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Author Gariazzo, S.; Martinez-Mirave, P.; Mena, O.; Pastor, S.; Tortola, M. url  doi
openurl 
  Title Non-unitary three-neutrino mixing in the early Universe Type Journal Article
  Year 2023 Publication Journal of Cosmology and Astroparticle Physics Abbreviated Journal J. Cosmol. Astropart. Phys.  
  Volume 03 Issue 3 Pages 046 - 18pp  
  Keywords cosmological neutrinos; neutrino properties; neutrino theory  
  Abstract Deviations from unitarity in the three-neutrino mixing canonical picture are expected in many physics scenarios beyond the Standard Model. The mixing of new heavy neutral leptons with the three light neutrinos would in principle modify the strength and flavour structure of charged-current and neutral-current interactions with matter. Non-unitarity effects would therefore have an impact on the neutrino decoupling processes in the early Universe and on the value of the effective number of neutrinos, Neff. We calculate the cosmological energy density in the form of radiation with a non-unitary neutrino mixing matrix, addressing the possible interplay between parameters. Highly accurate measurements of Neff from forthcoming cosmological observations can provide independent and complementary limits on the departures from unitarity. For completeness, we relate the scenario of small deviations from unitarity to non-standard neutrino interactions and compare the forecasted constraints to other existing limits in the literature.  
  Address [Gariazzo, Stefano] INFN, Sez Torino, Via P Giuria 1, I-10125 Turin, Italy, Email: gariazzo@to.infn.it;  
  Corporate Author Thesis  
  Publisher IOP Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (up) 1475-7516 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000959757500008 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5516  
Permanent link to this record
 

 
Author Pierre Auger Collaboration (Abreu, P. et al); Pastor, S. url  doi
openurl 
  Title Search for ultrahigh energy neutrinos in highly inclined events at the Pierre Auger Observatory Type Journal Article
  Year 2011 Publication Physical Review D Abbreviated Journal  
  Volume 84 Issue 12 Pages 122005  
  Keywords  
  Abstract The Surface Detector of the Pierre Auger Observatory is sensitive to neutrinos of all flavors above 0.1 EeV. These interact through charged and neutral currents in the atmosphere giving rise to extensive air showers. When interacting deeply in the atmosphere at nearly horizontal incidence, neutrinos can be distinguished from regular hadronic cosmic rays by the broad time structure of their shower signals in the water-Cherenkov detectors. In this paper we present for the first time an analysis based on down-going neutrinos. We describe the search procedure, the possible sources of background, the method to compute the exposure and the associated systematic uncertainties. No candidate neutrinos have been found in data collected from 1 January 2004 to 31 May 2010. Assuming an E(-2) differential energy spectrum the limit on the single-flavor neutrino is E(2)dN/dE < 1.74 x 10(-7)GeVcm(-2)s(-1)sr(-1) at 90% C.L. in the energy range 1 x 10(17) eV < E < 1 x 10(20)eV.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (up) 1550-7998 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000298667100001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ elepoucu @ Serial 863  
Permanent link to this record
 

 
Author Castorina, E.; Franca, U.; Lattanzi, M.; Lesgourgues, J.; Mangano, G.; Melchiorri, A.; Pastor, S. url  doi
openurl 
  Title Cosmological lepton asymmetry with a nonzero mixing angle theta(13) Type Journal Article
  Year 2012 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 86 Issue 2 Pages 023517 - 11pp  
  Keywords  
  Abstract While the baryon asymmetry of the Universe is nowadays well measured by cosmological observations, the bounds on the lepton asymmetry in the form of neutrinos are still significantly weaker. We place limits on the relic neutrino asymmetries using some of the latest cosmological data, taking into account the effect of flavor oscillations. We present our results for two different values of the neutrino mixing angle theta(13), and show that for large theta(13) the limits on the total neutrino asymmetry become more stringent, diluting even large initial flavor asymmetries. In particular, we find that the present bounds are still dominated by the limits coming from big bang nucleosynthesis, while the limits on the total neutrino mass from cosmological data are essentially independent of theta(13). Finally, we perform a forecast for Cosmic Origins Explorer, taken as an example of a future cosmic microwave background experiment, and find that it could improve the limits on the total lepton asymmetry approximately by up to a factor 6.6.  
  Address [Castorina, Emanuele] SISSA, I-34136 Trieste, Italy  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (up) 1550-7998 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000306320000003 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 1093  
Permanent link to this record
 

