A misleading CP violation measurement at DUNE induced by a Majorana phase
We show that the effects of a non-null Majorana phase, due to the existence of a decoherence environment, can cause a sizable distortion of the \textit{CP} violation phase δCP\delta_{\mathrm{CP}}δCP to be measured at DUNE. These distortions are quantified comparing the latter with an eventual T2HK measurement, which would represent an upgrade in precision of the current best fit value obtained at T2K. For a decoherence magnitude of Γ=1.5(2.5)×10−24GeV\Gamma=1.5(2.5)\times 10^{-24} \mathrm{GeV}Γ=1.5(2.5)×10−24GeV, the discrepancies for δCP\delta_{\mathrm{CP}}δCP are below the 2σ2\sigma2σ for null and positive values of the Majorana phase while for negative values, such as −0.5π-0.5\pi−0.5π, it can reach up to 3.8σ(5.8σ)3.8\sigma(5.8\sigma)3.8σ(5.8σ). Therefore, a novel finding of this letter is the possibility to reveal a non-null and negative value for the Majorana phase through oscillation physics.
Año de publicación: 2020
We show that the effects of a non-null Majorana phase, due to the existence of a decoherence environment, can cause a sizable distortion of the \textit{CP} violation phase δCP\delta_{\mathrm{CP}}δCP to be measured at DUNE. These distortions are quantified comparing the latter with an eventual T2HK measurement, which would represent an upgrade in precision of the current best fit value obtained at T2K. For a decoherence magnitude of Γ=1.5(2.5)×10−24GeV\Gamma=1.5(2.5)\times 10^{-24} \mathrm{GeV}Γ=1.5(2.5)×10−24GeV, the discrepancies for δCP\delta_{\mathrm{CP}}δCP are below the 2σ2\sigma2σ for null and positive values of the Majorana phase while for negative values, such as −0.5π-0.5\pi−0.5π, it can reach up to 3.8σ(5.8σ)3.8\sigma(5.8\sigma)3.8σ(5.8σ). Therefore, a novel finding of this letter is the possibility to reveal a non-null and negative value for the Majorana phase through oscillation physics.
Año de publicación: 2020
Neutrino oscillation and CPT violation due to quantum decoherence at DUNE
In this work we study the intrinsic CPT violation in the neutrino oscillations phenomena produced by quantum decoherence as sub-leading effect. In the usual density matrix representation, we find that only fifteen elements of the decoherence matrix violate the CPT symmetry intrinsically. We find exact solutions for the CPT asymmetry function in vacuum . We define an observable to make predictions of this model for the future Long-Baseline experiment, DUNE. We found values of the decoherence parameters with 5σ5σ of discrepancy to standard physics which are allowed by the current experimental limits, suggesting hints for new physics by this model in the context of future experiments.
Año de publicación: 2020
In this work we study the intrinsic CPT violation in the neutrino oscillations phenomena produced by quantum decoherence as sub-leading effect. In the usual density matrix representation, we find that only fifteen elements of the decoherence matrix violate the CPT symmetry intrinsically. We find exact solutions for the CPT asymmetry function in vacuum . We define an observable to make predictions of this model for the future Long-Baseline experiment, DUNE. We found values of the decoherence parameters with 5σ5σ of discrepancy to standard physics which are allowed by the current experimental limits, suggesting hints for new physics by this model in the context of future experiments.
Año de publicación: 2020
Majorana vs pseudo-Dirac neutrinos at the ILC
Neutrino masses could originate in seesaw models testable at colliders, with light mediators and an approximate lepton number symmetry. The minimal model of this type contains two quasi-degenerate Majorana fermions forming a pseudo-Dirac pair. An important question is to what extent future colliders will have sensitivity to the splitting between the Majorana components, since this quantity signals the breaking of lepton number and is connected to the light neutrino masses. We consider the production of these neutral heavy leptons at the ILC, where their displaced decays provide a golden signal: a forward-backward charge asymmetry, which depends crucially on the mass splitting between the two Majorana components. We show that this observable can constrain the mass splitting to values much lower than current bounds from neutrinoless double beta decay and natural loop corrections.
Año de publicación: 2019
Neutrino masses could originate in seesaw models testable at colliders, with light mediators and an approximate lepton number symmetry. The minimal model of this type contains two quasi-degenerate Majorana fermions forming a pseudo-Dirac pair. An important question is to what extent future colliders will have sensitivity to the splitting between the Majorana components, since this quantity signals the breaking of lepton number and is connected to the light neutrino masses. We consider the production of these neutral heavy leptons at the ILC, where their displaced decays provide a golden signal: a forward-backward charge asymmetry, which depends crucially on the mass splitting between the two Majorana components. We show that this observable can constrain the mass splitting to values much lower than current bounds from neutrinoless double beta decay and natural loop corrections.
