13,037,628 research outputs found

    A generalized Cartan decomposition for the double coset space U(n_1) x U(n_2) x U(n_3)) U(n) / U(p) x U(q)

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    Motivated by recent developments on visible actions on complex manifolds, we raise a question whether or not the multiplication of three subgroups LL, G′G' and HH surjects a Lie group GG in the setting that G/HG/H carries a complex structure and contains G′/G′∩HG'/G' \cap H as a totally real submanifold. Particularly important cases are when G/LG/L and G/HG/H are generalized flag varieties, and we classify pairs of Levi subgroups (L,H)(L, H) such that LG′H=GL G' H = G, or equivalently, the real generalized flag variety G′/H∩G′G'/H \cap G' meets every LL-orbit on the complex generalized flag variety G/HG/H in the setting that (G,G′)=(U(n),O(n))(G, G') = (U(n), O(n)). For such pairs (L,H)(L, H), we introduce a \textit{herringbone stitch} method to find a generalized Cartan decomposition for the double coset space L\G/HL \backslash G/H, for which there has been no general theory in the non-symmetric case. Our geometric results provides a unified proof of various multiplicity-free theorems in representation theory of general linear groups

    U-operators

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    Inspired by a statement of W. Luh asserting the existence of entire functions having together with all their derivatives and antiderivatives some kind of additive universality or multiplicative universality on certain compact subsets of the complex plane or of, respectively, the punctured complex plane, we introduce in this paper the new concept of U-operators, which are defined on the space of entire functions. Concrete examples, including differential and antidifferential operators, composition, multiplication and shift operators, are studied. A result due to Luh, Martirosian and Müller about the existence of universal entire functions with gap power series is also strengthened.Plan Andaluz de Investigación (Junta de Andalucía

    U-Manifolds

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    We use non-perturbative U-duality symmetries of type II strings to construct new vacuum solutions. In some ways this generalizes the F-theory vacuum constructions. We find the possibilities of new vacuum constructions are very limited. Among them we construct new theories with N=2 supersymmetry in 3-dimensions and (1, 1) supersymmetry in 2-dimensions.Comment: 11 pages, minor changes in references and text (version to appear in Phys. Lett. B

    TDHF investigations of the U+U quasifission process

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    The use of actinide collisions have been suggested as a way to produce neutron rich isotopes of high Z nuclei. The collision dynamics of these reactions can be studied using unrestricted time-dependent Hartree-Fock (TDHF) calculations. Here, we report on the recent studies of quasifission for the 238^{238}U+238^{238}U system.Comment: Presented at the XXXV Mazurian Lakes Conference on Physics, Piaski, Poland, September 3-9, 2017

    U(2) Flavor Physics without U(2) Symmetry

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    We present a model of fermion masses based on a minimal, non-Abelian discrete symmetry that reproduces the Yukawa matrices usually associated with U(2) theories of flavor. Mass and mixing angle relations that follow from the simple form of the quark and charged lepton Yukawa textures are therefore common to both theories. We show that the differing representation structure of our horizontal symmetry allows for new solutions to the solar and atmospheric neutrino problems that do not involve modification of the original charged fermion Yukawa textures, or the introduction of sterile neutrinos.Comment: 12 pages RevTeX, 1 eps figure. A few typos correcte

    Gluon Saturation Effects in Relativistic U+U Collisions

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    We examine entropy production in relativistic U+U collisions on the basis of a Color Glass Condensate (CGC) type picture as implemented in the Kharzeev-Levin-Nardi model (KLN). In this framework, we find that the peak entropy density produced in tip-on-tip U+U collisions is about 30% greater than that seen in central Au+Au collisions. Although the resulting difference in the produced charged particle multiplicity between tip-on-tip and side-on-side collisions is smaller than that predicted by previous Glauber model estimates, it is still large enough to allow for experimental discrimination between average orientations of the uranium nuclei. We also point out that in the saturation/CGC approach the collision geometry plays a more important role than previously believed, and that the observed centrality dependence of the produced particle multiplicity per participant in Au+Au collisions can be qualitatively reproduced even without running coupling effects.Comment: 7 pages, including 8 figure
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