arXiv subjects

Manuel Masip

Publications and source records attributed to Manuel Masip.

At least 19 recordsLinked to original sources

arXiv2026

Monochromatic neutrinos from scotogenic dark matter

The scotogenic model defines a framework for radiative neutrino masses and provides a viable dark matter candidate. Since the scotogenic dark matter is leptophilic, indirect searches appear as an especially interesting possibility. Here we propose a simple variation of the model with a very distinct phenomenology. The scotogenic fermion singlets are naturally grouped into pseudo-Dirac pairs of mass of 0.1-1 TeV. We show that the lightest one constitutes a dark matter candidate that near threshold annihilates with a 90% branching ratio into neutrino pairs. The model gives the observed relic abundance consistently with the bounds from direct searches and with all neutrino and charged lepton data. We also show that, for a sub-MeV dark matter particle, the model suggests a scenario that could address the lithium problem.

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arXiv2025

High energy gamma rays and neutrinos from the Sun, Jupiter and Earth

Cosmic rays reaching the atmosphere of an astrophysical object produce showers of secondary particles that may then escape into space. Here we obtain the flux of gamma rays and neutrinos of energy $E>10$ GeV emitted by the Sun, Jupiter and Earth. We show that, while the solar magnetic field induces a flux of gamma rays from all the points on the Sun's surface, the dipolar magnetic field in the planets implies high energy photons only from the very peripheral region. Neutrinos, in contrast, can cross these objects and emerge from any point on their surface. The emission from these astrophysical objects exceeds the diffuse flux from cosmic ray interactions with the interstellar medium and has a distinct spectrum and gamma ray to neutrino ratio.

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arXiv2025

J-PAS: Forecasting constraints on Neutrino Masses

The large-scale structure survey J-PAS is taking data since October 2023. In this work, we present a forecast based on the Fisher matrix method to establish its sensitivity to the sum of the neutrino masses. We adapt the Fisher Galaxy Survey Code (FARO) to account for the neutrino mass under various configurations applied to galaxy clustering measurements. This approach allows us to test the sensitivity of J-PAS to the neutrino mass across different tracers, with and without non-linear corrections, and under varying sky coverage. We perform our forecast for two cosmological models: $\Lambda CDM + \sum m_\nu$ and $w_0w_a CDM + \sum m_\nu$. We combine our J-PAS forecast with Cosmic Microwave Background (CMB) data from the Planck Collaboration and Type Ia supernova (SN) data from Pantheon Plus. Our analysis shows that, for a sky coverage of 8,500 square degrees, J-PAS galaxy clustering data alone will constrain the sum of the neutrino masses to an upper limit at 95% C.L of $\sum m_\nu < 0.32$ eV for the $\Lambda CDM + \sum m_\nu$ model, and $\sum m_\nu < 0.36$ eV for the $w_0w_a CDM + \sum m_\nu$ model. When combined with Planck data, the upper limit improves significantly. For J-PAS+Planck at 95% C.L, we find $\sum m_\nu < 0.061$ eV for the $\Lambda CDM + \sum m_\nu$ model, and for J-PAS+Planck+Pantheon Plus, we obtain $\sum m_\nu < 0.12$ eV for the $w_0w_a CDM + \sum m_\nu$ model. These results demonstrate that J-PAS clustering measurements can play a crucial role in addressing challenges in the neutrino sector, including potential tensions between cosmological and terrestrial measurements of the neutrino mass, as well as in determining the mass ordering.

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arXiv2025

J-PAS and PFS surveys in the era of dark energy and neutrino mass measurements

Fisher-matrix forecasts are presented for the cosmological surveys of the Javalambre Physics of the Accelerating Universe Astrophysical Survey (J-PAS) and the Subaru Prime Focus Spectrograph (PFS). The wide, low-redshift coverage of J-PAS and the high-density, high-redshift mapping of PFS are strongly complementary: combining the two reduces marginalized uncertainties on all primary parameters compared with either survey individually. Adding the joint J-PAS+PFS data to next-generation CMB measurements from the Simons Observatory (SO) and \textsc{LiteBird} yields an expected precision of $\sigma(\sum m_\nu)=0.017\,$eV in the $\Lambda$CDM$+\sum m_\nu+N_{\rm eff}$ framework, sufficient to disfavour the inverted neutrino hierarchy at $2.34\,\sigma$ if the true mass sum equals the normal-ordering minimum. Motivated by recent DESI results, we also forecast within a $w_0w_a$CDM$+\sum m_\nu+N_{\rm eff}$ cosmology, adopting the DESI\,DR2 best-fit values ($w_0=-0.758$, $w_a=-0.82$) as fiducial. The combination CMB+J-PAS+PFS then delivers $\sigma(w_0)=0.044$ and $\sigma(w_a)=0.18$, corresponding to a $5.1\,\sigma$ preference for a time-varying dark-energy equation of state. These findings show that J-PAS and PFS, especially when coupled with Stage-IV CMB observations, will provide competitive tests of neutrino physics and the dynamics of cosmic acceleration.

