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Ferrer, Francesc

Publications and source records attributed to Ferrer, Francesc.

6 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Imprints of a supercooled phase transition in the gravitational wave spectrum from a cosmic string network

A network of cosmic strings (CS), if present, would continue emitting gravitational waves (GW) as it evolves throughout the history of the Universe. This results in a characteristic broad spectrum making it a perfect source to infer the expansion history. In particular, a short inflationary period caused by a supercooled phase transition would cause a drop in the spectrum at frequencies corresponding to that event. However, the impact on the spectrum is similar to the ones caused by an early matter-dominated era or from particle production, making it difficult to disentangle these different physical origins. We point out that, in the case of a short inflationary period, the GW spectrum receives an additional contribution from the phase transition itself. This leads to a characteristic imprint of a peak on top of a wide plateau both visible at future GW observatories.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2023

New constraints on the dark matter-neutrino and dark matter-photon scattering cross sections from TXS 0506+056

The flux of high energy neutrinos and photons produced in a blazar could get attenuated when they propagate through the dark matter spike around the central black hole and the halo of the host galaxy. Using the observation by IceCube of a few high-energy neutrino events from TXS 0506+056, and their coincident gamma ray events, we obtain new constraints on the dark matter-neutrino and dark matter-photon scattering cross sections. Our constraints are orders of magnitude more stringent than those derived from considering the attenuation through the intergalactic medium and the Milky Way dark matter halo. When the cross-section increases with energy, our constraints are also stronger than those derived from the CMB and large-scale structure.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2021

Fast radio bursts from axion stars moving through pulsar magnetospheres

Here, we study the radio signals generated when an axion star enters the magnetosphere of a neutron star. As the axion star moves through the resonant region where the plasma-induced photon mass becomes equal to the axion mass, the axions can efficiently convert into photons, giving rise to an intense, transient radio signal. We show that a dense axion star with a mass ~10 -13 M ⊙ composed of ~10 μ eV axions can account for most of the mysterious fast radio bursts.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2019

Gravitational waves from first-order phase transition in a simple axion-like particle model

We consider a gauge-singlet complex scalar field Φ with a global U(1) symmetry that is spontaneously broken at some high energy scale ƒ a . As a result, the angular part of the Φ-field becomes an axion-like particle (ALP). We show that if the Φ-field has a nonzero coupling κ to the Standard Model Higgs boson, there exists a certain region in the (ƒ a , κ) parameter space where the global U(1) symmetry-breaking induces a strongly first order phase transition, thereby producing stochastic gravitational waves that are potentially observable in current and future gravitational-wave detectors. In particular, we find that future gravitational-wave experiments such as TianQin, BBO and Cosmic Explorer could probe a broad range of the energy scale 10 3 GeV ≳ ƒ a ≳ 108 GeV, independent of the ALP mass. Since all the ALP couplings to the Standard Model particles are proportional to inverse powers of the energy scale ƒ a (up to model-dependent O (1) coefficients), the gravitationalwave detection prospects are largely complementary to the current laboratory, astrophysical and cosmological probes of the ALP scenarios.

79 ASTRONOMY AND ASTROPHYSICS↗