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Author Mena, O.; Razzaque, S. url  doi
openurl 
  Title Hints of an axion-like particle mixing in the GeV gamma-ray blazar data? Type Journal Article
  Year 2013 Publication Journal of Cosmology and Astroparticle Physics Abbreviated Journal J. Cosmol. Astropart. Phys.  
  Volume 11 Issue 11 Pages 023 - 12pp  
  Keywords axions; active galactic nuclei  
  Abstract Axion-Like Particles (ALPs), if exist in nature, are expected to mix with photons in the presence of an external magnetic field. The energy range of photons which undergo strong mixing with ALPs depends on the ALP mass, on its coupling with photons as well as on the external magnetic field and particle density configurations. Recent observations of blazars by the Fermi Gamma-Ray Space Telescope in the 0.1-300 GeV energy range show a break in their spectra in the 1-10 GeV range. We have modeled this spectral feature for the flat-spectrum radio quasar 3C454.3 during its November 2010 outburst, assuming that a significant fraction of the gamma rays convert to ALPs in the large scale jet of this blazar. Using theoretically motivated models for the magnetic field and particle density con figurations in the kiloparsec scale jet, outside the broad-line region, we find an ALP mass m(a) similar to (1 – 3).10(-7) eV and coupling g(a gamma) similar to (1 – 3).10(-10) GeV-1 after performing an illustrative statistical analysis of spectral data in four different epochs of emission. The precise values of m(a) and g(a gamma) depend weakly on the assumed particle density con figuration and are consistent with the current experimental bounds on these quantities. We apply this method and ALP parameters found from fitting 3C454.3 data to another flat-spectrum radio quasar PKS1222+216 (4C+21.35) data up to 400 GeV, as a consistency check, and found good fit. We find that the ALP-photon mixing effect on the GeV spectra may not be washed out for any reasonable estimate of the magnetic field in the intergalactic media.  
  Address [Mena, Olga] Univ Valencia, CSIC, IFIC, E-46071 Valencia, Spain, Email: omena@ific.uv.es;  
  Corporate Author Thesis  
  Publisher Iop Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title (up)  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1475-7516 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000327843900024 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 1673  
Permanent link to this record
 

 
Author Diamanti, R.; Lopez-Honorez, L.; Mena, O.; Palomares-Ruiz, S.; Vincent, A.C. url  doi
openurl 
  Title Constraining dark matter late-time energy injection: decays and p-wave annihilations Type Journal Article
  Year 2014 Publication Journal of Cosmology and Astroparticle Physics Abbreviated Journal J. Cosmol. Astropart. Phys.  
  Volume 02 Issue 2 Pages 017 - 24pp  
  Keywords dark matter theory; CMBR theory  
  Abstract We use the latest cosmic microwave background (CMB) observations to provide updated constraints on the dark matter lifetime as well as on p-wave suppressed annihilation cross sections in the 1 MeV to 1 TeV mass range. In contrast to scenarios with an s-wave dominated annihilation cross section, which mainly affect the CMB close to the last scattering surface, signatures associated with these scenarios essentially appear at low redshifts (z less than or similar to 50) when structure began to form, and thus manifest at lower multipoles in the CMB power spectrum. We use data from Planck, WMAP9, SPT and ACT, as well as Lyman-alpha measurements of the matter temperature at z similar to 4 to set a 95% confidence level lower bound on the dark matter lifetime of similar to 4 x 10(25) s for m(chi) = 100 MeV. This bound becomes lower by an order of magnitude at m(chi) = 1 TeV due to inefficient energy deposition into the inter-galactic medium. We also show that structure formation can enhance the effect of p-wave suppressed annihilation cross sections by many orders of magnitude with respect to the background cosmological rate, although even with this enhancement, CMB constraints are not yet strong enough to reach the thermal relic value of the cross section.  
  Address [Diamanti, Roberta; Mena, Olga; Palomares-Ruiz, Sergio; Vincent, Aaron C.] Univ Valencia, CSIC, Inst Fis Corpuscular IFIC, E-46071 Valencia, Spain, Email: R.Diamanti@uva.nl;  
  Corporate Author Thesis  
  Publisher Iop Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title (up)  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1475-7516 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000332711400017 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 1732  
Permanent link to this record
 

