123 research outputs found
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Inclusive single muons at D0
We report preliminary results on b-quark production in p[bar p] collisions at [radical]s = 1.8 TeV from the current Run la of the Tevatron collider. Using an inclusive muon data sample which corresponds to an integrated luminosity of 50--70 nb[sup [minus]1] and by further requiring the muon to be accompanied by a jet we obtain an almost background free sample of muons consistent with b[bar b] [yields] [mu]X decay. A preliminary p[sub T][sup [mu]] spectrum and some characteristics of this decay, compared to the Monte Carlo expectations, are presented
Modeling of the transient interstitial diffusion of implanted atoms during low-temperature annealing of silicon substrates
It has been shown that many of the phenomena related to the formation of
"tails" in the low-concentration region of ion-implanted impurity distribution
are due to the anomalous diffusion of nonequilibrium impurity interstitials.
These phenomena include boron implantation in preamorphized silicon, a "hot"
implantation of indium ions, annealing of ion-implanted layers et cetera. In
particular, to verify this microscopic mechanism, a simulation of boron
redistribution during low-temperature annealing of ion-implanted layers has
been carried out under different conditions of transient enhanced diffusion
suppression. Due to the good agreement with the experimental data, the values
of the average migration length of nonequilibrium impurity interstitials have
been obtained. It has been shown that for boron implanted into a silicon layer
preamorphized by germanium ions the average migration length of impurity
interstitials at the annealing temperature of 800 Celsius degrees be reduced
from 11 nm to approximately 6 nm due to additional implantation of nitrogen.
The further shortening of the average migration length is observed if the
processing temperature is reduced to 750 Celsius degrees. It is also found that
for implantation of BF2 ions into silicon crystal, the value of the average
migration length of boron interstitials is equal to 7.2 nm for thermal
treatment at a temperature of 800 Celsius degrees.Comment: 10 pages, 6 figures, RevTe
Global QCD Analysis and the CTEQ Parton Distributions
The CTEQ program for the determination of parton distributions through a
global QCD analysis of data for various hard scattering processes is fully
described. A new set of distributions, CTEQ3, incorporating several new types
of data is reported and compared to the two previous sets of CTEQ
distributions. Comparison with current data is discussed in some detail. The
remaining uncertainties in the parton distributions and methods to further
reduce them are assessed. Comparisons with the results of other global analyses
are also presented.Comment: (Change in Latex style only: 2up style removed since many don't have
it.) 35 pages, 23 figures separately submitted as uuencoded compressed
ps-file; Michigan State Report # MSU-HEP/41024 and CTEQ 40
Charmonium Production at the Tevatron
We present in this work a study of large-\pt\ charmonium production in
hadronic collisions. We work in the framework of the factorization model of
Bodwin Braaten and Lepage, thereby including the color octet production
mechanism, and extract the values of the necessary nonperturbative parameters
from a comparison with the most recent data from the Fermilab 1.8 TeV
hadron collider. We extend the calculation to 630 \gev, and compare the results
with data published by the UA1 Collaboration. The global agreement is
satisfactory, indicating that the largest components of the production
mechanisms for charmonium production at high \pt\ have been isolated.Comment: 12 pages, Latex, epsfig, 4 tar-gzip-uuencoded figure
Hadron Energy Reconstruction for the ATLAS Calorimetry in the Framework of the Non-parametrical Method
This paper discusses hadron energy reconstruction for the ATLAS barrel
prototype combined calorimeter (consisting of a lead-liquid argon
electromagnetic part and an iron-scintillator hadronic part) in the framework
of the non-parametrical method. The non-parametrical method utilizes only the
known ratios and the electron calibration constants and does not require
the determination of any parameters by a minimization technique. Thus, this
technique lends itself to an easy use in a first level trigger. The
reconstructed mean values of the hadron energies are within of the
true values and the fractional energy resolution is . The value of the ratio
obtained for the electromagnetic compartment of the combined calorimeter is
and agrees with the prediction that for this
electromagnetic calorimeter. Results of a study of the longitudinal hadronic
shower development are also presented. The data have been taken in the H8 beam
line of the CERN SPS using pions of energies from 10 to 300 GeV.Comment: 33 pages, 13 figures, Will be published in NIM
Limits on WWZ and WW\gamma couplings from p\bar{p}\to e\nu jj X events at \sqrt{s} = 1.8 TeV
We present limits on anomalous WWZ and WW-gamma couplings from a search for
WW and WZ production in p-bar p collisions at sqrt(s)=1.8 TeV. We use p-bar p
-> e-nu jjX events recorded with the D0 detector at the Fermilab Tevatron
Collider during the 1992-1995 run. The data sample corresponds to an integrated
luminosity of 96.0+-5.1 pb^(-1). Assuming identical WWZ and WW-gamma coupling
parameters, the 95% CL limits on the CP-conserving couplings are
-0.33<lambda<0.36 (Delta-kappa=0) and -0.43<Delta-kappa<0.59 (lambda=0), for a
form factor scale Lambda = 2.0 TeV. Limits based on other assumptions are also
presented.Comment: 11 pages, 2 figures, 2 table
Zgamma Production in pbarp Collisions at sqrt(s)=1.8 TeV and Limits on Anomalous ZZgamma and Zgammagamma Couplings
We present a study of Z +gamma + X production in p-bar p collisions at
sqrt{S}=1.8 TeV from 97 (87) pb^{-1} of data collected in the eegamma
(mumugamma) decay channel with the D0 detector at Fermilab. The event yield and
kinematic characteristics are consistent with the Standard Model predictions.
We obtain limits on anomalous ZZgamma and Zgammagamma couplings for form factor
scales Lambda = 500 GeV and Lambda = 750 GeV. Combining this analysis with our
previous results yields 95% CL limits |h{Z}_{30}| < 0.36, |h{Z}_{40}| < 0.05,
|h{gamma}_{30}| < 0.37, and |h{gamma}_{40}| < 0.05 for a form factor scale
Lambda=750 GeV.Comment: 17 Pages including 2 Figures. Submitted to PR
Measurement of Dijet Angular Distributions and Search for Quark Compositeness
We have measured the dijet angular distribution in =1.8 TeV
collisions using the D0 detector. Order QCD
predictions are in good agreement with the data. At 95% confidence the data
exclude models of quark compositeness in which the contact interaction scale is
below 2 TeV.Comment: 11 pages, Latex, 3 postscript figure
Measurement of the Boson Mass
A measurement of the mass of the boson is presented based on a sample of
5982 decays observed in collisions at
= 1.8~TeV with the D\O\ detector during the 1992--1993 run. From a
fit to the transverse mass spectrum, combined with measurements of the
boson mass, the boson mass is measured to be .Comment: 12 pages, LaTex, style Revtex, including 3 postscript figures
(submitted to PRL
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