arXiv subjects

Joao A. B. Coelho

Publications and source records attributed to Joao A. B. Coelho.

3 recordsLinked to original sources

arXiv2017

Nonmaximal $θ_{23}$ mixing at NOvA from neutrino decoherence

In study of muon neutrino disappearance at 810 km, the NOvA experiment finds flavor mixing of the atmospheric sector to deviate from maximal ($\sin^2θ_{23} = 0.5$) by 2.6 $σ$. The result is in tension with the 295-km baseline measurements of T2K which are consistent with maximal mixing. We propose that $θ_{23}$ is in fact maximal, and that the disagreement is harbinger of environmentally-induced decoherence. The departure from maximal mixing can be accounted for by an energy-independent decoherence of strength $Γ= (2.3 \pm 1.1) \times 10^{-23}$ GeV.

hep-ph↗

arXiv2017

Probing new physics with atmospheric neutrinos at KM3NeT-ORCA

We present the prospects of ORCA searches for new physics phenomena using atmospheric neutrinos. Focus is given to exploiting the impact of strong matter effects on the oscillation of atmospheric neutrinos in light of expanded models, such as sterile neutrinos and non-standard interactions. In the presence of light sterile neutrinos that mix with active neutrinos, additional resonances and suppressions may occur at different energies. One may also use neutrino oscillations to probe the properties of the coherent forward scattering which may be altered by new interactions beyond the Standard Model. Preliminary studies show that ORCA would be able to probe some parameters of these models with sensitivity up to one order of magnitude better than current constraints.

hep-ex↗

arXiv2012

Constraints for non-standard interaction epsilon_{e tau}V_e from nu_e appearance in MINOS and T2K

Event rates for nu_e and anti-nu_e appearance oscillations reported by the MINOS and T2K long baseline experiments are used to set constraints on the strength of the non-standard interaction epsilon_{e tau}V_e matter potential. The ranges allowed for the magnitude and phase of epsilon_{e tau} are delineated for scenarios wherein i) other non-standard interactions for neutrinos propagating through the terrestrial crust are negligible, and ii) the real-valued, flavor-diagonal couplings epsilon_{e e} and epsilon_{tau tau} are also operative. Our analysis makes use of accurate analytic forms for the nu_e amplitude A(nu_mu --> nu_e) describing neutrino oscillation in constant-density matter in the presence of epsilon_{e tau}, epsilon_{e e} and epsilon_{tau tau} non- standard interactions.

hep-ph↗