 
Author Franca, U.; Lineros, R.A.; Palacio, J.; Pastor, S. url  doi
openurl 
  Title Probing interactions within the dark matter sector via extra radiation contributions Type Journal Article
  Year 2013 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 87 Issue 12 Pages 123521 - 6pp  
  Keywords  
  Abstract The nature of dark matter is one of the most thrilling riddles for both cosmology and particle physics nowadays. While in the typical models the dark sector is composed only by weakly interacting massive particles, an arguably more natural scenario would include a whole set of gauge interactions which are invisible for the standard model but that are in contact with the dark matter. We present a method to constrain the number of massless gauge bosons and other relativistic particles that might be present in the dark sector using current and future cosmic microwave background data, and provide upper bounds on the size of the dark sector. We use the fact that the dark matter abundance depends on the strength of the interactions with both sectors, which allows one to relate the freeze-out temperature of the dark matter with the temperature of this cosmic background of dark gauge bosons. This relation can then be used to calculate how sizable is the impact of the relativistic dark sector in the number of degrees of freedom of the early Universe, providing an interesting and testable connection between cosmological data and direct/indirect detection experiments. The recent Planck data, in combination with other cosmic microwave background experiments and baryonic acoustic oscillations data, constrains the number of relativistic dark gauge bosons, when the freeze-out temperature of the dark matter is larger than the top mass, to be N less than or similar to 14 for the simplest scenarios, while those limits are slightly relaxed for the combination with the Hubble constant measurements to N less than or similar to 20. Future releases of Planck data are expected to reduce the uncertainty by approximately a factor of 3, which will reduce significantly the parameter space of allowed models.  
  Address [Franca, Urbano; Lineros, Roberto A.; Palacio, Joaquim; Pastor, Sergio] Univ Valencia, CSIC, Inst Fis Corpuscular, Valencia 46071, Spain  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (up) 1550-7998 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000320765300005 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 1487  
Permanent link to this record
 

 
Author Pierre Auger Collaboration (Aab, A. et al); Pastor, S. url  doi
openurl 
  Title Probing the radio emission from air showers with polarization measurements Type Journal Article
  Year 2014 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 89 Issue 5 Pages 052002 - 18pp  
  Keywords  
  Abstract The emission of radio waves from air showers has been attributed to the so-called geomagnetic emission process. At frequencies around 50 MHz this process leads to coherent radiation which can be observed with rather simple setups. The direction of the electric field induced by this emission process depends only on the local magnetic field vector and on the incoming direction of the air shower. We report on measurements of the electric field vector where, in addition to this geomagnetic component, another component has been observed that cannot be described by the geomagnetic emission process. The data provide strong evidence that the other electric field component is polarized radially with respect to the shower axis, in agreement with predictions made by Askaryan who described radio emission from particle showers due to a negative charge excess in the front of the shower. Our results are compared to calculations which include the radiation mechanism induced by this charge-excess process.  
  Address [Aab, A.; Buchholz, P.; Foerster, N.; Froehlich, U.; Homola, P.; Niechciol, M.; Pontz, M.; Risse, M.; Settimo, M.; Ziolkowski, M.] Univ Siegen, D-57068 Siegen, Germany  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (up) 1550-7998 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000333105200001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 1739  
Permanent link to this record
 

 
Author Pierre Auger Collaboration (Aab, A. et al); Pastor, S. url  doi
openurl 
  Title Muons in air showers at the Pierre Auger Observatory: Measurement of atmospheric production depth Type Journal Article
  Year 2014 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 90 Issue 1 Pages 012012 - 15pp  
  Keywords  
  Abstract The surface detector array of the Pierre Auger Observatory provides information about the longitudinal development of the muonic component of extensive air showers. Using the timing information from the flash analog-to-digital converter traces of surface detectors far from the shower core, it is possible to reconstruct a muon production depth distribution. We characterize the goodness of this reconstruction for zenith angles around 60 degrees and different energies of the primary particle. From these distributions, we define X-max(mu) as the depth along the shower axis where the production of muons reaches maximum. We explore the potentiality of X-max(mu) as a useful observable to infer the mass composition of ultrahigh-energy cosmic rays. Likewise, we assess its ability to constrain hadronic interaction models.  
  Address [Aab, A.; Buchholz, P.; Erfani, M.; Froehlich, U.; Heimann, P.; Homola, P.; Niechciol, M.; Ochilo, L.; Risse, M.; Yushkov, A.; Ziolkowski, M.] Univ Siegen, D-57068 Siegen, Germany  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (up) 1550-7998 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000339922100001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 1866  
Permanent link to this record
 

