64,013 research outputs found

    Substantially Justified? The U.S. Government’s Use of Name-Check Technologies in Naturalization Procedures

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    The U.S. Citizenship and Immigration Services relies upon the Federal Bureau of Investigation to administer the National Name Check Program, which conducts background checks on applicants for naturalization. Backlogs have led to long delays for aspiring citizens and significant legal problems for the government. This iBrief examines the First Circuit’s ruling in Aronov v. Napolitano that an eighteen-month delay in adjudicating a naturalization application was substantially justified. While the government’s inefficiency can be explained partly by an understaffed bureaucracy, overwhelming evidence suggests that these problems are exacerbated by a technological infrastructure that is ill-equipped to handle the scope of the backlog. This iBrief argues that the government should be held liable for its failures; and that long-overdue technological improvements should be implemented to prevent these issues from recurring in the future

    Anomalous Gluon Self-Interactions and ttˉt \bar{t} Production

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    Strong-interaction physics that lies beyond the standard model may conveniently be described by an effective Lagrangian. The only genuinely gluonic CP-conserving term at dimension six is the three-gluon-field-strength operator G3G^3. This operator, which alters the 3-gluon and 4-gluon vertices form their standard model forms, turns out to be difficult to detect in final states containing light jets. Its effects on top quark pair production hold the greatest promise of visibility.Comment: Latex file using [aps,aipbook,floats,epsf]{revtex}. 12 pages, 4 Postscript figures. Full PS copy at http://smyrd.bu.edu/htfigs/htfigs.html Talk presented by EHS at the International Symposium on Vector Boson Self-Interactions, UCLA, Feb. 1-3, 199

    Super Jackstraws and Super Waterwheels

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    We construct various new BPS states of D-branes preserving 8 supersymmetries. These include super Jackstraws (a bunch of scattered D- or (p,q)-strings preserving supersymmetries), and super waterwheels (a number of D2-branes intersecting at generic angles on parallel lines while preserving supersymmetries). Super D-Jackstraws are scattered in various dimensions but are dynamical with all their intersections following a common null direction. Meanwhile, super (p,q)-Jackstraws form a planar static configuration. We show that the SO(2) subgroup of SL(2,R), the group of classical S-duality transformations in IIB theory, can be used to generate this latter configuration of variously charged (p,q)-strings intersecting at various angles. The waterwheel configuration of D2-branes preserves 8 supersymmetries as long as the `critical' Born-Infeld electric fields are along the common direction.Comment: 23 pages, 10 figure

    Strong and Electromagnetic Decays of Two New Lambdac∗Lambda_c^* Baryons

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    Two recently discovered excited charm baryons are studied within the framework of Heavy Hadron Chiral Perturbation Theory. We interpret these new baryons which lie 308 \MeV and 340 \MeV above the Λc\Lambda_c as I=0I=0 members of a P-wave spin doublet. Differential and total decay rates for their double pion transitions down to the Λc\Lambda_c ground state are calculated. Estimates for their radiative decay rates are also discussed. We find that the experimentally determined characteristics of the Λc∗\Lambda_c^* baryons may be simply understood in the effective theory.Comment: 16 pages with 4 figures not included but available upon request, CALT-68-191

    Stress-energy Tensor Correlators in N-dim Hot Flat Spaces via the Generalized Zeta-Function Method

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    We calculate the expectation values of the stress-energy bitensor defined at two different spacetime points x,x′x, x' of a massless, minimally coupled scalar field with respect to a quantum state at finite temperature TT in a flat NN-dimensional spacetime by means of the generalized zeta-function method. These correlators, also known as the noise kernels, give the fluctuations of energy and momentum density of a quantum field which are essential for the investigation of the physical effects of negative energy density in certain spacetimes or quantum states. They also act as the sources of the Einstein-Langevin equations in stochastic gravity which one can solve for the dynamics of metric fluctuations as in spacetime foams. In terms of constitutions these correlators are one rung above (in the sense of the correlation -- BBGKY or Schwinger-Dyson -- hierarchies) the mean (vacuum and thermal expectation) values of the stress-energy tensor which drive the semiclassical Einstein equation in semiclassical gravity. The low and the high temperature expansions of these correlators are also given here: At low temperatures, the leading order temperature dependence goes like TNT^{N} while at high temperatures they have a T2T^{2} dependence with the subleading terms exponentially suppressed by e−Te^{-T}. We also discuss the singular behaviors of the correlators in the x′→xx'\rightarrow x coincident limit as was done before for massless conformal quantum fields.Comment: 23 pages, no figures. Invited contribution to a Special Issue of Journal of Physics A in honor of Prof. J. S. Dowke
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