A measurement of ∧ and Ξ<Superscript>−</Superscript> polarization in inclusive production by Σ<Superscript>−</Superscript> of 340 GeV/c in C and Cu targetsof 340 GeV/c in C and Cu targets

We have measured the polarization of ∧ and Ξ^? hyperons produced inclusively by a Σ^? beam of 340 GeV/c momentum in nuclear targets, using samples of 9.5 million ∧ decays and 880000 Ξ^? decays. The large statistics allowed a two-dimensional analysis as functions ofx _F andp _t . The polarization w.r.t. the production normal is mainly positive for ∧ and negative for Ξ^?. The positive sign of the ∧ polarization is opposite to predictions. Atp _t >1 Gev/c, the ∧ polarization decreases to zero or even negative values, in sharp contrast to the plateau abovep _t <1 GeV/c observed in inclusive ∧ production by protons. No such effect is observed for the Ξ^? polarization, and its sign is as expected.     

Direct experimental evidence for current-transfer mode operation of nested tungsten wire arrays at 16-19 MA

Nested tungsten wire arrays (20-mm on 12-mm diam.) are shown for the first time to operate in a current-transfer mode at 16-19 MA, even for azimuthal interwire gaps of 0.2 mm that are the smallest typically used for any array experiment. After current transfer, the inner wire array shows discrete wire ablation and implosion characteristics identical to that of a single array, such as axially nonuniform ablation, delayed acceleration, and trailing mass and current. The presence of trailing mass from the outer and the inner arrays may play a role in determining nested array performance.     

Demonstration of radiation pulse shaping with nested-tungsten-wire-array pinches for high-yield inertial confinement fusion

Nested wire-array pinches are shown to generate soft x-ray radiation pulse shapes required for three-shock isentropic compression and hot-spot ignition of high-yield inertial confinement fusion capsules. We demonstrate a reproducible and tunable foot pulse (first shock) produced by interaction of the outer and inner arrays. A first-step pulse (second shock) is produced by inner array collision with a central CH2 foam target. Stagnation of the inner array at the axis produces the third shock. Capsules optimized for several of these shapes produce 290-900 MJ fusion yields in 1D simulations.     

Transverse energy production in the target fragmentation region in16O-nucleus reactions at 60 and 200A GeV

Charged pion yields and transverse energies of baryons are measured for the reaction¹⁶O+Cu, Ag, Au at 60 and 200A GeV bombarding energy in the target fragmentation region employing the Plastic Ball detector. Only little dependence of the measured quantities on the bombarding energy is found. The data are compared with the multi-chain fragmentation model of Ranft. As a result it turns out that a leading order formation zone cascade is not sufficient to explain the baryon yield and the transverse energies of baryons in the target fragmentation region.     

High transverse momentum prompt photon production by π− and π+ on protons at 280 GeV/c

The inclusive cross sections for prompt photon production by π^? and π⁺ on protons have been measured with a beam momentum of 280 GeV/c using a fine grained electromagnetic calorimeter and the CERN Omega spectrometer. The transverse momentum and Feynmanx _F ranges covered are 4.0<p _T <7.0GeV/c and ?0.45<x _F <0.55 respectively. A quantitative comparison of the prompt photon cross section with next-to-leading order QCD predictions using Duke and Owens structure functions is performed.     

Oxygen-induced reactions at 60A GeV and 200A GeV studied by calorimetry

Results based on calorimetric measurements are presented from reactions of 60A GeV and 200A GeV¹⁶O projectiles with C, Cu, Ag, and Au nuclei. Minimum-bias cross sections are discussed. Energy spectra measured at zero degrees and transverse-energy distributions for the pseudorapidity range 2.4≦η≤5.5 are shown. An analysis of the average transverse energy in terms of the number of participating nucleons and the number of binary nucleon-nucleon collisions is presented. Estimates of nuclear stopping and of attained energy densities are made.     

Study of the centrally producedK 1 0 K ± π∓ system at 85 GeV/c

We have analyzed theK ₁ ⁰ K ^± π^? system in the reactions π⁺/pp→π⁺/p(K ₁ ⁰ K ^± π^?)p. A spin-parity analysis of theK ₁ ⁰ K ^± π^? system in the “4C” channel confirms the existence of the 1⁺⁺ E meson which decays mainly throughK ^* \(\bar K\) . The data allow the presence of a 0^?+ wave at a level of 14% of theE/ι signal. The production ofD andE mesons in the channels where theK ₁ ⁰ K ^± π^? system is produced along with a π⁰ or π⁺π^? system is suppressed.