arXiv subjects

Mario A. Acero

Publications and source records attributed to Mario A. Acero.

At least 19 recordsLinked to original sources

arXiv2026

Latin American HECAP Physics Briefing Book 2025

The first process for the Latin American Strategy Forum for Research Infrastructure for High Energy, Cosmology and Astroparticle Physics (LASF4RI-HECAP) came to a conclusion in October 2020, with a Physics Briefing Book (PBB) presented in (2104.06852). Here we present an updated PBB, the result of the first update of LASF4RI-HECAP. The update process began with a call for White Papers from the HECAP community. The submitted contributions were presented at the III LASF4RI for HECAP Symposium: Update of the Strategic Plan, held at ICTP-SAIFR in São Paulo in August 26-29, 2024, with the participation of the Preparatory Group, High Level Strategy Group, Funding Agencies and representatives of similar efforts from around the globe. This updated PBB was written by the Preparatory Group based mainly on 46 White Papers submitted by the community and is organized around seven working groups: Astronomy, Astrophysics and Astroparticle Physics; Cosmology; Dark Matter; Neutrinos; Electroweak and Strong Interactions, Higgs Physics, CP and Flavour Physics and BSM; Instrumentation and Computing; Advanced Training and Capacity Building. It is intended to provide the essential input for the creation of a long-term HECAP strategy in the region.

hep-ex↗

arXiv2025

Observational constraints on a modified-gravity model with an exponential function of the curvature using the expansion history, the RSD, and the Pantheon+SH0ES data

Considering a well-motivated $f(R)$ modified-gravity model, in which an exponential function of the curvature is included, in this paper we implement a statistical data analysis to set constraints on the parameters of the model, taking into account an analytic approximate solution for the expansion rate, $H(z)$. Using a Monte Carlo Markov Chain-based analysis of the expansion rate evolution, the standardized SN distance modulus and the redshift space distortion observational data, we find that the preferred value for the perturbative parameter, $b$, quantifying the deviation of the $f(R)$ model from $Λ$CDM, lies in a region that excludes $b = 0$ at $\gtrsim 3.5 σ$ C.L., and that the predicted current value of the Hubble parameter, $H_0$, locates in between the two observational results currently under scrutiny from Planck and SH0ES collaborations. Under the implemented approximate solution, and with the constraints obtained for the parameters, the proposed $f(R)$ model successfully reproduces the observational data and the predicted evolution of interesting cosmological parameters resemble the results of $Λ$CDM, as expected, while an oscillatory behavior of the dark energy equation of state is observed, pointing to deviation from the concordance cosmological model. The results presented here reinforce the conclusion that the $f(R)$ modified-gravity model represents a viable alternative to describe the evolution of the Universe, avoiding the challenges faced by $Λ$CDM.

astro-ph.CO↗

arXiv2025

Evaluation of the Leggett-Garg inequality by means of the neutrino oscillations observed in reactor and accelerator experiments

We revisit the study of the violation of the Leggett-Garg inequality in neutrino oscillation data as a mean to test some of the fundamental aspects of quantum mechanics. In particular, we consider the results of the Daya Bay and RENO reactor experiments, and the MINOS and NOvA accelerator experiments. We find that DB and MINOS exhibit a strong manifestation of Leggett-Garg violation, whereas for RENO and NOvA data, the indication is weaker. Considering the particular baselines and energy ranges explored by each experiment, our results demonstrate that the Leggett-Garg violation is more evident for smaller baseline-to-energy ratios in all the data sets studied, a relevant aspect to consider when looking for evidence of quantum mechanical decoherence in neutrino oscillations.

hep-ph↗

arXiv2024

Cosmological dynamics and observational constraints on a viable $f(Q)$ non-metric gravity model

