167 research outputs found
Mis-Registration of Sliver Type Backdrill Impact in High Speed Signal Propagation
No full textNowadays, plated-through hole (PTH) via structures are extensively used in printed circuit boards (PCBs). As the data rate increases to Gigahertz range, the via stub resonance effect shows up, which will cause signal distortion and lead to signal integrity issue. In this paper, the impact caused by backdrill mis-registration issue is investigated
Measurement of the bottom quark production cross section in proton-antiproton collisions at ?s = 0.63 TeV
No full textWe summarize the results obtained in the UA1 experiment on the production of bottom quarks in proton-antiproton collisions at √s=0.63 TeV. Independent muon data samples are used to determine the bottom quark production cross section in different transverse momentum ranges from 6 to 30 GeV. A recent theoretical calculation to O(αs 3) of the inclusive bottom quark transverse momentum spectrum in hadronic collisions shows reasonable agreement with the data. We extrapolate the integral PT distribution to PT=0 and in rapidity to estimate the total cross section forthe production of bottom quark pairs. Assuming the shape in PT and rapidity given by the O(αs 3) calcultaion, we obtain σ(pp→bb+X) = 10.2 ±3.3 μb. © 1988
SEARCH FOR NEW HEAVY QUARKS IN PROTON - ANTI-PROTON COLLISIONS AT s**(1/2) = 0.63-TeV
No full textWe report on a search for new heavy quarks using data collected by the UA1 experiment during 1983, 1984 and 1985 at the CERN proton-antiproton collider, corresponding to an integrated luminosity of approximately 700 nb-1. Studying events with a muon or an isolated electron, accompanied by one or more jets, we find good agreement between our data and Monte Carlo predictions for the production of charm and beauty, without the need for a new quark. A top quark model, involving the decay W→t {Mathematical expression} and direct t {Mathematical expression} production via the strong interaction, is used to determine our detection efficiency for top. This allows us to place an upper limit on the cross section for producing top quarks as a function of the top quark mass. Our analysis is not sensitive to the W→t {Mathematical expression} process alone. By comparing our limit with a calculation of the t {Mathematical expression} cross section, added to the W→t {Mathematical expression} cross section derived from our own measurements of W →lv, we are able to place a lower limit on the mass of the top quark. From the lowest order (αs 2) calculation, using the choice of structure functions and Q2 scale that give the lowest cross section, we find: {Mathematical expression} Including an estimate of the next higher order (αs 2) and calculating the cross section with the EUROJET QCD Monte Carlo program using a less extreme choice for the structure functions and Q2 scale gives: {Mathematical expression} A search has also been made for a fourth generation, charge 1/3 quark (b'). Assuming that the b' mass is smaller than that of the top quark and that it can-not be produced in W decays, the mass limits, using the above procedures, are respectively mb'>32 GeV/c2 and mb'>44 GeV/c2, both at 95% confidence level. © 1988 Springer-Verlag
Rosette nanotubes with 1.4 nm inner diameter from a tricyclic variant of the Lehn–Mascal G∧C base
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