The construction and performance of a large aperture magnetic detector designed for use at the Cornell Electon Storage Ring is descr bed.

Three narrow resonances have been observed in ${e}^{+}{e}^{\ensuremath{-}}$ annihilation into hadrons at total energies between 9.4 and 10.4 GeV. Measurements of mass spacing and ratios of lepton pair widths support the interpretation of these "$\ensuremath{\Upsilon}$" states as the lowest triplet-$S$ levels of the $b\overline{b}$ quark-antiquark system.

We report measurements of the electroproduction of $\ensuremath{\varphi}$ mesons from hydrogen at ${Q}^{2}$ values of 0.23, 0.43, and 0.97 ${\mathrm{GeV}}^{2}$ with $|t|$ varying from 0.125 to 1.3 ${\mathrm{GeV}}^{2}$ at each ${Q}^{2}$ point. The data show no evidence for a ${Q}^{2}$ dependence of the slope of the $t$ distribution, the forward cross section falls with increasing ${Q}^{2}$ as the square of the $\ensuremath{\varphi}$ propagator, the decay angular distributions agree with the predictions of $s$-channel helicity conservation, and the ratio of the longitudinal to the transverse component increases linearly with ${Q}^{2}$.

We report measurements of the inclusive electroproduction reaction $e+p\ensuremath{\rightarrow}e+\ensuremath{\Lambda}+\mathrm{anything}$ for $\ensuremath{\Lambda}'\mathrm{s}$ produced along and near the direction of the virtual photon. The measurements cover the kinematic range $2.1<W<3.55$ GeV, $0.1<{Q}^{2}<1.5$ Ge${\mathrm{V}}^{2}$, $0<{{p}_{T}}^{2}<1.2$ ${\mathrm{GeV}}^{2}$, and $0<{x}^{\ensuremath{'}}<1$. The ${Q}^{2}$, $W$, ${{p}_{T}}^{2}$, and ${x}^{\ensuremath{'}}$ dependence of the invariant structure function is similar to that observed for forward protons. It is independent of ${Q}^{2}$, decreases with an increase of ${x}^{\ensuremath{'}}$, and shows a weak dependence on ${{p}_{T}}^{2}$.

We report measurements of the electroproduction of single charged pions from hydrogen and deuterium targets for values of epsilon in the range 0.35 < epsilon < 0.45. Data were taken with a hydrogen target at the (W,Q/sup 2/) points (2.15 GeV, 1.2 GeV/sup 2/), (2.65, 2.0), (2.65, 3.4), (2.65, 6.0), and (2.65, 10.0). Data were taken with a deuterium target at the (W, Q/sup 2/) points (2.15, 1.2) and (2.65, 2.0). The transverse cross section obtained by using these data in conjunction with earlier data at high epsilon to separate the longitudinal and transverse components is used in conjunction with the new data and the t-channel Born term to determine the pion form factor and to re-evaluate previously reported measurements. In the range 0.15 GeV/sup 2/ < Q/sup 2/ < 10.0 GeV/sup 2/ the pion form factor can be described by the simple pole form (1 + Q/sup 2//(0.462 +- 0.024))/sup -/1.

This paper reports a measurement of the photoproduction of charged-kaon pairs from hydrogen which was carried out to search for high-mass resonances in the mass range from 1.4 to 2.4 GeV. The only structure observed in the mass spectrum was a dip near 1.83 GeV. An analysis of the data indicates that this structure could be produced by a high-mass meson with a mass of about 1.83 GeV and a width of roughly 120 MeV which interfers with the kaon S\"oding amplitude.

We report measurements of the electroproduction of single charged pions from hydrogen and deuterium targets for values of $\\ensuremath{\\epsilon}$ in the range $0.35l\\ensuremath{\\epsilon}l0.45$. Data were taken with a hydrogen target at the ($W, {Q}^{2}$) points (2.15 GeV, 1.2 ${\\mathrm{GeV}}^{2}$), (2.65, 2.0), (2.65, 3.4), (2.65, 6.0), and (2.65, 10.0). Data were taken with a deuterium target at the ($W, {Q}^{2}$) points (2.15, 1.2) and (2.65, 2.0). The transverse cross section obtained by using these data in conjunction with earlier data at high $\\ensuremath{\\epsilon}$ to separate the longitudinal and transverse components is used in conjunction with the new data and the $t$-channel Born term to determine the pion form factor and to re-evaluate previously reported measurements. In the range $0.15 \\mathrm{Ge}{\\mathrm{V}}^{2}l{Q}^{2}l10.0 \\mathrm{Ge}{\\mathrm{V}}^{2}$ the pion form factor can be described by the simple pole form ${[1+\\frac{{Q}^{2}}{(0.462\\ifmmode\\pm\\else\\textpm\\fi{}0.024)}]}^{\\ensuremath{-}1}$.

We report measurements of the inclusive electroproduction reaction e + p ..-->.. e + ..lambda.. + anything for ..lambda..'s produced along and near the direction of the virtual photon. The measurements cover the kinematic range 2.1 < W < 3.55 GeV, 0.1 < Q/sup 2/ < 1.5 GeV/sup 2/, 0 < p/sub T//sup ts2/

We present evidence for a large scalar contribution to the cross section for the reaction ep ..-->.. eK/sup +/..lambda... No evidence for a scalar contribution is found for the reaction ep ..-->.. eK/sup +/..sigma../sup 0/. This is reminiscent of the results for the ..pi../sup +/n and ..pi../sup +/..delta../sup 0/ final states.

