91,614 research outputs found
An estimate of the QCD corrections to the decay Z --> W u d
We present an estimate of perturbative QCD corrections to the decay . A simple approximate approach is described in detail. The difference
of masses of and is used as an expansion parameter. A complete
analytical formula for a part of the corrections is also presented.Comment: 9 pages, late
How to Defeat W\"{u}thrich’s Abysmal Embarrassment Argument against Space-Time Structuralism
In his 2009 PSA Recent Ph.D. Award winning contribution to the bi-annual PSA Conference at Pittsburgh in 2008, C. Wu ̈thrich mounted an argument against struc- turalism about space-time in the context of the General Theory of Relativity (GTR), to the effect that structuralists cannot discern space-time points. An “abysmal embarrass- ment” for the structuralist, Wu ̈thrich judged. Wu ̈thrich’s characterisation of space-time structuralism is however incorrect. We demonstrate how, on the basis of a correct char- acterisation of space-time structuralism, it is possible to discern space-time points in the GTR-structures under consideration. Thus Wu ̈thrich’s argument crumbles
Review: Guan Wei at Hanart T Z Gallery
This review is scripted in English. It was published in Asian Art News in 1996 (March/April issue). (Jerry Wu\u2723).https://digital.kenyon.edu/zhoudocs/1092/thumbnail.jp
Dispelling the Anthropic Principle from the Dimensionality Arguments
It is shown that in d=11 supergravity, under a very reasonable ansatz, the
nearly flat spacetime in which we are living must be 4-dimensional without
appealing to the Anthropic Principle. Can we dispel the Anthropic Principle
completely from cosmology?Comment: 7 pages, Essa
Non-minimal Wu-Yang wormhole
We discuss exact solutions of three-parameter non-minimal Einstein-Yang-Mills
model, which describe the wormholes of a new type. These wormholes are
considered to be supported by SU(2)-symmetric Yang-Mills field, non-minimally
coupled to gravity, the Wu-Yang ansatz for the gauge field being used. We
distinguish between regular solutions, describing traversable non-minimal
Wu-Yang wormholes, and black wormholes possessing one or two event horizons.
The relation between the asymptotic mass of the regular traversable Wu-Yang
wormhole and its throat radius is analysed.Comment: 9 pages, 2 figures, typos corrected, 2 references adde
Optimal Competitive Auctions
We study the design of truthful auctions for selling identical items in
unlimited supply (e.g., digital goods) to n unit demand buyers. This classic
problem stands out from profit-maximizing auction design literature as it
requires no probabilistic assumptions on buyers' valuations and employs the
framework of competitive analysis. Our objective is to optimize the worst-case
performance of an auction, measured by the ratio between a given benchmark and
revenue generated by the auction.
We establish a sufficient and necessary condition that characterizes
competitive ratios for all monotone benchmarks. The characterization identifies
the worst-case distribution of instances and reveals intrinsic relations
between competitive ratios and benchmarks in the competitive analysis. With the
characterization at hand, we show optimal competitive auctions for two natural
benchmarks.
The most well-studied benchmark measures the
envy-free optimal revenue where at least two buyers win. Goldberg et al. [13]
showed a sequence of lower bounds on the competitive ratio for each number of
buyers n. They conjectured that all these bounds are tight. We show that
optimal competitive auctions match these bounds. Thus, we confirm the
conjecture and settle a central open problem in the design of digital goods
auctions. As one more application we examine another economically meaningful
benchmark, which measures the optimal revenue across all limited-supply Vickrey
auctions. We identify the optimal competitive ratios to be
for each number of buyers n, that is as
approaches infinity
Essay: Qiu Z(h)i-Jie: Artist as the Writing Hand
The document is printed except for a trivial amendment on the second page. (Jerry Wu\u2723).https://digital.kenyon.edu/zhoudocs/1216/thumbnail.jp
On the Radiatively Induced Lorentz and CPT Violating Chern-Simons Term
The radiatively induced Lorentz and CPT violating Chern-Simons terms in QED
is calculated based on the recently developed loop regularization method [Y.L.
Wu, Int.J.Mod.Phys.A18 (2003) 5363, hep-th/0209021; Y.L. Wu, Mod.Phys.Lett.A19
(2004) 2191, hep-th/0311082] for quantum field theories. It enables us to make
general comments on the various results in literature and obtain a consistent
result when simultaneously combining the evaluation for the chiral anomaly
which has a unique form once the vector current is kept conserved.Comment: 10 pages, no figures, published versio
Two-Dimensional QCD in the Wu-Mandelstam-Leibbrandt Prescription
We find the exact non-perturbative expression for a simple Wilson loop of
arbitrary shape for U(N) and SU(N) Euclidean or Minkowskian two-dimensional
Yang-Mills theory regulated by the Wu-Mandelstam-Leibbrandt gauge prescription.
The result differs from the standard pure exponential area-law of YM_2, but
still exhibits confinement as well as invariance under area-preserving
diffeomorphisms and generalized axial gauge transformations. We show that the
large N limit is NOT a good approximation to the model at finite N and conclude
that Wu's N=infinity Bethe-Salpeter equation for QCD_2 should have no bound
state solutions. The main significance of our results derives from the
importance of the Wu-Mandelstam-Leibbrandt prescription in higher-dimensional
perturbative gauge theory.Comment: 7 pages, LaTeX, REVTE
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