Bose-Einstein correlations in neutrino and antineutrino interactions in deuterium

Bose-Einstein correlations between pions of equal charge have been observed in Charged Current and Neutral Current (anti)neutrino-deuterium interactions in the BEBC bubble chamber exposed to the SPS wide band beam. The pion emission region is found to be essentially spherical with a mean radius of (0.48±0.07) fm; the chaoticity parameter is 0.36±0.04.     

Measurement of the branching ratio of the double Dalitz decayK L →e+e−e+e− and the CP parity of theK L -meson

Data from the NA31 experiment at CERN have been used to measure the branching ratio of the double Dalitz decay of the long-lived neutral kaon. Eight events have been found with negligible background. The measured distribution of the angle between the planes of the two e⁺e^?-pairs favours aCP=?1 state for the long-lived neutral kaon.     

High transverse momentumη production in π− p, π+ p,andpp interactions at 280 GeV/c

The inclusive cross sections for η production by the interactions of 280 GeV/c momentum π^?, π⁺, and proton beams in hydrogen have been measured. The kinematical range covered is ?0.45<x _F <0.45, and 4.0<P _T <7.0 GeV/c for Feynmanx _F and transverse momentum respectively. The η to π⁰ cross section ratios are given for the three reactions. The ratio of π^? p to π⁺ p cross sections for η production in the above kinematic ranges is 1.22±0.08±0.11.     

Event-by-event search for charged-neutral fluctuations in Pb-Pb collisions at 158 A⋅GeV

We analyse the proton electromagnetic form factor ratioR(Q ² ) =QF ₂ (Q ² )/F ₁ (Q ² ) as a function of momentum transferQ ² within perturbative QCD. We find that the prediction for (R(Q ² ) at large momentum transferQ depends on the exclusive quark wave functions, which are unknown. For a wide range of wave functions we find thatQF ₂ F ₁ ～ const. at large momentum transfer, which is in agreement with recent JLAB data.     

A study of the centrally producedK *0 K^{*0} \bar K^{*0} final state in the reactionpp→p f (K + K -π+π-)p s at 300 GeV/c

The reactionpp→p _f (K ⁺ K ^-π⁺π^-)p _s , where theK ⁺ K ^? π⁺π^- system is centrally produced, has been studied at 300 GeV/c. TheK ^*0 \(K^{*0} \bar K^{*0} \) final state has been observed and the cross sections for its central production are found to be the same at 300 and 85 GeV/c. TheK ^*0 \(K^{*0} \bar K^{*0} \) final state appears to be produced as a non-resonant threshold enhancement.