326 research outputs found

    Lepton asymmetry and the cosmic QCD transition

    Full text link
    We study the influence of lepton asymmetry on the evolution of the early Universe. The lepton asymmetry ll is poorly constrained by observations and might be orders of magnitude larger than the baryon asymmetry bb, l/b2×108|l|/b \leq 2\times 10^8. We find that lepton asymmetries that are large compared to the tiny baryon asymmetry, can influence the dynamics of the QCD phase transition significantly. The cosmic trajectory in the μBT\mu_B-T phase diagram of strongly interacting matter becomes a function of lepton (flavour) asymmetry. Large lepton asymmetry could lead to a cosmic QCD phase transition of first order.Comment: 23 pages, 14 figures; matches published version, including Erratum. Conclusions, pictures, numerics remained unchange

    Goldstone bosons and a dynamical Higgs field

    Full text link
    Higgs inflation uses the gauge variant Higgs field as the inflaton. During inflation the Higgs field is displaced from its minimum, which results in associated Goldstone bosons that are apparently massive. Working in a minimally coupled U(1) toy model, we use the closed-time-path formalism to show that these Goldstone bosons do contribute to the one-loop effective action. Therefore the computation in unitary gauge gives incorrect results. Our expression for the effective action is gauge invariant upon using the background equations of motion.Comment: 27 pages, 2 figures, published version with minor correction

    Detecting sterile neutrinos with KATRIN like experiments

    Full text link
    A sterile neutrino with mass in the eV range, mixing with the electron antineutrino, is allowed and possibly even preferred by cosmology and oscillation experiments. If such eV-mass neutrinos exist they provide a much better target for direct detection in beta decay experiments than the active neutrinos which are expected to have sub-eV masses. Their relatively high mass would allow for an easy separation from the primary decay signal in experiments such as KATRIN.Comment: 23 pages, 7 figures. References & Figures updated. Text reviewed and revised. Accepted for publication JCA

    Constraints on neutrino masses from WMAP5 and BBN in the lepton asymmetric universe

    Full text link
    In this paper, we put constraints on neutrino properties such as mass mνm_{\nu} and degeneracy parameters ξi\xi_i from WMAP5 data and light element abundances by using a Markov chain Monte Carlo (MCMC) approach. In order to take consistently into account the effects of the degeneracy parameters, we run the Big Bang Nucleosynthesis code for each value of ξi\xi_i and the other cosmological parameters to estimate the Helium abundance, which is then used to calculate CMB anisotropy spectra instead of treating it as a free parameter. We find that the constraint on mνm_{\nu} is fairly robust and does not vary very much even if the lepton asymmetry is allowed, and is given by mν<1.3eV\sum m_\nu < 1.3 \rm eV (9595 % \rm C.L.).Comment: 19 pages, 7 figures, 5 table

    Observational consequences of the Standard Model Higgs inflation variants

    Full text link
    We consider the possibility to observationally differentiate the Standard Model (SM) Higgs driven inflation with non-minimal couplingto gravity from other variants of SM Higgs inflation based on the scalar field theories with non-canonical kinetic term such as Galileon-like kinetic term and kinetic term with non-minimal derivative coupling to the Einstein tensor. In order to ensure consistent results, we study the SM Higgs inflation variants by using the same method, computing the full dynamics of the background and perturbations of the Higgs field during inflation at quantum level. Assuming that all the SM Higgs inflation variants are consistent theories, we use the MCMC technique to derive constraints on the inflationnoary parameters and the Higgs boson mass from their fit to WMAP7+SN+BAO data set. We conclude that a combination of a Higgs mass measurement by the LHC and accurate determination by the PLANCK satellite of the spectral index of curvature perturbations and tensor-to-scalar ratio will enable to distinguish among these models. We also show that the consistency relations of the SM Higgs inflation variants are distinct enough to differentiate the models.Comment: 22 pages, 4 figure

