49,832 research outputs found
Production of a Prompt Photon in Association with Charm at Next-to-Leading Order in QCD
A second order, , calculation in perturbative quantum
chromodynamics of the two particle inclusive cross section is presented for the
reaction for large values of the
transverse momentum of the prompt photon and charm quark. The combination of
analytic and Monte Carlo integration methods used here to perform phase-space
integrations facilitates imposition of photon isolation restrictions and other
selections of relevance in experiments. Differential distributions are provided
for various observables. Positive correlations in rapidity are predicted.Comment: 27 pages in RevTex plus 14 figures in one compressed PS fil
Why Solve the Hamiltonian Constraint in Numerical Relativity?
The indefinite sign of the Hamiltonian constraint means that solutions to
Einstein's equations must achieve a delicate balance--often among numerically
large terms that nearly cancel. If numerical errors cause a violation of the
Hamiltonian constraint, the failure of the delicate balance could lead to
qualitatively wrong behavior rather than just decreased accuracy. This issue is
different from instabilities caused by constraint-violating modes. Examples of
stable numerical simulations of collapsing cosmological spacetimes exhibiting
local mixmaster dynamics with and without Hamiltonian constraint enforcement
are presented.Comment: Submitted to a volume in honor of Michael P. Ryan, Jr. Based on talk
given at GR1
Single parameter testing application
Single parameter testing with growing exponential signals applied to servo loop controlling arm position on X-Y plotte
An upper limit on CP violation in the system
In a previous publication we noted that the time dependence of an incoherent
mixture undergoes a qualitative change when the magnitude of CP
violation exceeds a critical value. Requiring, on physical grounds,
that the system evolve from an initial incoherent state to a final pure state
in a monotonic way, yields a new upper limit for . The recent
measurement of the wrong charge semileptonic asymmetry of mesons
presented by the D0 collaboration is outside this bound by one standard
deviation. If this result is confirmed it implies the existence of a new
quantum mechanical oscillation phenomenon.Comment: 7 pages, 2 figures, version submitted for publication (Physical
Review
Cities in fiction: Perambulations with John Berger
This paper explores selected novels by John Berger in which cities play a central role. These cities are places, partially real and partially imagined, where memory, hope, and despair intersect. My reading of the novels enables me to trace important themes in recent discourses on the nature of contemporary capitalism, including notions of resistance and universality. I also show how Berger?s work points to a writing that can break free from the curious capacity of capitalism to absorb and feed of its critique
Spin Dependence of Massive Lepton Pair Production in Proton-Proton Collisions
We calculate the transverse momentum distribution for the production of
massive lepton-pairs in longitudinally polarized proton-proton reactions at
collider energies within the context of perturbative quantum chromodynamics.
For values of the transverse momentum Q_T greater than roughly half the pair
mass Q, Q_T > Q/2, we show that the differential cross section is dominated by
subprocesses initiated by incident gluons, provided that the polarized gluon
density is not too small. Massive lepton-pair differential cross sections
should be a good source of independent constraints on the polarized gluon
density, free from the experimental and theoretical complications of photon
isolation that beset studies of prompt photon production. We provide
predictions for the spin-averaged and spin-dependent differential cross
sections as a function of Q_T at energies relevant for the Relativistic Heavy
Ion Collider (RHIC) at Brookhaven, and we compare these with predictions for
real prompt photon production.Comment: 34 pages, RevTeX including 17 figures in .ps file
Erratum: Next-to-leading order supersymmetric QCD predictions for associated production of gauginos and gluinos [Phys. Rev. D 62, 095014 (2000)]
Errors in the published version of the paper are corrected, and new figures
are provided.Comment: 3 pages, latex, 4 figure
Teaching with Feminist Judgments: A Global Conversation
This conversational-style essay is an exchange among fourteen professors-representing thirteen universities across five countries-with experience teaching with feminist judgments.
Feminist judgments are \u27shadow\u27 court decisions rewritten from a feminist perspective, using only the precedent in effect and the facts known at the time of the original decision. Scholars in Canada, England, the U.S., Australia, New Zealand, Scotland, Ireland, India, and Mexico have published (or are currently producing) written collections of feminist judgments that demonstrate how feminist perspectives could have changed the legal reasoning or outcome (or both) in important legal cases.
This essay begins to explore the vast pedagogical potential of feminist judgments. The contributors to this conversation describe how they use feminist judgments in the classroom; how students have responded to the judgments; how the professors achieve specific learning objectives through teaching with feminist judgments; and how working with feminist judgments-whether studying them, writing them, or both-can help students excavate the multiple social, political, economic, and even personal factors that influence the development of legal rules, structures, and institutions. The primary takeaway of the essay is that feminist judgments are a uniquely enriching pedagogical tool that can broaden the learning experience. Feminist judgments invite future lawyers, and indeed any reader, to re-imagine what the law is, what the law can be, and how to make the law more responsive to the needs of all people
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