28,468 research outputs found
Axions at the International Axion Observatory
QCD axions with meV mass can be behind some stellar cooling anomalies and
form all or part of the cold dark matter of the universe. We discuss on a
proposed experiment to discover the solar flux of meV mass axions: the
International AXion Observatory: IAXO.Comment: 6 pages, 4 figures, Contributed to the 11th Patras Workshop on
Axions, WIMPs and WISPs, Zaragoza, June 22 to 26, 201
The Sun in Hidden Photons
We present some aspects and first results of the emission of sub-eV mass
hidden photons from the Sun. The contribution from a resonant region below the
photosphere can be quite significant, raising previous estimates. This is
relevant for the Telescope for Hidden Photon Search, TSHIPS I, currently
targeting at meV-mass hidden photons with O(10^-6) kinetic mixing with the
photon. These particles could account for the large effective number of
neutrinos pointed at by the cosmic microwave background and other large-scale
structure probes, and are motivated in some scenarios of string theory.Comment: 4 pages, 4 figures. Contribution to the 7th Patras Workshop on
Axions, WIMPs and WISPs, 27 June - 1 July 2011, Mykonos, Greec
Atlas of solar hidden photon emission
Hidden photons, gauge bosons of a U(1) symmetry of a hidden sector, can
constitute the dark matter of the universe and a smoking gun for large volume
compactifications of string theory. In the sub-eV mass range, a possible
discovery experiment consists on searching the copious flux of these particles
emitted from the Sun in a helioscope setup \`a la Sikivie. In this paper, we
compute the flux of transversely polarised HPs from the Sun, a necessary
ingredient for interpreting such experiments. We provide a detailed exposition
of photon-HP oscillations in inhomogenous media, with special focus on
resonance oscillations, which play a leading role in many cases. The region of
the Sun emitting HPs resonantly is a thin spherical shell for which we justify
an averaged-emission formula and which implies a distinctive morphology of the
angular distribution of HPs on Earth in many cases. Low mass HPs with energies
in the visible and IR have resonances very close to the photosphere where the
solar plasma is not fully ionised and requires building a detailed model of
solar refraction and absorption. We present results for a broad range of HP
masses (from 0-1 keV) and energies (from the IR to the X-ray range), the most
complete atlas of solar HP emission to date.Comment: 45 pages, 18 figure
Book review: L'allevamento ecologico del coniglio (Organic rabbit farming)
González-Redondo, P. (2011). Book review: L'allevamento ecologico del coniglio (Organic rabbit farming). World Rabbit Science. 19(3). doi:10.4995/wrs.2011.869.SWORD19
Hochschild cohomology via incidence algebras
Given an algebra A we associate an incidence algebra A(\Sigma) and compare
their Hochschild cohomology groups.Comment: 16 pages, Section 3.2 deleted, Section 4 adde
Axion results: what is new?
The PVLAS collaboration has obtained results that may be interpreted in terms
of a light axion-like particle, while the CAST collaboration has not found any
signal of such particles. Moreover, the PVLAS results are in gross
contradiction with astrophysical bounds. We develop a particle physics model
with two paraphotons and with a low energy scale in which these apparent
inconsistencies are circumvented.Comment: 10 pages, 4 figures. Based on two talks given at the International
Workshop "The dark side of the Universe", Madrid, June 2006: "Evading
astrophysical bounds on axion-like particles in paraphoton models" by J.
Redondo and "Axion results: what is new?" by E. Masso. To be published in the
Proceeding
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