8249400
Design and production of a new surface mount charge-integrating amplifier for CDF
The authors present their experiences in designing and producing 26000 new charge-integration amplifiers for the Collision Detector Facility (CDF), using surface-mount components. The new amplifiers were needed to instrument 920 new 24-channel CDF RABBIT boards, which are replacing an older design rendered obsolete by increases in the collision rate. Important design considerations were frequency response, physical size, and cost. Compared to the standard cascode, this amplifier has better power supply rejection, higher gain, higher bandwidth, and reasonably good noise figures. Higher than expected amplifier reliability, resulting in an easier checkout task, was an unexpected benefit.<<ETX>>
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.
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.
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.
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.
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.
119907461
Parity determination for the new generation of heavy neutral mesons
We consider how best to experimentally determine the parity quantum number of a new heavy neutral meson, including the possibility of exotic ${J}^{\mathrm{PC}}$. Multiquark and gluon bound states can have exotic ${J}^{\mathrm{PC}}$ quantum numbers forbidden to the nonrelativistic $q\overline{q}$ system. If only the existence of easily identifiable two-body hadronic modes is known, it is not possible to establish the parity so an "exotic" meson, $Jg0$, could be misidentified as a "normal" meson. Direction-linear-polarization coefficients, which would identify the parity, are also found to be small for $e\overline{e}\ensuremath{\rightarrow}{1}^{\ensuremath{-}\ensuremath{-}}\ensuremath{\rightarrow}{1}^{\ifmmode\pm\else\textpm\fi{}+}\ensuremath{\gamma},{0}^{\ifmmode\pm\else\textpm\fi{}+}\ensuremath{\gamma}$ with the high-energy photon externally converting into an $e\overline{e}$ pair. However, important parity tests do exist, independent of the polarization state of the decaying particle, which can be used to settle the confusion. These are listed in Sec. III of this paper.
14270584
Tau decays beyond the standard model
In a recent paper, 8 semileptonic parameters were defined to specify the most general Lorentz-invariant spin correlation functions for 2-body τ decays. These parameters can be used to search for anomalous Γ L , Γ T polarized-partial widths, for non-CKM-type leptonic CP violation, and for leptonic T FS violation. They can also be used to bound the effective-mass scales A for “new physics” arising from additional Lorentz structures, e.g. from lepton compositeness, tau weak magnetism, weak electricity, or second-class currents. It is emphasized that (i) for these tests “different modes have different merits” and that (ii) the parameters can be measured either by using spin-correlation techniques without polarized beams, or with longitudinally polarized beams.
118047130
Absence of strangeness-changing, neutral current effects from the symmetric quark model
202114504
Presence and Absence of Scaling Violations in Inclusive Leptoproduction
In the standard model, the heavy--quark-parton scaling variable is used to study the effects of the color-octet piece of the integrally-charged--quark-parton electromagnetic current which would violate scaling in deep-inelastic leptoproduction. With spin-1/2 partons it is found that sigma/sub L//sigma/sub T/ would deviate significantly from zero since (sigma/sub L//sigma/sub T/)/sub muN/ approx. = 4m/sub c//sup ts2/f/sub v/(z)/ 5Q/sup 2/f/sub v/(x), where f/sub v/(z) + u/sub v/(z) + d/sub v/(z), m/sub c//sup ts2/ = effective mass-squared of quark-parton in color-excited hadron, and z approx. = x + m/sub c//sup ts2//2MEy. Such scaling violations must occur in the ..mu.. data at currently available energies if the step of 2 units of R (beyond charm) in the 4-GeV region in the SPEAR data for ee-bar annihilation is due to a color threshold for the production of color-octet qq-bar mesons, qqq baryons, and/or quark-antiquark pairs. Consistency is shown between the scaling violations in the electroproduction data in the x < or = 0.2 region and the energy independence in the data of the CDHS collaboration for charged-current neutrino distributions for average y and for sigma/sup nu-bar/sigma/sup ..nu../. Exclusive final states responsible for electroproduction scaling violations in the x < or = 0.2 region would containmore » the tau-particle-antiparticle pairs (i.e., integrally charged quarks) and/or high-momentum photons (few GeV) from radiative decay modes of color-octet hadrons.« less