4,825 research outputs found
Numerical precision radiative corrections to the Dalitz plot of baryon semileptonic decays including the spin-momentum correlation of the decaying and emitted baryons
We calculate the radiative corrections to the angular correlation between the
polarization of the decaying and the direction of the emitted spin one-half
baryons in the semileptonic decay mode. The final results are presented, first,
with the triple integration of the bremsstrahlung photon ready to be performed
numerically and, second, in an analytical form. A third presentation of our
results in the form of numerical arrays of coefficients to be multiplied by the
quadratic products of form factors is discussed. This latter may be the most
practical one to use in Monte Carlo simulations. A series of crosschecks is
performed. Previous results to order (alpha/pi)(q/M_1) for the decays of
unpolarized baryons are reviewed, too, where q is the momentum transfer and M_1
is the mass of the decaying baryon. This paper is self-contained and organized
to make it accessible and reliable in the analysis of the Dalitz plot of
precision experiments involving heavy quarks and is not compromised to fixing
the form factors at predetermined values. It is assumed that the real photons
are kinematically discriminated. Otherwise, our results have a general
model-independent applicability.Comment: 34 pages, 4 tables, no figures. Some sections have been shortened.
Conclusions remain unchange
Generalizing Boolean Satisfiability I: Background and Survey of Existing Work
This is the first of three planned papers describing ZAP, a satisfiability
engine that substantially generalizes existing tools while retaining the
performance characteristics of modern high-performance solvers. The fundamental
idea underlying ZAP is that many problems passed to such engines contain rich
internal structure that is obscured by the Boolean representation used; our
goal is to define a representation in which this structure is apparent and can
easily be exploited to improve computational performance. This paper is a
survey of the work underlying ZAP, and discusses previous attempts to improve
the performance of the Davis-Putnam-Logemann-Loveland algorithm by exploiting
the structure of the problem being solved. We examine existing ideas including
extensions of the Boolean language to allow cardinality constraints,
pseudo-Boolean representations, symmetry, and a limited form of quantification.
While this paper is intended as a survey, our research results are contained in
the two subsequent articles, with the theoretical structure of ZAP described in
the second paper in this series, and ZAP's implementation described in the
third
Generalizing Boolean Satisfiability II: Theory
This is the second of three planned papers describing ZAP, a satisfiability
engine that substantially generalizes existing tools while retaining the
performance characteristics of modern high performance solvers. The fundamental
idea underlying ZAP is that many problems passed to such engines contain rich
internal structure that is obscured by the Boolean representation used; our
goal is to define a representation in which this structure is apparent and can
easily be exploited to improve computational performance. This paper presents
the theoretical basis for the ideas underlying ZAP, arguing that existing ideas
in this area exploit a single, recurring structure in that multiple database
axioms can be obtained by operating on a single axiom using a subgroup of the
group of permutations on the literals in the problem. We argue that the group
structure precisely captures the general structure at which earlier approaches
hinted, and give numerous examples of its use. We go on to extend the
Davis-Putnam-Logemann-Loveland inference procedure to this broader setting, and
show that earlier computational improvements are either subsumed or left intact
by the new method. The third paper in this series discusses ZAPs implementation
and presents experimental performance results
“The Dog Ate My Homework”: Embracing Risk in the Chilling Climate of No Excuses Schools
I realize that this title is both provocative and potentially very puzzling in the current environment of educational policy and reform. Many would ask: Haven’t we already risked too much? Indeed, haven’t we identified ourselves as an entire Nation at Risk, with an increasing number of students labeled at-risk
Waiting for Superman: He’s “Adequate” and Near Proficient!
In the second week of its national release, the documentary film Waiting for Superman-- about America’s so-called “failing” public school system-- jumped from number 194 in gross receipts to number 20 (Entertainment Weekly, 2010). It couldn’t have hurt that the film was featured as a cover story by Amanda Ripley (2010) in Time magazine only a few weeks earlier, with the provocative tag line: “Can a movie change education?” (Ripley, 2010). Or for that matter, that the film was lauded on The Oprah Winfrey Show (2010), during the course of which Oprah, so moved by the movie, pledged to give $6,000,000 (via her Angel Network) to charter schools across the country
WILLS-VALIDITY OF CONDITION AGAINST CONTEST-CONTEST BY MINOR
Defendant, a minor, contested his mother\u27s will which provided that if a beneficiary should make any effort to invalidate or alter the will, the provisions made for such person should be void. Defendant\u27s father, who had been appointed guardian ad litem, filed notice of contest and petitioned the probate court that the general guardian be compelled to contest the will. After hearing, it was so ordered, and a will contest was held in the circuit court, in which mental incompetency and undue influence were alleged. The contest being unsuccessful, the will was admitted to probate. Plaintiff, as executrix and beneficiary, unsuccessfully sought a decree that she was entitled to the entire estate, on the ground that defendant, the only other beneficiary, had disqualified himself to take by contesting the will. On appeal, held, affirmed. The condition against contest was void against a minor as tending to deprive the probate court of its duty to protect the interests of minors. Farr v. Whitefield, (Mich.1948) 33 N.W. (2d) 791
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