123120030
The CDF SVX: A silicon vertex detector for a hadron collider
Abstract A silicon microstrip vertex detector is being constructed as an upgrade to the CDF detector at the Fermilab Tevatron-1 p p collider. This device, which is designed to operate in the hadron collider environment, should allow the tagging of long-lived heavy flavors produced in p p collisions. The mechanical and electronic design of this device are described in this paper.
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>>
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.
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.
118047130
Absence of strangeness-changing, neutral current effects from the symmetric quark model
119987004
Rishon model of quarks and leptons with double SU(2) symmetry and Dirac magnetic moments
Abstract Two-doublet rishon models are proposed to avoid some of the kinematic and dynamic difficulties of the single-doublet rishon model. One has point-like magnetic moments only for leptons. The other, based on an anti-pairing hypothesis, has point-like leptons and quarks.
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
11827113
DETERMINATIONS OF P, AND CP, FOR HEAVY MESONS AND TESTS FOR THEIR VIOLATIONS WITHOUT POLARIZATION EXPERIMENTS
Powerful results are tabulated which can be used at modern colliders to make fundamental symmetry tests by analysis of sequential decays of X + V1V2. By generalization of the ty$ parity test which has recently been used to determine the parity of the r|c, the P (or CP) quantum number can always be determined for X of any spin J which decays P (or respectively CP) invariantly into VV or VV where each vector meson decays into two spin-0 bosons, or is (0. P can also always be determined from a mode like K + K °. A neutral spin-0 technipion and an elementary Higgs particle, for instance, can be distinguished by such CP invariant decay modes and by <j>p , <j)J, JT, or i£ sufficiently massive by <f>Z° or JZ° where J/\JJ and Z° go into a lepton-antilepton pair. Generalization to the gZ° and gg decay channels, g = gluon jet, which would be relevant to new resonance physics, for example, at the CERN collider is discussed. There are also very simple tests for possible violations of P, of the combination of C plus isospin, of both P and CP, and of both C and CP. The practicality and state-of-the-art property of the c)><|> parity test /1/ has been recently demonstrated by its use /2/ by the Mark III collaboration at SLAC-SPEAR to determine the parity of the t) . Less than twenty events were needed to measure the dependence of the decay correlation function I((ji) = 1 + 6 cos2<f) on the azimuthal angle <j> between the two <f> -* K+KT decay planes and to show agreement with B = -1 (pseudoscalar), instead of 0 <_ 6 <_ 1 (scalar). This (j)(j) parity test /1/ for a spin-zero particle was proposed by Ngee-Pong Chang and myself in 1978 as an analogue of Yang's parity test /3/ for the ir°. By means of the h'elicity formalism /4/, it was soon elegantly generalized /5/ by Trueman for a decaying X particle of any spin J. In the last few months the test has been extended /6,7/ to other V1V2 decay modes, for X of any spin J, including those of neutral X particles with odd chargeconjugation and those of charged X states. It has also been found that a spin-0 technipion and an elementary Higgs particle can be distinguished by a decay mode like (jxj) or JJ (identical vector mesons), K*°K ° (particle-antiparticle pair), <j)p°, <J)J, JT, or if sufficiently massive by cfiZ or JZO where j/t|i and Z° go into a leptonantilepton pair. In this talk we will summarize these new results, explain what has to be measured, and tabulate what can be learned from analysis of specific V1V2 decay modes. Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1985229 c2-262 JOURNAL DE PHYSIQUE The advantages of t h i s type of t e s t a r e t h a t it i s r igorous, t h a t t he s ignatures a r e s t r i k i n g , t h a t t he P/CP determination i s independent of t he po la r i za t ion s t a t e of t he decaying X system (and so the t e s t is independent of t he production mechanism), t h a t t he P/CP determination never f a i l s f o r J=0 o r when the re i s a Vlt*.V2 exchange property, and t h a t the t e s t i s normally applicable i n semi-inclusive p roduc t i on experiments s ince many X decay modes y i e ld observed s t a t e s with only charged pa r t i c l e s . We w i l l f i r s t consider t he following sequent ia l decay of an X system of any spin J X + v1 v2 Spin 0 mesons A1, B1, ... In t he X r e s t frame the nine h e l i c i t y amplitudes a r e speci f ied by where X = XI-X2 and @ , @ a r e the polar and azimuthal angles of V l . By Lorentzinvariance t h e general decay co r r e l a t i on funct ion is 161 + Bd(01,02) cos 2$ + Bx(01,02) s i n 2+ where the polar angles el and 82 f o r A 1 and A2 momenta a r e defined /5,6/ a s i n Fig. 1. In pa r t i cu l a r , although the azimuthal angle 4 i s invar iant under Lorentz boosts
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.