 
Author Anderson, L. et al; Mena, O. url  doi
openurl 
  Title The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: measuring D-A and H at z=0.57 from the baryon acoustic peak in the Data Release 9 spectroscopic Galaxy sample Type Journal Article
  Year 2014 Publication Monthly Notices of the Royal Astronomical Society Abbreviated Journal Mon. Not. Roy. Astron. Soc.  
  Volume 439 Issue 1 Pages 83-101  
  Keywords cosmological parameters; cosmology: observations; dark energy; distance scale; large scale structure of Universe  
  Abstract We present measurements of the angular diameter distance to and Hubble parameter at z = 0.57 from the measurement of the baryon acoustic peak in the correlation of galaxies from the Sloan Digital Sky Survey III Baryon Oscillation Spectroscopic Survey. Our analysis is based on a sample from Data Release 9 of 264 283 galaxies over 3275 square degrees in the redshift range 0.43 < z < 0.70. We use two different methods to provide robust measurement of the acoustic peak position across and along the line of sight in order to measure the cosmological distance scale. We find D-A(0.57) = 1408 +/- 45 Mpc and H(0.57) = 92.9 +/- 7.8 km s(-1) Mpc(-1) for our fiducial value of the sound horizon. These results from the anisotropic fitting are fully consistent with the analysis of the spherically averaged acoustic peak position presented in Anderson et al. Our distance measurements are a close match to the predictions of the standard cosmological model featuring a cosmological constant and zero spatial curvature.  
  Address [Anderson, Lauren] Univ Washington, Dept Astron, Seattle, WA 98195 USA, Email: djschlegel@lbl.gov  
  Corporate Author Thesis  
  Publisher Oxford Univ Press Place of Publication Editor  
  Language English Summary Language Original Title (up)  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0035-8711 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000333297700026 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 1738  
Permanent link to this record
 

 
Author Adey, D. et al; Cervera-Villanueva, A.; Donini, A.; Ghosh, T.; Gomez-Cadenas, J.J.; Hernandez, P.; Izmaylov, A.; Laing, A.; Mena, O.; Sorel, M.; Stamoulis, P. url  doi
openurl 
  Title Light sterile neutrino sensitivity at the nuSTORM facility Type Journal Article
  Year 2014 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 89 Issue 7 Pages 071301 - 7pp  
  Keywords  
  Abstract A facility that can deliver beams of electron and muon neutrinos from the decay of a stored muon beam has the potential to unambiguously resolve the issue of the evidence for light sterile neutrinos that arises in short-baseline neutrino oscillation experiments and from estimates of the effective number of neutrino flavors from fits to cosmological data. In this paper, we show that the nuSTORM facility, with stored muons of 3.8 GeV/c +/- 10%, will be able to carry out a conclusive muon neutrino appearance search for sterile neutrinos and test the LSND and MiniBooNE experimental signals with 10 sigma sensitivity, even assuming conservative estimates for the systematic uncertainties. This experiment would add greatly to our knowledge of the contribution of light sterile neutrinos to the number of effective neutrino flavors from the abundance of primordial helium production and from constraints on neutrino energy density from the cosmic microwave background. The appearance search is complemented by a simultaneous muon neutrino disappearance analysis that will facilitate tests of various sterile neutrino models.  
  Address [Adey, D.; Brice, S. J.; Bross, A. D.; Cease, H.; Geelhoed, M.; Kobilarcik, T.; Liu, A.; Mokhov, N.; Morfin, J.; Neuffer, D.; Palmer, M. A.; Parke, S.; Plunkett, R.; Popovic, M.; Rubinov, P.; Sen, T.; Snopok, P.; Striganov, S.] Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA, Email: Ryan.Bayes@glasgow.ac.uk  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title (up)  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1550-7998 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000334317200002 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 1753  
Permanent link to this record
 

