Ruiz Cembranos, José Alberto

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First Name
José Alberto
Last Name
Ruiz Cembranos
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Físicas
Física Teórica
Física Teórica
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Now showing 1 - 10 of 86
  • Publication
    La física y los medios audiovisuales
    (2022-09-12) Ruiz Cembranos, José Alberto; Álvarez Luna, Clara; Ángel Ortega, Sergio; Fernández Sanz, David; López Maroto, Antonio; Pantaleoni González, Michelangelo; Rivas Vargas, Ángel; Rodrigo Somolinos, Pablo Fernando
    En este documento se resumen los principales resultados del proyecto de innovación docente titulado “La física y los medios audiovisuales”. Dicho proyecto fue llevado a cabo en la Facultad de Ciencias Físicas de la Universidad Complutense entre los años 2021 y 2022.
  • Publication
    Antiproton signatures from astrophysical and dark matter sources at the galactic center
    (IOP Publishing, 2015-03) Ruiz Cembranos, José Alberto; Gammaldi, Viviana; López Maroto, Antonio
    The center of our Galaxy is a complex region characterized by extreme phenomena. The presence of the supermassive Sagittarius A* black hole, a high dark matter density and an even higher baryonic density are able to produce very energetic processes. Indeed, high energetic gamma-rays have been observed by different telescopes, although their origin is not clear. In this work, we estimate the possible antiproton flux component associated with this signal. The expected secondary astrophysical antiproton background already saturates the observed data. It implies that any other important astrophysical source leads to an inconsistent excess. We estimate the sensitivity of PAMELA to this new primary antiproton source, which depends on the diffusion model and its spectral features. In particular, we consider antiproton spectra described by a power-law, a monochromatic signal and a Standard Model particle-antiparticle channel production. This latter spectrum is typical in the production from annihilating or decaying dark matter. We pay particular attention to the case of a heavy dark matter candidate, which could be associated with the High Energy Stereoscopic System (HESS) data observed from the J1745-290 source.
  • Publication
    SKA-Phase 1 sensitivity to synchrotron radio emission from multi-TeV Dark Matter candidates.
    (Elsevier B.V., 2020-01) Ruiz Cembranos, José Alberto; Cruz Dombriz, Álvaro de la; Gammaldi, Viviana; Mendez Isla, Miguel
    In the era of radio astronomy, the high sensitivity of the Square Kilometre Array (SKA) could play a decisive role in the detection of new radio sources. In this work, we study the SKA sensitivity to the synchrotron radio emission expected by the annihilation of TeV DM candidate in the Draco dwarf spheroidal galaxy. On the one hand, we consider model-independent DM candidates: we find out that with 1000 h of data-taking, SKA1-MID will be able to exclude up to 10 TeV thermal DM candidates that annihilate in W+W- and b (b) over bar channels. We also study as these constraints improve by including a density enhancement due to a DM-spike associated with an intermediate-mass black hole in Draco. On the other hand, we consider extra-dimensional brane-world DM candidates, dubbed branons. In this specific scenario, SKA allows us to set constraints on the branon parameter space (f, M), where f is related to the coupling of the branon to the Standard Model particles and M is the mass of the branon itself. In particular, we consider two different branon DM candidates. We find out that SKA will be able to set more stringent constraints on the branon DM candidate required in order to fit the AMS-02 data, yet the sensitivity of the instrument should be improved in order to study the branon candidate for the Galactic Centre. Nonetheless, we show that SKA represents - among other detectors - the most promising instrument for multi-wavelength detection of synchrotron radio emission by annihilating multi-TeV DM. (C) 2019 Elsevier B.V. All rights reserved.
  • Publication
    Impact of dark matter direct searches and the LHC analyses on branon phenomenology
    (American Physical Socety, 2011-10-15) Ruiz Cembranos, José Alberto; Lorenzo Diaz-Cruz, J.; Prado, Lilian
    Dark Matter direct detection experiments are able to exclude interesting parameter space regions of particle models which predict an important amount of thermal relics. We use recent data to constrain the branon model and to compute the region that is favored by CDMS measurements. Within this work, we also update present colliders constraints with new studies coming from the LHC. Despite the present low luminosity, it is remarkable that for heavy branons, CMS and ATLAS measurements are already more constraining than previous analyses performed with TEVATRON and LEP data.
