arXiv subjects

Andrés Castillo

Publications and source records attributed to Andrés Castillo.

9 recordsLinked to original sources

arXiv2026

Confronting fuzzy dark matter with the rotation curves of nearby dwarf irregular galaxies

We investigate phenomenologically the viability of fuzzy dark matter (FDM). We do this by confronting the predictions of the model, in particular, the formation of a solitonic core at the center of dark matter halos, with a homogeneous and robust sample of high-resolution rotation curves from the "LITTLE THINGS in 3D" catalog. This comprises a collection of isolated, dark matter dominated dwarf-irregular galaxies that provides an optimal benchmark for cosmological studies. We use a statistical framework based on Markov chain Monte Carlo techniques that allows us to extract relevant parameters such as the axion mass, the mass of the solitonic core, the mass of the dark matter halo and its concentration parameter with a rather loose set of priors except for the implementation of a core-halo relation that is predicted by simulations. The results of the fits are used to perform various diagnostics on the predictions of the model. FDM provides an excellent fit to the rotation curves of the "LITTLE THINGS in 3D" catalog, with axion masses determined from different galaxies clustering around $m_a\approx2\times10^{-23}$ eV. However, we find two major problems in our analysis. First, the data follow scaling relations of the properties of the core which are not consistent with the predictions of the soliton. This problem is particularly acute in the core radius - mass relation with a tension that, at face value, has a significance $\gtrsim5σ$. The second problem is related to the strong suppression of the linear power spectrum that is predicted by FDM for the axion mass preferred by the data. This can be constrained very conservatively by the galaxy counts in our sample, which leads to a tension exceeding again $5σ$. We estimate the effects of baryons in our analysis and discuss whether they could alleviate the tensions of the model with observations.

astro-ph.GA↗

arXiv2024

Self-Interacting Dark Matter and flavor anomalies in an atlas of leptophilic models

We consider an atlas of leptophilic models with non-universal charges that combine the quantum numbers $(L_e - L_μ)$ and $(L_μ - L_τ)$ in various realizations. We explore diverse manifestations of the atlas to understand their impact on explaining the muon $(g-2)_μ$ anomaly, as well as the origin of self-interacting dark matter, which serves as a feasible explanation for the small-scale challenges of cold dark matter. We found that a single vector gauge boson with mass range of $\sim 10~\mathrm{MeV}$ and non-universal couplings as indicated successfully mediates interactions in the fermion and dark matter sectors in such a way that $(g-2)_μ$ additional contribution agrees with experimental constraints and the self-interacting dark matter fluid behaves as suggested by observations at different astrophysical length scales. Furthermore, the model requires a dark matter candidate within $10-100~ \mathrm{GeV}$ order mass and a strong dark coupling ($g_χ \sim 0.3$, much stronger than the lepton's couplings $g'_l \lesssim 10^{-4}$) to be a successful scenario to unravel astrophysical small scale problems.

hep-ph↗

arXiv2023

Searching for dark-matter waves with PPTA and QUIJOTE pulsar polarimetry

The polarization of photons emitted by astrophysical sources might be altered as they travel through a dark matter medium composed of ultra light axion-like particles (ALPs). In particular, the coherent oscillations of the ALP background in the galactic halo induce a periodic change on the polarization of the electromagnetic radiation emitted by local sources such as pulsars. Building up on previous works, we develop a new, more robust, analysis based on the generalised Lomb-Scargle periodogram to search for this periodic signal in the emission of the Crab supernova remnant observed by the QUIJOTE MFI instrument and 20 galactic pulsars from the Parkes Pulsar Timing Array (PPTA) project. We also carefully take into account the stochastic nature of the axion field, an effect often overlooked in previous works. This refined analysis leads to the strongest limits on the axion-photon coupling for a wide range of dark matter masses spanning $10^{-23}\text{ eV}\lesssim m_a\lesssim10^{-19} \text{ eV}$. Finally, we survey possible optimal targets and the potential sensitivity to axionic dark-matter in this mass range that could be achieved using pulsar polarimetry in the future.

astro-ph.CO↗

arXiv2022

Multicomponent scalar dark matter at high-intensity proton beam experiments

We study a scalar dark matter (DM) model with two DM species coupled to the Standard Model (SM) particles via a sub-GeV dark photon. In this model, we find that DM conversion occurs through the dark photon and it plays a fundamental role in setting the observed relic abundance. Furthermore, the two DM candidates can be produced at fixed-target experiments a la Beam- Dump. Detailed predictions for signal and backgrounds are obtained with the help of MadDump and NuWro Montecarlo generators. We explore the potential reach on the sensitivity of DUNE near detector and SHiP experiment, and we find that portions of the parameter space will be within reach of the two experiments

hep-ph↗

arXiv2017

Neutrino self-energy with new physics effects in an external magnetic field

We compute the magnetic dipole moment (MDM) for massive flavor neutrinos using the neutrino self-energy in a magnetized media. The framework to incorporate neutrino masses is one minimal extension of the Standard Model in which neutrinos are Dirac particles and their masses coming from tiny Yukawa couplings from a second Higgs doublet with a small vacuum expectation value. The computations are carried out by using proper time formalism in the weak field approximation $eB<<m_{e}^{2}$ and assuming normal hierarchy for neutrino masses and sweeping the charged Higgs mass. For $ν_τ$, analyses in the neutrino specific scenario indicate magnetic dipole moments greater than the values obtained to the MDM in the SM (with and without magnetic fields) and other flavor conserving models. This fact leading a higher proximity with experimental bounds and so on it is possible to get stronger exclusion limits over new physics parameter space.

