Test beam results from the CLEO III LiF-TEA RICH
NUCL INSTRUM METH A 419:2-3 (1998) 577-583
Abstract:
The CLEO collaboration is preparing a major upgrade of its present detector including a RICH detector for particle identification. This subdetector system follows the 'proximity focussing' design and uses Lithium Fluoride (LiF) crystal radiators and MWPCs filled with a CH4/TEA gas mixture. Part of the radiator crystals will have the new 'sawtooth' geometry. We have tested the first two of the 30 detector modules together with the first radiator crystals in a muon halo beam at Fermilab. For the measurement of the Cherenkov angle we obtain a single photon measurement error of 13.5 mrad for the conventional planar radiator. With 14 detected photons we find a resolution per track of 4.5 mrad. In the first measurement ever of a 'sawtooth' radiator we achieve a resolution of 11.8 mrad for single photons and 4.8 mrad per track for 12.3 detected photons with a reduced geometric acceptance. These results fulfill CLEO III requirements. (C) 1998 Elsevier Science B.V. All rights reserved.The NA48 LKr calorimeter digitizer electronics chain
NUCL INSTRUM METH A 419:2-3 (1998) 680-685
Abstract:
The 13500 channels of the NA48 liquid-krypton electromagnetic calorimeter readout electronics were put into operation in 1997. The digitizer electronics employs a new gain switching technique that expands the dynamic range of a standard 10-bit ADC to 14 bits at 40 MHz sampling rate employing a custom-developed integrated circuit (KRYPTON). The KRYPTON has been fabricated in 1.2 mu m BiCMOS technology and was successfully developed together with industry on a short timescale. The performance and the experience from the first year of the operation of the liquid-krypton calorimeter electronics will also be briefly discussed. (C) 1998 Elsevier Science B.V. All rights reserved.Probing hard color-singlet exchange in pp̄ collisions at √s = 630 GeV and 1800 GeV
Physics Letters Section B Nuclear Elementary Particle and High Energy Physics 440:1-2 (1998) 189-202
Abstract:
We present results on dijet production via hard color-singlet exchange in proton-antiproton collisions at √s = 630 GeV and 1800 GeV using the DØ detector. The fraction of dijet events produced via color-singlet exchange is measured as a function of jet transverse energy, separation in pseudorapidity between the two highest transverse energy jets, and proton-antiproton center-of-mass energy. The results are consistent with a color-singlet fraction that increases with an increasing fraction of quark-initiated processes and inconsistent with two-gluon models for the hard color-singlet. © 1998 Published by Elsevier Science B.V. All rights reserved.Continuum charged D* spin alignment at √s=10.5 GeV
Physical Review D Particles Fields Gravitation and Cosmology 58:5 (1998) 520031-520038
Abstract:
A measurement of the spin alignment of charged D* mesons produced in continuum e+e-→cc̄ events at √s = 10.5 GeV is presented. This study using 4.72 fb-1 of CLEO II data shows that there is little evidence of any D* spin alignment.Direct measurement of the top quark mass by the DØ Collaboration
Physical Review D - Particles, Fields, Gravitation and Cosmology 58:5 (1998)