Dark photon searches with atomic transitions

Dark matter could be made up of dark photons, massive but very light particles whose interactions with matter resemble those of usual photons but suppressed by a small mixing parameter. We analyze the main approaches to dark photon interactions and how they can be applied to direct detection experiments which test different ranges of masses and mixings. A new experiment based on counting dark photons from induced atomic transitions in a target material is proposed. This approach appears to be particularly appropriate for dark photon detection in the meV mass range, extending the constraints in the mixing parameter by up to eight orders of magnitude with respect to previous experiments.Comment: 16 pages, 3 figure

Renormalized masses of heavy Kaluza-Klein states

Several ways of computing the radiative corrections to the heavy boson masses in Kaluza-Klein theory are discussed. It is argued that only an intrinsically higher dimensional approach embodies all the desired physical properties.Comment: LaTeX, 22 pages. Fully rewritten and streamlined. Five and six dimensional cases treated separatelly. References adde

Sphenopteris asturica nueva especie

Se describe un ejemplar (holotipo) de la Cuenca de Tineo (Asturias) que se atribuye a una nueva especie del género Sphenopteris caracterizada por sus raquis acanalados que portan pínulas de contorno triangular alargado de bordes lobulados, con nervio central neto y sinuoso decurrente sobre el raquis que emite nervios secundarios de forma pecopterideana. Presenta esta especie semejanzas con Sph. burgkensis Sterzel (= Sph. leptophylla Bunb.) y con Sph. goniopteroides Lesqu.Se figura también un ejemplar de Commentry (Francia) así como dos pequeños fragmentos de Puerto Ventana. Todos los ejemplares figurados así como otro citado procedente de Surroca (Gerona) proceden de niveles estefanienses

Contribution a la connaissance de la flore carbonifère des pyrénñees basques (Larroun et Ibantelly)

In this work we descrive fossil plants collected in Piri- neos mountains. Here are classified 33 species of which thirteen lias been stated in the coaldfield for first time. The coaldfield is dated as the upper Stephanian B or as the low Stepha- nian C