What would it take to determine the neutrino mass hierarchy if θ13\theta_{13} were too small?

We discuss the experimental requirements for a mass hierarchy measurement for $\theta_{13}=0$ using muon neutrino disappearance. We find that a specially optimized neutrino factory at $L \simeq 6 \,000 \, \mathrm{km}$ could do this measurement using extreme luminosities. In particular, we do not require charge identification for this purpose. In order to measure the mass hierarchy for more adequate luminosities, we explore the capabilities of low energy narrow band off-axis beams, which have relatively more events at low energies. We find that, in this case, the energy resolution of the detector quickly becomes the limiting factor of the measurement, and significantly affects the baseline optimization for determining the mass hierarchy.Comment: 22 pages, 10 color figure

A Singlet Extension of the MSSM with a Dark Matter Portal

The minimal extension of the MSSM (NMSSM) has been widely studied in the search for a natural solution to the $\mu$ problem. In this work, we consider a variation of the NMSSM where an extra singlet is added and a Peccei-Quinn symmetry is imposed. We study its neutralino sector and compute the annihilation cross section of the lightest neutralino. We use existent cosmological and collider data to constrain the parameter space and consider the lightest neutralino, which is very light, as a dark matter candidate.Comment: 26 pages, 8 figures . v4: minor corrections; version accepted for publicatio

The Distribution of Stellar Orbits in the Giant Elliptical Galaxy NGC 2320

We present direct observational constraints on the orbital distribution of the stars in the giant elliptical NGC 2320. Long-slit spectra along multiple position angles are used to derive the stellar line-of-sight velocity distribution within one effective radius. In addition, the rotation curve and dispersion profile of an ionized gas disk are measured from the [OIII] emission lines. After correcting for the asymmetric drift, we derive the circular velocity of the gas, which provides an independent constraint on the gravitational potential. To interpret the stellar motions, we build axisymmetric three-integral dynamical models based on an extension of the Schwarzschild orbit- superposition technique. We consider two families of gravitational potential, one in which the mass follows the light (i.e. no dark matter) and one with a logarithmic gravitational potential. Using chi^2-statistics, we compare our models to both the stellar and gas data to constrain the value of the V-band mass-to-light ratio Upsilon-V. We find Upsilon-V = 15.0 \pm 0.6 h75 for the mass-follows-light models and Upsilon-V = 17.0 \pm 0.7 h75 for the logarithmic models. For the latter, Upsilon-V is defined within a sphere of 15'' radius. Models with radially constant Upsilon-V and logarithmic models with dark matter provide comparably good fits to the data and possess similar dynamical structure. Across the full range of Upsilon-V permitted by the observational constraints, the models are radially anisotropic in the equatorial plane over the radial range of our kinematical data (1'' < r < 40''). Along the true minor axis, they are more nearly isotropic. (abridged)Comment: 26 pages, 13 figures, accepted for publication in the Astrophysical Journa