116135045
Eta gamma Decays of rho0, omega, and phi Mesons
eta..gamma.. decays of rho/sup 0/, ..omega.., and phi are studied. We find GAMMA (phi..-->..eta..gamma..) =55 +- 12 keV. Our data admit two solutions for (rho/sup 0/, ..omega..) ..-->..eta..gamma..: Either GAMMA (rho/sup 0/..-->..eta..gamma..) =50 +- 13 keV, GAMMA (..omega -->..eta..gamma..) =3.0/sup +2//sup .//sup 5//sub -//sub 1//sub .//sub 8/ keV, and the (..omega..,rho) ..-->..eta..gamma.. relative decay phase is near zero; or GAMMA (rho/sup 0/..-->..eta..gamma..) =76 +- 15 keV, GAMMA (..omega -->..eta..gamma..) =29 +- 7 keV, and the decay phase is near 180degree. (AIP)
121484834
Avoidance of counter-example to non-abelian Bloch-Nordsieck conjecture by using coherent state approach
It is shown that the counter-example to the non-abelian Bloch-Nordsieck conjecture in “q + q → γ∗ + soft gluons” to order αs2 is avoided at the cross section level if the initial st prepared according to the coherent state approach for treatment of the infrared region of non-abelian gauge theories.
44977344
The upgraded CDF front end electronics for calorimetry
The front-end electronics used in the calorimetry of the Collision Detector Facility (CDF) detector has been upgraded to meet system requirements for higher expected luminosity. A fast digitizer utilizing a 2- mu s, 16-b analog-to-digital converter (ADC) has been designed and built. Improvements to the front-end trigger circuitry have been implemented, including the production of 900 new front-end modules. Operational experience with the previous system is presented, with discussion of the problems and performance goals.<<ETX>>
17434613
Proton irradiation effects on 2Gb flash memory
We report total ionizing dose and single event effects on 2 Gb Samsung flash memory devices after exposure to 200 MeV protons to various doses up to 83 krad(Si). We characterize observed failures and single event upsets on 22 devices from two different lots. Devices from both lots are robust to greater than 20 krad(Si) although we see evidence for lot-to-lot variation where only one lot appears robust up to about 50 krad(Si). Single event upsets are observed at a relatively low rate and are consistent with single isolated bit flips within registers that transfer bits to and from the flash memory cells.
122601142
SVX', the new CDF silicon vertex detector
Abstract The Collider Detector at Fermilab (CDF) radiation hardened silicon vertex detector (SVX') is described. The new detector has several improvements over its predecessor such as better signal to noise and higher efficiency. It is expected to have a radiation tolerance in excess of 1 Mrad. It has been taking data for several months and some preliminary results are shown.
62166546
The design and PCB layout of the CDF Run 2 calorimetry readout module
The CDF Calorimetry Readout module, called the ADMEM, has been designed to contain both the analog circuitry which digitizes the phototube charge pulses and the digital logic which supports the readout of the results through the CDF Run 2 DAQ system. The ADMEM module is a 9U/spl times/400 mm VMEbus module, which is housed in a CDF VMEbus VIPA crate. The ADMEM must support near deadtimeless operation, with data being digitized and stored for possible readout every 132 ns or 7.6 MHz. This paper discusses the implementation of the analog and digital portions of the ADMEM module, and how the board was laid out to avoid the coupling of digital noise into the analog circuitry.
124235284
Infrared Properties of Unusual Initial State Interactions
The related roles of gauge invariance and of initial coherent/ degenerate states in the factorization of QCD processes into short-distance and long-distance parts are discussed. For ππ →μ+μ - + X it is shown that although the systematic summation over all possible spectator interactions removes the outside soft-IR divergences in the non- overlapping ladder Glauber diagrams, unphysical inside soft-IR divergences persist. So, the on-shell Glauber region is not a gauge invariant concept which can be physically isolated from radiative corrections which non-trivially involve other diagrammatic regions. It is conjectured that in QCD non-factorization is inconsistent with local gauge invariance.
122358666
Production thresholds for quark and for diquark pairs in ee-bar annihilation as tests of charm, then color, excitation
We have pointed out earlier that the decrease at high energies in the ratio of charged-particle energy to total energy in ee-bar annihilation into hadrons and the rise in R in the 4-GeV region suggest first charm, then color, excitation. We present here an analysis of the pair-production thresholds for quarks (responsible for ..mu..e events) and for diquarks (threshold near 4.3 GeV) based on the simple mass spectrum generated by the popular color-octet vector-meson-exchange mechanism, but here in the context of R data and the integrally charged three-quartet model. Our emphasis throughout is a phenomenological one, with special attention to experimental signatures in annihilation and lepton-pair production which can exclude this economical model. For this spectrum we find there must exist a new color-symmetry-violating coupling responsible for the decays of quarks. From the identification of the U particles as quarks, it is suggested that this includes a weak interaction mediated by colored, right-handed quark-neutrino currents coupled to the usual charged currents.
115882781
Cheng-wu picture applied to gamma p ---> rho0 p and phi p
54182981
Parastatistical Factors for Cascade Emission of a Pair of Paraparticles
The empirical absence to date of particles obeying parastatistics in high energy collider experiments might be due to their large masses and lack of gauge couplings. If there is a portal to such particles, they might be cascade emitted as a pair of para-Majorana neutrinos or as a pair of scalar paraparticles. In this paper, for an assumed portal Lagrangian, the associated parastatistical factors are obtained for the case of order p=2 parastatistics and the, in general differing factors, for the cases of emission of a non-degenerate or a degenerate pair of particles which obey normal statistics.
121474561
Color models of hadrons
Abstract The evidence for a three-valued “color” degree of freedom in hadron physics is reviewed. The structure of color model is discussed. Consequences of color models for elementary particle physics are discussed, including saturation properties of hadronic states, π o → 2 ψ and related decays, leptoproduction, and lepton pair annihilation. Signatures are given which distinguish theories with isolated colored particles from those in which color is permanently bound.