R. J. Morrison

First measurement of Γ(D* +) and precision measurement of m D*+-m D0

We present the first measurement of the D*+ width using 9/fb of e+ e- data collected near the Upsilon(4S) resonance by the CLEO II.V detector. Our method uses advanced tracking techniques and a reconstruction method that takes advantage of the small vertical size of the CESR beam spot to measure the energy release distribution from the D*+ -> D0 pi+ decay. We find Gamma(D*+) = 96 +- 4 (Statistical) +- 22 (Systematic) keV. We also measure the energy release in the decay and compute Delta m = m(D*+) - m(D0) = 145.412 +- 0.002 (Statistical) +- 0.012 (Systematic) MeV/c^2

Study of the semileptonic decay mode D0-->K-e+ nu e.

We present an analysis of the exclusive semileptonic decay mode D/sup 0/ ..-->.. K/sup -/e/sup +/nu/sub e/. We have measured the ratio of decay rates GAMMA(D/sup 0/ ..-->.. K/sup -/e/sup +/nu/sub e/)/GAMMA(D/sup 0/ ..-->.. K/sup -/..pi../sup +/). After correcting for the reconstruction efficiencies and subtracting the contribution from other decay modes we have found the ratio to be equal to 0.77 +- 0.12(stat) +- 0.13(syst).

Measurement of Ds+/- and D+/- decays to nonstrange states.

Using the data from Fermilab experiment 691, we have observed signals for the decays D/sub s//sup +- / and D/sup +- /..--> pi../sup -/..pi../sup +/..pi../sup +- / and have analyzed these modes for the fraction due to rho/sup 0/..pi../sup +- / and f/sub 0/(975)..pi../sup +- /. In addition, we have searched for the decays D/sub s//sup +- / and D/sup +- /..--> pi../sup -/..pi../sup +/..pi../sup -/..pi../sup +/..pi../sup +- /. Values or upper limits are reported for the relative branching fractions for all of the above decays.

Experimental study of the semileptonic decay D+-->K-bar

The decay D/sup +/..-->..K/sup -/..pi../sup +/e/sup +/..nu../sub e/ has been studied in the Fermilab photoproduction experiment E691. The ratio of branching ratios, B(D/sup +/..-->..K-bar/sup *//sup 0/e/sup +/..nu../sub e/)/B (D/sup +/..-->..K/sup -/..pi../sup +/..pi../sup +/), is found to be 0.49 +- 0.04 +- 0.05, corresponding to a D/sup +/..-->..K-bar/sup *//sup 0/e/sup +/..nu../sub e/ branching ratio of (4.5 +- 0.7 +- 0.5)%. The branching ratio to the nonresonant (K/sup -/..pi../sup +/)/sub NR/e..nu../sub e/ final state is found to be less than 0.7% at the 90% confidence level. The K/sup *//sup 0/ mesons have a ratio of longitudinal to transverse polarization of 2.4/sub -0.9//sup +1.7/ +- 0.2. .AE

A general method of estimating physical parameters from a distribution with acceptance and smearing effects

Abstract A generalization of the maximum likelihood method of estimating physical parameters is presented which can be used when the data set has been distorbed by acceptance and smearing effects. This method employs events from a Monte Carlo simulation of the experiment directly in the calculation of the likelihood. It is sufficiently general that it can be used consistently, over any number of dimensions, and does not waste information contained in the data set. Systematic errors associated with this technique can be estimated and, if needed, reduced by including more Monte Carlo events.

Inclusive π0 electroproduction in the deep inelastic region

Abstract Using 20.5 GeV electrons on protons, we measured inclusive π0s (of transverse momentum, pT, from 0 to 1.4 GeV/c) produced by virtual photons of energy, ν, from 4 to 16.5 GeV and four-momentum squared, q2, from −1.8 to −8.5 (GeV/c)2. Comparing with charged pion data, we find σ π 0 = 1 2 (σ π + + σ π − ) , supporting the quark model. Photon knockout of a quark is favored as the interpretation of these data because of scaling in z = Eπ/ν and similarity in z-dependence of other pion production data. Consistent with this interpretation are the dependence of 〈pT〉 on q2, the azimuthal dependence, and fits to the constituent interchange model. We also observe a possible pT−4 dependence at large |q2| over a limited pT range.

A Dalitz plot analysis of D ---> K pi pi decays

Decays of the [ital D][sup 0] meson to [ital K][sup [minus]][pi][sup +][pi][sup 0] and [ital [bar K]][sup 0][pi][sup +][pi][sup [minus]] and of the [ital D][sup +] to [ital K][sup [minus]][pi][sup +][pi][sup +] have been analyzed for resonant substructure. We present results on the amplitudes and phases of each decay mode and compare the results with other measurements. We confirm the highly nonresonant nature of the [ital D][sup +] to [ital K][sup [minus]][pi][sup +][pi][sup +] decays. There is general agreement with theoretical models for the branching ratios measured.

An Inexpensive Large Area Shower Detector With High Spatial and Energy Resolution

Abstract A 59-layer lead-liquid scintillator shower detector has been tested in an electron beam at SLAC. The energy resolution is about 9%/√E. The detector is optically segmented into counters by means of thin, teflon-coated, bent aluminum panels. The position of the shower is determined to a precision of a few mm by comparing the relative sizes of the signals from neighboring counters.

Precision comparison of inelastic electron and positron scattering from hydrogen

Using 13.5--GeV beams at Stanford Linear Accelerator Center, electron and positron inelastic scattering have been compared over the range 1.2

Development and construction of the SLD Cherenkov ring-imaging detector☆

Abstract We report on the development and construction of the Cherenkov ring-imaging detector (CRID) for the SLD experiment at the SLAC linear collider. In particular, we outline recent progress in the construction and results from testing the first components of the barrel CRID, including the drift boxes, liquid radiator trays and mirror system. We also review progress in the construction of the barrel CRID gas radiator vessel, the liquid radiator recirculator system, and the electronic readout system. The development of a comprehensive monitor and control system - upon which the stable operation and physics efficacy of the CRID depend — is also described.