hep-ph↗

arXiv2017

Top-antitop production from $W_L^+ W_L^-$ and $Z_L Z_L$ scattering under a strongly-interacting symmetry-breaking sector

By using a Non-linear Electroweak Chiral Lagrangian, including the Higgs, coupled to heavy quarks, and the Equivalence Theorem, we compute (in the regime $M_t^2/v^2\ll\sqrt{s}M_t/v^2\ll s/v^2$) the one-loop amplitudes $W^+W^-\to t\bar t$, $ZZ\to t\bar t$ and $hh\to t\bar t$ (to NLO in the effective theory). We calculate the scalar partial-wave helicity amplitudes which allow us to check unitarity at the perturbative level in both $M_t/v$ and $s/v$. As with growing energy perturbative unitarity deteriorates, we also introduce a new unitarization method with the right analytical behavior on the complex $s$-plane and that can support poles on the second Riemann sheet to describe resonances in terms of the Lagrangian couplings. Thus we have achieved a consistent phenomenological description of any resonant $t\bar t$ production that may be enhanced by a possible strongly interacting Electroweak Symmetry Breaking Sector.

hep-ph↗

arXiv2016

Contribution to the neutrino magnetic moment coming from 2HDM in presence of magnetic fields

The confirmation of the neutrino mass by oscillation phenomena converts the study of the magnetic dipole moment (MDM) of the neutrino, in vacuum and regions where existing external magnetic fields, a topic of particular interest from the theoretical point of view. The MDM has an implicit relation with neutrino masses, and this is a possible benchmark from new physics in the solution of open questions in neutrino physics. Besides we know that this kind of phenomena has significant consequences on cosmology and astrophysics, e.g., under the influence of combined effects of neutrinos in the compact objects formation and evolution of primordials magnetic fields. We calculate and analyze such effects introducing charged Higgs bosons based on the parameter space of several 2HDMs with and without flavor conservation in neutral currents.

hep-ph↗

arXiv2016

Study of vacuum behavior for inert models with discrete $Z_{2}$-like and abelian $U(1)$ symmetries

We study the vacuum behavior at one loop level in extended Higgs sectors with two doublets (2HDM), where $U(1)$ and $Z_{2}$ symmetries are considered to protect the $CP$ symmetry in the Higgs potential and to avoid Flavor Changing Neutral Currents at tree level in the Yukawa sector. In the Inert Higgs Model case, a detailed comparison is made between both models by using the energy evolution of couplings, which should satisfy energy scale dependent relations deduced for minima and stationary points of the Higgs potential at tree level. Besides, perturbative unitarity constraints at tree level are considered to generate the allowed parameter space compatible with perturbativity (absence of Landau poles). Our studies illustrate exclusion regions for Higgs masses and other combinations of couplings in the scalar sector, in particular for splittings of mass square for neutral scalars $A^{0}$ and $H^{0}$, as well as the difference between the sum of these and the charged Higgs mass square. From the vacuum stability for inert-2HDM at the tree and one loop levels, analyses lead us to find out new hierarchical structures for scalar masses. To complete vacuum studies on the Inert model, and based on reparameterization invariance of the Higgs potential, we compute original discriminants that allow ensuring the presence of a global electroweak minimum at tree level. Moreover, the behavior in high energy scales drives out analyzing criticality phenomena for the additional parameters of extended Higgs sectors. Finally, and using the consistency with the electroweak precision analyses of oblique parameters, we describe several implications from different regimes of the inert model on charged and pseudoscalar Higgs searches.

hep-ph↗

arXiv2016

Phenomenological aspects from vacuum stability and metastability in models with soft breaking of a \texorpdfstring{$U\left( 1\right)$}{lg} global symmetry

We study the vacuum behavior of an extended Higgs sector with two doublets in a scenario with a softly broken \texorpdfstring{$U(1)$}{lg} global symmetry. The soft-violation term is introduced to avoid massless-axion particles arising when the global symmetry becomes spontaneously broken. This model has metastable states through the possible presence of multiple non-degenerate minima, which is unwanted from the phenomenological point of view if the metastable state is not long-lived enough. The analysis of this fact leads to find possible exclusion limits over parameter space of quartic couplings. Results improve the individual behavior of initial conditions for renormalization group equations; also determining unstable zones for the effective Higgs potential at one loop level. Besides vacuum stability analyses, the influence of absence of charge violation minima is considered as a limiting case excluding zones in the parameter space. Extremal cases for the model as well as criticality phenomena are discussed with the aid of relation among Higgs masses or splittings among them. From vacuum behavior and LHC results, phenomenological aspects in the searching of charged and heavier Higgs bosons are considered to evaluate the scalar alignment regimen of the two Higgs doublet model.

hep-ph↗