Año de publicación: 2019
Using a portable muon detector for radioactive source measurements and identification
We have re-purposed portable plastic scintillator muon detectors, designed by the CosmicWatch project, for the measurement of electrons emitted by the decay of radioactive sources. For the latter purpose we have first calibrated the detectors using the local atmospheric muon flux, performing angular distribution and attenuation measurements. In addition, we have simulated the detector using Geant4 in a detailed fashion for a cross-check and better understanding of the device. Then, we have developed a method to evaluate the activity of -sources and to discriminate different -sources by looking into their respective voltage spectrum output.
Año de publicación: 2019
We have re-purposed portable plastic scintillator muon detectors, designed by the CosmicWatch project, for the measurement of electrons emitted by the decay of radioactive sources. For the latter purpose we have first calibrated the detectors using the local atmospheric muon flux, performing angular distribution and attenuation measurements. In addition, we have simulated the detector using Geant4 in a detailed fashion for a cross-check and better understanding of the device. Then, we have developed a method to evaluate the activity of -sources and to discriminate different -sources by looking into their respective voltage spectrum output.
Año de publicación: 2019
Testing quantum decoherence at DUNE
We address some theoretical issues of the quantum decoherence phenomenon within the neutrino oscillation framework and carry out various tests the under DUNE simulated experimental environment. On the theoretical side, we provide a general expression for an invariant decoherence matrix under a quantum basis rotation. On the simulated experimental side, considering a rotation-invariant and noninvariant decoherence matrix, we study the impact on the fitting of the standard oscillation parameters, the sensitivity in the mass hierarchy, and the CP violation, combining the neutrino and antineutrino mode and all available neutrino oscillation probabilities channels. Furthermore, a sensitivity for the decoherence parameter of the order 10−24 GeV at 3σ is obtained for our best case. We also note that a degeneracy between the decoherence parameter and the CP violation phase remains, even though our analysis includes neutrino/antineutrino mode and all probabilities channels.
Año de publicación: 2019
We address some theoretical issues of the quantum decoherence phenomenon within the neutrino oscillation framework and carry out various tests the under DUNE simulated experimental environment. On the theoretical side, we provide a general expression for an invariant decoherence matrix under a quantum basis rotation. On the simulated experimental side, considering a rotation-invariant and noninvariant decoherence matrix, we study the impact on the fitting of the standard oscillation parameters, the sensitivity in the mass hierarchy, and the CP violation, combining the neutrino and antineutrino mode and all available neutrino oscillation probabilities channels. Furthermore, a sensitivity for the decoherence parameter of the order 10−24 GeV at 3σ is obtained for our best case. We also note that a degeneracy between the decoherence parameter and the CP violation phase remains, even though our analysis includes neutrino/antineutrino mode and all probabilities channels.
Año de publicación: 2019
Probing CPT breaking induced by quantum decoherence at DUNE
We show that the decoherence phenomena applied to the neutrino system could lead to an observable breaking of the fundamental CPT symmetry. We require specific textures of nondiagonal decoherence matrices, with nonzero δCP, for making such observations. Using the information from the CPT conjugate channels νμ→νμ and ¯νμ→¯νμ and their corresponding backgrounds, we have estimated the sensitivity of the DUNE experiment for testing CPT under the previous conditions. Four scenarios for energy-dependent decoherence parameters, ΓEν=Γ×(Eν/GeV)n, n=−1, 0, 1, and 2, are taken into account, and for most of them, DUNE is able to achieve a 5σ discovery potential, having Γ in O(10−23 GeV) for δCP=3π/2. Meanwhile, for δCP=π/2, we reach 3σ for Γ in O(10−24 GeV).
Año de publicación: 2019
We show that the decoherence phenomena applied to the neutrino system could lead to an observable breaking of the fundamental CPT symmetry. We require specific textures of nondiagonal decoherence matrices, with nonzero δCP, for making such observations. Using the information from the CPT conjugate channels νμ→νμ and ¯νμ→¯νμ and their corresponding backgrounds, we have estimated the sensitivity of the DUNE experiment for testing CPT under the previous conditions. Four scenarios for energy-dependent decoherence parameters, ΓEν=Γ×(Eν/GeV)n, n=−1, 0, 1, and 2, are taken into account, and for most of them, DUNE is able to achieve a 5σ discovery potential, having Γ in O(10−23 GeV) for δCP=3π/2. Meanwhile, for δCP=π/2, we reach 3σ for Γ in O(10−24 GeV).
Año de publicación: 2019
Gamma-ray counterparts of radio astrophysical sources
In this paper we study two newly discovered classes of radio sources: the highly energetic, short-lived events, known as Fast Radio Bursts (FRBs), and a new category of compact sources known as Fanaroff-Riley type 0 radio galaxies (FR0s). Due to a possible catastrophic event origin for the FRBs and a previous correlation found with an FR0 in the γ-ray spectrum, it is possible that these radio sources could also emit high energy photons in the Fermi-LAT satellite energy range (20 MeV–300 GeV). Here we present an exhaustive time-dependent and spatial search of all up-to-date observed FRBs and FR0s, respectively. We perform a likelihood analysis of the radio sources by modeling the excess flux of gamma rays with a varying index power law function using data from Fermi-LAT and the 4FGL catalog. Sources with test statistic greater than 16 (corresponding to about 4σ) were further analyzed including 2 FRBs and 7 FR0s. No correlations with more than 5σ were found after taking into account nearby sources. Therefore, upper limits for all sources were calculated.
