arXiv subjects

Amalia Betancur

Publications and source records attributed to Amalia Betancur.

6 recordsLinked to original sources

arXiv2026

Probing inelastic sub-GeV dark matter at the DUNE near detector

We study inelastic dark matter (iDM) in a minimal and ultraviolet-complete framework in which the dark photon mass arises from a dark Higgs mechanism. The spontaneous breaking of a $U(1)_D$ symmetry splits the Dirac fermion into two Majorana states, thus opening new annihilation channels mediated by the dark Higgs. Focusing on sub-GeV dark matter, we assess the sensitivity of DUNE's liquid argon cube at the near detector (ND-LAr) to this scenario. We find that the ND-LAr can probe regions of parameter space consistent with the observed relic abundance due to these new annihilation channels, particularly for large dark photon-to-DM mass ratios where decay-based searches lose sensitivity. Our results highlight the complementarity between cosmological constraints and fixed-target experiments and demonstrate the potential of DUNE's ND-LAr to explore iDM scenarios with extended dark sectors.

hep-ph↗

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↗

arXiv2020

Inert doublet as multicomponent dark matter

In this work, we study multicomponent dark sectors comprised of a fermionic and a scalar dark matter candidate. In the scalar sector, we mostly focus on the Inert Doublet Model while in the fermionic sector we study three different models. For all of them, we investigate the impact that dark matter conversion and regular WIMP dark matter annihilating processes have on the relic abundance. We mostly recover the region between the electroweak scale and $\sim$ 550 GeV for the scalar dark matter mass, which is usually excluded in the Inert Doublet Model. We also consider current constraints from both direct detection and indirect detection experiments and include future prospects to probe the models. Additionally, we investigate constraints from collider searches on the fermionic dark matter candidates.

hep-ph↗

arXiv2019

Measuring the mass, width, and couplings of semi-invisible resonances with the Matrix Element Method

We demonstrate the use of the Matrix Element Method (MEM) for the measurement of masses, widths, and couplings in the case of single or pair production of semi-invisibly decaying resonances. For definiteness, we consider the two-body decay of a generic resonance to a visible particle from the Standard Model (SM) and a massive invisible particle. It is well known that the mass difference can be extracted from the endpoint of a transverse kinematic variable like the transverse mass, $M_T$, or the Cambridge $M_{T2}$ variable, but measuring the overall mass scale is a very difficult problem. We show that the MEM can be used to obtain not only the absolute mass scale, but also the width of the resonance and the tensor structure of its couplings. Apart from new physics searches, our results can be readily applied to the case of SM $W$ boson production at the CERN Large Hadron Collider (LHC), where one can repeat the measurements of the $W$ properties in a general and model-independent framework.

hep-ph↗

arXiv2018

Phenomenology of doublet-triplet fermionic dark matter in nonstandard cosmology and multicomponent dark sectors

We consider the doublet-triplet fermionic model in the scheme of the custodial limit when the dark matter (DM) candidate is pure doublet and lies at the electroweak scale. This scheme, despite being an appealing and promising DM model, is severely constrained by the interplay between the DM relic density constraint and the LHC measurement of the Higgs diphoton decay rate. In this work, the DM relic density is considered to arise from either a nonstandard cosmology scenario or as a part of a larger sector encompassing other DM particles, this in order to saturate the observed relic abundance. For these scenarios we investigate the impact of the new sector in different collider observables, and study constraints coming from direct detection and indirect detection of gamma-rays both in the diffuse and linelike spectrum. As a result, we find that in the nonstandard cosmology scenario most experiments impose, up to a certain point, restrictions, though large portions of the parameter space are still viable. For the multicomponent case, only direct detection imposes constraints.

hep-ph↗

arXiv2017

Doublet-triplet dark matter with neutrino masses

We consider a dark matter (DM) model that arises from the interplay of two simplified dark matter models, namely the doublet-triplet fermion model and the doublet-triplet scalar model. Despite being excellent exponents of the WIMP paradigm, the physics related to DM in each of these models fails at the same time to account for neutrino masses. It turns out that from the combination of these two models it is possible to generate neutrino masses at one-loop level in the four topologies that are realizations of the Weinberg operator for neutrino masses at one-loop. In this work, we combine both models focusing mostly on fermionic dark matter lying at the electroweak scale. We analyze the impact of the extra charged fields on the Higgs diphoton decay and find that, thanks to the presence of the charged scalars, it is possible to have a viable DM region at the electroweak scale.

hep-ph↗