We present the measurement of R = B(t →Wb)/B(t →Wq) in pp̄ collisions at √s = 1.96 TeV, using 230 pb−1 of data collected by the DØ experiment at the Fermilab Tevatron Collider. We fit simultaneously R and the number (Ntt̄ ) of selected top quark pairs (t t̄ ), to the number of identified b-quark jets in events with one electron or one muon, three or more jets, and high transverse energy imbalance....

For the past 12 years we have been studying optical micro-variability of a sample of 15 Blazars. We summarize the results of this study and draw some basic conclusions about the characteristics of micro-variability. The intermittency, the stochastic nature, and the similar profile shapes seen in micro-variations at different times and in different objects have led us to a possible model to expl...

The jets observed to emanate from many compact accreting objects may arise from the twisting of a magnetic field threading a differentially rotating accretion disk which acts to magnetically extract angular momentum and energy from the disk. Two main regimes have been discussed, hydromagnetic jets, which have a significant mass flux and have energy and angular momentum carried by both matter an...

Gamma-ray emission from AGN provides us with unprecedented insights into the physics of extragalactic jets. The emission from these jets fits naturally into the existing theoretical framework of relativistic jets as inferred from parsec scale and kiloparsec scale observations. Models of the γ-ray fluxes give us important knowledge of jet parameters, in particular magnetic fields and the size of...

The amplitude of jet distortions and accompanying pressure and velocity fluctuations resulting from Kelvin-Helmholtz instability of three dimensional relativistic jets are explored. The effect of instability on jets as they accelerate from subto super-Alfvénic speeds is explored and a relativistic stabilization mechanism for trans-Alfvénic jets is proposed. The level to which asymmetric instabi...

We present an analysis of OH, CN, and C2 jets observed in the coma of Comet Hale– Bopp on UT April 22, 23, and 25, 1997. Monte Carlo models designed to simulate the gas jets were employed to analyze the nuclear active areas responsible for the observed coma gas jets. Our results indicate that four active areas are necessary to reproduce the CN and C2 jets while five active areas are required to...

We present multi-dimensional simulations of magnetized radiative jets appropriate to Young Stellar Objects. Magnetized jets subject to collisionally excited radiative losses have not, as yet, received extensive scrutiny. The purpose of this letter is to articulate the propagation dynamics of radiative MHD jets in the context of the extensive jet literature. Most importantly, we look for morphol...

The main objective of this experimental investigation is to examine favourable machining conditions by utilising fewer resources industries for the techno-economical and ecological benefits. operations are performed in turning SS 304 using coated carbide tool inserts under dry, water-soluble cutting fluid solution form flood cooling small-quantity lubrication (SQL) employing a newly formed micr...

Stable water-in-oil emulsion is essential to digital PCR and many other bioanalytical reactions that employ droplets as microreactors. We developed a novel technology to produce monodisperse emulsion droplets with high efficiency and high throughput using a bench-top centrifuge. Upon centrifugal spinning, the continuous aqueous phase is dispersed into monodisperse droplet jets in air through a ...

abstract in the present article, effective parameters of the buoyant jets have been evaluated in the stagnant ambient fluid. the jet parameters, geometry parameters and environmental parameters are investigated. using dimensional analysis, a set of dimensionless functions was obtained. to achieve the exact functions, a physical model was built in the hydraulic laboratory of shahid chamran unive...