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Author |
Capozziello, S.; Harko, T.; Koivisto, T.S.; Lobo, F.S.N.; Olmo, G.J. |
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Title |
Cosmology of hybrid metric-Palatini f(X)-gravity |
Type |
Journal Article |
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Year |
2013 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
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Volume |
04 |
Issue |
4 |
Pages |
011 - 25pp |
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Keywords |
modified gravity; dark energy theory |
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Abstract |
A new class of modified theories of gravity, consisting of the superposition of the metric Einstein-Hilbert Lagrangian with an f(R) term constructed a la Palatini was proposed recently. The dynamically equivalent scalar-tensor representation of the model was also formulated, and it was shown that even if the scalar field is very light, the theory passes the Solar System observational constraints. Therefore the model predicts the existence of a long-range scalar field, modifying the cosmological and galactic dynamics. An explicit model that passes the local tests and leads to cosmic acceleration was also obtained. In the present work, it is shown that the theory can be also formulated in terms of the quantity X equivalent to kappa T-2 + R, where T and R are the traces of the stress-energy and Ricci tensors, respectively. The variable X represents the deviation with respect to the field equation trace of general relativity. The cosmological applications of this hybrid metric-Palatini gravitational theory are also explored, and cosmological solutions coming from the scalar-tensor representation of f(X)-gravity are presented. Criteria to obtain cosmic acceleration are discussed and the field equations are analyzed as a dynamical system. Several classes of dynamical cosmological solutions, depending on the functional form of the effective scalar field potential, describing both accelerating and decelerating Universes are explicitly obtained. Furthermore, the cosmological perturbation equations are derived and applied to uncover the nature of the propagating scalar degree of freedom and the signatures these models predict in the large-scale structure. |
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Address  |
Univ Naples Federico II, Dipartimento Fis, Naples, Italy, Email: capozzie@na.infn.it; |
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Corporate Author |
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Publisher |
Iop Publishing Ltd |
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 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 |
1475-7516 |
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 |
WOS:000318556200011 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1444 |
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Author |
Volpe, C.; Vaananen, D.; Espinoza, C. |
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Title |
Extended evolution equations for neutrino propagation in astrophysical and cosmological environments |
Type |
Journal Article |
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Year |
2013 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
87 |
Issue |
11 |
Pages |
113010 - 17pp |
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Keywords |
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Abstract |
We derive the evolution equations for a system of neutrinos interacting among themselves and with a matter background, based upon the Bogoliubov-Born-Green-Kirkwood-Yvon hierarchy. This theoretical framework gives an (unclosed) set of first-order coupled integro-differential equations governing the evolution of the reduced density matrices. By employing the hierarchy, we first rederive the mean-field evolution equations for the neutrino one-body density matrix associated with a system of neutrinos and antineutrinos interacting with matter and with an anisotropic neutrino background. Then, we derive extended evolution equations to determine neutrino flavor conversion beyond the commonly used mean-field approximation. To this aim we include neutrino-antineutrino pairing correlations to the two-body density matrix. The inclusion of these new contributions leads to an extended evolution equation for the normal neutrino density and to an equation for the abnormal one involving the pairing mean field. We discuss the possible impact of neutrino-antineutrino correlations on neutrino flavor conversion in the astrophysical and cosmological environments, and possibly upon the supernova dynamics. Our results can be easily generalized to an arbitrary number of neutrino families. |
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Address |
Univ Paris 07, AstroParticule & Cosmol APC, CNRS, F-75205 Paris 13, France, Email: volpe@apc.univ-paris7.fr; |
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Corporate Author |
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Thesis |
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Publisher |
Amer Physical Soc |
Place of Publication |
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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 |
1550-7998 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000320951500001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1478 |
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Author |
Robert, C.; Dedes, G.; Battistoni, G.; Bohlen, T.T.; Buvat, I.; Cerutti, F.; Chin, M.P.W.; Ferrari, A.; Gueth, P.; Kurz, C.; Lestand, L.; Mairani, A.; Montarou, G.; Nicolini, R.; Ortega, P.G.; Parodi, K.; Prezado, Y.; Sala, P.R.; Sarrut, D.; Testa, E. |
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Title |
Distributions of secondary particles in proton and carbon-ion therapy: a comparison between GATE/Geant4 and FLUKA Monte Carlo codes |
Type |
Journal Article |
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Year |
2013 |
Publication |
Physics in Medicine and Biology |
Abbreviated Journal |
Phys. Med. Biol. |
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Volume |
58 |
Issue |
9 |
Pages |
2879-2899 |
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Keywords |
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Abstract |
