Related papers: Galactic Positrons as a Probe of Large Extra Dimen…
In extra dimension theories, where the gauge bosons of the standard model propagate in the bulk of the extra dimensions, there are Kaluza-Klein excitations of the standard model gauge bosons that can couple to the standard model fermions.…
Recent highly sensitive detections of line emission from extended gas in the local universe demonstrate the feasibility of detecting H$\alpha$ emitting galactic halos out to $z\sim1$. We determine the form of the surface brightness vs.…
In the universal extra dimensions models, Kaluza Klein excitations of matter are generaly produced in pairs. However, if matter lives on a fat brane embedded in a larger space, gravity-matter interactions do not obey KK number conservation,…
It is shown that Eddington-like accretion event in the Galactic center several million years ago and particle acceleration at accompanying shocks and jets could explain the observed cosmic ray spectrum at energies above 1 PeV. Cosmic ray…
We discuss phenomenology of extra time dimensions in a scenario where the standard model particles are localized in ``our'' time, whereas gravity can propagate in all time dimensions. For an odd number of extra times, at small distances,…
We discuss an exotic class of Kaluza-Klein models in which the internal space is neither compact nor even of finite volume. Rather than using the usual compact internal space we consider the case where particles are gravitationally trapped…
We consider the production of gravitational KK modes via cosmological photon-photon and electron-positron annihilation in models with large factorisable extra dimensions. We place constraints on this production using recent results from a…
A search for large extra spatial dimensions via virtual-graviton exchange in the diphoton channel has been carried out with the CMS detector at the LHC. No excess of events above the standard model expectations is found using a data sample…
Over the last three years, several satellite and balloon observatories have suggested intriguing features in the cosmic ray lepton spectra. Most notably, the PAMELA satellite has suggested an "anomalous" rise with energy of the cosmic ray…
The high degeneracy of KK modes in models which have bulk axions moving in some extra, compact dimensions which are larger than O (Angstrom)strongly tightens the supernova upper bounds on the axion photon coupling making axions practically…
Using a new instrument, the HEAT collaboration has confirmed the excess of cosmic ray positrons that they first detected in 1994. We explore the possibility that this excess is due to the annihilation of neutralino dark matter in the…
It is pointed out in a class of models with large extra dimensions that the cross section of processes with virtual Kaluza-Klein graviton exchanges becomes either much smaller or much larger by many orders of magnitude than what is expected…
If extra spacetime dimensions and low-scale gravity exist, black holes will be produced in observable collisions of elementary particles. For the next several years, ultra-high energy cosmic rays provide the most promising window on this…
Gravitational scattering in the ADD-model is studied and it is argued that no cut-off is needed for the exchange of virtual Kaluza--Klein modes. By introduction of a small coordinate in the extra dimensions a unique form of the…
We show that the positron excess measured by the PAMELA experiment in the region between 10 and 100 GeV may well be a natural consequence of the standard scenario for the origin of Galactic cosmic rays. The 'excess' arises because of…
We review recently developed models of galactic discrete sources of high energy neutrinos. Some of them are based on a simple rescaling of the TeV $\gamma$-ray fluxes from recently detected galactic sources, such as, shell-type supernova…
We study the inverse Compton scattering of solar photons by Galactic cosmic-ray electrons. We show that the gamma-ray emission from this process is substantial with the maximum flux in the direction of the Sun; the angular distribution of…
We present an overview of some of the issues surrounding current models of galaxy formation, highlighting recent insights obtained from cosmological hydrodynamic simulations. Detailed examination of gas accretion processes show a hot mode…
We report calculations of cosmic-ray proton, nuclei, antiproton, electron and positron energy spectra within a "two-halo model" of diffusive transport. The two halos represent a simple, physically consistent generalization of the standard…
The recent observations of microlensing events in the LMC by the MACHO and EROS collaborations suggest that an important fraction of the galactic halo is in the form of Massive Halo Objects (MHO) of about 0.1 M_{\odot}. Here, we argue that…