Inspired by an exponential $f(R)$ gravity model studied in the literature, in this work we introduce a new and viable $f(Q)$ gravity model, which can be represented as a perturbation of $Λ$CDM. Typically, within the realm of $f(Q)$ gravity, the customary approach to investigate cosmological evolution involves employing a parametrization of the Hubble expansion rate in terms of the redshift, $H(z)$, among other strategies. In this work we have implemented a different strategy, deriving an analytical approximation for $H(z)$, from which we deduce approximated analytical expressions for the parameters $w_{\rm{DE}}$, $w_{\rm{eff}}$, and $Ω_{\rm{DE}}$, as well as the deceleration parameter $q$. In order to verify the viability of this approximate analytical solution, we examined the behavior of the these parameters in the late-time regime\textbf, in terms of the free parameter of the model, $b$. We find that for $b>0$, $w_{\rm{DE}}$ shows a quintessence-like behavior, while for $b<0$, it shows a phantom-like behavior. However, regardless of the sign of $b$, $w_{\rm{eff}}$ exhibits a quintessence-like behavior. Furthermore, it has been deduced that as the magnitude of the parameter $b$ increases, the present model deviates progressively from $Λ$CDM. We have also performed a Markov Chain Monte Carlo statistical analysis to test the model predictions with the Hubble parameter, the Pantheon supernova (SN) observational data, and the combination of those samples, obtaining constraints on the parameters of the model and the current values of the Hubble parameter and the matter density. Our findings indicate that this $f(Q)$ gravity model is indeed a viable candidate for describing the late-time evolution of the Universe at the background level.

astro-ph.CO↗

arXiv2023

Late-time cosmology in a model of modified gravity with an exponential function of the curvature

In this work, we analyse the late-time evolution of the universe for a particular $f(R)$ gravity model built from an exponential function of the scalar curvature. Following the literature, we write the field equations in terms of a suited statefinder function ($y_H(z)$) and considering well motivated physical initial conditions, the resulting equations are solved numerically. Also, the cosmological parameters $w_{\rm{DE}}$, $w_{\rm{eff}}$, $Ω_{\rm{DE}}$ and $H(z)$ and the statefinder quantities $q$, $j$, $s$ and $Om(z)$ are explicitly expressed in terms of $y_H(z)$ and its derivatives. Furthermore, setting an appropriate set of values for the model parameters, the cosmological parameters as well as the statefinder quantities are plotted, and their present values (at $z=0$), are shown to be compatible with Planck 2018 observations and the $Λ$CDM-model values. Considering updated measurements from the dynamics of the expansion of the universe, $H(z)$, we perform an statistical analysis to constrain the free parameters of the model, finding a particular set of values that fit the data well and predict acceptable values for the cosmological and statefinder parameters at present time. Therefore, the $f(R)$ gravity model is found to be consistent with the considered observational data, and a viable alternative to explain the late-time acceleration of the universe.

gr-qc↗

arXiv2022

Barrow holographic dark energy with Granda-Oliveros cut-off

A study on the effects of implementing the Granda-Oliveros infrared cutoff in the recently introduced Barrow Holographic Dark Energy model is presented, and its cosmological evolution is investigated. We find how the deformation parameter, $Δ$, affects the values of $H(z)$, and find that from this model it is possible to obtain an accelerated expansion regime of the universe at late times. We also obtain that increasing $Δ$ causes the EoS parameter to transition from quintessence to phantom. In addition, we show that the model can be used to describe the know eras of dominance. Finally, after studying the stability of the proposed model, a fit of the corresponding parameters is preformed, utilizing the measurements of the expansion rate of the universe, $H(z)$. The best fit of the parameters is found to be $(α,\, β,\, Δ) = (1.00^{+0.02}_{-0.02},\,0.69^{+0.03}_{-0.02},\,0.000^{+0.004}_{-0.000})$ at $1σ$ C.L, for which the Bekenstein-Hawking relation is favored.

gr-qc↗

arXiv2020

Deep Underground Neutrino Experiment (DUNE), Far Detector Technical Design Report, Volume I: Introduction to DUNE