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arXiv2024

Reconstructing a Heavy Neutral Lepton at the LHC

Heavy lepton singlets $N$ slightly mixed with a standard neutrino $\nu_\ell$ are usually searched for at the LHC in the trilepton plus $p_{\rm T}^{\rm miss}$ channel: $pp \to W^+ \to \ell^+ N$ with $N\to \ell^- W^+ \to \ell^- \ell'^+ \nu$. We show that, although the longitudinal momentum of the final $\nu$ escapes detection, the mass of the heavy lepton can be reconstructed. While this possibility has not been considered in recent LHC searches, we find that the search for a mass peak could systematically improve the current collider bounds on the mixing $|V_{\ell N}|^2$ for any mass $m_N\ge M_W$.

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arXiv2023

Photon to axion conversion during Big Bang Nucleosynthesis

We investigate how the resonant conversion at a temperature $\bar{T}=25$-$65$ keV of a fraction of the CMB photons into an axion-like majoron affects BBN. The scenario, that assumes the presence of a primordial magnetic field and the subsequent decay of the majorons into neutrinos at $T\approx 1$ eV, has been proposed to solve the $H_0$ tension. We find two main effects. First, since we lose photons to majorons at $\bar{T}$, the baryon to photon ratio is smaller at the beginning of BBN $(T>\bar{T})$ than during decoupling and structure formation ($T\ll \bar{T}$). This relaxes the $2σ$ mismatch between the observed deuterium abundance and the one predicted by the standard $Λ$CDM model. Second, since the conversion implies a sudden drop in the temperature of the CMB during the final phase of BBN, it interrupts the synthesis of lithium and beryllium and reduces their final abundance, possibly alleviating the lithium problem.

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arXiv2023

Ultra-peripheral collisions of charged hadrons in extensive air showers

We discuss the electromagnetic collisions of high energy protons, pions and kaons with atmospheric nuclei. In particular, we use the equivalent photon approximation to estimate (i) the diffractive collisions where the projectile scatters inelastically off a nucleus, and (ii) the usual radiative processes (bremsstrahlung, pair production and photonuclear interactions) of these charged hadrons in the air. We then include the processes in the simulator AIRES and study how they affect the longitudinal development of extensive air showers. For $10^{9-11}$ GeV proton primaries we find that they introduce a very small reduction (below 1%) in the average value of both $X_{\rm max}$ and $ΔX_{\rm max}$. At a given shower age (relative slant depth from $X_{\rm max}$), these electromagnetic processes slightly increase the number of charged particles at the shower maximum and reduce the number of muons when it is old, decreasing by 1% the muon-to-($γ+e$) near the ground level. the muon-to-($γ + e$) near the ground level.

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arXiv2023

Monochromatic neutrinos from dark matter through the Higgs portal

We define a minimal model of dark matter with a fermion singlet $χ$ coupled to the visible sector through the Higgs portal and with a heavy Dirac neutrino $N$ that opens the annihilation channel $χχ\to N ν$. The model provides the observed relic abundance consistently with bounds from direct searches and implies a monochromatic neutrino signal at 10 GeV-1 TeV in indirect searches. In particular, we obtain the capture rate of $χ$ by the Sun and show that the signal could be above the "neutrino floor" produced by cosmic rays showering in the solar surface. In most benchmark models this solar astrophysical background is above the expected dark matter signal, so the model that we propose is a canonical example of WIMP not excluded by direct searches that could be studied at neutrino telescopes and also at colliders.

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arXiv2023

The solar disk at high energies

High energy cosmic rays "illuminate" the Sun and produce an image that could be observed in up to five different channels: a cosmic ray shadow (whose energy dependence has been studied by HAWC); a gamma ray flux (observed at $E\le 200$ GeV by Fermi-LAT); a muon shadow (detected by ANTARES and IceCube); a neutron flux (undetected, as there are no hadronic calorimeters in space); and a flux of high energy neutrinos. Since these signals are correlated, the ones already observed can be used to reduce the uncertainty in the still undetected ones. Here we define a simple set up that uses the Fermi-LAT and HAWC observations to imply very definite fluxes of neutrons and neutrinos from the solar disk. In particular, we provide a fit of the neutrino flux at 10 GeV-10 TeV that includes its dependence on the zenith angle and on the period of the solar cycle. This flux represents a neutrino floor in indirect dark matter searches. We show that in some benchmark models the current bounds on the dark matter-nucleon cross section push the solar signal below this neutrino floor.

