\stackrel{\ensuremath{\rightarrow}}{B}{D}^{(*)}{D}^{(*)}\mathrm{KX}$ rate. Assuming factorization, the ${D}_{s1}^{+}$ decay constant is constrained to be ${f}_{{D}_{s1}^{+}}$114 MeV at the 90% confidence level, at least 2.5 times smaller than that of ${D}_{s}^{+}$.

Using data collected on the $\ensuremath{\Upsilon}(4S)$ resonance and the nearby continuum by the CLEO-II detector, we have studied combinations of baryons with leptons produced in the process $\ensuremath{\Upsilon}(4S)\ensuremath{\rightarrow}B\overline{B}$, $B\ensuremath{\rightarrow}\mathrm{lepton}+X$, $\overline{B}\ensuremath{\rightarrow}\mathrm{baryon}+X$. Our results do not support models which attribute the bulk of ${\ensuremath{\Lambda}}_{c}$ production in $\overline{B}$ decay to the process $b\ensuremath{\rightarrow}{\mathrm{cW}}^{\ensuremath{-}}{,W}^{\ensuremath{-}}\ensuremath{\rightarrow}\overline{c}s$.

Using the CLEO II detector at the Cornell Electron Storage Ring we have measured the Ξ0c decay asymmetry parameter in the decay Ξ0c→Ξ−π+. We find αΞ0cαΞ=0.26±0.18(stat)+0.05−0.04(syst); using the world average value of αΞ=−0.456±0.014 we obtain αΞ0c=−0.56±0.39(stat)+0.10−0.09(syst). The physically allowed range of a decay asymmetry parameter is −1<α<+1. Our result prefers a negative value: αΞ0c is <0.1 at the 90% C.L. The central value occupies the middle of the theoretically expected range but is not yet precise enough to choose between models.Received 20 November 2000DOI:https://doi.org/10.1103/PhysRevD.63.111102©2001 American Physical Society

We have studied the leptonic decay of the γ (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(γ(1S) → τ+τ−) = (2.61±0.12−0.13+0.09)%. The result is consistent with expectations from lepton universality

We have observed two new decay modes of the charmed baryon Ξc+ into Σ+K−π+ and Σ+K∗0 using data collected with the CLEO II detector. We also present the first measurement of the branching fraction for the previously observed decay mode Ξc+ → ΛK−π+π+. The branching fractions for these three modes relative to Ξc+ → Ξ−π+π+ are measured to be 1.18 ± 0.26 ± 0.17, 0.92 ± 0.27 ± 0.14, and 0.58 ± 0.16 ± 0.07, respectively.

Error propagation formulae are derived for the expectation-maximization iterative unfolding algorithm regularized by a smoothing step. The effective number of parameters in the fit to the observed data is defined for unfolding procedures. Based upon this definition, the Akaike information criterion is proposed as a principle for choosing the smoothing parameters in an automatic, data-dependent manner. The performance and the frequentist coverage of the resulting method are investigated using simulated samples. A number of issues of general relevance to all unfolding techniques are discussed, including irreducible bias, uncertainty increase due to a data-dependent choice of regularization strength, and presentation of results.

We explore clustering stability of sequential recombination jet reconstruction algorithms. Events are reconstructed many times, using random variations of kinematic properties of the jet fragmentation process. Sensitivity of different algorithms to initial conditions are quantified by introducing probabilistic assignment of initial particles to jets (fuzzy clustering). A criterion detecting unstable configurations (bifurcation points) is proposed, based on the overall fuzziness of the event.

