Bayesian analysis of the spin distribution of LIGO/Virgo black holes

Gravitational wave detection from binary black hole (BBH) inspirals has become routine thanks to the LIGO/Virgo interferometers. The nature of these black holes remains uncertain. We study here the spin distributions of LIGO/Virgo black holes from the first catalog GWTC-1 and the first four published BBH events from run O3. We compute the Bayes evidence for several independent priors: flat, isotropic, spin-aligned and anti-aligned. We find strong evidence for low spins in all of the cases, and significant evidence for small isotropic spins versus any other distribution. When considered as a homogeneous population of black holes, these results give support to the idea that LIGO/Virgo black holes are primordialJGB and ERM thank the Theory Division for their generous hospitality during their Sabbatical at CERN in 2018, when this work originated. The authors acknowledge support from the Research Project PGC2018-094773-B-C32 (MINECO-FEDER, Spain) and the Centro de Excelencia Severo Ochoa Program, Spain SEV-2016-059

False alarms induced by Gaussian noise in gravitational wave detectors

Gaussian noise is an irreducible component of the background in gravitational wave (GW) detectors. Although stationary Gaussian noise is uncorrelated in frequencies, we show that there is an important correlation in time when looking at the matched filter signal-to-noise ratio (SNR) of a template, with a typical autocorrelation time that depends on the template and the shape of the noise power spectral density (PSD). Taking this correlation into account, we compute from first principles the false alarm rate (FAR) of a template in Gaussian noise, defined as the number of occurrences per unit time that the template's matched filter SNR goes over a threshold ρ. We find that the Gaussian FAR can be well approximated by the usual expression for uncorrelated noise, if we replace the sampling rate by an effective sampling rate that depends on the parameters of the template, the noise PSD, and the threshold ρ. This results in a minimum SNR threshold needed for a given GW trigger, if we want to keep events generated from Gaussian noise below a certain FAR. We extend the formalism to multiple detectors and to the analysis of GW events. We apply our method to the GW candidates added in the GWTC-3 catalog and discuss the possibility that GW200308_173609 and GW200322_091133 could be generated by Gaussian noise fluctuation

El glosario como herramienta en interpretación consecutiva. Estudio de un caso práctico: la conciliación en Ruanda

En el presente artículo buscamos, basándonos en un encargo real de interpretación consecutiva y bilateral, para las combinaciones lingüísticas francés-español y español-francés, poner de manifiesto la importancia del proceso de documentación previo al ejercicio de la interpretación en el ámbito de las Relaciones Internacionales. El testimonio de Yolande Mukagasana, superviviente del genocidio de Ruanda de 1994, es el eje temático de este trabajo que, a partir de la recopilación y el estudio de textos paralelos, ofrece como resultado un glosario ad hoc (francés-español y español-francés), una herramienta de referencia para el intérprete ante cuestiones relacionadas con el conflicto de Ruanda (1990-1994).G.I. HUM 767 (ayudas a Grupos de Investigación de la Junta de Andalucía) / Editorial Comares (colección interlingua

Particle production from symmetry breaking after inflation and leptogenesis

Recent studies suggest that the process of symmetry breaking after inflation typically occurs very fast, within a single oscillation of the symmetry-breaking field, due to the spinodal growth of its long-wave modes, otherwise known as `tachyonic preheating'. We show how this sudden transition from the false to the true vacuum can induce a significant production of particles, bosons and fermions, coupled to the symmetry-breaking field. We find that this new mechanism of particle production in the early Universe may have interesting consequences for the origin of supermassive dark matter and the generation of the observed baryon asymmetry through leptogenesis.Comment: 17 pages, 2 figures. Significantly enlarged version, including a more detailed discussion of leptogenesis. To appear in Physics Letters

Study of gamma gamma -> W_L W_L and gamma gamma -> Z_L Z_L reactions with Chiral Lagrangians

We analyze the effects of a strongly interacting symmetry breaking sector of the Standard Model in $\gamma \gamma -> W_L^+ W_L^-$ and $\gamma \gamma -> Z_L Z_L$ reactions at TeV energies by using Chiral Lagrangians and Chiral Perturbation Theory. We find significant deviations from the Standard Model predictions for the differential cross sections at high invariant mass of the gauge bosons pair. We study the experimental signals that could be obtained in a high energy and high luminosity dedicated $\gamma\gamma$ collider and estimate the sensitivity that such experiments could reach to the values of the effective lagrangian parameters.Comment: 14 pages, LaTeX, 4 figures (not included), FTUAM92/2

The Electroweak Chiral Lagrangian for the Standard Model with a Heavy Higgs

The most general chiral Lagrangian for electroweak interactions with the complete set of $SU(2)_L\times U(1)_Y$ invariant operators up to dimension four is considered. The two-point and three-point functions with external gauge fields are derived from this effective chiral Lagrangian to one-loop order in a generic $R_\xi$-gauge. The same set of Green's functions are paralelly studied in the renormalizable standard model to one-loop order, in a $R_\xi$-gauge and in the large Higgs mass limit. An appropriate set of matching conditions connecting the Green's functions of the two theories allows us to derive, systematically, the values of the chiral Lagrangian coefficients corresponding to the large Higgs mass limit of the standard model. These chiral parameters represent the non-decoupling effects of a heavy Higgs particle and incorporate both the leading logarithmic dependence on \mh and the next to leading constant contributions. Some phenomenological implications are also discussed.Comment: pg.23, LaTeX, 3 figures (not included), FTUAM-93/2

Primordial black holes and their gravitational-wave signatures

In the recent years, primordial black holes (PBHs) have emerged as one of the most interesting and hotly debated topics in cosmology. Among other possibilities, PBHs could explain both some of the signals from binary black hole mergers observed in gravitational wave detectors and an important component of the dark matter in the Universe. Significant progress has been achieved both on the theory side and from the point of view of observations, including new models and more accurate calculations of PBH formation, evolution, clustering, merger rates, as well as new astrophysical and cosmological probes. In this work, we review, analyse and combine the latest developments in order to perform end-to-end calculations of the various gravitational wave signatures of PBHs. Different ways to distinguish PBHs from stellar black holes are emphasized. Finally, we discuss their detectability with LISA, the first planned gravitational-wave observatory in space.Comment: 161 pages, 47 figures, comments welcom