How Magnetic is the Neutrino?

The existence of a neutrino magnetic moment implies contributions to the neutrino mass via radiative corrections. We derive model-independent "naturalness" upper bounds on the magnetic moments of Dirac and Majorana neutrinos, generated by physics above the electroweak scale. For Dirac neutrinos, the bound is several orders of magnitude more stringent than present experimental limits. However, for Majorana neutrinos the magnetic moment bounds are weaker than present experimental limits if $\mu_\nu$ is generated by new physics at ~ 1 TeV, and surpass current experimental sensitivity only for new physics scales > 10 -- 100 TeV. The discovery of a neutrino magnetic moment near present limits would thus signify that neutrinos are Majorana particles.Comment: 9 pages, 6 figures. Talk given at Festschrift in honour of B. H. J McKellar and G. C. Josh

A regional perspective on the "Great Moderation"

The Great Moderation impacted job growth across nearly all regions over a fairly short period of time.Recessions ; Economic conditions - United States ; Economic conditions - Texas

The 'Great Moderation' in output and employment volatility: an update

The reduced aggregate volatility that began in 1984 has continued into the new millennium.

Capture of Leptophilic Dark Matter in Neutron Stars

Dark matter particles will be captured in neutron stars if they undergo scattering interactions with nucleons or leptons. These collisions transfer the dark matter kinetic energy to the star, resulting in appreciable heating that is potentially observable by forthcoming infrared telescopes. While previous work considered scattering only on nucleons, neutron stars contain small abundances of other particle species, including electrons and muons. We perform a detailed analysis of the neutron star kinetic heating constraints on leptophilic dark matter. We also estimate the size of loop induced couplings to quarks, arising from the exchange of photons and Z bosons. Despite having relatively small lepton abundances, we find that an observation of an old, cold, neutron star would provide very strong limits on dark matter interactions with leptons, with the greatest reach arising from scattering off muons. The projected sensitivity is orders of magnitude more powerful than current dark matter-electron scattering bounds from terrestrial direct detection experiments.Comment: 26 pages, 8 figures, 3 tables, 2 appendices. Discussion extended, references added, matches JCAP published versio