Correlations associated with particles produced at small angles in pp collisions at the CERN ISR

Data on correlations between momentum analysed protons, pions or K mesons, and charged particles produced in pp collisions at the CERN ISR are presented. The charged particles were detected in a ～4π scintillation counter hodoscope. The pseudo-rapidity distributions are well described by production within the limits of cylindrical phase space, with negative kaons and antiprotons yielding narrower distributions than protons, pions and positive kaons. The azimuthal distributions show symmetry around the t-channel axis in the rest frame of the recoiling mass M_x in pp → aX (a = detected proton, pion, positive kaon).     

Note on the diffusion of brownian particles in two dimensions

The use of linear hydrodynamics leads to a logarithmic secular divergence in the diffusion constant for Brownian particles in a quasi-two-dimensional system.     

Correlations in quasi-elastic proton-proton scattering at total c.m. energies of 23 and 31 GeV

Data are reported on angular and rapidity (η) distributions of a charged particle c produced in quasi-elastic proton-proton scattering (p+p→p+c+anything) at the CERN ISR.     

Correlations associated with small angle protons produced in proton-proton collisions at 31 GeV total energy

High energy inelastic protons with $\text{x = 2 p}{}_{\mathrm{<mtext>L</mtext>}}\text{/s}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{> 0.99}$ observed in 15.3/15.3 GeV proton-proton collisions at the CERN ISR are accompanied by particles whose angular distribution is confined to a narrow cone in the opposite direction. In constrast, lower energy protons (0.72 < x < 0.84) are accompanied in addition, by particles emitted at larger angles. The ratio of the associated charged multiplicities is approximately 0.4.     

A two-variable generalization of the Stieltjes-type continued fraction

A continued fraction expansion in two variables is described and shown to correspond to a double power series. This continued fraction is a natural generalization of the S-fraction and can be truncated to form a sequence of rational approximants.A simple algorithm is derived for computing the coefficients of the two-variable fraction and the theorem of Van Vleck is adapted to establish the convergence of some simple examples. Numerical results are given comparing the method with Chisholm approximants.     

Phenyl (1-bromo-1,2,2,2-tetrafluoroethyl)mercury: a useful tetrafluoroethylidene source

The reaction of phenylmercuric chloride, 1-bromo-2,2,2-tetrafluoroethane and methanolic sodium methoxide in THF at ?35° gave PhHgCFBrCF₃ in good yield. Thermolysis of this mercurial at 155° for 24 h in the presence of olefins gave gem-fluoro(trifluoromethyl)cyclopropanes, while its reaction with triethylsilane produced Et₃SiCHFCF₃.     

Simplicity of crossed products by endomorphisms

Conditions are given for simplicity of the crossed product of a unital C^*-algebra by an endomorphism.