Monte Carlo simulations play a crucial role for in-vivo treatment monitoring based on PET and prompt gamma imaging in proton and carbon-ion therapies. The accuracy of the nuclear fragmentation models implemented in these codes might affect the quality of the treatment verification. In this paper, we investigate the nuclear models implemented in GATE/Geant4 and FLUKA by comparing the angular and energy distributions of secondary particles exiting a homogeneous target of PMMA. Comparison results were restricted to fragmentation of O-16 and C-12. Despite the very simple target and set-up, substantial discrepancies were observed between the two codes. For instance, the number of high energy (>1 MeV) prompt gammas exiting the target was about twice as large with GATE/Geant4 than with FLUKA both for proton and carbon ion beams. Such differences were not observed for the predicted annihilation photon production yields, for which ratios of 1.09 and 1.20 were obtained between GATE and FLUKA for the proton beam and the carbon ion beam, respectively. For neutrons and protons, discrepancies from 14% (exiting protons-carbon ion beam) to 57% (exiting neutrons-proton beam) have been identified in production yields as well as in the energy spectra for neutrons. |
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Address |
Univ Paris 07, IMNC, CNRS, UMR 8165, F-91406 Orsay, France, Email: robert@imnc.in2p3.fr |
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Corporate Author |
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Thesis |
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Publisher |
Iop Publishing Ltd |
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 |
0031-9155 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000317579900010 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1407 |
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Author |
ANTARES Collaboration (Adrian-Martinez, S. et al); Bigongiari, C.; Emanuele, U.; Gomez-Gonzalez, J.P.; Hernandez-Rey, J.J.; Lambard, G.; Mangano, S.; Ruiz-Rivas, J.; Salesa, F.; Sanchez-Losa, A.; Yepes, H.; Zornoza, J.D.; Zuñiga, J. |
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Title |
First search for neutrinos in correlation with gamma-ray bursts with the ANTARES neutrino telescope |
Type |
Journal Article |
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Year |
2013 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
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Volume |
03 |
Issue |
3 |
Pages |
006 - 16pp |
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Keywords |
neutrino experiments; neutrino astronomy; gamma ray bursts theory |
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Abstract |
A search for neutrino-induced muons in correlation with a selection of 40 gamma-ray bursts that occurred in 2007 has been performed with the ANTARES neutrino telescope. During that period, the detector consisted of 5 detection lines. The ANTARES neutrino telescope is sensitive to TeV-PeV neutrinos that are predicted from gamma-ray bursts. No events were found in correlation with the prompt photon emission of the gamma-ray bursts and upper limits have been placed on the flux and fluence of neutrinos for different models. |
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Address |
Univ Politecn Valencia, Inst Invest Gestio Integrada Zones Costaneres IGI, Gandia 46730, Spain, Email: mieke.bouwhuis@nikhef.nl |
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Corporate Author |
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Thesis |
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Publisher |
Iop Publishing Ltd |
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 |
1475-7516 |
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 |
WOS:000316989200007 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1433 |
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Author |
Manera, M.; Scoccimarro, R.; Percival, W.J.; Samushia, L.; McBride, C.K.; Ross, A.J.; Sheth, R.K.; White, M.; Reid, B.A.; Sanchez, A.G.; de Putter, R.; Xu, X.Y.; Berlind, A.A.; Brinkmann, J.; Maraston, C.; Nichol, B.; Montesano, F.; Padmanabhan, N.; Skibba, R.A.; Tojeiro, R.; Weaver, B.A. |
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Title |
The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: a large sample of mock galaxy catalogues |
Type |
Journal Article |
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Year |
2013 |
Publication |
Monthly Notices of the Royal Astronomical Society |
Abbreviated Journal |
Mon. Not. Roy. Astron. Soc. |
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Volume |
428 |
Issue |
2 |
Pages |
1036-1054 |
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Keywords |
galaxies: haloes; large-scale structure of Universe |
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Abstract |
We present a fast method for producing mock galaxy catalogues that can be used to compute the covariance of large-scale clustering measurements and test analysis techniques. Our method populates a second-order Lagrangian perturbation theory (2LPT) matter field, where we calibrate masses of dark matter haloes by detailed comparisons with N-body simulations. We demonstrate that the clustering of haloes is recovered at similar to 10 per cent accuracy. We populate haloes with mock galaxies using a halo occupation distribution (HOD) prescription, which has been calibrated to reproduce the clustering measurements on scales between 30 and 80 h(-1) Mpc. We compare the sample covariance matrix from our mocks with analytic estimates, and discuss differences. We have used this method to make catalogues corresponding to Data Release 9 of the Baryon Oscillation Spectroscopic Survey (BOSS), producing 600 mock catalogues of the 'CMASS' galaxy sample. These mocks have enabled detailed tests of methods and errors, and have formed an integral part of companion analyses of these galaxy data. |
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Address |
Univ Portsmouth, Inst Cosmol & Gravitat, Portsmouth PO1 3FX, Hants, England, Email: marc.manera@port.ac.uk |
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Corporate Author |
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Thesis |
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Publisher |
Oxford Univ Press |
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 |
0035-8711 |
ISBN |
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Conference |
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Notes |
WOS:000318229000007 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1471 |
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