The preponderance of matter over antimatter in the early universe, the dynamics of the supernovae that produced the heavy elements necessary for life, and whether protons eventually decay -- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our universe, its current state, and its eventual fate. The Deep Underground Neutrino Experiment (DUNE) is an international world-class experiment dedicated to addressing these questions as it searches for leptonic charge-parity symmetry violation, stands ready to capture supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. The DUNE far detector technical design report (TDR) describes the DUNE physics program and the technical designs of the single- and dual-phase DUNE liquid argon TPC far detector modules. This TDR is intended to justify the technical choices for the far detector that flow down from the high-level physics goals through requirements at all levels of the Project. Volume I contains an executive summary that introduces the DUNE science program, the far detector and the strategy for its modular designs, and the organization and management of the Project. The remainder of Volume I provides more detail on the science program that drives the choice of detector technologies and on the technologies themselves. It also introduces the designs for the DUNE near detector and the DUNE computing model, for which DUNE is planning design reports. Volume II of this TDR describes DUNE's physics program in detail. Volume III describes the technical coordination required for the far detector design, construction, installation, and integration, and its organizational structure. Volume IV describes the single-phase far detector technology. A planned Volume V will describe the dual-phase technology.

physics.ins-det↗

arXiv2020

Deep Underground Neutrino Experiment (DUNE), Far Detector Technical Design Report, Volume III: DUNE Far Detector Technical Coordination

The preponderance of matter over antimatter in the early universe, the dynamics of the supernovae that produced the heavy elements necessary for life, and whether protons eventually decay -- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our universe, its current state, and its eventual fate. The Deep Underground Neutrino Experiment (DUNE) is an international world-class experiment dedicated to addressing these questions as it searches for leptonic charge-parity symmetry violation, stands ready to capture supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. The DUNE far detector technical design report (TDR) describes the DUNE physics program and the technical designs of the single- and dual-phase DUNE liquid argon TPC far detector modules. Volume III of this TDR describes how the activities required to design, construct, fabricate, install, and commission the DUNE far detector modules are organized and managed. This volume details the organizational structures that will carry out and/or oversee the planned far detector activities safely, successfully, on time, and on budget. It presents overviews of the facilities, supporting infrastructure, and detectors for context, and it outlines the project-related functions and methodologies used by the DUNE technical coordination organization, focusing on the areas of integration engineering, technical reviews, quality assurance and control, and safety oversight. Because of its more advanced stage of development, functional examples presented in this volume focus primarily on the single-phase (SP) detector module.

physics.ins-det↗

arXiv2020

Deep Underground Neutrino Experiment (DUNE), Far Detector Technical Design Report, Volume IV: Far Detector Single-phase Technology

The preponderance of matter over antimatter in the early universe, the dynamics of the supernovae that produced the heavy elements necessary for life, and whether protons eventually decay -- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our universe, its current state, and its eventual fate. DUNE is an international world-class experiment dedicated to addressing these questions as it searches for leptonic charge-parity symmetry violation, stands ready to capture supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. Central to achieving DUNE's physics program is a far detector that combines the many tens-of-kiloton fiducial mass necessary for rare event searches with sub-centimeter spatial resolution in its ability to image those events, allowing identification of the physics signatures among the numerous backgrounds. In the single-phase liquid argon time-projection chamber (LArTPC) technology, ionization charges drift horizontally in the liquid argon under the influence of an electric field towards a vertical anode, where they are read out with fine granularity. A photon detection system supplements the TPC, directly enhancing physics capabilities for all three DUNE physics drivers and opening up prospects for further physics explorations. The DUNE far detector technical design report (TDR) describes the DUNE physics program and the technical designs of the single- and dual-phase DUNE liquid argon TPC far detector modules. Volume IV presents an overview of the basic operating principles of a single-phase LArTPC, followed by a description of the DUNE implementation. Each of the subsystems is described in detail, connecting the high-level design requirements and decisions to the overriding physics goals of DUNE.

physics.ins-det↗

arXiv2020

Deep Underground Neutrino Experiment (DUNE), Far Detector Technical Design Report, Volume II: DUNE Physics

