A precise determination of the energy scale of jets at the Collider Detector at Fermilab at the Tevatron
p
p
¯
collider is described. Jets are used in many analyses to estimate the energies of ...partons resulting from the underlying physics process. Several correction factors are developed to estimate the original parton energy from the observed jet energy in the calorimeter. The jet energy response is compared between data and Monte Carlo simulation for various physics processes, and systematic uncertainties on the jet energy scale are determined. For jets with transverse momenta above 50
GeV the jet energy scale is determined with a
3
%
systematic uncertainty.
Electron lifetime detector for liquid argon
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
07/1990
Journal Article
Free-ion yields have been measured as a function of applied electric field for several room-temperature liquids containing silicon, germanium, or tin atoms. The results show that tetra-alkyl ...compounds of the same molecular structure have similar free-ion yields independent of the nature of the central group-IV atom. Tetramethylsilane, tetramethylgermane, and tetramethylstannane have similar field-dependent yields. Similarly, tetraethylsilane and tetraethylstannane have comparable yields; the same is true for tetrabutylgermane and tetrabutylstannane. The yields do depend on the nature of the attached alkyl groups: the tetramethyl liquids have higher yields than the tetraethyl liquids, which in turn have higher yields than the tetrabutyl liquids. Fitting the field-dependent free-ion yields to extract a measure of the average thermalization ranges of electrons liberated in the liquids by the ionization process we find that within the precision of our measurements the products of the average electron range times the dielectric constant of the liquid are identical for tetra-alkyl liquids with similar molecular structures. The field-dependent free-ion yields for binary mixtures of high-yield liquid hydrocarbons have also been measured. The yields in these mixtures tend to be less than the yields in either of the pure components. This suggests shorter electron thermalization lengths in mixtures than in pure liquids.
Phys.Rev.D73:014026,2006 We review the experimental status of the b-quark production at the Fermilab
Tevatron. We compare all available measurements to perturbative QCD predictions
(NLO and FONLL) ...and also to the parton-level cross section evaluated with
parton-shower Monte Carlo generators. We examine both the single $b$ cross
section and the so called b bar{b} correlations. The review shows that the
experimental situation is quite complicated because the measurements appear to
be inconsistent among themselves. In this situation, there is no solid basis to
either claim that perturbative QCD is challenged by these measurements or, in
contrast, that long-standing discrepancies between data and theory have been
resolved by incrementally improving the measurements and the theoretical
prediction.
We present a phenomenological conjecture of new physics that is suggested by the topology and kinematic properties of the multi-muon events recently reported by the CDF collaboration. We show that ...the salient features of the data can be accounted for by postulating the pair production of three new states h1, h2, and h3 with masses in the range of 15, 7.3 and 3.6 GeV/c^2, respectively. The heavier states cascade-decay into the lighter ones, whereas the lightest state decays into a tau pair with a lifetime of the order of 20 ps.
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