  • Publication
    Stability in quadratic torsion theories (vol 77, 755, 2017): Erratum
    (Springer, 2022) Borislavov Vasilev, Teodor; Ruiz Cembranos, José Alberto; Gigante Valcarcel, Jorge; Martín Moruno, Prado
  • Publication
    Possible dark matter origin of the gamma ray emission from the Galactic Center observed by HESS
    (American Physical Society, 2012-11-06) López Maroto, Antonio; Ruiz Cembranos, José Alberto; Gammaldi, Viviana
    We show that the gamma ray spectrum observed with the HESS array of Cherenkov telescopes coming from the Galactic Center region and identified with the source HESS J1745-290 is well fitted by the secondary photons coming from dark matter (DM) annihilation over a diffuse power law background. The amount of photons and morphology of the signal localized within a region of few parsecs, require compressed DM profiles as those resulting from baryonic contraction, which offer 103 enhancements in the signal over DM alone simulations. The fitted background from HESS data is consistent with recent Fermi-LAT observations of the same region.
  • Publication
    Fermion dynamics in torsion theories.
    (Iop Publishing, 2019-04) Ruiz Cembranos, José Alberto; Gigante Valcarcel, Jorge; Maldonado Torralba, F. J.
    In this work we study the non-geodesical behaviour of particles with spin 1/2 in Poincare gauge theories of gravity via the WKB method. Within this approach, we calculate the trajectories in a particular Poincare gauge theory, discussing the viability of measuring such a motion.
  • Publication
    Gravitational Coleman-Weinberg mechanism
    (Springer, 2023-02-24) Álvarez Luna, Clara; La Calle Leal, Sergio de; Ruiz Cembranos, José Alberto; Sanz Cillero, Juan José
    The Coleman-Weinberg mechanism provides a procedure by which a scalar field, which initially has no mass parameters, acquires a mass due to the anomalous nature of scale symmetry. Loop corrections trigger a spontaneous symmetry breaking and the appearance of a non-trivial vacuum. We first review the basic example of the Coleman-Weinberg mechanism, scalar Quantum Electrodynamics, in a perturbative regime where the scalar particle becomes massive through photon loops. We then present the main results of this article, what we name the gravitational Coleman-Weinberg mechanism: we analyse the same effect in a gravitational theory without explicit energy scales at tree-level. Finally, we also study the mechanism for two scalar fields in the mentioned gravitational theory. We will derive the gravitational Coleman-Weinberg potentials, analyse the parameter space where we have a symmetry breaking, and obtain the value of the corresponding scalar masses.
  • Publication
    Indirect constraints to branon dark matter
    (Amer Inst Physics, 2012) López Maroto, Antonio; Ruiz Cembranos, José Alberto; Cruz Dombriz, Álvaro de la; Gammaldi, Viviana
    If the present dark matter in the Universe annihilates into Standard Model particles, it must contribute to the gamma ray fluxes detected on the Earth. Here we briefly review the present constraints for the detection of gamma ray photons produced in the annihilation of branon dark matter. We show that observations of dwarf spheroidal galaxies and the galactic center by EGRET, Fermi-LAT or MAGIC are below the sensitivity limits for branon detection. However, future experiments such as CTA could be able to detect gamma-ray photons from annihilating branons of masses above 150 GeV.
  • Publication
    Branon search in hadronic colliders
    (American Physical Society, 2004-11) Ruiz Cembranos, José Alberto; Dobado González, Antonio; López Maroto, Antonio
    In the context of the brane-world scenarios with compactified extra dimensions, we study the production of brane fluctuations (branons) in hadron colliders (p (p) over bar, pp, and e(+/-)p) in terms of the brane tension parameter f, the branon mass M, and the number of branons N. From the absence of monojet events at HERA and Tevatron (run I), we set bounds on these parameters and we also study how such bounds could be improved at Tevatron (run II) and the future LHC. The single-photon channel is also analyzed for the two last colliders.