The preponderance of matter over antimatter in the early universe, the dynamics of the supernovae that produced the heavy elements necessary for life, and whether protons eventually decay -- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our universe, its current state, and its eventual fate. DUNE is an international world-class experiment dedicated to addressing these questions as it searches for leptonic charge-parity symmetry violation, stands ready to capture supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. The DUNE far detector technical design report (TDR) describes the DUNE physics program and the technical designs of the single- and dual-phase DUNE liquid argon TPC far detector modules. Volume II of this TDR, DUNE Physics, describes the array of identified scientific opportunities and key goals. Crucially, we also report our best current understanding of the capability of DUNE to realize these goals, along with the detailed arguments and investigations on which this understanding is based. This TDR volume documents the scientific basis underlying the conception and design of the LBNF/DUNE experimental configurations. As a result, the description of DUNE's experimental capabilities constitutes the bulk of the document. Key linkages between requirements for successful execution of the physics program and primary specifications of the experimental configurations are drawn and summarized. This document also serves a wider purpose as a statement on the scientific potential of DUNE as a central component within a global program of frontier theoretical and experimental particle physics research. Thus, the presentation also aims to serve as a resource for the particle physics community at large.

hep-ex↗

arXiv2020

Inflation driven by a holographic energy density

In this letter we study a model of inflation in which the inflationary regimen comes from a type of holographic energy density. In particular, we consider the Granda-Oliveros proposal for the holographic energy density, which contains two free dimensionless parameters, $α$ and $β$. This holographic energy density is associated to the so-called Granda-Oliveros infrared cutoff (G-O cutoff). Additionally, since in the inflationary regimen the energy scales are very high, it is necessary to modify the G-O cutoff taking into account a correction due to the ultraviolet cutoff. In this way, we obtain an algebraic equation which implicitly includes the Hubble parameter (as a function of e-folding number, $N$) and from this, we calculate the Hubble slow-roll parameters and the values of the inflationary observables: the scalar spectral index of the curvature perturbations and its running, the tensor spectral index and the tensor-to-scalar ratio. Finally, since the values for these inflationary observables are known (Planck 2018 observations), we present constraints on the parameters $α$ and $β$ to make this a viable model.

gr-qc↗

arXiv2020

Neutrino oscillation analysis of 217 live-days of Daya Bay and 500 live-days of RENO

We present a neutrino oscillation analysis of two particular data sets from the Daya Bay and RENO reactor neutrino experiments aiming to study the increase in precision in the oscillation parameters $\sin^2{2θ}_{13}$ and the effective mass splitting $Δm^2_{ee}$ gained by combining two relatively simple to reproduce analyses available in the literature. For Daya Bay the data from 217 days between December 2011 and July 2012 were used. For RENO we used the data from 500 live days between August 2011 and January 2012. We reproduce reasonably well the results of the individual analyses, both, rate-only and spectral, defining a suitable $χ^2$ statistic for each case. Finally, we performed a combined spectral analysis and extract tighter constraints on the parameters, with an improved precision between 30-40\% with respect of the individual analyses considered.

hep-ph↗

arXiv2018

Recent results from Long-Baseline Neutrino experiments

Understanding the physics of neutrinos is of paramount relevance for the development of high energy physics, cosmology and astrophysics, thanks to their characteristics and phenomenology. In particular, the property of changing flavor while neutrinos travel, the so-called neutrino oscillation phenomenon, provides us with valuable information about their behavior and their impact on the standard model of particles and the evolution of the universe, for instance. Here I present an overview of the most recent results as reported by relevant experiments studying neutrinos produced by accelerator facilities and detected after traveling long distances: the so-called Long-Baseline neutrino experiments.

hep-ex↗

arXiv2015

Late cosmic acceleration in a vector--Gauss-Bonnet gravity model

In this work we study a general vector-tensor model of dark energy with a Gauss-Bonnet term coupled to a vector field and without explicit potential terms. Considering a spatially flat FRW type universe and a vector field without spatial components, the cosmological evolution is analysed from the field equations of this model, considering two sets of parameters. In this context, we have shown that it is possible to obtain an accelerated expansion phase of the universe, since the equation state parameter $w$ satisfies the restriction $-1<w<-1/3$ (for suitable values of model parameters). Further, analytical expressions for the Hubble parameter $H$, equation state parameter $w$ and the invariant scalar $ϕ$ are obtained. We also find that the square of the speed of sound is negative for all values of redshift, therefore, the model presented here shows a sign of instability under small perturbations. We finally perform an analysis using $H(z)$ observational data and we find that for the free parameter $ξ$ in the interval $(-23.9, -3.46)\times 10^{-5}$, at $99.73\%$ C.L. (and fixing $η= -1$ and $ω= 1/4$), the model has a good fit to the data.