The CLEO collaboration is preparing a major upgrade of its present detector including a RICH detector for particle identification. This subdetector system follows the ‘proximity focussing’ design and uses Lithium Fluoride (LiF) crystal radiators and MWPCs filled with a CH4/TEA gas mixture. Part of the radiator crystals will have the new ‘sawtooth’ geometry. We have tested the first two of the 30 detector modules together with the first radiator crystals in a muon halo beam at Fermilab. For the measurement of the Cherenkov angle we obtain a single photon measurement error of 13.5 mrad for the conventional planar radiator. With 14 detected photons we find a resolution per track of 4.5 mrad. In the first measurement ever of a ‘sawtooth’ radiator we achieve a resolution of 11.8 mrad for single photons and 4.8 mrad per track for 12.3 detected photons with a reduced geometric acceptance. These results fulfill CLEO III requirements.

Using data recorded by the CLEO-II detector at CESR, we report new measurements of the branching fractions for the decays of the charmed baryon ${\ensuremath{\Lambda}}_{c}^{+}$ into ${\mathrm{pK}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{0},$ $p{K}^{0},$ $p{K}^{0}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}},$ and $p{K}^{0}{\ensuremath{\pi}}^{0},$ all measured relative to ${\mathrm{pK}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}.$ The relative branching fractions are $0.67\ifmmode\pm\else\textpm\fi{}0.04\ifmmode\pm\else\textpm\fi{}0.11,0.46\ifmmode\pm\else\textpm\fi{}0.02\ifmmode\pm\else\textpm\fi{}0.04,0.52\ifmmode\pm\else\textpm\fi{}0.04\ifmmode\pm\else\textpm\fi{}0.05,$ and $0.66\ifmmode\pm\else\textpm\fi{}0.05\ifmmode\pm\else\textpm\fi{}0.07,$ respectively.

We report a measurement of the magnitude of the tau neutrino helicity from tau-pair events taken with the CLEO detector at the CESR electron-positron storage ring. Events in which each tau undergoes the decay tau -> h nu, with h a charged pion or kaon, are analyzed for energy correlations between the daughter hadrons, yielding |xi| = 2*|h_nu| = 1.03 +/- 0.06 +/- 0.04, with the first error statistical and the second systematic.

Using the angular correlation between the $\pi^+$ emitted in a $D^{*+} \rightarrow D^0 \pi^+$ decay and the $e^+$ emitted in the subsequent $D^0 \rightarrow Xe^+\nu$ decay, we have measured the branching fraction for the inclusive semi-electronic decay of the $D^0$ meson to be: {\cal B}(D^0 \rightarrow X e^+ \nu) = [6.64 \pm 0.18 (stat.) \pm 0.29 (syst.)] \%. The result is based on 1.7 fb$^{-1}$ of $e^+e^-$ collisions recorded by the CLEO II detector located at the Cornell Electron Storage Ring (CESR). Combining the analysis presented in this paper with previous CLEO results we find, \frac{{\cal B} (D^0 \rightarrow X e^+ \nu)} {{\cal B} (D^0 \rightarrow K^- \pi^+)} = 1.684 \pm 0.056 (stat.) \pm 0.093(syst.) and \frac{{\cal B}(D\rightarrow K^-e^+\nu)} {{\cal B}(D\rightarrow Xe^+\nu)} = 0.581 \pm 0.023 (stat.) \pm 0.028(syst.). The difference between the inclusive rate and the sum of the measured exclusive branching fractions (measured at CLEO and other experiments) is $(3.3 \pm 7.2) \%$ of the inclusive rate.

This article describes the FFTJet software package designed to perform jet reconstruction in the analysis of high energy physics experimental data. A two-stage approach is adopted in which pattern recognition is performed first, utilizing multiresolution filtering techniques in the frequency domain. Jet energy reconstruction follows, conditional upon the choice of signal topology. The method is efficient, global, collinear and infrared safe, and allows the user to identify and avoid the event topology bifurcation points when energy reconstruction is performed.

