[en] We describe test results on the operation of a time projection chamber incorporated into a Cherenkov counter to track a particle while it is emitting its Cherenkov light. The common Cherenkov and drift chamber medium is high-pressure hydrogen. The ring-imaging counter detects and digitizes Cherenkov photons by means of an image-intensifier and matrix-camera. The TPC measures the particle trajectory without obscuring the Cherenkov light. In a beam of 5.4 GeV/c pions, the particle direction is determined to within 82 μrad and the particle velocity to within 9 ppm. (orig.)

[en] A drift chamber which measures the drift time of photoelectrons emitted from the cathode surface by means of a UV laser pulse has been built. The chamber is used for monitoring the drift time changes in the muon chambers of the L3 detector at CERN due to changes of gas parameters with the accuracy of 0.1%. The construction and experiments to determine the accuracy and stability of the device are described. (orig.)

[en] The Region One detector is the innermost of three nested drift chamber packages of the CLAS spectrometer at Jefferson Laboratory. This detector, with 7776 drift cells, was optimized for the CLAS torodial magnet geometry, and consits of six wedge-shaped sectors integrated into a single unit. Each sector has thin and relatively weak aluminum endplates which support the large mechanical loads from the wire tensions and associated readout hardware. The unusual feature of the use of massive structural support. We discuss the design criteria, mechanical components, and assembly procedures. (author)

No abstract available

[en] The structure of the nucleon is studied by means of deep-inelastic neutrino-nucleon scattering at high energies through the weak neutral current. The neutrino-nucleon scattering events were observed in a 340-metric-ton fine-grained calorimeter exposed to a narrow-band (dichromatic) neutrino beam at Fermilab. The data sample after analysis cuts consists of 9200 charged-current and 3000 neutral-current neutrino and antineutrino events. The neutral-current valence and sea nucleon structure functions are extracted from the x distribution reconstructed from the measured angle and energy of the recoil-hadron shower and the incident narrow-band neutrino-beam energy. They are compared to those extracted from charged-current events analyzed as neutral-current events. It is shown that the nucleon structure is independent of the type of neutrino interaction, which confirms an important aspect of the standard model. The data are also used to determine the value of sin²θ_W=0.238±0.013±0.015±0.010 for a single-parameter fit, where the first error is from statistical sources, the second from experimental systematic errors, and the third from estimated theoretical errors

[en] The E885 collaboration utilized the 1.8 GeV/c K^- beam line at the AGS to accumulate greater than 10 times the world's existing data sample of (K^-,K⁺) events on carbon. The data were used to search for signatures of the production of Ξ hypernuclei, double-Λ hypernuclei, and H Dibaryons. Evidence for the creation of ¹²_ΞBe is seen. Reasonable agreement between the data and theory is achieved by assuming a Ξ-nucleus Wood-Saxon potential well depth, V_0Ξ, of about 14 MeV. Upper limits for the production of double-Λ hypernuclei are presented. Upper limits for H-Dibaryon production are presented which are a factor of 50 below calculated rates

[en] Strange Dibaryons, six valence-quark hadrons constructed from one or more strange quarks, are predicted to have greater binding than dibaryons in the non-strange sector. The flavor-singlet dibaryon with quark structure open-quotes uuddssclose quotes is of particular theoretical and experimental interest. A brief review of the status of H dibaryon studies is presented with emphasis on experiment E813 currently taking data at the AGS

[en] A review is made of those past, present, and planned experiments at the AGS whose primary purpose is to determine whether the H-dibaryon exists. Preliminary results are given for experiment E813, based on partially-completed analysis. copyright 1995 American Institute of Physics

[en] Recent estimates suggest that the production of strange exotic objects, such as the hypothetical H dibaryon (H), is surprisingly large in Au collisions at AGS energies. Two possible bound states of the H, namely H-³He and H-d, would be well separated in mass from known nuclear isotopes and therefore could be uniquely identified by experiment. We report the null result of a first search for these objects in Au+Pt collisions at the AGS, and limit their production cross sections for stable systems to ∼10^-5 mb/(GeV)², near y=0.6 and p_t/Z=0.18 GeV/c

[en] A high-sensitivity search for the strangeness S=-2 H dibaryon (uuddss) was conducted at the Brookhaven Alternating Gradient Synchrotron (AGS) using the reaction ³He(K^-,K⁺)Hn at P_K^-=1.8GeV/ c. The sensitivity was independent of H lifetime and decay modes. No evidence for H production was observed. In a mass range extending from about 50 to 380MeV/c² below the ΛΛ threshold of 2.231GeV/c², the resulting upper limits on the H-production cross section are in the range of 0.058 to 0.021μb/sr, approximately 1 order of magnitude below a theoretical calculation. copyright 1997 The American Physical Society