Miranda, O. G., & Valle, J. W. F. (2016). Neutrino oscillations and the seesaw origin of neutrino mass. Nucl. Phys. B, 908, 436–455.
Abstract: The historical discovery of neutrino oscillations using solar and atmospheric neutrinos, and subsequent accelerator and reactor studies, has brought neutrino physics to the precision era. We note that CP effects in oscillation phenomena could be difficult to extract in the presence of unitarity violation. As a result upcoming dedicated leptonic CP violation studies should take into account the non-unitarity of the lepton mixing matrix. Restricting non-unitarity will shed light on the seesaw scale, and thereby guide us towards the new physics responsible for neutrino mass generation.
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Miranda, O. G., Tortola, M., & Valle, J. W. F. (2016). New Ambiguity in Probing CP Violation in Neutrino Oscillations. Phys. Rev. Lett., 117(6), 061804–5pp.
Abstract: If neutrinos get mass via the seesaw mechanism the mixing matrix describing neutrino oscillations can be effectively nonunitary. We show that in this case the neutrino appearance probabilities involve a new CP phase phi associated with nonunitarity. This leads to an ambiguity in extracting the “standard” three-neutrino phase delta(CP), which can survive even after neutrino and antineutrino channels are combined. Its existence should be taken into account in the planning of any oscillation experiment aiming at a robust measurement of delta(CP).
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Miranda, O. G., Pasquini, P., Tortola, M., & Valle, J. W. F. (2018). Exploring the potential of short-baseline physics at Fermilab. Phys. Rev. D, 97(9), 095026–9pp.
Abstract: We study the capabilities of the short-baseline neutrino program at Fermilab to probe the unitarity of the lepton mixing matrix. We find the sensitivity to be slightly better than the current one. Motivated by the future DUNE experiment, we have also analyzed the potential of an extra liquid Argon near detector in the LBNF beamline. Adding such a near detector to the DUNE setup will substantially improve the current sensitivity on nonunitarity. This would help to remove CP degeneracies due to the new complex phase present in the neutrino mixing matrix. We also study the sensitivity of our proposed setup to light sterile neutrinos for various configurations.
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Miranda, O. G., Papoulias, D. K., Tortola, M., & Valle, J. W. F. (2019). Probing neutrino transition magnetic moments with coherent elastic neutrino-nucleus scattering. J. High Energy Phys., 07(7), 103–23pp.
Abstract: We explore the potential of current and next generation of coherent elastic neutrino-nucleus scattering (CE nu NS) experiments in probing neutrino electromagnetic interactions. On the basis of a thorough statistical analysis, we determine the sensitivities on each component of the Majorana neutrino transition magnetic moment (TMM), vertical bar Lambda(i)vertical bar, that follow from low-energy neutrino-nucleus experiments. We derive the sensitivity to neutrino TMM from the first CE nu NS measurement by the COHERENT experiment, at the Spallation Neutron Source. We also present results for the next phases of COHERENT using HPGe, LAr and NaI[Tl] detectors and for reactor neutrino experiments such as CONUS, CONNIE, MINER, TEXONO and RED100. The role of the CP violating phases in each case is also briefly discussed. We conclude that future CE nu NS experiments with low-threshold capabilities can improve current TMM limits obtained from Borexino data.
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Miranda, O. G., Papoulias, D. K., Tortola, M., & Valle, J. W. F. (2020). Probing new neutral gauge bosons with CE nu NS and neutrino-electron scattering. Phys. Rev. D, 101(7), 073005–13pp.
Abstract: The potential for probing extra neutral gauge boson mediators (Z') from low-energy measurements is comprehensively explored. Our study mainly focuses on Z' mediators present in string-inspired E-6 models and left-right symmetry. We estimate the sensitivities of coherent-elastic neutrino-nucleus scattering (CE nu NS) and neutrino-electron scattering experiments. Our results indicate that such low-energy high-intensity measurements can provide a valuable probe, complementary to high-energy collider searches and electroweak precision measurements.
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Miranda, O. G., Papoulias, D. K., Tortola, M., & Valle, J. W. F. (2020). XENON1T signal from transition neutrino magnetic moments. Phys. Lett. B, 808, 135685–5pp.
