Showing papers by "Vincenzo Cavasinni published in 1976"

Measurement of Two-Particle Semi-Inclusive Rapidity Distributions at the CERN ISR.

Abstract: We present data on the semi-inclusive distributions of rapidities of secondary particles produced in pp collisions at very high energies. Our experiment was performed at the CERN Intersecting Storage Rings (ISR). The data given here, at centre-of-mass energies of √s=23 and 62 GeV, include the single-particle distributions and two-particle correlations. The semi-inclusive correlations show pronounced short-range correlation effects which have a width considerably narrower than in the case of inclusive correlations. We show that these short-range effects can be understood empirically in terms of three parameters whose energy and multiplicity dependence are studied. The data support the picture of multiparticle production in which clusters of small multiplicity and small dispersion are emitted with subsequent decay into hadrons.

Charged-particle multiplicities associated with large-transverse-momentum photons

Abstract: We have measured the charged-particle multiplicities of events containing a large-transverse-momentum (p/sub perpendicular/) photon produced near center-of-mass polar angles (theta) of 90 degree, 17.5degree, and 8degree in proton-proton collisions. The data were obtained at the CERN Intersecting Storage Rings at center-of-mass energies of 23, 31, 45, 53, and 62 GeV and for the transverse-momentum range 0 < or = p/sub perpendicular/ < or = 4.5 GeV/c. When the photons are detected near theta = 90degree, the associated multiplicity in the hemisphere away from the observed photon is found to increase with increasing photon transverse momentum. In the hemisphere containing the photon, the associated multiplicity decreases at the lowest energy and is approximately constant at the highest energies. The data at theta = 17.5 degree and 8degree are similar, with the exception that the particle multiplicities near the detected photon are found to decrease with increasing photon p/sub perpendicular/ at all energies. No strong back-to-back structure is observed in the data; however, as the photon emission angle is changed, some shift of the multiplicity distributions in the direction opposite the photon is observed. The data at all three polar angles show a broad peak in the azimuthal angular distributions at phimore » = 180degree (opposite the detected photon). Finally, the data are compared to a simplified picture for particle production in high-p/sub perpendicular/ events, and to the various classes of high-p/sub perpendicular/ models that have been proposed. (AIP)« less