 
Author Anderson, L. et al; Mena, O. url  doi
openurl 
  Title The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: baryon acoustic oscillations in the Data Releases 10 and 11 Galaxy samples Type Journal Article
  Year 2014 Publication Monthly Notices of the Royal Astronomical Society Abbreviated Journal Mon. Not. Roy. Astron. Soc.  
  Volume 441 Issue 1 Pages 24-62  
  Keywords cosmological parameters; cosmology: observations; dark energy; distance scale; large-scale structure of Universe  
  Abstract We present a one per cent measurement of the cosmic distance scale from the detections of the baryon acoustic oscillations (BAO) in the clustering of galaxies from the Baryon Oscillation Spectroscopic Survey, which is part of the Sloan Digital Sky Survey III. Our results come from the Data Release 11 (DR11) sample, containing nearly one million galaxies and covering approximately 8500 square degrees and the redshift range 0.2 < z < 0.7. We also compare these results with those from the publicly released DR9 and DR10 samples. Assuming a concordance A cold dark matter (ACDM) cosmological model, the DR11 sample covers a volume of 13 Gpc(3) and is the largest region of the Universe ever surveyed at this density. We measure the correlation function and power spectrum, including density- field reconstruction of the BAO feature. The acoustic features are detected at a significance of over 7s in both the correlation function and power spectrum. Fitting for the position of the acoustic features measures the distance relative to the sound horizon at the drag epoch, r(d), which has a value of r(d,fid) = 149.28 Mpc in our fiducial cosmology. We find D-V = (1264 +/- 25 Mpc)(r(d)/r(d,fid)) at z = 0.32 and D-V = (2056 +/- 20 Mpc)(r(d)/r(d,fid)) at z = 0.57. At 1.0 per cent, this latter measure is the most precise distance constraint ever obtained from a galaxy survey. Separating the clustering along and transverse to the line of sight yields measurements at z = 0.57 of D-A = (1421 +/- 20 Mpc)(r(d)/r(d,fid)) and H = (96.8 +/- 3.4 kms(-1) Mpc(-1))(r(d),(fid)/r(d)). Our measurements of the distance scale are in good agreement with previous BAO measurements and with the predictions from cosmic microwave background data for a spatially flat CDM model with a cosmological constant.  
  Address [Anderson, Lauren; Bhardwaj, Vaishali] Univ Washington, Dept Astron, Seattle, WA 98195 USA, Email: djschlegel@lbl.gov;  
  Corporate Author Thesis  
  Publisher Oxford Univ Press Place of Publication Editor  
  Language English Summary Language Original Title (up)  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0035-8711 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000336249300002 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 1791  
Permanent link to this record
 

 
Author Di Valentino, E.; Giusarma, E.; Lattanzi, M.; Melchiorri, A.; Mena, O. url  doi
openurl 
  Title Axion cold dark matter: Status after Planck and BICEP2 Type Journal Article
  Year 2014 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 90 Issue 4 Pages 043534 - 11pp  
  Keywords  
  Abstract We investigate the axion dark matter scenario (ADM), in which axions account for all of the dark matter in the Universe, in light of the most recent cosmological data. In particular, we use the Planck temperature data, complemented by WMAP E-polarization measurements, as well as the recent BICEP2 observations of B-modes. Baryon acoustic oscillation data, including those from the baryon oscillation spectroscopic survey, are also considered in the numerical analyses. We find that, in the minimal ADM scenario and for Delta(QCD) = 200 MeV, the full data set implies that the axion mass m(a) = 82.2 +/- 1.1 μeV [corresponding to the Peccei-Quinn symmetry being broken at a scale f(a) = (7.54 +/- 0.10) x 10(10) GeV], or m(a) = 76.6 +/- 2.6 μeV [f(a) = (8.08 +/- 0.27) x 10(10) GeV] when we allow for a nonstandard effective number of relativistic species N-eff. We also find a 2 sigma preference for N-eff > 3.046. The limit on the sum of neutrino masses is Sigma m(v) < 0.25 eV at 95% C.L. for N-eff = 3.046, or Sigma m(v) < 0.47 eV when N-eff is a free parameter. Considering extended scenarios where either the dark energy equation-of-state parameter w, the tensor spectral index n(t), or the running of the scalar index dn(s)/d ln k is allowed to vary does not change significantly the axion mass-energy density constraints. However, in the case of the full data set exploited here, there is a preference for a nonzero tensor index or scalar running, driven by the different tensor amplitudes implied by the Planck and BICEP2 observations. We also study the effect on our estimates of theoretical uncertainties, in particular the imprecise knowledge of the QCD scale Delta(QCD), in the calculation of the temperature-dependent axion mass. We find that in the simplest ADM scenario the Planck + WP data set implies that the axion mass m(a) = 63.7 +/- 1.2 μeV for Delta(QCD) = 400 MeV. We also comment on the possibility that axions do not make up for all the dark matter, or that the contribution of string-produced axions has been grossly underestimated; in that case, the values that we find for the mass can conservatively be considered as lower limits. Dark matter axions with mass in the 60-80 μeV (corresponding to an axion-photon coupling G(a gamma gamma) similar to 10(-14) GeV-1) range can, in principle, be detected by looking for axion-to-photon conversion occurring inside a tunable microwave cavity permeated by a high-intensity magnetic field, and operating at a frequency nu similar or equal to 15-20 GHz. This is out of the reach of current experiments like the axion dark matter experiment (limited to a maximum frequency of a few GHzs), but is, on the other hand, within the reach of the upcoming axion dark matter experiment-high frequency experiment that will explore the 4-40 GHz frequency range and then be sensitive to axion masses up to similar to 160 μeV.  
  Address [Di Valentino, Eleonora; Giusarma, Elena; Melchiorri, Alessandro] Univ Roma La Sapienza, Dept Phys, I-00185 Rome, Italy  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title (up)  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1550-7998 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000340890100001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 1893  
Permanent link to this record
 

