Browsing by Author "Martinez-Soler, Ivan"
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- Heavy neutrino searches through double-bang events at Super-Kamiokande, DUNE, and Hyper-KamiokandeAtkinson, M. C.; Coloma, Pilar; Martinez-Soler, Ivan; Rocco, Noemi; Shoemaker, Ian M. (2022-04-28)Abstract A variety of new physics scenarios allows for neutrinos to up-scatter into a heavy neutral lepton state. For a range of couplings and neutrino energies, the heavy neutrino may travel some distance before decaying to visible final states. When both the up-scattering and decay occur within the detector volume, these “double bang” events produce distinctive phenomenology with very low background. In this work, we first consider the current sensitivity at Super-Kamiokande via the atmospheric neutrino flux, and find current data may already provide new constraints. We then examine projected future sensitivity at DUNE and Hyper-Kamiokande, including both atmospheric and beam flux contributions to double-bang signals.
- Measuring tau neutrino appearance probability via unitarityMartinez-Soler, Ivan; Minakata, Hisakazu (American Physical Society, 2021-11-16)We propose a unitarity method for determining tau neutrino appearance probability P(nu mu -> nu tau) in longbaseline (LBL) accelerator experiments and atmospheric neutrino observations. When simultaneous in situ measurements of P(nu mu -> nu mu) and P(nu mu -> nu e) proceed, as is typical in the LBL experiments, one can use unitarity to "measure" P(nu mu -> nu tau). A theorists' toy analysis for the model-independent determination of P(nu mu -> nu mu) and P(nu mu -> nu e) is presented by using the NOvA data. It is shown in our analysis that less than or similar to 5% (8%) measurement of tau neutrino appearance probability in neutrino (antineutrino) mode is possible in the peak region 1.5 less than or similar to E nu less than or similar to 2.5 GeV. The nu SM-independent nature of determination of the probabilities is emphasized.
- Physics of parameter correlations around the solar-scale enhancement in neutrino theory with unitarity violationMartinez-Soler, Ivan; Minakata, Hisakazu (2020-11)We discuss the physics of the three neutrino flavor transformation with non-unitary mixing matrix, with particular attention to the correlation between the nu SM- and the alpha parameters which represent the effect of unitarity-violating (UV) new physics. Towards this goal, a new perturbative framework is created to illuminate the effect of non-unitarity in the region of the solar-scale enhanced oscillations. We refute the skepticism about the physical reality of the nu Standard Model CP phase delta-alpha parameter phase correlation by analysis with the SOL convention of U-MNS, in which e(+/- i delta) is attached to s(12). Then, a comparative study between the solar- and atmospheric-scale oscillation regions allowed by the framework reveals a dynamical delta-(blobs of the a parameters) correlation in the solar oscillation region, in sharp contrast to the "chiral"-type phase correlation [e(-i delta) (alpha) over bar (mu e), e(-i delta)(alpha) over bar (tau e), (alpha) over bar (tau mu)] in the Particle Data Group convention seen in the atmospheric oscillation region. An explicit perturbative calculation to the first order in the nu(mu) -> nu(e) channel allows us to decompose the UV related part of the probability into the unitary evolution part and the genuine non-unitary part. We observe that the effect of non-unitarity tends to cancel between these two parts, as well as between the different alpha(beta gamma) parameters.