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Author |
Barenboim, G.; Fernandez-Martinez, E.; Mena, O.; Verde, L. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
The dark side of curvature |
Type |
Journal Article |
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Year |
2010 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
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Volume |
03 |
Issue |
3 |
Pages |
008 - 17pp |
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Keywords |
dark energy experiments; baryon acoustic oscillations; cosmological parameters from CMBR |
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Abstract |
Geometrical tests such as the combination of the Hubble parameter H(z) and the angular diameter distance d(A)(z) can, in principle, break the degeneracy between the dark energy equation of state parameter w(z), and the spatial curvature Omega(k) in a direct, model-independent way. In practice, constraints on these quantities achievable from realistic experiments, such as those to be provided by Baryon Acoustic Oscillation (BAO) galaxy surveys in combination with CMB data, can resolve the cosmic confusion between the dark energy equation of state parameter and curvature only statistically and within a parameterized model for w(z). Combining measurements of both H(z) and d(A)(z) up to sufficiently high redshifts z similar to 2 and employing a parameterization of the redshift evolution of the dark energy equation of state are the keys to resolve the w(z) – Omega(k) degeneracy. |
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Address |
[Barenboim, Gabriela] Univ Valencia, Dept Fis Teor, E-46100 Valencia, Spain, Email: Gabriela.Barenboim@uv.es |
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Publisher |
Iop Publishing Ltd |
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English |
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Series Volume |
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ISSN |
1475-7516 |
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Notes |
ISI:000276103000026 |
Approved |
no |
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Is ISI ![sorted by Is ISI field, ascending order (up)](img/sort_asc.gif) |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ elepoucu @ |
Serial |
465 |
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Permanent link to this record |
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Author |
Mena, O.; Razzaque, S.; Villaescusa-Navarro, F. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
Signatures of photon and axion-like particle mixing in the gamma-ray burst jet |
Type |
Journal Article |
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Year |
2011 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
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Volume |
02 |
Issue |
2 |
Pages |
030 - 16pp |
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Keywords |
axions; magnetic fields; gamma ray bursts theory; gamma ray burst experiments |
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Abstract |
Photons couple to Axion-Like Particles (ALPs) or more generally to any pseudo Nambu-Goldstone boson in the presence of an external electromagnetic field. Mixing between photons and ALPs in the strong magnetic field of a Gamma-Ray Burst (GRB) jet during the prompt emission phase can leave observable imprints on the gamma-ray polarization and spectrum. Mixing in the intergalactic medium is not expected to modify these signatures for ALP mass > 10(-14) eV and/or for < nG magnetic field. We show that the depletion of photons due to conversion to ALPs changes the linear degree of polarization from the values predicted by the synchrotron model of gamma ray emission. We also show that when the magnetic field orientation in the propagation region is perpendicular to the field orientation in the production region, the observed synchrotron spectrum becomes steeper than the theoretical prediction and as detected in a sizable fraction of GRB sample. Detection of the correlated polarization and spectral signatures from these steep-spectrum GRBs by gamma-ray polarimeters can be a very powerful probe to discover ALPs. Measurement of gamma-ray polarization from GRBs in general, with high statistics, can also be useful to search for ALPs. |
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Address |
[Mena, Olga; Villaescusa-Navarro, F.] Univ Valencia, CSIC, IFIC, E-46071 Valencia, Spain, Email: omena@ific.uv.es |
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Publisher |
Iop Publishing Ltd |
Place of Publication |
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English |
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ISSN |
1475-7516 |
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Notes |
ISI:000287859800031 |
Approved |
no |
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Is ISI ![sorted by Is ISI field, ascending order (up)](img/sort_asc.gif) |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
559 |
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Permanent link to this record |
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Author |
Bridges, M.; Cranmer, K.; Feroz, F.; Hobson, M.; Ruiz de Austri, R.; Trotta, R. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
A coverage study of the CMSSM based on ATLAS sensitivity using fast neural networks techniques |
Type |
Journal Article |
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Year |
2011 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
03 |
Issue |
3 |
Pages |
012 - 23pp |
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Keywords |
Supersymmetry; Phenomenology |
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Abstract |
We assess the coverage properties of confidence and credible intervals on the CMSSM parameter space inferred from a Bayesian posterior and the profile likelihood based on an ATLAS sensitivity study. In order to make those calculations feasible, we introduce a new method based on neural networks to approximate the mapping between CMSSM parameters and weak-scale particle masses. Our method reduces the computational effort needed to sample the CMSSM parameter space by a factor of similar to 10(4) with respect to conventional techniques. We find that both the Bayesian posterior and the profile likelihood intervals can significantly over-cover and identify the origin of this effect to physical boundaries in the parameter space. Finally, we point out that the effects intrinsic to the statistical procedure are conflated with simplifications to the likelihood functions from the experiments themselves. |