 
Author de Salas, P.F.; Lattanzi, M.; Mangano, G.; Miele, G.; Pastor, S.; Pisanti, O. url  doi
openurl 
  Title Bounds on very low reheating scenarios after Planck Type Journal Article
  Year 2015 Publication Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 92 Issue 12 Pages 123534 - 9pp  
  Keywords  
  Abstract We consider the case of very low reheating scenarios [T-RH similar to O(MeV)] with a better calculation of the production of the relic neutrino background (with three-flavor oscillations). At 95% confidence level, a lower bound on the reheating temperature T-RH > 4.1 MeV is obtained from big bang nucleosynthesis, while T-RH > 4.7 MeV from Planck data (allowing neutrino masses to vary), the most stringent bound on the reheating temperature to date. Neutrino masses as large as 1 eV are possible for very low reheating temperatures.  
  Address [de Salas, P. F.; Pastor, S.] Univ Valencia, CSIC, Inst Fis Corpuscular, Paterna 46980, Valencia, Spain, Email: lattanzi@fe.infn.it  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (up) 1550-7998 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000367078600010 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 2502  
Permanent link to this record
 

 
Author Lesgourgues, J.; Pastor, S. url  doi
openurl 
  Title Neutrino Mass from Cosmology Type Journal Article
  Year 2012 Publication Advances in High Energy Physics Abbreviated Journal Adv. High. Energy Phys.  
  Volume 2012 Issue Pages 608515 - 34pp  
  Keywords  
  Abstract Neutrinos can play an important role in the evolution of the universe, modifying some of the cosmological observables. In this contribution we summarize the main aspects of cosmological relic neutrinos, and we describe how the precision of present cosmological data can be used to learn about neutrino properties, in particular their mass, providing complementary information to beta decay and neutrinoless double-beta decay experiments. We show how the analysis of current cosmological observations, such as the anisotropies of the cosmic microwave background or the distribution of large-scale structure, provides an upper bound on the sum of neutrino masses of order 1 eV or less, with very good perspectives from future cosmological measurements which are expected to be sensitive to neutrino masses well into the sub-eV range.  
  Address [Pastor, Sergio] Univ Valencia, CSIC, Inst Fis Corpuscular, Valencia 46071, Spain, Email: pastor@ific.uv.es  
  Corporate Author Thesis  
  Publisher Hindawi Publishing Corporation Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (up) 1687-7357 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000312317500001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 1278  
Permanent link to this record
 

 
Author Pierre Auger Collaboration (Abreu, P. et al); Pastor, S. url  doi
openurl 
  Title Ultrahigh Energy Neutrinos at the Pierre Auger Observatory Type Journal Article
  Year 2013 Publication Advances in High Energy Physics Abbreviated Journal Adv. High. Energy Phys.  
  Volume 2013 Issue Pages 708680 - 18pp  
  Keywords  
  Abstract The observation of ultrahigh energy neutrinos (UHE nu s) has become a priority in experimental astroparticle physics. UHE nu s can be detected with a variety of techniques. In particular, neutrinos can interact in the atmosphere (downward-going nu) or in the Earth crust (Earth-skimming nu), producing air showers that can be observed with arrays of detectors at the ground. With the surface detector array of the Pierre Auger Observatory we can detect these types of cascades. The distinguishing signature for neutrino events is the presence of very inclined showers produced close to the ground (i.e., after having traversed a large amount of atmosphere). In this work we review the procedure and criteria established to search for UHE nu s in the data collected with the ground array of the Pierre Auger Observatory. This includes Earth-skimming as well as downward-going neutrinos. No neutrino candidates have been found, which allows us to place competitive limits to the diffuse flux of UHE nu s in the EeV range and above.  
  Address Univ Tecn Lisboa, LIP, Lisbon, Portugal  
  Corporate Author Thesis  
  Publisher Hindawi Publishing Corporation Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (up) 1687-7357 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000317204500001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 1398  
Permanent link to this record
 

 
Author Pierre Auger Collaboration (Abreu, P. et al); Pastor, S. doi  openurl
  Title The Pierre Auger Observatory scaler mode for the study of solar activity modulation of galactic cosmic rays Type Journal Article
  Year 2011 Publication Journal of Instrumentation Abbreviated Journal J. Instrum.  
  Volume 6 Issue Pages P01003 - 16pp  
  Keywords Cherenkov detectors; Large detector systems for particle and astroparticle physics; Particle detectors  
  Abstract Since data-taking began in January 2004, the Pierre Auger Observatory has been recording the count rates of low energy secondary cosmic ray particles for the self-calibration of the ground detectors of its surface detector array. After correcting for atmospheric effects, modulations of galactic cosmic rays due to solar activity and transient events are observed. Temporal variations related with the activity of the heliosphere can be determined with high accuracy due to the high total count rates. In this study, the available data are presented together with an analysis focused on the observation of Forbush decreases, where a strong correlation with neutron monitor data is found.  
  Address [Abreu, P.; Andringa, S.; Assis, P.; Brogueira, P.; Cazon, L.; Conceicao, R.; Goncalves, P.; Pimenta, M.; Santo, C. E.; Santos, E.; Tome, B.] LIP, P-1000 Lisbon, Portugal  
  Corporate Author Thesis  
  Publisher Iop Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (up) 1748-0221 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000291345600003 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 646  
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