    WIMP abundance and lepton (flavour) asymmetry

    Full text link
    We investigate how large lepton asymmetries affect the evolution of the early universe at times before big bang nucleosynthesis and in particular how they influence the relic density of WIMP dark matter. In comparison to the standard calculation of the relic WIMP abundance we find a decrease, depending on the lepton flavour asymmetry. We find an effect of up to 20 per cent for lepton flavour asymmetries lf=O(0.1)l_f= {\cal O}(0.1).Comment: 16 pages, 4 figures; v2:minor changes to some wording

    Neutrino mass from cosmology: Impact of high-accuracy measurement of the Hubble constant

    Full text link
    Non-zero neutrino mass would affect the evolution of the Universe in observable ways, and a strong constraint on the mass can be achieved using combinations of cosmological data sets. We focus on the power spectrum of cosmic microwave background (CMB) anisotropies, the Hubble constant H_0, and the length scale for baryon acoustic oscillations (BAO) to investigate the constraint on the neutrino mass, m_nu. We analyze data from multiple existing CMB studies (WMAP5, ACBAR, CBI, BOOMERANG, and QUAD), recent measurement of H_0 (SHOES), with about two times lower uncertainty (5%) than previous estimates, and recent treatments of BAO from the Sloan Digital Sky Survey (SDSS). We obtained an upper limit of m_nu < 0.2eV (95% C.L.), for a flat LambdaCDM model. This is a 40% reduction in the limit derived from previous H_0 estimates and one-third lower than can be achieved with extant CMB and BAO data. We also analyze the impact of smaller uncertainty on measurements of H_0 as may be anticipated in the near term, in combination with CMB data from the Planck mission, and BAO data from the SDSS/BOSS program. We demonstrate the possibility of a 5 sigma detection for a fiducial neutrino mass of 0.1eV or a 95% upper limit of 0.04eV for a fiducial of m_nu = 0eV. These constraints are about 50% better than those achieved without external constraint. We further investigate the impact on modeling where the dark-energy equation of state is constant but not necessarily -1, or where a non-flat universe is allowed. In these cases, the next-generation accuracies of Planck, BOSS, and 1% measurement of H_0 would all be required to obtain the limit m_nu < 0.05 - 0.06eV (95% C.L.) for the fiducial of m_nu = 0eV. The independence of systematics argues for pursuit of both BAO and H_0 measurements.Comment: 22 pages, 6 figures, 12 table

    Potential-driven Galileon inflation

    Full text link
    For the models of inflation driven by the potential energy of an inflaton field ϕ\phi, the covariant Galileon Lagrangian (ϕ)2ϕ(\partial\phi)^2\Box \phi generally works to slow down the evolution of the field. On the other hand, if the Galileon self-interaction is dominant relative to the standard kinetic term, we show that there is no oscillatory regime of inflaton after the end of inflation. This is typically accompanied by the appearance of the negative propagation speed squared cs2c_s^2 of a scalar mode, which leads to the instability of small-scale perturbations. For chaotic inflation and natural inflation we clarify the parameter space in which inflaton oscillates coherently during reheating. Using the WMAP constraints of the scalar spectral index and the tensor-to-scalar ratio as well, we find that the self coupling λ\lambda of the potential V(ϕ)=λϕ4/4V(\phi)=\lambda \phi^4/4 is constrained to be very much smaller than 1 and that the symmetry breaking scale ff of natural inflation cannot be less than the reduced Planck mass MplM_{\rm pl}. We also show that, in the presence of other covariant Galileon Lagrangians, there are some cases in which inflaton oscillates coherently even for the self coupling λ\lambda of the order of 0.1, but still the instability associated with negative cs2c_s^2 is generally present.Comment: 22 pages, 15 figure

