443,656 research outputs found
Cuts and coproducts of massive triangle diagrams
Relations between multiple unitarity cuts and coproducts of Feynman integrals
are extended to allow for internal masses. These masses introduce new branch
cuts, whose discontinuities can be derived by placing single propagators on
shell and identified as particular entries of the coproduct. First entries of
the coproduct are then seen to include mass invariants alone, as well as
threshold corrections for external momentum channels. As in the massless case,
the original integral can possibly be recovered from its cuts by starting with
the known part of the coproduct and imposing integrability contraints. We
formulate precise rules for cuts of diagrams, and we gather evidence for the
relations to coproducts through a detailed study of one-loop triangle integrals
with various combinations of external and internal masses.Comment: 60 page
Application of the coal mine roof rating (CMRR) to extended cuts
"Since it was first introduced, the Coal Mine Roof Rating (CMRR) has been widely accepted as a tool for geologic characterization and mine planning. This paper discusses the application of the CMRR to another practical ground control problem. Extended cuts (cuts greater than 6 m (20 ft) in length) are commonly used with remote control continuous miners. Extended cuts can greatly increase productivity, but they have been associated with a number of fatal roof fall accidents. When extended cuts are attempted in weak roof, the roof may collapse before it can be bolted, causing hazardous conditions. Until now, it has not been possible to predict where conditions may not be suitable for extended cuts. In this study, data on the CMRR and extended cut experience were collected at 36 mines in 7 states. It was found that when the CMRR was greater than 55, deep cuts were routine in nearly every case. When the CMRR was less than 37, extended cuts were almost never taken. Between 38 and 55, extended cuts were feasible sometimes but not others. The data also shows that extended cuts are less likely to be stable if either the entry span or the depth of cover increases." - NIOSHTIC-2NIOSHTIC no. 20000128199
Online Appendix to "Transitional Dynamics of Dividend and Capital Gains Tax Cuts"
In this appendix, we present the details of the extended model with debt in our paper "Transitional Dynamics of Dividend and Capital Gains Tax Cuts." Section 1 presents the extended model and results. Section 2 presents the numerical algorithm to solve this model. Section 3 presents an extensiongure for the simulation conducted in Section 3 of our original paper.additional
Power Spectrum of Primordial Inhomogeneity Determined from the 4-Year COBE DMR Sky Maps
Fourier analysis and power spectrum estimation of the cosmic microwave
background anisotropy on an incompletely sampled sky developed by Gorski (1994)
has been applied to the high-latitude portion of the 4-year COBE DMR 31.5, 53
and 90 GHz sky maps. Likelihood analysis using newly constructed Galaxy cuts
(extended beyond |b| = 20deg to excise the known foreground emission) and
simultaneously correcting for the faint high latitude galactic foreground
emission is conducted on the DMR sky maps pixelized in both ecliptic and
galactic coordinates. The Bayesian power spectrum estimation from the
foreground corrected 4-year COBE DMR data renders n ~ 1.2 +/- 0.3, and
Q_{rms-PS} ~ 15.3^{+3.7}_{-2.8} microK (projections of the two-parameter
likelihood). These results are consistent with the Harrison-Zel'dovich n=1
model of amplitude Q_{rms-PS} ~ 18 microK detected with significance exceeding
14sigma (dQ/Q < 0.07). (A small power spectrum amplitude drop below the
published 2-year results is predominantly due to the application of the new,
extended Galaxy cuts.)Comment: 9 pages of text in LaTeX, 1 postscript Table, 4 postscript figures (2
color plates), submitted to The Astrophysical Journal (Letters
Color transparency in hadronic attenuation of rho0 mesons
Ongoing experiments at JLAB investigate the nuclear transparency in exclusive
rho0(770) electroproduction off nuclei. In this work we present transport model
predictions for the attenuation of rho0s in nuclei and for color transparency
(CT) effects as observable at CLAS with a 5 GeV electron beam energy. A full
event simulation presented here permits to study the impact of actual
experimental acceptance conditions and kinematical cuts. The exclusive
(e,e'rho0) cross section off nucleons is described by diffractive and color
string breaking mechanisms extended toward the onset of the deep inelastic
regime. Different hadronization and CT scenarios are compared. We show that a
detailed analysis of elementary cross section, nuclear effects and experimental
cuts is needed to reveal the early onset of rho0-CT at present JLAB energies.Comment: 10 pages, 11 figure
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