hep-th↗

arXiv2014

New holographic dark energy model with non-linear interaction

In this paper the cosmological evolution of a holographic dark energy model with a non-linear interaction between the dark energy and dark matter components in a FRW type flat universe is analysed. In this context, the deceleration parameter $q$ and the equation state $w_Λ$ are obtained. We found that, as the square of the speed of sound remains positive, the model is stable under perturbations since early times; it also shows that the evolution of the matter and dark energy densities are of the same order for a long period of time, avoiding the so--called coincidence problem. We have also made the correspondence of the model with the dark energy densities and pressures for the quintessence and tachyon fields. From this correspondence we have reconstructed the potential of scalar fields and their dynamics.

hep-th↗

arXiv2013

Phenomenology of Quantum Gravity and its Possible Role in Neutrino Anomalies

New phenomenological models of Quantum Gravity have suggested that a Lorentz-Invariant discrete spacetime structure may become manifest through a nonstandard coupling of matter fields and spacetime curvature. On the other hand, there is strong experimental evidence suggesting that neutrino oscillations cannot be described by simply considering neutrinos as massive particles. In this manuscript we motivate and construct one particular phenomenological model of Quantum Gravity that could account for the so-called neutrino anomalies.

gr-qc↗

arXiv2008

Cosmological constraints on a light non-thermal sterile neutrino

Although the MiniBooNE experiment has severely restricted the possible existence of light sterile neutrinos, a few anomalies persist in oscillation data, and the possibility of extra light species contributing as a subdominant hot (or warm) component is still interesting. In many models, this species would be in thermal equilibrium in the early universe and share the same temperature as active neutrinos, but this is not necessarily the case. In this work, we fit up-to-date cosmological data with an extended LambdaCDM model, including light relics with a mass typically in the range 0.1 -10 eV. We provide, first, some nearly model-independent constraints on their current density and velocity dispersion, and second, some constraints on their mass, assuming that they consist either in early decoupled thermal relics, or in non-resonantly produced sterile neutrinos. Our results can be used for constraining most particle-physics-motivated models with three active neutrinos and one extra light species. For instance, we find that at the 3 sigma confidence level, a sterile neutrino with mass m_s = 2 eV can be accommodated with the data provided that it is thermally distributed with (T_s/T_nu) < 0.8, or non-resonantly produced with (Delta N_eff) < 0.5. The bounds become dramatically tighter when the mass increases. For m_s < 0.9 eV and at the same confidence level, the data is still compatible with a standard thermalized neutrino.

astro-ph↗

arXiv2008

Limits on nu_e and anti-nu_e disappearance from Gallium and reactor experiments

The deficit observed in the Gallium radioactive source experiments is interpreted as a possible indication of the disappearance of electron neutrinos. In the effective framework of two-neutrino mixing we obtain $\sin^{2}2\vartheta \gtrsim 0.03$ and $Δ{m}^{2} \gtrsim 0.1 \text{eV}^{2}$. The compatibility of this result with the data of the Bugey and Chooz reactor short-baseline antineutrino disappearance experiments is studied. It is found that the Bugey data present a hint of neutrino oscillations with $0.02 \lesssim \sin^{2}2\vartheta \lesssim 0.08$ and $Δ{m}^{2} \approx 1.8 \text{eV}^{2}$, which is compatible with the Gallium allowed region of the mixing parameters. This hint persists in the combined analyses of Bugey and Chooz data, of Gallium and Bugey data, and of Gallium, Bugey, and Chooz data.

hep-ph↗