arXiv subjects

S. T. Love

Publications and source records attributed to S. T. Love.

At least 37 records · Page 2Linked to original sources

arXiv2005

Nonlinear realization of local symmetries of AdS space

Coset methods are used to construct the action describing the dynamics associated with the spontaneous breaking of the local symmetries of AdS_{d+1} space due to the embedding of an AdS_d brane. The resulting action is an SO(2,d) invariant AdS form of the Einstein-Hilbert action, which in addition to the AdS_d gravitational vielbein, also includes a massive vector field localized on the brane. Its long wavelength dynamics is the same as a massive Abelian vector field coupled to gravity in AdS_d space.

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arXiv2005

AdS_{d+1} --> AdS_d

Coset methods are used to construct the action describing the dynamics of the (massive) Nambu-Goldstone scalar degree of freedom associated with the spontaneous breaking of the isometry group of AdS_{d+1} space to that of an AdS_d subspace. The resulting action is an SO(2,d) invariant AdS generalization of the Nambu-Goto action. The vector field theory equivalent action is also determined.

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arXiv2004

Nonlinear Realization of Supersymmetry and Superconformal Symmetry

Nonlinear realizations describing the spontaneous breakown of supersymmetry and R symmetry are constructed using the Goldstino and R axion fields. The associated R current, supersymmetry current and energy-momentum tensor are shown to be related under the nonlinear supersymmetry transformations. Nonlinear realizations of the superconformal algebra carried by these degrees of freedom are also displayed. The divergences of the R and dilatation currents are related to the divergence of the superconformal currents through nonlinear supersymmetry transformations which in turn relates the explicit breakings of these symmetries.

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arXiv2003

Muonium-Antimuonium oscillations and massive Majorana neutrinos

The electron and muon number violating muonium-antimuonium oscillation process can proceed provided neutrinos have non-zero masses and mix among the various generations. Modifying the Standard Model only by the inclusion of singlet right handed neutrino fields and allowing for general neutrino masses and mixings, the leading order matrix element contributing to this process is computed. For the particularly interesting case where the neutrino masses are generated by a see-saw mechanism with a very large Majorana mass $M_R>>M_W$, it is found that both the very light and very heavy Majorana neutrinos each give comparable contributions to the oscillation time scale proportional to $M_R^2$. Present experimental limits set by the non-observation of the oscillation process sets a lower limit on $M_R$ of roughly of order $10^4$ GeV.

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arXiv2003

Gauging internal fermionic symmetries and spin 3/2 fields

Field theoretic models possessing a global internal fermionic shift symmetry are considered. When such a symmetry is realized locally, spin 3/2 fields appear naturally as gauge fields. Implementation of the gauging procedure requires not only the usual replacement of ordinary derivatives by covariant derivatives containing the spin 3/2 fields, but also the inclusion of additional monomials. The Higgs mechanism and the high energy Nambu-Goldstone fermion equivalence theorem are explicitly demonstrated.

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arXiv2001

Nonrelativistic spin 1/2 particle in an arbitrary non-Abelian magnetic field in two spatial dimensions

The (group and spin space) matrix Hamiltonian describing the dynamics of a nonrelativistic spin 1/2 particle moving in a static, but spatially dependent, non-Abelian magnetic field in two spatial dimensions is shown to take the form of an anticommutator of a nilpotent operator and its hermitian conjugate. Consequently, the (group space) matrix Hamiltonians for the two different spin projections form partners of a supersymmetric quantum mechanical system. The resulting supersymmetry algebra is exploited to explicitly construct the exact zero energy ground state wavefunction(s) for the system. The remaining eigenstates and eigenvalues of the two partner Hamiltonians form positive energy degenerate pairs.

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arXiv2001

The supercharge and superconformal symmetry for N=1 supersymmetric quantum mechanics

The superspace Lagrangian formulation of N=1 supersymmetric quantum mechanics is presented. The general Lagrangian constructed out of chiral and antichiral supercoordinates containing up to two derivatives and with a canonically normalized kinetic energy term describes the motion of a nonrelativistic spin 1/2 particle with Landé g-factor 2 moving in two spatial dimensions under the influence of a static but spatially dependent magnetic field. Noether's theorem is derived for the general case and is used to construct superspace dependent charges whose lowest components give the superconformal generators. The supercoordinate of charges containing an R symmetry charge, the supersymmetry charges and the Hamiltonian are combined to form a supercharge supercoordinate. Superconformal Ward identities for the quantum effective action are derived from the conservation equations and the source of potential symmetry breaking terms are identified.

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arXiv2001

The Akulov-Volkov Lagrangian, Symmetry Currents and Spontaneously Broken Extended Supersymmetry

A generalization of the Akulov-Volkov effective Lagrangian governing the self interactions of the Nambu-Goldstone fermions associated with spontaneously broken extended supersymmetry as well as their coupling to matter is presented and scrutinized. The resulting currents associated with R-symmetry, supersymmetry and space-time translations are constructed and seen to form a supermultiplet structure.

