119619533
Lepton flavour violation in unparticle physics
Abstract Recently H. Georgi has introduced an unparticle U in order to describe the low energy physics of a nontrivial scale invariant sector of an effective theory. In this work we have explored the phenomenology of an unparticle using the lepton flavour violating decay μ − → e − e + e − , and found that the branching ratio of this decay is strongly dependent on the scaling dimension.
40698564
Graviton emission from a higher-dimensional black hole
We discuss the graviton absorption probability (greybody factor) and the cross-section of a higher-dimensional Schwarzschild black hole (BH). We are motivated by the suggestion that a great many BHs may be produced at the LHC and bearing this fact in mind, for simplicity, we shall investigate the intermediate energy regime for a static Schwarzschild BH. That is, for (2M)1/(n?1)? ~ 1, where M is the mass of the black hole and ? is the energy of the emitted gravitons in (2+n)-dimensions. To find easily tractable solutions we work in the limit l >> 1, where l is the angular momentum quantum number of the graviton.
16133041
Neutrino lensing and modification of Newtonian gravity at large distances.
The nature of the modification to neutrino lensing from galaxies, as caused by possible modifications to Newtonian gravity at large distances, is studied.
16070485
Non-Abelian Monopole and Dyon Solutions in a Modified Einstein-Yang-Mills-Higgs System
We have studied a modied Yang-Mills-Higgs system coupled to Einstein gravity. The modication of the Einstein-Hilbert action involves a direct coupling of the Higgs eld to the scalar curvature. In this modied system we are able to write a Bogomol’nyi type condition in curved space and demonstrate that the positive static energy functional is bounded from below. We then investigate non-Abelian spherically symmetric static solutions in a similar fashion to the ’t Hooft-Polyakov monopole. After reviewing previously studied monopole solutions of this type, we extend the formalism to included electric charge and we present dyon solutions.
197479972
Signature of Randall-Sundrum Quantum Gravity model in $\gamma\gamma$ scattering in the TeV range
8914218
Rossby Wave Instability of Keplerian Accretion Disks
We find a linear instability of nonaxisymmetric Rossby waves in a thin nonmagnetized Keplerian disk when there is a local maximum in the radial profile of a key function (r)≡(r)S2/Γ(r), where −1=(∇×v)/Σ is the potential vorticity, S=P/ΣΓ is the entropy, Σ is the surface mass density, P is the vertically integrated pressure, and Γ is the adiabatic index. We consider in detail the special case where there is a local maximum in the disk entropy profile S(r). This maximum acts to trap the waves in its vicinity if its height-to-width ratio max(S)/Δr is larger than a threshold value. The pressure gradient derived from this entropy variation provides the restoring force for the wave growth. We show that the trapped waves act to transport angular momentum outward. A plausible way to produce an entropy variation is when an accretion disk is starting from negligible mass and temperature, therefore, negligible entropy. As mass accumulates by either tidal torquing, magnetic torquing, or Roche-lobe overflow, confinement of heat will lead to an entropy maximum at the outer boundary of the disk. Possible nonlinear developments from this instability include the formation of Rossby vortices and the formation of spiral shocks. What remains to be determined from hydrodynamic simulations is whether or not Rossby wave packets (or vortices) "hold together" as they propagate radially inward.