16,882 research outputs found

    Effects of unparticle on top spin correlation at the Large Hadron Collider

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    We study effects of the scale invariant hidden sector, unparticle, proposed by Georgi, on top spin correlation at the Large Hadron Collider. Assuming no flavor changing interaction between the unparticles and the Standard Model particles, there arises the top-antitop quark pair production process through virtual unparticle exchanges in the s-channel in addition to the Standard Model processes. In particular, we consider contributions of scalar and vector unparticles and find that these make sizable deviations of the top spin correlation from the Standard Model one.Comment: 29 pages, 1 table, 12 figures, 2 figures added, typos in captions corrected, version accepted for publication in PR

    A Hardy's Uncertainty Principle Lemma in Weak Commutation Relations of Heisenberg-Lie Algebra

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    In this article we consider linear operators satisfying a generalized commutation relation of a type of the Heisenberg-Lie algebra. It is proven that a generalized inequality of the Hardy's uncertainty principle lemma follows. Its applications to time operators and abstract Dirac operators are also investigated

    Comments on N = 2 supersymmetric sigma models in projective superspace

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    For the most general off-shell N = 2 supersymmetric sigma model in projective superspace, we elaborate on its formulation in terms of N = 1 chiral superfields. A universal (model-independent) expression is obtained for the holomorphic symplectic two-form, which determines the second supersymmetry transformation. This two-form is associated with the two complex structures of the hyperkahler target space, which are complimentary to the one used to realize the target space as a Kahler manifold.Comment: 7 pages; V2: reference [18] correcte

    Massive Hyper-Kahler Sigma Models and BPS Domain Walls

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    With the non-Abelian Hyper-Kahler quotient by U(M) and SU(M) gauge groups, we give the massive Hyper-Kahler sigma models that are not toric in the N=1 superfield formalism. The U(M) quotient gives N!/[M! (N-M)!] (N is a number of flavors) discrete vacua that may allow various types of domain walls, whereas the SU(M) quotient gives no discrete vacua. We derive BPS domain wall solution in the case of N=2 and M=1 in the U(M) quotient model.Comment: 16 pages, 1 figure, contribution to the Proceedings of the International Conference on "Symmetry Methods in Physics (SYM-PHYS10)" held at Yerevan, Armenia, 13-19 Aug. 200

    Polar supermultiplets, Hermitian symmetric spaces and hyperkahler metrics

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    We address the construction of four-dimensional N=2 supersymmetric nonlinear sigma models on tangent bundles of arbitrary Hermitian symmetric spaces starting from projective superspace. Using a systematic way of solving the (infinite number of) auxiliary field equations along with the requirement of supersymmetry, we are able to derive a closed form for the Lagrangian on the tangent bundle and to dualize it to give the hyperkahler potential on the cotangent bundle. As an application, the case of the exceptional symmetric space E_6/SO(10) \times U(1) is explicitly worked out for the first time.Comment: 17 page

    Distinguished self-adjoint extensions of Dirac operators via Hardy-Dirac inequalities

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    We prove some Hardy-Dirac inequalities with two different weights including measure valued and Coulombic ones. Those inequalities are used to construct distinguished self-adjoint extensions of Dirac operators for a class of diagonal potentials related to the weights in the above mentioned inequalities.Comment: 16 page

    The minimal B-L model naturally realized at TeV scale

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    In a previous paper, we have proposed the minimal B-L extended standard model as a phenomenologically viable model that realizes the Coleman-Weinberg-type breaking of the electroweak symmetry. Assuming the classical conformal invariance and stability up to the Planck scale, we will show in this paper that the model naturally predicts TeV scale B-L breaking as well as a light standard-model singlet Higgs boson and light right-handed neutrinos around the same energy scale. We also study phenomenology and detectability of the model at the Large Hadron Collider (LHC) and the International Linear Collider (ILC).Comment: 24pages, 8figure

    Quantum Hall effects of graphene with multi orbitals: Topological numbers, Boltzmann conductance and Semi-classical quantization

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    Hall conductance σxy\sigma_{xy} as the Chern numbers of the Berry connection in the magnetic Brillouin zone is calculated for a realistic multi band tight-band model of graphene with non-orthogonal basis. It is confirmed that the envelope of σxy\sigma_{xy} coincides with a semi-classical result when magnetic field is sufficiently small. The Hall resistivity ρxy\rho_{xy} from the weak-field Boltzmann theory also explains the overall behaviour of the σxy\sigma_{xy} if the Fermi surface is composed of a single energy band. The plateaux of σxy\sigma_{xy} are explained from semi-classical quantization and necessary modification is proposed for the Dirac fermion regimes.Comment: 5pages, 3figure
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