We study the properties of several likelihood-based statistics commonly used in testing for the presence of a known signal under a mixture model with known background, but unknown signal fraction. Under the null hypothesis of no signal, all statistics follow a standard normal distribution in large samples, but substantial deviations can occur at low sample sizes. Approximations for respective $p$-values are derived to various orders of accuracy using the methodology of Edgeworth expansions. Adherence to normality is studied, and the magnitude of deviations is quantified according to resulting inflation or deflation. We find that approximations to third-order accuracy are generally sufficient to guarantee $p$-values with nominal false positive error rates in the five sigma range ($p$-value $= 2.87 \times 10^{-7}$) for the classic Wald, score, and likelihood ratio (LR) statistics at relatively low samples. Not only does LR have better adherence to normality, but it also consistently outperforms all other statistics in terms of false negative error rates. The reasons for this are shown to be connected with high-order cumulant behavior gleaned from fourth order Edgeworth expansions. Finally, a conservative procedure is suggested for making finite sample adjustments while accounting for the look elsewhere effect with the theory of random fields (a.k.a. the Gross-Vitells method).

Abstract The Intermediate Silicon Layers Detector is presently being built as part of the CDF upgrades to prepare for the next Tevatron data taking run, scheduled to start in the year 2000. The ISL will be located in the radial region between the Silicon Vertex Detector and the Central Outer Tracker. It will add tracking in the forward region and significantly improve tracking in the central region. Together with the SVX II, the ISL forms a standalone, 3D silicon tracker. In this article we present the design of the ISL and the current status of its construction.

A search for the lepton family number violating decays {tau} {yields} e{gamma} and {tau} {yields} {mu}{gamma} has been performed using CLEO-II data. No evidence of a signal has been found and the corresponding upper limits are B({tau} {yields} e{gamma}) < 2.7 x 10{sup -6} and B({tau} {yields} {mu}{gamma}) < 3.0 c 10{sup -6} at 90% CL.

We have measured the vector-pseudoscalar mass splitting M(D*+s)-M(D+s)=144.22±0.47±0.37 MeV significantly more precisely than the previous world average. We minimize the systematic errors by also measuring the vector-pseudoscalar mass difference M(D*0)-M(D0) using the radiative decay D*0→D0γ, obtaining [M(D*+s)-M(D+s)]-[M(D*0)-M(D0)] =2.09±0.47±0.37 MeV. This is then combined with our previous high-precision measurement of M(D*0)-M(D0), which used the decay D*0→D0π0. We also measure the mass difference M(D+s)-M(D+)=99.5±0.6±0.3 MeV, using the φπ+ decay modes of the D+s and D+ mesons.Received 27 January 1994DOI:https://doi.org/10.1103/PhysRevD.50.1884©1994 American Physical Society

The CLEO detector is undergoing major improvements in conjunction with a high luminosity upgrade of the CESR e+e− collider. A novel element is a state of the art particle identification system, based on a proximity focused Ring Imaging Cherenkov detector. This detector will provide an excellent hadron identification at all the momenta relevant to the study of the decays of B mesons produced at the ϒ(4S) resonance. Some features unique to our design will be discussed together with some results achieved on individual components.

hadron calorimeter (HCAL) for Run 2, performing analyses of Run 2 data, and making initial studies and plans for the second phase of upgrades in CMS. Our research has primarily focused on searches for Beyond Standard Model (BSM) physics via dijets, monophotons, and monojets. We also made significant contributions to the analyses of the semileptonic Higgs decays and Standard Model (SM) measurements in Run 1. Our work on the operations of the CMS detector, especially the performance monitoring of the HCAL in Run 1, was indispensable to the experiment. Our team members, holding leadership positions in HCAL, have played key roles in the R&D, construction, and commissioning of these detectors in the last decade. We also maintained an active program in jet studies that builds on our expertise in calorimetry and algorithm development. In Run 2, we extended some of our analyses at 8 TeV to 13 TeV, and we also started to investigate new territory, e.g., dark matter searches with unexplored signatures. The objective of dual-readout calorimetry R&D was intended to explore (and, if possible, eliminate) the obstacles that prevent calorimetric detection of hadrons and jets with a comparable level of precision as we have grown accustomed to for electrons and photons. The initial prototype detector was successfully tested at the SPS/CERN in 2003-2004 and evolved over the last decade. In 2012-2015, several other prototypes were built to further reduce leakage fluctuations, improve Cherenkov light yield, increase fiber attenuation length, and other related phenomena. During this grant period, we graduated two students with Ph.D. degrees, and five undergraduate students from our labs went on to prestigious graduate programs in the US and Europe. Also, the TTU HEP team has participated in the QuarkNet program every year since 2001. We are dedicated to working with area teachers and students at all levels and to training the next generation of scientists. Over 20 high school teachers have participated in our program since its inception.