The dipolar and quadrupolar hyperfine coupling constants, $A$ and $B$, respectively, and the atomic ${g}_{J}$ factor have been measured for the $^{4}S_{\\frac{3}{2}}$ ground state of atomic nitrogen 14. An atomic hydrogen maser oscillating at the $\\ensuremath{\\Delta}{M}_{F}=\\ensuremath{-}1$ transition in a magnetic field ranging from 0.008 to 8 G was used as a detector of transitions in both hydrogen and nitrogen. The magnetic field was calibrated by the hydrogen Zeeman transition frequency. Values of the constants were found to be $A=10450929.12(10)$ Hz, $B=1.27(10)$ Hz, and ${g}_{J}=2.002134652(64)$. These results are compared to current theoretical results and other experimental measurements.

We use new measurements of the inclusive electroproduction reactions $\mathrm{eN}\ensuremath{\rightarrow}{e}^{\ensuremath{'}}{\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}X$ and $\mathrm{eN}\ensuremath{\rightarrow}{e}^{\ensuremath{'}}\mathrm{pX}$ with $\ensuremath{\epsilon}$ values in the range $0.35<\ensuremath{\epsilon}<0.45$ together with earlier measurements with $0.85<\ensuremath{\epsilon}<0.95$ to determine the contributions to the cross section due to transversely and longitudinally polarized photons in the range $1.2 \mathrm{Ge}{\mathrm{V}}^{2}<{Q}^{2}<3.3 \mathrm{Ge}{\mathrm{V}}^{2}$. The longitudinal component is small and consistent with that observed in the total virtual-photoproduction cross section.

This paper reports measurements of the inclusive pion electroproduction reaction $e+N\ensuremath{\rightarrow}e+{\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}+$ anything with both proton and neutron targets for pions produced along and near the direction of the virtual photon. Two independent purposes of these measurements were to provide data at low $\ensuremath{\epsilon}$ and at high ${Q}^{2}$. Data are reported for the ($W$,${Q}^{2}$,$\ensuremath{\epsilon}$) points (2.2 GeV, 1.2 ${\mathrm{GeV}}^{2}$, 0.45), (2.7, 2.0, 0.35), (2.7, 3.3, 0.40), (2.7, 6.2, 0.40), and (2.7, 9.5, 0.40). The data are used to test Feynman scaling and to compare the ratio of the cross sections for charged-pion production to the quark-model predictions. The data are also used in conjunction with the data from earlier experiments to separate the scalar and transverse components of the cross section.

We report new measurements of inclusive proton electroproduction. Data were taken with a hydrogen target at the ($W$, ${Q}^{2}$) points (2.2 GeV, 1.2 Ge${\mathrm{V}}^{2}$), (2.7, 2.0), (2.7, 3.3), (2.7, 6.2), and (2.7, 9.5) and with a deuterium target at (2.2, 1.2), (2.7, 2.0), (2.7, 6.2), and (2.7, 9.5). The invariant structure function is studied as a function of $W$, ${Q}^{2}$, $\ensuremath{\omega}$, and ${x}^{\ensuremath{'}}$. The data are compared with the predictions of the constituent-interchange model.

We present evidence for a large scalar contribution to the cross section for the reaction $\mathrm{ep}\ensuremath{\rightarrow}e{K}^{+}\ensuremath{\Lambda}$. No evidence for a scalar contribution is found for the reaction $\mathrm{ep}\ensuremath{\rightarrow}e{K}^{+}{\ensuremath{\Sigma}}^{0}$. This is reminiscent of the results for the ${\ensuremath{\pi}}^{+}n$ and ${\ensuremath{\pi}}^{+}{\ensuremath{\Delta}}^{0}$ final states.

We report measurements of the electroproduction of $\ensuremath{\phi}$ mesons from hydrogen at ${Q}^{2}$ values of 0.23, 0.43, and 0.97 Ge${\mathrm{V}}^{2}$ with $|t|$ varying from 0.125 to 1.3 Ge${\mathrm{V}}^{2}$ at each ${Q}^{2}$ point. The data show no evidence for a ${Q}^{2}$ dependence of the slope of the $t$ distribution; the forward cross section falls with increasing ${Q}^{2}$ as the square of the $\ensuremath{\phi}$ propagator; the decay angular distributions agree with the predictions of $s$-channel helicity conservation; and the ratio of the longitudinal to the transverse component increases linearly with ${Q}^{2}$.

We report measurements of the inclusive electroproduction reaction $\mathrm{ep}\ensuremath{\rightarrow}e{\ensuremath{\pi}}^{+}X$ for pions produced at 90\ifmmode^\circ\else\textdegree\fi{} in the virtual-photon-proton center-of-mass system. Data are presented at the ($W,{Q}^{2}$) points (2.2 GeV, 1.2 ${\mathrm{GeV}}^{2}$), (2.2,3.6), (2.65,1.2), (2.65,2.0), (2.65,2.8), (2.65, 3.6), (3.1, 1.2), and (3.1, 2.0). The invariant structure function is studied as a function of $W$, ${Q}^{2}$, ${x}_{T}$, $p_{T}^{}{}_{}{}^{2}$, and the square of the invariant undetected mass.

We report measurements of the exclusive electroproduction reaction $e+p\ensuremath{\rightarrow}e+{\ensuremath{\pi}}^{+}+n$ for pions produced near 0\ifmmode^\circ\else\textdegree\fi{} in the virtual-photon-proton center-of-mass system with values of $\ensuremath{\epsilon}$ in the range $0.35<\ensuremath{\epsilon}<0.45$. Combination with data taken at $\ensuremath{\epsilon}$ near 1 allows us to separate the contributions from transversely polarized and scalar photons in the range $1.2 {\mathrm{GeV}}^{2}<{Q}^{2}<3.3 {\mathrm{GeV}}^{2}$.