IR multiple-photon excitation distribution probed by IR fluorescence

Vibrational fluorescence induced by IR multiple-photon excitation of hexafluorocyclobutene was measured as a function of laser frequencies. The width and shift of the inhomogeneous broadened fluorescence bands represent the excitation energy. The contrasting shapes of the excitation and previously measured chemical yield spectra are explained by the Poisson distribution of the molecules in the quasicontinuum.     

Microscopic irreversibility in the neutral kaon system and the thermodynamical arrow of time,II. CPT violating case

The expression for the entropy production in the decay of a neutral kaon interacting with a thermal bath of bosons, introduced in a previous article [1], is reformulated without assuming CPT conservation. The relation between the sign of Re ? and the thermodynamical arrow of time is further discussed, and the ambiguity due to the definitions of matter-antimatter is resolved.     

Charged multiplicity distributions in pd and π+d interactions at 195 GeV/c

Topological inelastic cross-sections and average multiplicities for pd and π⁺d interactions at 195 GeV/c, are obtained from an exposure of the NAL 30″ proportional wire chamber-bubble chamber hybrid system to a positive π⁺/p beam. We find that 〈n_c〉_pn = 7.67 ± 0.25, and 〈n_c〉_π⁺n = 7.56 ± 0.30, yielding a negative multiplicity difference between pn and pp of 0.50 ± 0.14, and that σ_n(pp) is approximattely interleaved between σ_n?1(pn).     

Bragg reflection waveguides

The possibility of using Bragg reflection to obtain lossless confined propagation in slabs with a lower dielectric constant than that of the surrounding media is proposed and analyzed.     

Fabrication of grating structures with variable period

Photoresist gratings with variable period have been fabricated by recording the interference pattern of a collimated laser beam with a converging one. The period variation as a function of position, as well as the wavelength dependent focal properties of the gratings, has also been analyzed.     

Inclusive π+ to π− ratios and quark distributions of pions and nucleons

The ratio R of inclusive $\text{π}{}^{\mathrm{+}}\text{π}{}^{\mathrm{?}}$ production at low transverse momenta is measured in π⁺ n and pn interactions at 195 GeV/c.$\text{R (}\text{1}\text{R}\text{)}$ in the proton (neutron) fragmentation region increases with Feynman-x and is smaller than R from π⁺ fragmentation. The results agree with a quark-quark scattering model originally proposed for “hard” processes and disagree with a modified version of the model which includes gluon scattering.     

Inclusive particle spectra in p(π+)n interactions at 195 GeV/c

We present results on single-particle inclusive distributions in p(π⁺)n reactions from a Fermilab experiment using the hybrid 30″ bubble chamber and PWC facility. Distributions in rapidity, y, Feynman x and p²_T for π⁺ and π^? are presented and compared with other experiments. The effects of different targets and projectiles (neutrons, protons and pions) on the distributions are demonstrated and discussed in terms of projectile and target fragmentation. The average transverse momentum 〈P_T〉 is studied as a function of x, y and multiplicity.     

Charge transfer and rapidity gap analysis inp(π+)n interactions at 195GeV/c

We present charge transfer probabilities between CM hemispheres inpn and π⁺ n interactions at 195 GeV/c. The relative probabilities for charge exchanges |ΔQ|>1 as a function of rapidity gap length,r, are given. Both results are compared with those of π^? p interactions at 200GeV/c. The average ofr, viz. <r>, is given as a function of the gap number and of ΔQ for various multiplicities, and the reduced average gap lengths <r>/y _max forpn interactions are compared with data at a lower energy.