Condition of the asymptotic normality of the signal fraction estimate by maximum likelihood is derived under the null hypothesis of no signal. Consequences of this condition for determination of signal significance taking in to account the look elsewhere effect are discussed.

A Local Orthogonal Polynomial Expansion (LOrPE) of the empirical density function is proposed as a novel method to estimate the underlying density. The estimate is constructed by matching localized expectation values of orthogonal polynomials to the values observed in the sample. LOrPE is related to several existing methods, and generalizes straightforwardly to multivariate settings. By manner of construction, it is similar to Local Likelihood Density Estimation (LLDE). In the limit of small bandwidths, LOrPE functions as Kernel Density Estimation (KDE) with high-order (effective) kernels inherently free of boundary bias, a natural consequence of kernel reshaping to accommodate endpoints. Faster asymptotic convergence rates follow. In the limit of large bandwidths, LOrPE is equivalent to Orthogonal Series Density Estimation (OSDE) with Legendre polynomials. We compare the performance of LOrPE to KDE, LLDE, and OSDE, in a number of simulation studies. In terms of mean integrated squared error, the results suggest that with a proper balance of the two tuning parameters, bandwidth and degree, LOrPE generally outperforms these competitors when estimating densities with sharply truncated supports.

The high energy physics group at Texas Tech University (TTU) concentrates its research efforts on the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC) and on generic detector R&D for future applications. Our research programs have been continuously supported by the US Department of Energy for over two decades, and this final report summarizes our achievements during the last grant period from May 1, 2012 to March 31, 2016. After having completed the Run 1 data analyses from the CMS detector, including the discovery of the Higgs boson in July 2012, we concentrated on commissioning the CMS hadron calorimeter (HCAL) for Run 2, performing analyses of Run 2 data, and making initial studies and plans for the second phase of upgrades in CMS. Our research has primarily focused on searches for Beyond Standard Model (BSM) physics via dijets, monophotons, and monojets. We also made significant contributions to the analyses of the semileptonic Higgs decays and Standard Model (SM) measurements in Run 1. Our work on the operations of the CMS detector, especially the performance monitoring of the HCAL in Run 1, was indispensable to the experiment. Our team members, holding leadership positions in HCAL, have played key roles in the R&D, construction, and commissioning of these detectors in the last decade. We also maintained an active program in jet studies that builds on our expertise in calorimetry and algorithm development. In Run 2, we extended some of our analyses at 8 TeV to 13 TeV, and we also started to investigate new territory, e.g., dark matter searches with unexplored signatures. The objective of dual-readout calorimetry R&D was intended to explore (and, if possible, eliminate) the obstacles that prevent calorimetric detection of hadrons and jets with a comparable level of precision as we have grown accustomed to for electrons and photons. The initial prototype detector was successfully tested at the SPS/CERN in 2003-2004 and evolved over the last decade. In 2012-2015, several other prototypes were built to further reduce leakage fluctuations, improve Cherenkov light yield, increase fiber attenuation length, and other related phenomena. During this grant period, we graduated two students with Ph.D. degrees, and five undergraduate students from our labs went on to prestigious graduate programs in the US and Europe. Also, the TTU HEP team has participated in the QuarkNet program every year since 2001. We are dedicated to working with area teachers and students at all levels and to training the next generation of scientists. Over 20 high school teachers have participated in our program since its inception.

