arXiv subjects

Jorge Venzor

Publications and source records attributed to Jorge Venzor.

8 recordsLinked to original sources

arXiv2026

CosmoVerse Data Challenge: How Tip of the Red Giant Branch Analysis Choices Shape the Inferred Hubble Constant

Tip of the red giant branch (TRGB)-based determinations of the Hubble constant ($H_0$), the current expansion rate of the Universe, depend on choices made in selecting and analyzing stellar photometry and in assembling the sample of calibrator galaxies hosting Type Ia supernovae (SNe Ia). The CosmoVerse Data Challenge invites participants to analyze public photometric catalogs within a shared distance-ladder framework, opening each step of the measurement to the community and testing how these choices propagate into $H_0$. Participants independently selected photometric catalogs, galaxies, and TRGB measurement settings, while using a common SN Ia compilation and fitting procedure to convert distances into $H_0$. Supported by public notebooks and a training school, the challenge received 26 submissions from 22 participants. All submissions used the same analysis notebook, many participants were trainees at the school, and the true galaxy distances are unknown; the results therefore characterize the sensitivity of the submissions to analysis and sample-selection choices and are not a combined determination of $H_0$ or an estimate of the systematic uncertainty in published TRGB measurements. The inferred $H_0$ values have a median of $77.10\,\mathrm{km\,s^{-1}\,Mpc^{-1}}$ and a standard deviation of $7.38\,\mathrm{km\,s^{-1}\,Mpc^{-1}}$ $(5.11\,\mathrm{km\,s^{-1}\,Mpc^{-1}}$ for the scaled median absolute deviation), $\sim 3.4$ $(\sim 2.4)$ times the typical quoted uncertainty of a submission. Differences in the measured tip of the anchor galaxy NGC 4258 add a coherent shift in the distance scale. The challenge shows how different choices within a common framework can produce substantially different values of $H_0$, and provides an open basis for tracing these differences and for making datasets and tools more transparent and accessible.

astro-ph.GA↗

arXiv2026

Neutrino self-interactions in light of DESI and CMB-SPA

We present an updated analysis of non-standard neutrino self-interactions, where the interaction is effectively mediated by a heavy particle, using the latest available data from DESI and the CMB. The considered data include combinations of DESI DR1 full-shape galaxy clustering (FS), BAO distance measurements, Lyman-$α$ 1D power spectra (Ly-$α$), and a combined CMB likelihood (CMB-SPA) using data from Planck, ACT, and SPT. First, we probe two DESI DR1-only datasets, where the effective interaction parameter $G_{\rm eff}$ is multimodal in the profile likelihood, leading us to analyze two different regimes: moderately interacting (MI$_ν$) and strongly interacting (SI$_ν$) neutrinos. With FS+BAO, the evidence disfavors the SI$_ν$ mode, a trend that becomes slightly stronger with the inclusion of Ly-$α$. However, in the latter dataset, the MI$_ν$ region shows a bimodality in which the intermediate mode is very sharp and peaks around $G_{\rm eff\,} \simeq 10^{-3} \mathrm{MeV}^{-2}$; interestingly, this mode is not penalized versus the weaker standard-like mode. Furthermore, we test CMB and DESI joint data and show that the SI$_ν$ mode is more disfavored by CMB-SPA than by Planck-only data. In particular, the evidence against this mode becomes the strongest thus far (with odds of 5:100000) in the FS+BAO+CMB-SPA combination.

astro-ph.CO↗

arXiv2026

Towards a complete scheme of cosmological neutrino self-interactions: Collision term for a wide range of mediator masses

Neutrino self-interactions (NSI) offer a potential pathway to address anomalies in standard cosmology and explain existing cosmological tensions. In this work, we present a novel framework to obtain the neutrino--neutrino collision term within the Boltzmann hierarchy, incorporating both neutrino and mediator masses as free parameters. Our calculations encompass both Dirac-like and Majorana neutrinos and distinguish between two neutrino mass eigenstates. This work provides a valuable tool for future analyses, should a NSI signal be detected. Remarkably, our results show a smooth transition from the light to the heavy mediator approximation as the Universe cools down for non-resonant cases. Thus, for the widely studied heavy mediator, our new scheme eliminates the need to approximate at high redshifts when the temperature increases above the mediator mass, and it provides the tools to test the threshold of validity of the heavy mediator paradigm. While this work focuses on NSI mediated by a scalar particle, the presented framework could be adapted to a broader range of neutrino NSI and possibly to warm dark matter self-interacting scenarios.

hep-ph↗

arXiv2025

Resonant neutrino self-interactions: Insights from the full shape galaxy power spectrum

This paper investigates resonant neutrino self-interactions in cosmology by employing, for the first time, the effective field theory of large-scale structure to model their impact on the matter distribution up to mildly nonlinear scales. We explore a broad range of mediator masses in two main analyses: one combining BOSS Full Shape (FS) galaxy clustering with Big Bang Nucleosynthesis (BBN), and another combining FS with Planck Cosmic Microwave Background (CMB) data. Our results place the strongest cosmological constraints to date on the resonant self interactions when using FS+Planck data, reaching up to $g_ν< 10.8 \times 10^{-14}$ at $95\%$ confidence for the 1 eV mediator. Notably, FS+BBN can constrain the interaction for the 10 eV mediator independently of CMB data, yielding $g_ν< 7.33 \times 10^{-12}$ at $95\%$ confidence. Our results suggest that resonant neutrino self-interactions are unlikely to resolve existing cosmological tensions within the standard $Λ$CDM framework.