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arXiv2022

Cosmology of an Axion-Like Majoron

We propose a singlet majoron model that defines an inverse seesaw mechanism in the $ν$ sector. The majoron $ϕ$ has a mass $m_ϕ\approx 0.5$ eV and a coupling to the $τ$ lepton similar to the one to neutrinos. In the early universe it is initially in thermal equilibrium, then it decouples at $T\approx 500$ GeV and contributes with just $ΔN_{\rm eff}=0.026$ during BBN. At $T=26$ keV (final stages of BBN) a primordial magnetic field induces resonant $γ\leftrightarrow ϕ$ oscillations that transfer 6% of the photon energy into majorons, implying $ΔN_{\rm eff}=0.55$ and a 4.7% increase in the baryon to photon ratio. At $T\approx m_ϕ$ the majoron enters in thermal contact with the heaviest neutrino and it finally decays into $ν\bar ν$ pairs near recombination, setting $ΔN_{\rm eff}=0.85$. The boost in the expansion rate at later times may relax the Hubble tension (we obtain $H_0=(71.4\pm 0.5)$ km/s/Mpc), while the processes $ ν\bar ν\leftrightarrow ϕ$ suppress the free streaming of these particles and make the model consistent with large scale structure observations. Its lifetime and the fact that it decays into neutrinos instead of photons lets this axion-like majoron avoid the strong bounds that affect other axion-like particles of similar mass and coupling to photons.

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arXiv2021

Neutrino events within muon bundles at neutrino telescopes

The atmospheric neutrino flux includes a component from the prompt decay of charmed hadrons that becomes significant only at $E\ge 10$ TeV. At these energies, however, the diffuse flux of cosmic neutrinos discovered by IceCube seems to be larger than the atmospheric one. Here we study the possibility to detect a neutrino interaction in down-going atmospheric events at km$^3$ telescopes. The neutrino signal will always appear together with a muon bundle that reveals its atmospheric origin and, generically, it implies an increase in the detector activity with the slant depth. We propose a simple algorithm that could separate these events from regular muon bundles.

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arXiv2020

The Sun at TeV energies: gammas, neutrons, neutrinos and a cosmic ray shadow

High energy cosmic rays reach the surface of the Sun and start showers with thousands of secondary particles. Most of them will be absorbed by the Sun, but a fraction of the neutral ones will escape and reach the Earth. Here we incorporate a new ingredient that is essential to understand the flux of these solar particles: the cosmic ray shadow of the Sun. We use Liouville's theorem to argue that the only effect of the solar magnetic field on the isotropic cosmic ray flux is to interrupt some of the trajectories that were aiming to the Earth and create a shadow. This shadow reveals the average solar depth crossed by cosmic rays of a given rigidity. The absorbed cosmic ray flux is then processed in the thin Solar surface and, assuming that the emission of neutral particles by low-energy charged particles is isotropic, we obtain (i) a flux of gammas that is consistent with Fermi-LAT observations, (ii) a flux of 100-300 neutrons/(year m^2) produced basically in the spallation of primary He nuclei, and (iii) a neutrino flux that is above the atmospheric neutrino background at energies above 0.1-0.6 TeV (depending on the solar phase and the zenith inclination). More precise measurements of the cosmic ray shadow and of the solar gamma flux, together with the possible discovery of the neutron and neutrino signals, would provide valuable information about the magnetic field, the cycle, and the interior of the Sun.

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arXiv2020

High energy muons in extensive air showers

The production of very high energy muons inside an extensive air shower is observable at $ν$ telescopes and sensitive to the composition of the primary cosmic ray. Here we discuss five different sources of these muons: pion and kaon decays; charmed hadron decays; rare decays of unflavored mesons; photon conversion into a muon pair; and photon conversion into a $J/ψ$ vector meson decaying into muons. We solve the cascade equations for a $10^{10.5}$ GeV proton primary and find that unflavored mesons and gamma conversions are the two main sources of $E\ge 10^{8.5}$ GeV muons, while charm decays dominate at $10^{5.5}\,{\rm GeV}< E< 10^{8.5}\,{\rm GeV}$. In inclined events one of these muons may deposite a large fraction of its energy near the surface, implying fluctuations in the longitudinal profile of the shower and in the muon to electron count at the ground level. In particular, we show that 1 out of 6 proton showers of $10^{10.5}$ GeV include an $E>10^6$ GeV deposition within 500 g/cm$^2$, while only in 1 out of 330 showers it is above $10^7$ GeV. We also show that the production of high energy muons is very different in proton, iron or photon showers ({e.g., conversions $γ\to μ^+ μ^-$ are the main source of $E\ge 10^4$ GeV muons in photon showers). Finally, we use Monte Carlo simulations to discuss the validity of our results.

