Single-photon Spectra Research Articles

Correlation with large transverse momentum photons and the gluon structure function

The inclusive two-particle cross section for the production of largep T photons and opposite side charged hadrons in proton-proton collisions is examined in detail in the framework of QCD. The model, with the parametrization as in our previous work, agrees with the measured single photon spectra. Quantitative predictions are made for two-particle distributions to be measured at the ISR. The contributions due to the photon bremsstrahlung and the effects coming from the intrinsic constituent motion are estimated. It is shown that indeed the direct subprocess gluon+quark→photon+quark gives the dominant contribution in the experimentally relevant region of phase space, and that direct information about the gluon structure function can be obtained from such measurements.

Two photon excitation of the vacuum ultraviolet fluorescence of carbon monoxide

The vacuum ultraviolet fourth positive band spectrum (A 1Πχ 1σ +) of CO was excited by two photon absorption of ultraviolet radiation which was produced by frequency doubling the output of a nitrogen laser pumped tunable dye laser. The (0–0) through (9–0) bands were observed. Position monitoring of the ultraviolet beam provided feedback control for continuous adjustment of the orientation of the angle tuned frequency doubling crystal. In this way the orientation for maximum efficiency of the doubling crystal and the point of focus of the ultraviolet beam in the sample cell was maintained during the wavelength scan of a band. A solar-blind photomultiplier was used to detect the vacuum ultraviolet fluorescence. O, P, Q, R, and S rotational branches were observed, and the new band-head positions agree with those predicted from the previously observed single-photon spectra.