    Planck intermediate results. VIII. Filaments between interacting clusters

    Get PDF
    About half of the baryons of the Universe are expected to be in the form of filaments of hot and low density intergalactic medium. Most of these baryons remain undetected even by the most advanced X-ray observatories which are limited in sensitivity to the diffuse low density medium. The Planck satellite has provided hundreds of detections of the hot gas in clusters of galaxies via the thermal Sunyaev-Zel'dovich (tSZ) effect and is an ideal instrument for studying extended low density media through the tSZ effect. In this paper we use the Planck data to search for signatures of a fraction of these missing baryons between pairs of galaxy clusters. Cluster pairs are good candidates for searching for the hotter and denser phase of the intergalactic medium (which is more easily observed through the SZ effect). Using an X-ray catalogue of clusters and the Planck data, we select physical pairs of clusters as candidates. Using the Planck data we construct a local map of the tSZ effect centered on each pair of galaxy clusters. ROSAT data is used to construct X-ray maps of these pairs. After having modelled and subtracted the tSZ effect and X-ray emission for each cluster in the pair we study the residuals on both the SZ and X-ray maps. For the merging cluster pair A399-A401 we observe a significant tSZ effect signal in the intercluster region beyond the virial radii of the clusters. A joint X-ray SZ analysis allows us to constrain the temperature and density of this intercluster medium. We obtain a temperature of kT = 7.1 +- 0.9, keV (consistent with previous estimates) and a baryon density of (3.7 +- 0.2)x10^-4, cm^-3. The Planck satellite mission has provided the first SZ detection of the hot and diffuse intercluster gas.Comment: Accepted by A&

    Time-dependent search for neutrino emission from X-ray binaries with the ANTARES telescope

