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Full-Text Articles in Physical Sciences and Mathematics
Supersymmetry And Stationary Solutions In Dilaton-Axion Gravity, R Kallosh, David Kastor, T Ortín, T Torma
Supersymmetry And Stationary Solutions In Dilaton-Axion Gravity, R Kallosh, David Kastor, T Ortín, T Torma
Physics Department Faculty Publication Series
New stationary solutions of four-dimensional dilaton-axion gravity are presented, which correspond to the charged Taub-NUT and Israel-Wilson-Perjés (IWP) solutions of Einstein-Maxwell theory. The charged axion-dilaton Taub-NUT solutions are shown to have a number of interesting properties: (i) manifest SL(2,R) symmetry; (ii) an infinite throat in an extremal limit; (iii) the throat limit coincides with an exact CFT construction. The IWP solutions are shown to admit supersymmetric Killing spinors, when embedded in d=4,N=4 supergravity. This poses a problem for the interpretation of supersymmetric rotating solutions as physical ground states. In the context of 10-dimensional geometry, we show that dimensionally lifted versions …
Supersymmetric Self-Gravitating Solitons, G Gibbons, David Kastor, L London, P Townsend, Jennie Traschen
Supersymmetric Self-Gravitating Solitons, G Gibbons, David Kastor, L London, P Townsend, Jennie Traschen
Physics Department Faculty Publication Series
We show that the “instantonic” soliton of five-dimensional Yang-Mills theory and the closely related BPS monopole of four-dimensional Yang-Mills/Higgs theory continue to be exact static, and stable, solutions of these field theories even after the inclusion of gravitational, electromagnetic and, in the four-dimensional case, dilatonic interactions, provided that certain non-minimal interactions are included. With the inclusion of these interactions, which would be required by supersymmetry, these exact self-gravitating solitons saturate a gravitational version of the Bogomol'nyi bound on the energy of an arbitrary field configuration.
Pair Creation Of Dilaton Black Holes, F Dowker, J Gauntlett, David Kastor, Jennie Traschen
Pair Creation Of Dilaton Black Holes, F Dowker, J Gauntlett, David Kastor, Jennie Traschen
Physics Department Faculty Publication Series
We consider dilaton gravity theories in four spacetime dimensions parametrized by a constant a, which controls the dilaton coupling, and construct new exact solutions. We first generalize the C metric of Einstein-Maxwell theory (a=0) to solutions corresponding to oppositely charged dilaton black holes undergoing uniform acceleration for general a. We next develop a solution-generating technique which allows us to ‘‘embed’’ the dilaton C metrics in magnetic dilaton Melvin backgrounds, thus generalizing the Ernst metric of Einstein-Maxwell theory. By adjusting the parameters appropriately, it is possible to eliminate the nodal singularities of the dilaton C metrics. For a<1 (but not for a≥1), it is possible to further restrict the parameters so that the dilaton Ernst solutions have a smooth Euclidean section with topology S2×S2-{pt}, corresponding to instantons describing the pair production of dilaton black holes in a magnetic field. A different restriction on the parameters leads to smooth instantons for all values of a with topology S2×openR2.
The Reactions Gamma-Gamma-]Wl(+)Wl(-) And Gamma-Gamma-]Z(L)Z(L) In Su(N) Strongly Interacting Theories, Jf Donoghue, T Torma
The Reactions Gamma-Gamma-]Wl(+)Wl(-) And Gamma-Gamma-]Z(L)Z(L) In Su(N) Strongly Interacting Theories, Jf Donoghue, T Torma
Physics Department Faculty Publication Series
In theories in which the parameters of the low energy theory are not unique, perhaps having different values in different domains of the universe as is possible in some inflationary models, the fermion masses would be distributed with respect to some weight. In such a situation the specifics of the fermion masses do not have a unique explanation, yet the weight provides the visible remnant of the structure of the underlying theory. This paper introduces this concept of a weight for the distribution of masses and provides a quantitative estimate of it from the observed quarks and leptons. The weight …
Light Quark Masses And Mixing Angles, John Donoghue
Light Quark Masses And Mixing Angles, John Donoghue
Physics Department Faculty Publication Series
I review the present state of our knowledge about the masses and weak mixing elements of the u, d, s quarks. This is the written version of lectures given in the 1993 Theoretical Advanced Study Institute (TASI).