astro-ph.CO↗

arXiv2025

Resonant neutrino self-interactions and the $H_0$ tension

In this work, we study the previously unexplored resonant region of neutrino self-interactions. Current disagreement on late and early time observations of the Universe expansion could be solved with new physics acting before the recombination era. Nonstandard neutrino self-interactions are among the most appealing candidates to solve this issue since they could be testable in the near (or midterm) future. We use linear cosmological datasets to test neutrino self-interactions for a sample of fixed scalar mediator masses in the range $10^{-2}$ eV $\leq m_φ\leq 10^{2}$ eV. The resonant behavior produces observable effects at lower couplings than those reported in the literature for heavy and light mediators. We observe that in the best case scenario, using the Planck + BAO dataset, the tension with local measurements of $H_0$ eases from 4.9$σ$ (for $Λ$CDM) down to 2.8$σ$. Albeit, this is driven mainly by the addition of extra radiation, with $ΔN_{\rm eff}\sim 0.5$. The joint dataset which includes Planck, BAO, and $H_0$ prefers a nonzero interaction from 2.3$σ$ to 3.9$σ$ significance in the range $0.5$ eV $\leq m_φ\leq 10$ eV. Although, this last result is obtained with data that are still in tension. These results add the last piece in the parameter space of neutrino self-interactions at the linear perturbation regime.

astro-ph.CO↗

arXiv2022

Massive neutrino self-interactions with a light mediator in cosmology

Nonstandard self-interactions can alter the evolution of cosmological neutrinos, mainly by damping free streaming, which should leave traces in cosmological observables. Although overall effects are opposite to those produced by neutrino mass and a larger $N_{\rm eff}$, they cannot be totally canceled by these last. We harness cosmological data that includes Cosmic Microwave Background from Plank 2018, BAO measurements, local $H_0$, Ly-$α$ and SNIa, to constrain massive neutrino self-interactions with a very light scalar mediator. We find that the effective coupling constant, at the 95\% C.L., should be $g_{\rm eff}< 1.94 \times 10^{-7}$ for only Planck 2018 data and $1.97\times10^{-7}$ when Planck + BAO are considered. This bound relaxes to $2.27\times 10^{-7}$ ($2.3\times 10^{-7}$) for $H_0$ ($H_0$+SNe+Ly-$α$) data. Using the Planck + BAO dataset, the $H_0$ tension lowers from 4.3$σ$ (for $Λ$CDM) to 3.2$σ$. The Akaike Information Criterion penalizes the self-interacting model due to its larger parameter space for Plank or Planck + BAO data, but favors the interacting model when we use local $H_0$ measurements. A somewhat larger value for $H_0$ is preferred when we include the whole data pool, which comes accompanied with a larger value of $N_{\rm eff}$ and a more constricted bound on $Σm_ν$.

astro-ph.CO↗

arXiv2021

Bounds on neutrino-scalar nonstandard interactions from big bang nucleosynthesis

Coherent forward scattering processes by neutrino-scalar nonstandard interactions (SNSI) induce an effective neutrino mass. In the Early Universe, a large neutrino effective mass restricts the production of neutrinos. The SNSI effect is modulated by two effective couplings, these account for the coupling between neutrinos and electrons/positrons, $G_{\rm eff}$, and the neutrino self-interaction, $G_{\rm S}$. These parameters are directly related to the effective number of relativistic species and non-zero values imply a smaller than expected $N_{\rm eff}$. We employ big bang nucleosynthesis to constraint the SNSI effect. We find that $ G_{\rm eff }< 1.2$ MeV$^{-2}$ and $ G_{\rm S }< 2.0 \times 10^{7}$ MeV$^{-2}$ at 68\% CL. For a scalar mass in the range $10^{-15} {\rm eV}\lesssim m_ϕ\lesssim 10^{-5}{\rm eV}$, our neutrino-scalar coupling constraint is more restrictive than any previous result.

hep-ph↗

arXiv2020

Constraints on the velocity dispersion of Dark Matter from Cosmology and new bounds on scattering from the Cosmic Dawn

The observational value of the velocity dispersion, $Δ\upsilon$, is missing in the Dark Matter (DM) puzzle. Non-zero or non-thermal DM velocities can drastically influence Large Scale Structure and the 21-cm temperature at the epoch of the Cosmic Dawn, as well as the estimation of DM physical parameters, such as the mass and the interaction couplings. To study the phenomenology of $Δ\upsilon$ we model the evolution of DM in terms of a simplistic and generic Boltzmann-like momentum distribution. Using cosmological data from the Cosmic Microwave Background, Baryonic Acoustic Oscillations, and Red Luminous Galaxies, we constrain the DM velocity dispersion for a broad range of masses $10^{-3} eV < m_χ< 10^9 eV$, finding $Δ\upsilon_0 \lesssim$ 0.33 km/s (99% CL). Including the EDGES $T_{21}$-measurements, we extend our study to constrain the baryon-DM interaction in the range of DM velocities allowed by our analysis. As a consequence, we present new bounds on two electromagnetic models of DM, namely minicharged particles (MCPs) and electric dipole moment (EDM). For MCPs, the parameter region that is consistent with EDGES and independent bounds on cosmological and stellar physics is very small, pointing to the sub-eV mass regime of DM. A window in the MeV-GeV may still be compatible with these bounds for MCP models without a hidden photon. But the EDM parameter region consistent with EDGES is excluded by Big-Bang Nucleosynthesis and Collider Physics.

astro-ph.CO↗