2,425 research outputs found
Production of -hypernuclei via the () reaction in a quark-meson coupling model
We study the production of -hypernuclei, Be and
Mg, via the () reaction within a covariant effective
Lagrangian model, employing the bound and proton spinors calculated by
the latest quark-meson coupling model. The present treatment yields the
differential cross sections for the formation of simple s-state
particle-hole states peak at a beam momentum around 1.0 GeV/c with a
value in excess of 1 b.Comment: Accepted version with miner changes, 4 pages, 2 figures, Presented at
the 20th International IUPAP Conference on Few-Body Problems in Physics, 20 -
25 August, 2012, Fukuoka, Japa
Photoproduction of hypernuclei within the quark-meson coupling model
We study the photoproduction of the ^12{_Lambda}B hypernucleus within a fully
covariant effective Lagrangian based model, employing Lambda bound state
spinors derived from the latest quark-meson coupling model. The kaon production
vertex is described via creation, propagation and decay of N*(1650), N*(1710),
and N*(1720) intermediate baryonic resonant states in the initial collision of
the photon with a target proton in the incident channel. The parameters of the
resonance vertices are fixed by describing the total and differential cross
section data on the elementary gamma (p, K+) Lambda reaction in the energy
regime relevant to the hypernuclear production. It is found that the
hypernuclear production cross sections calculated with the quark model based
hyperon bound state spinors differ significantly from those obtained with the
phenomenological Dirac single particle wave functions.Comment: 16 pages, 5 figures, version to appear in Phys. Lett.
Studying the Imaging Characteristics of Ultra Violet Imaging Telescope (UVIT) through Numerical Simulations
Ultra-Violet Imaging Telescope (UVIT) is one of the five payloads aboard the
Indian Space Research Organization (ISRO)'s ASTROSAT space mission. The science
objectives of UVIT are broad, extending from individual hot stars, star-forming
regions to active galactic nuclei. Imaging performance of UVIT would depend on
several factors in addition to the optics, e.g. resolution of the detectors,
Satellite Drift and Jitter, image frame acquisition rate, sky background,
source intensity etc. The use of intensified CMOS-imager based photon counting
detectors in UVIT put their own complexity over reconstruction of the images.
All these factors could lead to several systematic effects in the reconstructed
images. A study has been done through numerical simulations with artificial
point sources and archival image of a galaxy from GALEX data archive, to
explore the effects of all the above mentioned parameters on the reconstructed
images. In particular the issues of angular resolution, photometric accuracy
and photometric-nonlinearity associated with the intensified CMOS-imager based
photon counting detectors have been investigated. The photon events in image
frames are detected by three different centroid algorithms with some energy
thresholds. Our results show that in presence of bright sources, reconstructed
images from UVIT would suffer from photometric distortion in a complex way and
the presence of overlapping photon events could lead to complex patterns near
the bright sources. Further the angular resolution, photometric accuracy and
distortion would depend on the values of various thresholds chosen to detect
photon events.Comment: Submitted to PASP, 16 Pages, 9 figure
A Foucauldian Theory of American Islamophobia
With the emergence of ISIS andAmerican public furor over allowing Syrian refugees safe haven, Muslim Americans find themselves once again in the cross-hairs of a nation obsessed with searching for answers and someone to blame. I argue that the premise behind American anti-Muslim sentiment is rooted in two of Michel Foucault’s concepts -“biopower” and “pastoral power.” This article is divided in two halves. In the first, I argue that American nationalism is articulated in a unique way, particularly through “pastoral power.” In conjunction with an “imagined” American nationhood (Anderson 1983), it has created a state that is often viewed as secular, but is quite Christian ideologically and structurally. Drawing on Göle (1996), I surmise that the Western “culture of confession,” an extension of pastoral power, is incompatible with Islam – or at least is viewed as such. In the second half, I present my main argument towards a new understanding of Foucault’s (1990) biopower in the context of the sovereign and its ability to designate who is “sacred,” a la Agamben (1998). I suggest that a new evaluation of Agamben (1998) should be undertaken to account for the renewed racialization of and discrimination towards American Muslims
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