9,130 research outputs found
Heavy Flavour results from Tevatron
The CDF and D0 experiments finalize the analysis of their full statistics
collected in the collisions at a center-of-mass energy of TeV at the Fermilab Tevatron collider. This paper presents several new
results on the properties of hadrons containing heavy - and -quarks
obtained by both collaborations. These results include the search for the rare
decays (CDF), the study of CP asymmetry in decay (CDF, D0), the measurement of the like-sign dimuon charge
asymmetry (D0), the measurement of CP asymmetry in and decays (CDF), and the new measurement of the branching fraction (CDF). Both experiments still expect
to produce more results on the properties of heavy flavours.Comment: Contribution to the XLVIIth Rencontres de Moriond session devoted to
Electroweak Interactions and Unified Theorie
Antiferromagnetic ordering of energy levels for spin ladder with four-spin cyclic exchange: Generalization of the Lieb-Mattis theorem
The Lieb-Mattis theorem is generalized to an antiferromagnetic spin-ladder
model with four-spin cyclic exchange interaction. We prove that for J>2K, the
antiferromagnetic ordering of energy levels takes place separately in two
sectors, which remain symmetric and antisymmetric under the reflection with
respect to the longitudinal axis of the ladder. We prove also that at the
self-dual point J=2K, the Lieb-Mattis rule holds in the sectors with fixed
number of rung singlets. In both cases, it agrees with the similar rule for
Haldane chain with appropriate spin number.Comment: 4 pages, some references updated and added, typos corrected, to
appear in Phys. Rev.
Frequency-dependent and correlational selection pressures have conflicting consequences for assortative mating in a color-polymorphic lizard, Uta stansburiana
Acknowledgments We would like to thank the numerous undergraduate researchers involved with this project for their invaluable assistance in lizard rearing and data collection. We also thank D. Haisten, A. Runemark, Y. Takahashi, and M. Verzijden for insightful comments on the manuscript. This project was funded by National Science Foundation DEBOS-15973 to A.G.M. and B.R.S.Peer reviewedPublisher PD
Extensive lava flow fields on Venus: Preliminary investigation of source elevation and regional slope variations
Large-volume lava flow fields have been identified on Venus, the most areally extensive of which are known as fluctus and have been subdivided into six morphologic types. Sheetlike flow fields (Type 1) lack the numerous, closely spaced, discrete lava flow lobes that characterize digitate flow fields. Transitional flow fields (Type 2) are similar to sheetlike flow fields but contain one or more broad flow lobes. Digitate flow fields are divided further into divergent (Types 3-5) and subparallel (Type 6) classes on the basis of variations in the amount of downstream flow divergence. As a result of our previous analysis of the detailed morphology, stratigraphy, and tectonic associations of Mylitta Fluctus, we have formulated a number of questions to apply to all large flow fields on Venus. In particular, we would like to address the following: (1) eruption conditions and style of flow emplacement (effusion rate, eruption duration), (2) the nature of magma storage zones (presence of neutral buoyancy zones, deep or shallow crustal magma chambers), (3) the origin of melt and possible link to mantle plumes, and (4) the importance of large flow fields in plains evolution. To answer these questions we have begun to examine variations in flow field dimension and morphology; the distribution of large flow fields in terms of elevation above the mean planetary radius; links to regional tectonic or volcanic structures (e.g., associations with large shield edifices, coronae, or rift zones); statigraphic relationships between large flow fields, volcanic plains, shields, and coronae; and various models of flow emplacement in order to estimate eruption parameters. In this particular study, we have examined the proximal elevations and topographic slopes of 16 of the most distinctive flow fields that represent each of the 6 morphologic types
Optimal Unambiguous State Discrimination of two density matrices and its link with the Fidelity
Recently the problem of Unambiguous State Discrimination (USD) of mixed
quantum states has attracted much attention. So far, bounds on the optimum
success probability have been derived [1]. For two mixed states they are given
in terms of the fidelity. Here we give tighter bounds as well as necessary and
sufficient conditions for two mixed states to reach these bounds. Moreover we
construct the corresponding optimal measurement strategies. With this result,
we provide analytical solutions for unambiguous discrimination of a class of
generic mixed states. This goes beyond known results which are all reducible to
some pure state case. Additionally, we show that examples exist where the
bounds cannot be reached.Comment: 10 page
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