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De Romeri, V., Miranda, O. G., Papoulias, D. K., Sanchez Garcia, G., Tortola, M., & Valle, J. W. F. (2023). Physics implications of a combined analysis of COHERENT CsI and LAr data. J. High Energy Phys., 04(4), 035–41pp.
Abstract: The observation of coherent elastic neutrino nucleus scattering has opened the window to many physics opportunities. This process has been measured by the COHERENT Collaboration using two different targets, first CsI and then argon. Recently, the COHERENT Collaboration has updated the CsI data analysis with a higher statistics and an improved understanding of systematics. Here we perform a detailed statistical analysis of the full CsI data and combine it with the previous argon result. We discuss a vast array of implications, from tests of the Standard Model to new physics probes. In our analyses we take into account experimental uncertainties associated to the efficiency as well as the timing distribution of neutrino fluxes, making our results rather robust. In particular, we update previous measurements of the weak mixing angle and the neutron root mean square charge radius for CsI and argon. We also update the constraints on new physics scenarios including neutrino nonstandard interactions and the most general case of neutrino generalized interactions, as well as the possibility of light mediators. Finally, constraints on neutrino electromagnetic properties are also examined, including the conversion to sterile neutrino states. In many cases, the inclusion of the recent CsI data leads to a dramatic improvement of bounds.
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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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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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Escrihuela, F. J., Flores, L. J., Miranda, O. G., & Rendon, J. (2021). Global constraints on neutral-current generalized neutrino interactions. J. High Energy Phys., 07(7), 061–26pp.
Abstract: We study generalized neutrino interactions (GNI) for several neutrino processes, including neutrinos from electron-positron collisions, neutrino-electron scattering, and neutrino deep inelastic scattering. We constrain scalar, pseudoscalar, and tensor new physics effective couplings, based on the standard model effective field theory at low energies. We have performed a global analysis for the different effective couplings. We also present the different individual constraints for each effective parameter (scalar, pseudoscalar, and tensor). Being a global analysis, we show robust results for the restrictions on the different GNI parameters and improve some of these bounds.
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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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Escrihuela, F. J., Forero, D. V., Miranda, O. G., Tortola, M., & Valle, J. W. F. (2017). Probing CP violation with non-unitary mixing in long-baseline neutrino oscillation experiments: DUNE as a case study. New J. Phys., 19, 093005–14pp.
Abstract: When neutrino masses arise from the exchange of neutral heavy leptons, as in most seesaw schemes, the effective lepton mixing matrix N describing neutrino propagation is non-unitary, hence neutrinos are not exactly orthonormal. New CP violation phases appear in N that could be confused with the standard phase delta(CP) characterizing the three neutrino paradigm. We study the potential of the long-baseline neutrino experiment DUNE in probing CP violation induced by the standard CP phase in the presence of non-unitarity. In order to accomplish this we develop our previous formalism, so as to take into account the neutrino interactions with the medium, important in long baseline experiments such as DUNE. We find that the expected CP sensitivity of DUNE is somewhat degraded with respect to that characterizing the standard unitary case. However the effect is weaker than might have been expected thanks mainly to the wide neutrino beam. We also investigate the sensitivity of DUNE to the parameters characterizing non-unitarity. In this case we find that there is no improvement expected with respect to the current situation, unless the near detector setup is revamped.
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Escrihuela, F. J., Tortola, M., Valle, J. W. F., & Miranda, O. G. (2011). Global constraints on muon-neutrino nonstandard interactions. Phys. Rev. D, 83(9), 093002–8pp.
Abstract: The search for new interactions of neutrinos beyond those of the standard model may help to elucidate the mechanism responsible for neutrino masses. Here, we combine existing accelerator neutrino data with restrictions coming from a recent atmospheric neutrino data analysis in order to lift parameter degeneracies and improve limits on new interactions of muon neutrinos with quarks. In particular, we reconsider the results of the E-815 experiment at Fermilab (NuTeV) in view of a new evaluation of its systematic uncertainties. We find that, although constraints for muon neutrinos are better than those applicable to tau or electron neutrinos, they lie at the few X 10(-2) level, not as strong as previously believed. We briefly discuss prospects for further improvement.
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Garces, E. A., Miranda, O. G., Tortola, M., & Valle, J. W. F. (2012). Low-energy neutrino-electron scattering as a standard model probe: The potential of LENA as case study. Phys. Rev. D, 85(7), 073006–6pp.
Abstract: Several proposals for studying neutrinos with large detectors are currently under discussion. We suggest that they could provide a precise measurement of the electroweak mixing angle as well as a probe for new physics, such as nonstandard neutrino interactions, and the electroweak gauge structure. We illustrate this explicitly for the case of the LENA proposal, either with an artificial radioactive source or by using the solar neutrino flux.
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Kosmas, T. S., Miranda, O. G., Papoulias, D. K., Tortola, M., & Valle, J. W. F. (2015). Probing neutrino magnetic moments at the Spallation Neutron Source facility. Phys. Rev. D, 92(1), 013011–12pp.
Abstract: Majorana neutrino electromagnetic properties are studied through neutral current coherent neutrinonucleus scattering. We focus on the potential of the recently planned COHERENT experiment at the Spallation Neutron Source to probe muon-neutrino magnetic moments. The resulting sensitivities are determined on the basis of chi(2) analysis employing realistic nuclear structure calculations in the context of the quasiparticle random phase approximation. We find that they can improve existing limits by half an order of magnitude. In addition, we show that these facilities allow for standard model precision tests in the low energy regime, with a competitive determination of the weak mixing angle. Finally, they also offer the capability to probe other electromagnetic neutrino properties, such as the neutrino charge radius. We illustrate our results for various choices of experimental setup and target material.
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Escrihuela, F. J., Forero, D. V., Miranda, O. G., Tortola, M., & Valle, J. W. F. (2015). On the description of nonunitary neutrino mixing. Phys. Rev. D, 92(5), 053009–16pp.
Abstract: Neutrino oscillations are well established and the relevant parameters determined with good precision, except for the CP phase, in terms of a unitary lepton mixing matrix. Seesaw extensions of the Standard Model predict unitarity deviations due to the admixture of heavy isosinglet neutrinos. We provide a complete description of the unitarity and universality deviations in the light-neutrino sector. Neutrino oscillation experiments involving electron or muon neutrinos and antineutrinos are fully described in terms of just three new real parameters and a new CP phase, in addition to the ones describing oscillations with unitary mixing. Using this formalism we describe the implications of nonunitarity for neutrino oscillations and summarize the model-independent constraints on heavy-neutrino couplings that arise from current experiments.
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