118155642
Development and tests of an anode readout TPC with high track separability for large solid angle relativistic ion experiments
We have developed, constructed and tested an anode readout TPC with high track separability which is suitable for large solid angle relativistic ion experiments. The readout via rows of short anode wires parallel to the beam has been found in tests to allow two-track separability of approx.2-3 mm. The efficiency of track reconstruction for events from a target, detected inside the MPS 5 KG magnet, is estimated to be >90% for events made by incident protons and pions. 15 GeV/c x A Si ion beams at a rate of approx.25 K per AGS pulse were permitted to course through the chamber and did not lead to any problems. When the gain was reduced to simulate the total output of a minimum ionizing particle, many Si ion tracks were also detected simultaneously with high efficiency. The resolution along the drift direction (parallel to the MPS magnetic field and perpendicular to the beam direction) was <1 mm and the resolution along the other direction /perpendicular/ to the beam direction was <1 mm also. 3 refs., 5 figs.
120365910
Modular TPCs for relativistic heavy-ion experiments☆
Abstract A description is given of a TPC system that operates in a relativistic heavy-ion beam and yields good track reconstruction efficiency in very-high-multiplicity events. The mechanical construction of the chamber is discussed. A set of custom hybrid circuits are used to build a very compact, cost-effective electronics system mounted directly on the chamber. Results from running in test beams and from preliminary experimental runs are given.
198138883
Experimental information on the pion gluon distribution function
An experiment performed at Fermilab used double-arm calorimeter triggers to study di-jet production by 400 GeV protons and 200 GeVπ− mesons incident on liquid hydrogen. The observed ratio of positive to negative leading particles in the jets was compared forpp andπp production using a tree level parton scattering model. The results are moderately sensitive to the form of the pion gluon distribution function and yieldx g(x)⋍(1−x)2.75±0.40±0.75.
120544624
Triggering on high-transverse-momentum jets
We compare the characteristics of events selected by ''global'' and ''two-high'' triggers in large-transverse-energy hadron-hadron collisions. Using a QCD-based Monte Carlo model of Fox and collaborators, we find that the former is effectively a high-multiplicity trigger, the latter a high-planarity trigger favoring unusually clean jet events. Predictions of the model for both triggers are in good qualitative agreement with recent data.
119722876
Measurement of the dijet cross section in 400-GeV pp collisions
The invariant cross section for production of jet pairs in 400-GeV/c pp interactions has been measured as a function of p{tau} in the p{tau} range 4 to 9 GeV/c. The results are in good agreement with predictions of perturbative QCD models. 20 refs., 3 figs., 1 tab.
125525593
HADRON JETS IN 400-GeV p p COLLISIONS
119386675
Regge phenomenology of inclusive spectra in the central region
Abstract In the light of new data from the ISR, initial steps are taken towards the Regge analysis of inclusive spectra in the central region. It is shown that some features in the data necessitate the introduction of a further singularity in addition to the Pomeron and the meson trajectories ϱ - f - ω - A 2 . The resulting model yields many predictions via duality and factorisation which can easily be tested at ISR and Batavia energies.
121154418
Dual properties of strangeness annihilation processes
Abstract The dual properties of strangeness annihilation processes are studied. Experimental evidence is presented for such processes building up a low-lying Regge singularity. Quark-diagram arguments suggest that this singularity is the exchange degenerate f'- ϕ trajectory. The possibility of studying the factorization properties of strangeness annihilation processes using hyperon beams is pointed out.
121736887
Diffraction scattering and the parton structure of hadrons
We apply parton-model concepts to the ''soft'' (small-momentum- transfer) processes which make up the majority of the hadronic total cross section. Diffraction is calculated as the shadow of these soft processes. We obtain an attractive picture of the essential features of total, elastic, and diffractive-inelastic scattering. In particular, the rather large cross section for inelastic diffraction, which is observed experimentally, results from fluctuations in the distribution of the wee partons which initiate interactions. These fluctuations lead to diffractive production by the mechanism of Good and Walker. The observed peripheral character of diffraction as a function of impact parameter, the absence of a forward dip in dsigma/dt dm/sup 2/, the correct integrated cross section, and the correct small-t slope of diffraction all follow naturally in our approach.
120502863
Hadronic Production with a Drell-Yan Trigger
The ratio of cross sections for producing fast ${\ensuremath{\pi}}^{+}'\mathrm{s}$ and ${\ensuremath{\pi}}^{\ensuremath{-}}'\mathrm{s}$ in association with a massive dilepton should be a strongly varying function of the mass of the pair, reducing at small mass to its value in the absence of a pair. For $\frac{{{M}_{\ensuremath{\mu}\ensuremath{\mu}}}^{2}}{s}g0.1$, the $\frac{{\ensuremath{\pi}}^{+}}{{\ensuremath{\pi}}^{\ensuremath{-}}}$ ratio should fall by a factor of 1.7 in the reactions $p+\overline{p}\ensuremath{\rightarrow}\ensuremath{\pi}+({\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}})+X$ and $p+{\ensuremath{\pi}}^{\ensuremath{-}}\ensuremath{\rightarrow}\ensuremath{\pi}+({\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}})+X$, rise by a factor of 2.6 in $p+{\ensuremath{\pi}}^{+}\ensuremath{\rightarrow}\ensuremath{\pi}+({\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}})+X$, and fall by about 25% in $p+p\ensuremath{\rightarrow}\ensuremath{\pi}+({\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}})+X$.
121815942
Evidence that hadronic interiors have a denser matter than charge distribution
Abstract An analysis of high-energy elastic and inelastic diffraction scattering provides strong evidence that the charge and matter densities of hadrons are different. When hadrons are treated as composite objects, then a correct Glauber analysis leads to an optical model with important corrections due to the hadronic wave function: One expects inelastic diffraction due to the fluctuations in the matter density of hadrons. Conversely, the experimental existence of dissociation processes gives phenomenological information about the hadronic wave function. We find the distribution of matter in nucleons to be denser than the observed charge distribution. This result has a natural interpretation from a constituent description of hadrons made from spin 1 2 quarks and colored vector gluons, which is a generalization of the Chou-Yang picture of diffraction scattering.