Abstract: The recent puzzling results of the XENONIT collaboration at few keV electronic recoils could be due to the scattering of solar neutrinos endowed with finite Majorana transition magnetic moments (TMMs). Within such general formalism, we find that the observed excess in the XENONIT data agrees well with this interpretation. The required TMM strengths lie within the limits set by current experiments, such as Borexino, specially when one takes into account a possible tritium contamination.
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Miranda, O. G., Papoulias, D. K., Sanders, O., Tortola, M., & Valle, J. W. F. (2020). Future CEvNS experiments as probes of lepton unitarity and light sterile neutrinos. Phys. Rev. D, 102(11), 113014–14pp.
Abstract: We determine the sensitivities of short-baseline coherent elastic neutrino-nucleus scattering (CE nu NS) experiments using a pion decay at rest neutrino source as a probe for nonunitarity in the lepton sector, as expected in low-scale type-I seesaw schemes. We also identify the best configuration for probing light sterile neutrinos at future ton-scale liquid argon CE nu NS experiments, estimating the projected sensitivities on the sterile neutrino parameters. Possible experimental setups at the Spallation Neutron Source, Lujan facility and the European Spallation Source are discussed. Provided that systematic uncertainties remain under control, we find that CE nu NS experiments will be competitive with oscillation measurements in the long run.
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Miranda, O. G., Papoulias, D. K., Sanders, O., Tortola, M., & Valle, J. W. F. (2021). Low-energy probes of sterile neutrino transition magnetic moments. J. High Energy Phys., 12(12), 191–24pp.
Abstract: Sterile neutrinos with keV-MeV masses and non-zero transition magnetic moments can be probed through low-energy nuclear or electron recoil measurements. Here we determine the sensitivities of current and future searches, showing how they can probe a previously unexplored parameter region. Future coherent elastic neutrino-nucleus scattering (CEvNS) or elastic neutrino-electron scattering (EvES) experiments using a monochromatic 'Cr source can fully probe the region indicated by the recent XENONIT excess.
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Miranda, O. G., Papoulias, D. K., Sanchez Garcia, G., Sanders, O., Tortola, M., & Valle, J. W. F. (2020). Implications of the first detection of coherent elastic neutrino-nucleus scattering (CEvNS) with liquid Argon. J. High Energy Phys., 05(5), 130–17pp.
Abstract: The CENNS-10 experiment of the COHERENT collaboration has recently reported the first detection of coherent-elastic neutrino-nucleus scattering (CEvNS) in liquid Argon with more than 3 sigma significance. In this work, we exploit the new data in order to probe various interesting parameters which are of key importance to CEvNS within and beyond the Standard Model. A dedicated statistical analysis of these data shows that the current constraints are significantly improved in most cases. We derive a first measurement of the neutron rms charge radius of Argon, and also an improved determination of the weak mixing angle in the low energy regime. We also update the constraints on neutrino non-standard interactions, electromagnetic properties and light mediators with respect to those derived from the first COHERENT-CsI data.
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Mandal, S., Miranda, O. G., Sanchez Garcia, G., Valle, J. W. F., & Xu, X. J. (2022). Toward deconstructing the simplest seesaw mechanism. Phys. Rev. D, 105(9), 095020–32pp.
Abstract: The triplet or type-II seesaw mechanism is the simplest way to endow neutrinos with mass in the Standard Model (SM). Here we review its associated theory and phenomenology, including restrictions from S, T, U parameters, neutrino experiments, charged lepton flavor violation as well as collider searches. We also examine restrictions coming from requiring consistency of electroweak symmetry breaking, i.e., perturbative unitarity and stability of the vacuum. Finally, we discuss novel effects associated to the scalar mediator of neutrino mass generation namely, (i) rare processes, e.g., l(alpha)-> l(beta)gamma decays, at the intensity frontier, and also (ii) four-lepton signatures in colliders at the high-energy frontier. These can be used to probe neutrino properties in an important way, providing a test of the absolute neutrino mass and mass ordering, as well as of the atmospheric octant. They may also provide the first evidence for charged lepton flavor violation in nature. In contrast, neutrino nonstandard interaction strengths are found to lie below current detectability.
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