Año de publicación: 2019
In this paper we study two newly discovered classes of radio sources: the highly energetic, short-lived events, known as Fast Radio Bursts (FRBs), and a new category of compact sources known as Fanaroff-Riley type 0 radio galaxies (FR0s). Due to a possible catastrophic event origin for the FRBs and a previous correlation found with an FR0 in the γ-ray spectrum, it is possible that these radio sources could also emit high energy photons in the Fermi-LAT satellite energy range (20 MeV–300 GeV). Here we present an exhaustive time-dependent and spatial search of all up-to-date observed FRBs and FR0s, respectively. We perform a likelihood analysis of the radio sources by modeling the excess flux of gamma rays with a varying index power law function using data from Fermi-LAT and the 4FGL catalog. Sources with test statistic greater than 16 (corresponding to about 4σ) were further analyzed including 2 FRBs and 7 FR0s. No correlations with more than 5σ were found after taking into account nearby sources. Therefore, upper limits for all sources were calculated.
Año de publicación: 2019
Search for Gamma-ray Counterparts of Newly Discovered Radio Astrophysical Sources
We study two newly discovered classes of radio sources: the highly energetic, short-lived events, known as Fast Radio Bursts (FRBs), and a new category of compact radio galaxies known as...
Año de publicación: 2019
We study two newly discovered classes of radio sources: the highly energetic, short-lived events, known as Fast Radio Bursts (FRBs), and a new category of compact radio galaxies known as...
Año de publicación: 2019
Matter effects in neutrino visible decay at future long-baseline experiments
Neutrino visible decay in the presence of matter is re-evaluated. We study these effects in two future long-baseline experiments where matter effects are relevant: DUNE (1300 km) and a hypothetical beam aimed towards ANDES (7650 km). We find that matter effects are negligible for the visible component of neutrino decay at DUNE, being much more relevant at ANDES. We perform a detailed simulation of DUNE, considering νμ disappearance and νe appearance channels, for both FHC and RHC modes. The sensitivity to the decay constant α3 can be as low as 2×10−6 eV2 at 90% C.L., depending on the neutrino masses and type of coupling. We also show the impact of neutrino decay in the determination of θ23 and δCP, and find that the best-fit value of θ23 can move from a true value at the lower octant towards the higher octant.
Año de publicación: 2018
Neutrino visible decay in the presence of matter is re-evaluated. We study these effects in two future long-baseline experiments where matter effects are relevant: DUNE (1300 km) and a hypothetical beam aimed towards ANDES (7650 km). We find that matter effects are negligible for the visible component of neutrino decay at DUNE, being much more relevant at ANDES. We perform a detailed simulation of DUNE, considering νμ disappearance and νe appearance channels, for both FHC and RHC modes. The sensitivity to the decay constant α3 can be as low as 2×10−6 eV2 at 90% C.L., depending on the neutrino masses and type of coupling. We also show the impact of neutrino decay in the determination of θ23 and δCP, and find that the best-fit value of θ23 can move from a true value at the lower octant towards the higher octant.
Año de publicación: 2018
Revisiting quantum decoherence for neutrino oscillations in matter with constant density
We reexamine the matter neutrino oscillation probabilities considering the decoherence phenomenon as a subleading effect. In this paper we point out the relevance of having the correct interpretation of the decoherence matrix in the different quantum bases, within the framework of neutrino oscillation probabilities in matter. Based on this treatment we develop an analytical formula for matter neutrino oscillation probabilities for three generations, with a range of application up to the decoherence parameter Γ∼10-23 GeV. We observe that, due to decoherence, the amplitudes of the neutrino/antineutrino oscillation probabilities increase in an energy independent way. We also find that decoherence can reduce the absolute value of the CP asymmetry, relative to its value at the pure oscillation case. As a side effect we have found a degeneracy between the decoherence parameter Γ and the CP violation phase δ.
Año de publicación: 2018
We reexamine the matter neutrino oscillation probabilities considering the decoherence phenomenon as a subleading effect. In this paper we point out the relevance of having the correct interpretation of the decoherence matrix in the different quantum bases, within the framework of neutrino oscillation probabilities in matter. Based on this treatment we develop an analytical formula for matter neutrino oscillation probabilities for three generations, with a range of application up to the decoherence parameter Γ∼10-23 GeV. We observe that, due to decoherence, the amplitudes of the neutrino/antineutrino oscillation probabilities increase in an energy independent way. We also find that decoherence can reduce the absolute value of the CP asymmetry, relative to its value at the pure oscillation case. As a side effect we have found a degeneracy between the decoherence parameter Γ and the CP violation phase δ.
Año de publicación: 2018