 
Author Mena, O.; Palomares-Ruiz, S.; Vincent, A.C. url  doi
openurl 
  Title Flavor Composition of the High-Energy Neutrino Events in IceCube Type Journal Article
  Year 2014 Publication Physical Review Letters Abbreviated Journal Phys. Rev. Lett.  
  Volume 113 Issue 9 Pages 091103 - 5pp  
  Keywords  
  Abstract The IceCube experiment has recently reported the observation of 28 high-energy (> 30 TeV) neutrino events, separated into 21 showers and 7 muon tracks, consistent with an extraterrestrial origin. In this Letter, we compute the compatibility of such an observation with possible combinations of neutrino flavors with relative proportion (alpha(e:)alpha(mu):alpha tau)(circle plus). Although the 7: 21 track-to-shower ratio is naively favored for the canonical (1:1:1)(circle plus) at Earth, this is not true once the atmospheric muon and neutrino backgrounds are properly accounted for. We find that, for an astrophysical neutrino E-2 energy spectrum, (1:1:1)(circle plus). at Earth is disfavored at 81% C. L. If this proportion does not change, 6 more years of data would be needed to exclude (1:1:1)(circle plus) at Earth at 3 sigma C.L. Indeed, with the recently released 3-yr data, that flavor composition is excluded at 92% C. L. The best fit is obtained for (1:0:0)(circle plus). at Earth, which cannot be achieved from any flavor ratio at sources with averaged oscillations during propagation. If confirmed, this result would suggest either a misunderstanding of the expected background events or a misidentification of tracks as showers, or even more compellingly, some exotic physics which deviates from the standard scenario.  
  Address [Mena, Olga; Palomares-Ruiz, Sergio; Vincent, Aaron C.] Univ Valencia, CSIC, Inst Fis Corpuscular IFIC, E-46071 Valencia, Spain, Email: omena@ific.uv.es;  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title (up)  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0031-9007 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000341292800005 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 1920  
Permanent link to this record
 