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arXiv2020

TeV gravity searches

In scenarios with extra dimensions the gravitational interaction may become strong at TeV energies. This could modify the $ν$$N$ cross section and imply distinct signals at neutrino telescopes. In particular, cosmogenic neutrinos of $E\approx 10^9$ GeV could experience frequent interactions with matter where they lose a very small fraction of their energy. We define a consistent model of strong gravity at the TeV scale with just one extra dimension and a first Kaluza-Klein excitation of the graviton of mass around 1 GeV. We describe the collisions at transplanckian energies (multigraviton exchange, graviton emission and black hole formation) as well as the possible signature of these processes at km$^3$ telescopes and their impact in cosmogenic neutrino searches.

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arXiv2018

Heavy sterile neutrinos in stellar core-collapse

We perform spherically symmetric simulations of the core collapse of a single progenitor star of zero age main sequence mass $M_{\rm ZAMS} = 15 \, M_{\odot}$ with two models of heavy sterile neutrinos in the mass range of hundred MeV$/c^2$. According to both models, these hypothetical particles are copiously produced in the center, stream outwards a subsequently decay releasing energy into final states (including neutrinos) of the Standard Model. We find that they can lead to a successful explosion in otherwise non-exploding progenitors. Depending on their unknown parameters (e.g., mass and coupling constants with matter), we obtain either no explosion or an explosion of one of two types, i.e., through heating of gas downstream of the stalled shock wave, similarly to the standard scenario for supernova explosions or through heating of gas at higher radii that ejects matter from the outer core or the envelope while the center continues to accrete matter. In both cases, the explosion energies can be very high. We presume that this new type of explosion would produce an electromagnetic signal that significantly differs from common events because of the relative absence of heavy elements in the ejecta. The combination of core-collapse simulations and astrophysical observations may further constrain the parameters of the sterile neutrinos.

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arXiv2014

Magnetic fields and cosmic ray anisotropies at TeV energies

Several cosmic-ray observatories have provided a high accuracy map of the sky at TeV--PeV energies. The data reveals an O(0.1%) deficit from north galactic directions that peaks at 10 TeV and then evolves with the energy, together with other anisotropies at smaller angular scales. Using Boltzmann's equation we derive expressions for the cosmic-ray flux that fit most of these features. The anisotropies depend on the local interstellar magnetic field B_{IS}, on the average galactic field B_{R} in our vicinity, and on the distribution of dominant cosmic-ray sources. We show that the initial dipole anisotropy along B_{IS} can be modulated by changes in the global cosmic ray wind, and that a variation in the dipole direction would imply a given radius of coherence for B_{IS}. We also show that small and medium-scale anisotropies may appear when the full-sky anisotropy finds a turbulence acting as a magnetic lens.

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arXiv2014

A new physics interpretation of the IceCube data

IceCube has recently observed 37 events of TeV-PeV energies. The angular distribution, with a strong preference for downgoing directions, the spectrum, and the small muon to shower ratio in the data can not be accommodated assuming standard interactions of atmospheric neutrinos. We obtain an excellent fit, however, if a diffuse flux of ultrahigh energy (cosmogenic) neutrinos experiences collisions where only a small fraction of the energy is transferred to the target nucleon. We show that consistent models of TeV gravity or other non-Wilsonian completions of the standard model provide cross sections with these precise features. An increased statistics could clearly distinguish our scenario from the one assumed by IceCube (a diffuse flux of astrophysical neutrinos with a E^{-2} spectrum) and establish the need for new physics in the interpretation of the data.

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arXiv2014

A sterile neutrino at MiniBooNE and IceCube

We discuss the possibility that a sterile neutrino of mass around 50 MeV slightly mixed with the muon flavor may be the origin of the MiniBooNE anomaly. We show that its production in the atmosphere in a fraction of kaon decays would imply an excess of contained showers at IceCube from down-going and near-horizontal directions.

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