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Address |
[Bridges, Michael; Feroz, Farhan; Hobson, Mike] Univ Cambridge, Cavendish Lab, Astrophys Grp, Cambridge CB3 0HE, England, Email: mb435@mrao.cam.ac.uk |
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Publisher |
Springer |
Place of Publication |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1126-6708 |
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Conference |
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Notes |
ISI:000289295200012 |
Approved |
no |
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Is ISI ![sorted by Is ISI field, ascending order (up)](img/sort_asc.gif) |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
610 |
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Permanent link to this record |
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Author |
ANTARES Collaboration (Aguilar, J.A. et al); Bigongiari, C.; Dornic, D.; Emanuele, U.; Gomez-Gonzalez, J.P.; Hernandez-Rey, J.J.; Mangano, S.; Salesa, F.; Toscano, S.; Yepes, H.; Zornoza, J.D.; Zuñiga, J. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
Time calibration of the ANTARES neutrino telescope |
Type |
Journal Article |
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Year |
2011 |
Publication |
Astroparticle Physics |
Abbreviated Journal |
Astropart Phys. |
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Volume |
34 |
Issue |
7 |
Pages |
539-549 |
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Keywords |
Time calibration; Neutrino telescopes; ANTARES |
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Abstract |
The ANTARES deep-sea neutrino telescope comprises a three-dimensional array of photomultipliers to detect the Cherenkov light induced by upgoing relativistic charged particles originating from neutrino interactions in the vicinity of the detector. The large scattering length of light in the deep sea facilitates an angular resolution of a few tenths of a degree for neutrino energies exceeding 10 TeV. In order to achieve this optimal performance, the time calibration procedures should ensure a relative time calibration between the photomultipliers at the level of similar to 1 ns. The methods developed to attain this level of precision are described. |
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Address |
[Aguilar, J. A.; Bigongiari, C.; Dornic, D.; Emanuele, U.; Gomez-Gonzalez, J. P.; Hernandez-Rey, J. J.; Mangano, S.; Salesa, F.; Toscano, S.; Yepes, H.; Zornoza, J. D.; Zuniga, J.] Univ Valencia, CSIC, Inst Fis Corpuscular, IFIC, Valencia 46071, Spain, Email: zornoza@ific.uv.es |
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Corporate Author |
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Thesis |
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Publisher |
Elsevier Science Bv |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0927-6505 |
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Conference |
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Notes |
ISI:000287955500004 |
Approved |
no |
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Is ISI ![sorted by Is ISI field, ascending order (up)](img/sort_asc.gif) |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
560 |
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Permanent link to this record |
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Author |
Casas, J.A.; Moreno, J.M.; Rius, N.; Ruiz de Austri, R.; Zaldivar, B. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
Fair scans of the seesaw. Consequences for predictions on LFV processes |
Type |
Journal Article |
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Year |
2011 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
03 |
Issue |
3 |
Pages |
034 - 22pp |
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Keywords |
Neutrino Physics; Supersymmetric Standard Model |
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Abstract |
We give a straightforward procedure to scan the seesaw parameter-space, using the common “R-parametrization”, in a complete way. This includes a very simple rule to incorporate the perturbativity requirement as a condition for the entries of the R-matrix. As a relevant application, we show that the somewhat propagated belief that BR(mu -> e, gamma) in supersymmetric seesaw models depends strongly on the value of theta(13) is an “optical effect” produced by incomplete scans, and does not hold after a careful analytical and numerical study. When the complete scan is done, BR(mu -> e, gamma) gets very insensitive to theta(13). This holds even if the right-handed neutrino masses are kept constant or under control (as is required for succesful leptogenesis). In most cases the values of BR(mu -> e, gamma) are larger than the experimental upper bound. Including (unflavoured) leptogenesis does not introduce any further dependence on theta(13), although decreases the typical value of BR(mu -> e, gamma). |
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Address |
[Alberto Casas, J.; Moreno, Jesus M.; Zaldivar, Bryam] UAM, IFT UAM CSIC, Inst Fis Teor, Madrid 28049, Spain, Email: alberto.casas@uam.es |
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Corporate Author |
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Thesis |
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Publisher |
Springer |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1126-6708 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
ISI:000289295200034 |
Approved |
no |
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Is ISI ![sorted by Is ISI field, ascending order (up)](img/sort_asc.gif) |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
612 |
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Permanent link to this record |