Dispersion-Relations And The Nucleon Polarizability, Br Holstein, Am Nathan
Dispersion-Relations And The Nucleon Polarizability, Br Holstein, Am Nathan
Physics Department Faculty Publication Series
Recent experimental results on the proton and neutron polarizabilities are examined from the point of view of backward dispersion relations. Results are found to be in reasonable agreement with the measured values. A rigorous relationship between the nucleon and pion polarizabilities is derived and shown to be in excellent agreement with several models.
Leading Quantum Correction To The Newtonian Potential, Jf Donoghue
Leading Quantum Correction To The Newtonian Potential, Jf Donoghue
Physics Department Faculty Publication Series
I argue that the leading quantum corrections, in powers of the energy or inverse powers of the distance, may be computed in quantum gravity through knowledge of only the low-energy structure of the theory. As an example, I calculate the leading quantum corrections to the Newtonian gravitational potential.
General-Relativity As An Effective-Field Theory - The Leading Quantum Corrections, Jf Donoghue
General-Relativity As An Effective-Field Theory - The Leading Quantum Corrections, Jf Donoghue
Physics Department Faculty Publication Series
I describe the treatment of gravity as a quantum effective field theory. This allows a natural separation of the (known) low energy quantum effects from the (unknown) high energy contributions. Within this framework, gravity is a well behaved quantum field theory at ordinary energies. In studying the class of quantum corrections at low energy, the dominant effects at large distance can be isolated, as these are due to the propagation of the massless particles (including gravitons) of the theory and are manifested in the nonlocal/nonanalytic contributions to vertex functions and propagators. These leading quantum corrections are parameter-free and represent necessary …
Chiral Sum-Rules And Their Phenomenology, Jf Donoghue, Eugene Golowich
Chiral Sum-Rules And Their Phenomenology, Jf Donoghue, Eugene Golowich
Physics Department Faculty Publication Series
We present an analysis of four sum rules, each based on chiral symmetry and containing the difference ρV(s) − ρA(s) of isovector vector and axialvector spectral functions. Experimental data from tau lepton decay and electron-positron scattering identify the spectral functions over a limited kinematic domain. We summarize the status of the existing database. However, a successful determination of the sum rules requires additional content, in the form of theoretical input. We show how chiral symmetry and the operator product expansion can be used to constrain the spectral functions in the low energy and the high energy limits and proceed to …
Symmetry-Tests And Standard Model Backgrounds, Br Holstein
Symmetry-Tests And Standard Model Backgrounds, Br Holstein
Physics Department Faculty Publication Series
No abstract provided.
K(S)-]Gamma-Gamma, K(L)-]Pi(0)Gamma-Gamma And Unitarity, J Kambor, Br Holstein
K(S)-]Gamma-Gamma, K(L)-]Pi(0)Gamma-Gamma And Unitarity, J Kambor, Br Holstein
Physics Department Faculty Publication Series
Agreement between the experimental value Γ(KS→γγ) and the number predicted via a one-loop chiral perturbation theory calculation has been cited as a success for the latter. On the other hand the one-loop prediction for the closely related process KL→π0γγ has been found to be a factor 3 below the experimental value. Using the inputs of unitarity and dispersion relations, we demonstrate the importance of higher order loop effects to both of these processes.
Testing Cosmic Censorship With Black Hole Collisions, D Brill, G Horowitz, David Kastor, Jennie Traschen
Testing Cosmic Censorship With Black Hole Collisions, D Brill, G Horowitz, David Kastor, Jennie Traschen
Physics Department Faculty Publication Series
There exists an upper limit on the mass of black holes when the cosmological constant Λ is positive. We study the collision of two black holes whose total mass exceeds this limit. Our investigation is based on a recently discovered exact solution describing the collision of Q=M black holes with Λ>0. The global structure of this solution is analyzed. We find that if the total mass is less than the extremal limit, then the black holes coalesce. If it is greater, then a naked singularity forms to the future of a Cauchy horizon. However, the horizon is not smooth. …