    Get PDF
    [EN] ANTARES is currently the largest neutrino telescope operating in the Northern Hemisphere, aiming at the detection of high-energy neutrinos from astrophysical sources. Neutrino telescopes constantly monitor at least one complete hemisphere of the sky, and are thus well-suited to detect neutrinos produced in transient astrophysical sources. A time-dependent search has been applied to a list of 33 X-ray binaries undergoing high flaring activities in satellite data (RXTE/ASM, MAXI and Swift/BAT) and during hardness transi-tion states in the 2008 2012 period. The background originating from interactions of charged cosmic rays in the Earth s atmosphere is drastically reduced by requiring a directional and temporal coincidence with astrophysical phenomena. The results of this search are presented together with comparisons between the neutrino flux upper limits and the neutrino flux predictions from astrophysical models. The neutrino flux upper limits resulting from this search limit the jet parameter space for some astrophysical models.The authors acknowledge the financial support of the funding agencies: Centre National de la Recherche Scientifique (CNRS), Commissariat a l'energie atomique et aux energies alternatives (CEA), Commission Europeenne (FEDER fund and Marie Curie Program), Institut Universitaire de France (IUF), IdEx program and UnivEarthS Labex program at Sorbonne Paris Cite (ANR-10-LABX-0023 and ANR-11-IDEX-0005-02), Labex OCEVU (ANR-11-LABX-0060) and the A* MIDEX project (ANR-11-IDEX-0001-02), Region Ile-de-France (DIM-ACAV), Region Alsace (contrat CPER), Region Provence-Alpes-Cote d'Azur, Departement du Var and Ville de La Seyne-sur-Mer, France; Bundesministerium fur Bildung und Forschung (BMBF), Germany; Istituto Nazionale di Fisica Nucleare (INFN), Italy; Stichting voor Fundamenteel Onderzoek der Materie (FOM), Nederlandse organisatie voor Weten-schappelijk Onderzoek (NWO), the Netherlands; Council of the President of the Russian Federation for young scientists and leading scientific schools supporting grants, Russia; National Authority for Scientific Research (ANCS), Romania; Ministerio de Economia y Competitividad (MINECO): Plan Estatal de Investigacion (refs. FPA2015-65150-C3-1-P, -2-P and -3-P, (MINECO/FEDER)), Severo Ochoa Centre of Excellence and MultiDark Consolider (MINECO), and Prometeo and Grisolia programs (Generalitat Valenciana), Spain; Agence de l'Oriental and CNRST, Morocco. We also acknowledge the technical support of Ifremer, AIM and Foselev Marine for the sea operation and the CC-IN2P3 for the computing facilitiesAlbert, A.; Andre, M.; Anton, G.; Ardid Ramírez, M.; Aubert, J.; Avgitas, T.; Baret, B.... (2017). Time-dependent search for neutrino emission from X-ray binaries with the ANTARES telescope. JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS. 4(19):1-23. https://doi.org/10.1088/1475-7516/2017/04/019S123419Vila, G. S., Romero, G. E., & Casco, N. A. (2012). An inhomogeneous lepto-hadronic model for the radiation of relativistic jets. Astronomy & Astrophysics, 538, A97. doi:10.1051/0004-6361/201118106Pepe, C., Vila, G. S., & Romero, G. E. (2015). Lepto-hadronic model for the broadband emission of Cygnus X-1. Astronomy & Astrophysics, 584, A95. doi:10.1051/0004-6361/201527156Blandford, R. D., & Payne, D. G. (1982). Hydromagnetic flows from accretion discs and the production of radio jets. Monthly Notices of the Royal Astronomical Society, 199(4), 883-903. doi:10.1093/mnras/199.4.883Trigo, M. D., Miller-Jones, J. C. A., Migliari, S., Broderick, J. W., & Tzioumis, T. (2013). Baryons in the relativistic jets of the stellar-mass black-hole candidate 4U 1630-47. Nature, 504(7479), 260-262. doi:10.1038/nature12672Heinz, S. (2006). Composition, Collimation, Contamination: The Jet of Cygnus X‐1. The Astrophysical Journal, 636(1), 316-322. doi:10.1086/497954Levinson, A., & Waxman, E. (2001). Probing Microquasars with TeV Neutrinos. Physical Review Letters, 87(17). doi:10.1103/physrevlett.87.171101Sahakyan, N., Piano, G., & Tavani, M. (2013). HADRONIC GAMMA-RAY AND NEUTRINO EMISSION FROM CYGNUS X-3. The Astrophysical Journal, 780(1), 29. doi:10.1088/0004-637x/780/1/29Adrián-Martínez, S., Albert, A., Al Samarai, I., André, M., Anghinolfi, M., Anton, G., … Aubert, J.