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arXiv2000

Charged spin 1/2 particle in an arbitrary magnetic field in two spatial dimensions: a supersymmetric quantum mechanical system

It is shown that the 2 X 2 matrix Hamiltonian describing the dynamics of a charged spin 1/2 particle with g-factor 2 moving in an arbitrary, spatially dependent, magnetic field in two spatial dimensions can be written as the anticommuator of a nilpotent operator and its hermitian conjugate. Consequently, the Hamiltonians for the two different spin projections form partners of a supersymmetric quantum mechanical system. The resulting supersymmetry algebra can then be exploited to explicitly construct the exact zero energy ground state wavefunction for the system. Modulo this ground state, the remainder of the eigenstates and eigenvalues of the two partner Hamiltonians form positive energy degenerate pairs. We also construct the spatially asymptotic form of the magnetic field which produces a finite magnetic flux and associated zero energy normalizable ground state wavefunction.

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arXiv2000

The Effective Potential And Additional Large Radius Compactified Space-Time Dimensions

The consequences of large radius extra space-time compactified dimensions on the four dimensional one loop effective potential are investigated for a model which includes scalar self interactions and Yukawa coupling to fermions. The Kaluza-Klein tower of states associated with the extra compact dimensions shifts the location of the effective potential minimum and modifies its curvature. The dependence of these effects on the radius of the extra dimension is illustrated for various choices of coupling constants and masses. For large radii, the consequence of twisting the fermion boundary condition on the compactified dimensions is numerically found to produce but a negligible effect on the effective potential.

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arXiv1999

Twisted Boundary Conditions and Matching to the Effective Four Dimensional Theory

Nontrivial twisted boundary conditions associated with extra compact dimensions produce an ambiguity in the value of the four dimensional coupling constants of the renormalizable interactions of the twisted fields' zero modes. Resolving this indeterminancy would require a knowledge of the exact form of the higher dimensional action including the coefficients of higher dimensional operators. For the case of moderately sized extra dimensions, the uncertainty in the coupling constants can be of order one and may lead to modifications in the stability of the model.

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arXiv1999

Incompatibility of simultaneous non-linear realizations of scale symmetry and supersymmetry

Simultaneous nonlinear realizations of supersymmetry and softly broken scale and chiral symmetries are investigated. To guarantee Nambu-Goldstone realizations of the symmetries, the Goldstino decay constant is forced to vary as the explicit soft scale and chiral symmetry breaking parameters. Consequently, it must vanish in the chiral limit and the simultaneous nonlinear realizations of the super and scale symmetries proves inconsistent.

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arXiv1999

The Effective Kähler Potential And Extra Space-Time Dimensions

The effects of extra space-time dimensions on the Wilsonian effective Kähler potential and the perturbative one loop effective Kähler potential are determined within the framework of an Abelian gauge theory with N=2 supersymmetric field content. The relation between the Kähler metric and the effective gauge couplings which leads to the absence of radiative corrections to the Kähler potential is expressed as a function of the radius of compactification of a fifth dimension. In general, the quantum corrections to the low energy Kähler potential are shown to grow with this radius reflecting the underlying higher dimensional nature of the theory.

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arXiv1997

On the Interactions of Light Gravitinos

In models of spontaneously broken supersymmetry, certain light gravitino processes are governed by the coupling of its Goldstino components. The rules for constructing SUSY and gauge invariant actions involving the Goldstino couplings to matter and gauge fields are presented. The explicit operator construction is found to be at variance with some previously reported claims. A phenomenological consequence arising from light gravitino interactions in supernova is reexamined and scrutinized.

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arXiv1997

The Wilson Effective Kähler Potential For Supersymmetric Nonlinear Sigma Models

Renormalization group methods are used to determine the evolution of the low energy Wilson effective action for supersymmetric nonlinear sigma models in four dimensions. For the case of supersymmetric $CP^{(N-1)}$ models, the Kähler potential is determined exactly and is shown to exhibit a nontrivial ultraviolet fixed point in addition to a trivial infrared fixed point. The strong coupling behavior of the theory suggests the possible existence of additional relevant operators or nonperturbative degrees of freedom.

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arXiv1996

On the Holomorphic Structure of a Low Energy Supersymmetric Wilson Effective Action

The Wilson (exact) renormalization group equations are used to determine the evolution of a general low energy N=1 supersymmetric action containing a U(1) gauge vector multiplet and a neutral chiral multiplet. The effective theory evolves towards satisfying a fixed relation where the Kähler potential and effective gauge coupling are obtained from a N=2 supersymmetric holomorphic prepotential.

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arXiv1996

Goldstino Couplings to Matter

A nonlinearly realized supersymmetric action describing the invariant couplings of the Goldstino to matter is constructed. Using the Akulov-Volkov Lagrangian, any operator can be made part of a supersymmetric invariant action. Of particular interest are interaction terms which include the product of the Akulov-Volkov Lagrangian with the ordinary matter Lagrangian as well as the coupling of the product of the covariant derivative of the Goldstino field to the matter supersymmetry current. The later is the lowest dimensional operator linear in the Goldstino field. A Goldstino Goldberger-Treiman relation is established and shown to be satisfied by the effective action.

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arXiv1995

The Supercurrent In Supersymmetric Field Theories

A supercurrent superfield whose components include a conserved energy-momentum tensor and supersymmetry current as well as a (generally broken) R-symmetry current is constructed for a generic effective N=1 supersymmetric gauge theory. The general form of the R-symmetry breaking is isolated. Included within the various special cases considered is the identification of those models which exhibit an unbroken R-symmetry. One such example corresponds to a non-linearly realized gauge symmetry where the chiral field R-weight is required to vanish.

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