A Local Orthogonal Polynomial Expansion (LOrPE) of the empirical density function is proposed as a novel method to estimate the underlying density. The estimate is constructed by matching localized expectation values of orthogonal polynomials to the values observed in the sample. LOrPE is related to several existing methods, and generalizes straightforwardly to multivariate settings. By manner of construction, it is similar to Local Likelihood Density Estimation (LLDE). In the limit of small bandwidths, LOrPE functions as Kernel Density Estimation (KDE) with high-order (effective) kernels inherently free of boundary bias, a natural consequence of kernel reshaping to accommodate endpoints. Faster asymptotic convergence rates follow. In the limit of large bandwidths, LOrPE is equivalent to Orthogonal Series Density Estimation (OSDE) with Legendre polynomials. We compare the performance of LOrPE to KDE, LLDE, and OSDE, in a number of simulation studies. In terms of mean integrated squared error, the results suggest that with a proper balance of the two tuning parameters, bandwidth and degree, LOrPE generally outperforms these competitors when estimating densities with sharply truncated supports.

Error propagation formulae are derived for the expectation-maximization iterative unfolding algorithm regularized by a smoothing step. The effective number of parameters in the fit to the observed data is defined for unfolding procedures. Based upon this definition, the Akaike information criterion is proposed as a principle for choosing the smoothing parameters in an automatic, data-dependent manner. The performance and the frequentist coverage of the resulting method are investigated using simulated samples. A number of issues of general relevance to all unfolding techniques are discussed, including irreducible bias, uncertainty increase due to a data-dependent choice of regularization strength, and presentation of results.

Using data samples taken at the $\ensuremath{\Upsilon}(4S)$ resonance and nearby continuum ${e}^{+}{e}^{\ensuremath{-}}$ annihilation with the CLEO-II detector at CESR, we have measured the inclusive branching fraction $\mathcal{B}(B\ensuremath{\rightarrow}\ensuremath{\eta}X)=(17.6\ifmmode\pm\else\textpm\fi{}1.1\ifmmode\pm\else\textpm\fi{}1.2)%$, and the momentum distribution of the $\ensuremath{\eta}$ mesons from $B$ meson decay. The $\ensuremath{\eta}$ yield cannot be explained as arising solely from the decay of intermediate charmed mesons.

We have measured the neutron fraction event-by-event in beam test data taken at CERN by the DREAM collaboration. I will review these measurements in the context of the importance of neutrons to future high-precision calorimetry, and bring together the data from SPACAL, the GLD compensating calorimeter, and DREAM to estimate the impact neutron fraction measurements will make on hadronic energy resolution in dual-readout calorimeters.

A local orthogonal polynomial expansion (LOrPE) of the empirical density function is proposed as a novel method to estimate the underlying density. The estimate is constructed by matching localised expectation values of orthogonal polynomials to the values observed in the sample. LOrPE is related to several existing methods, and generalises straightforwardly to multivariate settings. By manner of construction, it is similar to local likelihood density estimation (LLDE). In the limit of small bandwidths, LOrPE functions as kernel density estimation (KDE) with high-order (effective) kernels inherently free of boundary bias, a natural consequence of kernel reshaping to accommodate endpoints. Consistency and faster asymptotic convergence rates follow. In the limit of large bandwidths LOrPE is equivalent to orthogonal series density estimation (OSDE) with Legendre polynomials, thereby inheriting its consistency. We compare the performance of LOrPE to KDE, LLDE, and OSDE, in a number of simulation studies. In terms of mean integrated squared error, the results suggest that with a proper balance of the two tuning parameters, bandwidth and degree, LOrPE generally outperforms these competitors when estimating densities with sharply truncated supports.