Baryon-antibaryon annihilations,unitarity and the pomeron

We show that baryon-antibaryon annihilations into mesons contribute, via unitarity, mainly to the pomeron term in the total $\text{B}$B cross section. The meson-exchange term is mainly built by non-annihilation processes. These results are contrary to previous ideas according to which $\text{B}$B annihilations are responsible for the difference between $\text{σ}{}_{\mathrm{<mtext>tot</mtext>}}\text{(}\text{B}\text{B}\text{)}$ and σ_tot(BB) and contribute to the meson exchange term. Our conclusions are based on an explicit duality diagram model which we discuss in some detail. However, a much wider class of models give similar results. Experimental tests of our ideas are proposed.     

Photogalvanic cell based on the photolysis of rubidium anions in THF

A photogalvanic cell composed of two half cells of the type [Rb-THF]_I and [Rb-THF, crown ether (or kryptand)]_II is reported. Photocurrents and photovoltages, recorded at low temperatures, in the order of 6 nA and 80 mV, respectively are obtained with light excitation at wavelenghts above 640 nm. The corresponding values with excitation above 320 nm, are 30 nA and 250 mV, respectively.     

Global and local choice functions

We prove, by an elementary reflection method, without the use of forcing, that ZFGC (ZF with a global choice function) is a conservative extension of ZFC and that every model of ZFC whose ordinals are cofinal (from the outside) withω can be expanded to a model of ZFGC (without adding new members). The results are then generalized to various weaker forms of the axiom of choice which have global versions.     

PHOTOREDUCTION OF PORPHYRINS TO CHLORINS BY TERTIARY AMINES IN THE VISIBLE SPECTRAL RANGE. OPTICAL AND EPR STUDIES

Abstract— The photoreduction of free base porphyrins by tertiary amines in the visible spectral range leads to the formation of chlorin. The increase of the apparent first order rates to yield chlorin is correlated with the inductive effect on the nitrogen of the amine used. A mechanism involving a charge transfer interaction between the photoexcited singlet of the prophyrin and the amine is proposed. The porphyrin radicals formed recombine to form a light sensitive dimer which disproportionates in the dark to yield chlorin and porphyrin. The mechanism is elucidated by the use of EPR, laser and flash photolysis.     

Quarks and leptons

We review the physics of quarks and leptons within the framework of gauge theories for the weak and electromagnetic interactions. The Weinberg-Salam SU(2) × U(1) theory is used as a “reference point” but models based on larger gauge groups, especially SU(2)_L × SU(2)_R × U(1), are discussed. We distinguish among thre “generations” of fundamental fermions: The first generation (e^?, ν_e, u, d), the second generation (μ^?, ν_μ, c, s) and the third generation (τ^?, ν_τ, t, b). For each generation we discuss the classification of all fermions, the charged and neutral weak currents, possible right-handed currents, parity and CP-violation, fermion masses and Cabibbo-like angles and related problems. We review theoretical ideas as well as experimental evidence, emphasizing open theoretical problems and possible experimental tests. The possibility of unifying the weak, electromagnetic and strong interactions in a grand unification scheme is reviewed. The problems and their possible solutions are presented, generation by generation, but a brief subject-index (following the table of contents) enables the interested reader to follow any specific topic throughout the three generations.