9,871 research outputs found
Hadron Physics at BABAR
The BaBar experiment at SLAC is designed to measure CP violation in the B
meson system, however the very high statistics combined with the different
electron and positron beam energies, the detector design and the open trigger
allow a wide variety of spectroscopic measurements. We are beginning to tap
this potential via several production mechanisms. Here we present recent
results from initial state radiation, hadronic jets, few body B and D hadron
decays, and interactions in the detector material. We also summarize
measurements relevant to Ds meson spectroscopy, pentaquarks and charmonium
spectroscopy from multiple production mechanisms.Comment: 10 pages, 7 eps figures, contributed to the Proceedings of HADRON0
Measurement of Inclusive Production of Light Charged Hadrons at BaBar
Inclusive hadron production cross sections in e+e-collisions shed light on
the fundamental fragmentation and hadronization processes. We present
measurements of the inclusive spectra of charged pions, kaons and protons in
hadronic events at a center-of-mass energy of 10.54 \gev. These results are
compared with theoretical predictions and the predictions of three
hadronization models. Along with previous measurements at higher energies, they
are also used to study the scaling properties of hadron production.Comment: 7 pages, Presentation at the DPF 2013 Meeting of the American
Physical Society Division of Particles and Fields, Santa Cruz, California,
August 13-17, 201
Topflavor: A Separate SU(2) for the Third Family
We consider an extended electroweak gauge group: SU(2) SU(2) U(1) where the first and second generation of fermions couple to
SU(2) and the third generation couples to SU(2). Bounds based on heavy
gauge boson searches and current precision electroweak measurements are placed
on the masses of the new heavy gauge bosons. In particular we find that the
mass of the heavy W boson can not be less than 800 GeV. For some range of the
allowed parameter space, these heavy gauge bosons produce observable signals at
the Tevatron and LEP-II.Comment: LaTeX, 11 pages, some comments on FCNC interactions and single top
production added, additional references include
Cluster Algebras of Grassmannians are Locally Acyclic
Considered as commutative algebras, cluster algebras can be very unpleasant
objects. However, the first author introduced a condition known as "local
acyclicity" which implies that cluster algebras behave reasonably. One of the
earliest and most fundamental examples of a cluster algebra is the homogenous
coordinate ring of the Grassmannian. We show that the Grassmannian is locally
acyclic. Morally, we are in fact showing the stronger result that all positroid
varieties are locally acyclic. However, it has not been shown that all
positroid varieties have cluster structure, so what we actually prove is that
certain cluster varieties associated to Postnikov's alternating strand diagrams
are locally acylic. Moreover, we actually establish a slightly stronger
property than local acyclicity, which we term the Louise property, that is
designed to facilitate proofs involving the Mayer-Vietores sequence.Comment: 14 pages, 8 figures, minor edits from previous version, added
references to recent work of LeCler
Pittsburgh's Failed Industry Targeting Strategy of the 1960s
In the 1960's and early 1970's, public and private leaders made a substantial effort to promote Pittsburgh's existing transportation industry as a center for the emerging urban transportation market. The selection of the rapid transit industry for targeting in the 1960's purportedly addressed two issues. Despite national acclaim for its Renaissance redevelopment since World War II, the metropolitan region still needed an effective mass transportation system. Moreover, industrial development efforts had not substantially diversified the region's manufacturing base that still specialized in primary metals. Operating in the region's Renaissance tradition of a public and private partnership, corporate executives and public officials pursued a three-pronged strategy: build an innovative rapid transportation system for Allegheny County, use it as a showcase for testing and marketing rapid transit hardware of regional corporations, and promote the city as a center of the rapid transportation industry. They settled on Westinghouse's automated, rubber-tired vehicle running on a separate cement guideway, known locally as "Skybus," for the demonstration project and the region's mass transit solution. The mass transit plan and industry targeting strategy foundered by the early 1970's because leadership weakened in both poles of the partnership. The Westinghouse technology divided the corporate community, while populist political sentiment diminished the ability of the Democratic party's political machine to deliver key public decisions. The Pittsburgh case suggests that a successful industry targeting strategy may depend more on effective leadership and local politics than on the quality of the selection process and vigorous pursuit of traditional economic development programs in support of the targeted industry
Automatic document classification of biological literature
Background: Document classification is a wide-spread problem with many applications, from organizing search engine snippets to spam filtering. We previously described Textpresso, a text-mining system for biological literature, which marks up full text according to a shallow ontology that includes terms of biological interest. This project investigates document classification in the context of biological literature, making use of the Textpresso markup of a corpus of Caenorhabditis elegans literature.
Results: We present a two-step text categorization algorithm to classify a corpus of C. elegans papers. Our classification method first uses a support vector machine-trained classifier, followed by a novel, phrase-based clustering algorithm. This clustering step autonomously creates cluster labels that are descriptive and understandable by humans. This clustering engine performed better on a standard test-set (Reuters 21578) compared to previously published results (F-value of 0.55 vs. 0.49), while producing cluster descriptions that appear more useful. A web interface allows researchers to quickly navigate through the hierarchy and look for documents that belong to a specific concept.
Conclusions: We have demonstrated a simple method to classify biological documents that embodies an improvement over current methods. While the classification results are currently optimized for Caenorhabditis elegans papers by human-created rules, the classification engine can be adapted to different types of documents. We have demonstrated this by presenting a web interface that allows researchers to quickly navigate through the hierarchy and look for documents that belong to a specific concept
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