 
Author Barranco, L.; Boubekeur, L.; Mena, O. url  doi
openurl 
  Title Model-independent fit to Planck and BICEP2 data Type Journal Article
  Year 2014 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 90 Issue 6 Pages 063007 - 7pp  
  Keywords  
  Abstract Inflation is the leading theory to describe elegantly the initial conditions that led to structure formation in our Universe. In this paper, we present a novel phenomenological fit to the Planck, WMAP polarization (WP) and the BICEP2 data sets using an alternative parametrization. Instead of starting from inflationary potentials and computing the inflationary observables, we use a phenomenological parametrization due to Mukhanov, describing inflation by an effective equation of state, in terms of the number of e-folds and two phenomenological parameters alpha and beta. Within such a parametrization, which captures the different inflationary models in a model-independent way, the values of the scalar spectral index n(s), its running and the tensor-to-scalar ratio r are predicted, given a set of parameters (alpha, beta). We perform a Markov Chain Monte Carlo analysis of these parameters, and we show that the combined analysis of Planck and WP data favors the Starobinsky and Higgs inflation scenarios. Assuming that the BICEP2 signal is not entirely due to foregrounds, the addition of this last data set prefers instead the phi(2) chaotic models. The constraint we get from Planck and WP data alone on the derived tensor-to-scalar ratio is r < 0.18 at 95% C.L., value which is consistent with the one quoted from the BICEP2 Collaboration analysis, r = 0.16(-0.05)(+0-06), after foreground subtraction. This is not necessarily at odds with the 2 sigma tension found between Planck and BICEP2 measurements when analyzing data in terms of the usual n(s) and r parameters, given that the parametrization used here, for the preferred value n(s) similar or equal to 0.96, allows only for a restricted parameter space in the usual (n(s), r) plane.  
  Address [Barranco, Laura; Boubekeur, Lotfi; Mena, Olga] Univ Valencia, CSIC, Inst Fis Corpuscular, E-46071 Valencia, Spain  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title (up)  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1550-7998 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000342128700002 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 1933  
Permanent link to this record
 

 
Author Boubekeur, L.; Giusarma, E.; Mena, O.; Ramirez, H. url  doi
openurl 
  Title Current status of modified gravity Type Journal Article
  Year 2014 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 90 Issue 10 Pages 103512 - 10pp  
  Keywords  
  Abstract We revisit the cosmological viability of the Hu-Sawicki modified gravity scenario. The impact of such a modification on the different cosmological observables, including gravitational waves, is carefully described. The most recent cosmological data, as well as constraints on the relationship between the clustering parameter sigma(8) and the current matter mass-energy density Omega(m) from cluster number counts and weak lensing tomography, are considered in our numerical calculations. The strongest bound we find is vertical bar f(R0)vertical bar < 3.7 x 10(-6) at 95% C.L. Forthcoming cluster surveys covering 10 000 deg(2) in the sky, with galaxy surface densities of O(10) arcmin(-2) could improve the precision in the sigma(8)-Omega(m) relationship, tightening the above constraint.  
  Address [Boubekeur, Lotfi; Mena, Olga; Ramirez, Hector] Univ Valencia, CSIC, Inst Fis Corpuscular IFIC, E-46071 Valencia, Spain  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title (up)  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1550-7998 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000345534500005 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 2017  
Permanent link to this record
 

 
Author Archidiacono, M.; Lopez-Honorez, L.; Mena, O. url  doi
openurl 
  Title Current constraints on early and stressed dark energy models and future 21 cm perspectives Type Journal Article
  Year 2014 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 90 Issue 12 Pages 123016 - 10pp  
  Keywords  
  Abstract Despite the great progress of current cosmological measurements, the nature of the dominant component of the Universe, coined dark energy, is still an open question. Early dark energy is a possible candidate which may also alleviate some fine-tuning issues of the standard paradigm. Using the latest available cosmological data, we find that the 95% C.L. upper bound on the early dark energy density parameter is Tau(eDE) < 0.009. On the other hand, the dark energy component may be a stressed and inhomogeneous fluid. If this is the case, the effective sound speed and the viscosity parameters are unconstrained by current data. Future omniscopelike 21 cm surveys, combined with present cosmic microwave background data, could be able to distinguish between standard quintessence scenarios from other possible models with 2 sigma significance, assuming a non-negligible early dark energy contribution. The precision achieved on the Omega(eDE) parameter from these 21 cm probes could be below O(10%).  
  Address [Archidiacono, Maria] Aarhus Univ, Dept Phys & Astron, DK-8000 Aarhus C, Denmark  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title (up)  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1550-7998 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000347194400007 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 2066  
Permanent link to this record
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