17,066 research outputs found

    An efficient prescription to find the eigenfunctions of point interactions Hamiltonians

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    A prescription invented a long time ago by Case and Danilov is used to get the wave function of point interactions in two and three dimensions.Comment: 6 page

    Bounds on Z′Z^\prime from 3-3-1 model at the LHC energies

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    The Large Hadron Collider will restart with higher energy and luminosity in 2015. This achievement opens the possibility of discovering new phenomena hardly described by the Standard Model, that is based on two neutral gauge bosons: the photon and the ZZ. This perspective imposes a deep and systematic study of models that predicts the existence of new neutral gauge bosons. One of such models is based on the gauge group SU(3)C×SU(3)L×U(1)NSU(3)_C \times SU(3)_L \times U(1)_N called 3-3-1 model for short. In this paper we perform a study with Z′Z^\prime predicted in two versions of the 3-3-1 model and compare the signature of this resonance in each model version. By considering the present and future LHC energy regimes, we obtain some distributions and the total cross section for the process p+p⟶ℓ++ℓ−+Xp + p \longrightarrow \ell^{+} + \ell^{-} + X. Additionally, we derive lower bounds on Z′Z^\prime mass from the latest LHC results. Finally we analyze the LHC potential for discovering this neutral gauge boson at 14 TeV center-of-mass energy.Comment: 6 pages, 9 figures, 2 table

    Dirac's hole theory versus quantum field theory

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    Dirac's hole theory and quantum field theory are usually considered equivalent to each other. For models of a certain type, however, the equivalence may not hold as we discuss in this Letter. This problem is closely related to the validity of the Pauli principle in intermediate states of perturbation theory.Comment: No figure

    Fermion masses in a model for spontaneous parity breaking

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    In this paper we discuss a left-right symmetric model for elementary particles and their connection with the mass spectrum of elementary fermions. The model is based on the group SU(2)L⊗SU(2)R⊗U(1)SU(2)_L\otimes SU(2)_R\otimes U(1). New mirror fermions and a minimal set of Higgs particles that breaks the symmetry down to U(1)emU(1)_{em} are proposed. The model can accommodate a consistent pattern for charged and neutral fermion masses as well as neutrino oscillations. An important consequence of the model is that the connection between the left and right sectors can be done by the neutral vector gauge bosons Z and a new heavy Z'.Comment: 7 pages, 3 figures. Accepted in Eur. Phys. J.

    Two definitions of the electric polarizability of a bound system in relativistic quantum theory

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    For the electric polarizability of a bound system in relativistic quantum theory, there are two definitions that have appeared in the literature. They differ depending on whether or not the vacuum background is included in the system. A recent confusion in this connection is clarified

    Validity of Feynman's prescription of disregarding the Pauli principle in intermediate states

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    Regarding the Pauli principle in quantum field theory and in many-body quantum mechanics, Feynman advocated that Pauli's exclusion principle can be completely ignored in intermediate states of perturbation theory. He observed that all virtual processes (of the same order) that violate the Pauli principle cancel out. Feynman accordingly introduced a prescription, which is to disregard the Pauli principle in all intermediate processes. This ingeneous trick is of crucial importance in the Feynman diagram technique. We show, however, an example in which Feynman's prescription fails. This casts doubts on the general validity of Feynman's prescription
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