Tibor Torma

Supersymmetry and stationary solutions in dilaton-axion gravity

New stationary solutions of four-dimensional dilaton-axion gravity are presented, which correspond to the charged Taub-NUT and Israel-Wilson-Perjes (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,[ital 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 [ital d]=4,[ital 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 of the IWP solutions are dual to certain gravitational waves in string theory.

Infrared Behavior of Graviton-graviton Scattering

The quantum effective theory of general relativity, independent of the eventual full theory at high energy, expresses graviton-graviton scattering at one loop order O E 4 � with only one parameter, Newton’s constant. Dunbar and Norridge have calculated the one loop amplitude using string based techniques. We complete the calculation by showing that the 1 d 4 divergence which remains in their result comes from the infrared sector and that the cross section is finite and model independent when the usual bremsstrahlung diagrams are included.

Power counting of loop diagrams in general relativity

A class of loop diagrams in general relativity appears to have a behavior which would upset the utility of the energy expansion for quantum effects. We show through the study of specific diagrams that cancellations occur which restore the expected behaviour of the energy expansion. By considering the power counting in a physical gauge we show that the apparent bad behavior is a gauge artifact, and that the quantum loops enter with a well behaved energy expansion.

Charmonium production at neutrino factories

At existing and planned neutrino factories (high energy and high intensity neutrino beam facilities) precision studies of QCD in neutrino-nucleon interactions are a realistic opportunity. We investigate charmonium production in fixed target neutrino experiments. We find that

The reactions γγ → WL+WL− and γγ → ZLZL in SU(N) strongly interacting theories

J/\psi

A systematic analysis of new physics effects in spin correlations in qbar q→ tbar t

production in neutrino-nucleon collision is dominated by the color octet

New physics intt¯spin correlations at the Fermilab Tevatron

^3S_1

Symmetry breaking via fermion 4-point functions

NRQCD matrix element in a neutral current process, which is not accessible in photo or leptoproduction. Neutrino experiments at a future Muon Collider will acquire sufficient event rate to accurately measure color octet matrix element contributions. The currently running high energy neutrino experiments, NOMAD and NuTeV could also observe several such events.

Intersecting branes and the cosmological constant

Abstract Building on recent phenomenology of γγ → ππ , we discuss the expectation for two-photon production of longitudinal gauge boson pairs in SU ( N ) technicolor theories. The treatment involves a matching of dispersive techniques with the methodology of chiral perturbation theory.

New axial interactions at 1 TeV

I show that there are eight new physics operators that contribute to top pair production and subsequent decay in interference with the leading SM process at the Tevatron and estimate their expected statistical inaccuracies. All fully differential cross sections are calculated in the 6-particle phase space. The observation of angular correlations dramatically improves the accuracy of the extraction.