-J. (2013). Search for muon neutrinos from gamma-ray bursts with the ANTARES neutrino telescope using 2008 to 2011 data. Astronomy & Astrophysics, 559, A9. doi:10.1051/0004-6361/201322169Adrián-Martínez, S., Albert, A., André, M., Anghinolfi, M., Anton, G., Ardid, M., … Barrios, J. (2014). A search for time dependent neutrino emission from microquasars with the ANTARES telescope. Journal of High Energy Astrophysics, 3-4, 9-17. doi:10.1016/j.jheap.2014.06.002Aartsen, M. G., Ackermann, M., Adams, J., Aguilar, J. A., Ahlers, M., Ahrens, M., … Arguelles, C. (2015). SEARCHES FOR TIME-DEPENDENT NEUTRINO SOURCES WITH ICECUBE DATA FROM 2008 TO 2012. The Astrophysical Journal, 807(1), 46. doi:10.1088/0004-637x/807/1/46Remillard, R. A., & McClintock, J. E. (2006). X-Ray Properties of Black-Hole Binaries. Annual Review of Astronomy and Astrophysics, 44(1), 49-92. doi:10.1146/annurev.astro.44.051905.092532Corbel, S., Kaaret, P., Jain, R. K., Bailyn, C. D., Fender, R. P., Tomsick, J. A., … McCollough, M. L. (2001). X‐Ray States and Radio Emission in the Black Hole Candidate XTE J1550−564. The Astrophysical Journal, 554(1), 43-48. doi:10.1086/321364Miller-Jones, J. C. A., Jonker, P. G., Maccarone, T. J., Nelemans, G., & Calvelo, D. E. (2011). A DEEP RADIO SURVEY OF HARD STATE AND QUIESCENT BLACK HOLE X-RAY BINARIES. The Astrophysical Journal, 739(1), L18. doi:10.1088/2041-8205/739/1/l18Vieyro, F. L., Sestayo, Y., Romero, G. E., & Paredes, J. M. (2012). Nonthermal processes and neutrino emission from the black hole GRO J0422+32 in a bursting state. Astronomy & Astrophysics, 546, A46. doi:10.1051/0004-6361/201219961Miller-Jones, J. C. A., Moin, A., Tingay, S. J., Reynolds, C., Phillips, C. J., Tzioumis, A. K., … Tudose, V. (2011). The first resolved imaging of milliarcsecond-scale jets in Circinus X-1. Monthly Notices of the Royal Astronomical Society: Letters, 419(1), L49-L53. doi:10.1111/j.1745-3933.2011.01176.xSguera, V., Romero, G. E., Bazzano, A., Masetti, N., Bird, A. J., & Bassani, L. (2009). DISSECTING THE REGION OF 3EG J1837-0423 AND HESS J1841-055 WITHINTEGRAL. The Astrophysical Journal, 697(2), 1194-1205. doi:10.1088/0004-637x/697/2/1194García, F., Aguilera, D. N., & Romero, G. E. (2014). Exploring jet-launching conditions for supergiant fast X-ray transients. Astronomy & Astrophysics, 565, A122. doi:10.1051/0004-6361/201323157Giovannelli, F., & Graziati, L. S. (1992). A 0535 + 26/HDE 245770: A typical X-ray/Be system. Space Science Reviews, 59(1-2), 1-81. doi:10.1007/bf01262537Anchordoqui, L. A., Torres, D. F., McCauley, T. P., Romero, G. E., & Aharonian, F. A. (2003). Neutrinos from Accreting Neutron Stars. The Astrophysical Journal, 589(1), 481-486. doi:10.1086/374551Scargle, J. D. (1981). Studies in astronomical time series analysis. I - Modeling random processes in the time domain. The Astrophysical Journal Supplement Series, 45, 1. doi:10.1086/190706Scargle, J. D. (1998). Studies in Astronomical Time Series Analysis. V. Bayesian Blocks, a New Method to Analyze Structure in Photon Counting Data. The Astrophysical Journal, 504(1), 405-418. doi:10.1086/306064Scargle, J. D., Norris, J. P., Jackson, B., & Chiang, J. (2013). STUDIES IN ASTRONOMICAL TIME SERIES ANALYSIS. VI. BAYESIAN BLOCK REPRESENTATIONS. The Astrophysical Journal, 764(2), 167. doi:10.1088/0004-637x/764/2/167collaboration, T. A. (2015). Search for muon-neutrino emission from GeV and TeV gamma-ray flaring blazars using five years of data of the ANTARES telescope. Journal of Cosmology and Astroparticle Physics, 2015(12), 014-014. doi:10.1088/1475-7516/2015/12/014Kappes, A., Hinton, J., Stegmann, C., & Aharonian, F. A. (2007). Potential Neutrino Signals from Galactic γ‐Ray Sources. The Astrophysical Journal, 656(2), 870-878. doi:10.1086/508936Outline of a Theory of Statistical Estimation Based on the Classical Theory of Probability. (1937). Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences, 236(767), 333-380. doi:10.1098/rsta.1937.0005Romero, G. E., & Vila, G. S. (2008). The proton low-mass microquasar: high-energy emission. Astronomy & Astrophysics, 485(3), 623-631. doi:10.1051/0004-6361:200809563Reynoso, M. M., Romero, G. E., & Christiansen, H. R. (2008). Production of gamma rays and neutrinos in the dark jets of the microquasar SS433. Monthly Notices of the Royal Astronomical Society, 387(4), 1745-1754. doi:10.1111/j.1365-2966.2008.13364.xReynoso, M. M., & Romero, G. E. (2008). Magnetic field effects on neutrino production in microquasars. Astronomy & Astrophysics, 493(1), 1-11. doi:10.1051/0004-6361:200811004Bednarek, W. (2005). TeV Neutrinos from Microquasars in Compact Massive Binaries. The Astrophysical Journal, 631(1), 466-470. doi:10.1086/432411Romero, G. E., Vieyro, F. L., & Vila, G. S. (2010). Non-thermal processes around accreting galactic black holes. Astronomy and Astrophysics, 519, A109. doi:10.1051/0004-6361/200913663Miller-Jones, J. C. A., Fender, R. P., & Nakar, E. (2006). Opening angles, Lorentz factors and confinement of X-ray binary jets. Monthly Notices of the Royal Astronomical Society, 367(4), 1432-1440. doi:10.1111/j.1365-2966.2006.10092.xBlandford, R. D., & Konigl, A. (1979). Relativistic jets as compact radio sources. The Astrophysical Journal, 232, 34. doi:10.1086/157262Zhang, J. F., Feng, Y. G., Lei, M. C., Tang, Y. Y., & Tian, Y. P. (2010). High-energy neutrino emission from low-mass microquasars. Monthly Notices of the Royal Astronomical Society, 407(4), 2468-2474. doi:10.1111/j.1365-2966.2010.17072.xHeinz, S., Burton, M., Braiding, C., Brandt, W. N., Jonker, P. G., Sell, P., … Schulz, N. S. (2015). LORD OF THE RINGS: A KINEMATIC DISTANCE TO CIRCINUS X-1 FROM A GIANT X-RAY LIGHT ECHO. The Astrophysical Journal, 806(2), 265. doi:10.1088/0004-637x/806/2/265Bednarek, W. (2009). TeV neutrinos from accreting x-ray pulsars. Physical Review D, 79(12). doi:10.1103/physrevd.79.123010Adrián-Martínez, S., Ageron, M., Aharonian, F., Aiello, S., Albert, A., Ameli, F., … Anghinolfi, M. (2016). Letter of intent for KM3NeT 2.0. Journal of Physics G: Nuclear and Particle Physics, 43(8), 084001. doi:10.1088/0954-3899/43/8/084001Russell, D. M., Markoff, S., Casella, P., Cantrell, A. G., Chatterjee, R., Fender, R. P., … Shahbaz, T. (2012). Jet spectral breaks in black hole X-ray binaries. Monthly Notices of the Royal Astronomical Society, 429(1), 815-832. doi:10.1093/mnras/sts377Stirling, A. M., Spencer, R. E., de La Force, C. J., Garrett, M. A., Fender, R. P., & Ogley, R. N. (2001). A relativistic jet from Cygnus X-1 in the low/hard X-ray state. Monthly Notices of the Royal Astronomical Society, 327(4), 1273-1278. doi:10.1046/j.1365-8711.2001.04821.xCorbel, S., Kaaret, P., Fender, R. P., Tzioumis, A. K., Tomsick, J. A., & Orosz, J. A. (2005). Discovery of X‐Ray Jets in the Microquasar H1743−322. The Astrophysical Journal, 632(1), 504-513. doi:10.1086/432499Paragi, Z., van der Horst, A. J., Belloni, T., Miller-Jones, J. C. A., Linford, J., Taylor, G., … Wijers, R. A. M. J. (2013). VLBI observations of the shortest orbital period black hole binary, MAXI J1659−152. Monthly Notices of the Royal Astronomical Society, 432(2), 1319-1329. doi:10.1093/mnras/stt545Mainzer, A., Masiero, J., Grav, T., Bauer, J., Tholen, D. J., McMillan, R. S., … Maleszewski, C. (2011). NEOWISE STUDIES OF ASTEROIDS WITH SLOAN PHOTOMETRY: PRELIMINARY RESULTS. The Astrophysical Journal, 745(1), 7. doi:10.1088/0004-637x/745/1/
    corecore