arXiv subjects

Riya Barick

Publications and source records attributed to Riya Barick.

6 recordsLinked to original sources

arXiv2025

Probing Geometrical NSI at the DUNE experiment

In this work, we investigate the implications of a novel non-standard interaction (NSI) of neutrinos. This interaction is geometric in origin -- it arises because the propagation of fermions in curved spacetime induces torsion. This torsion is non-propagating and can be eliminated from the action, resulting in a four-fermion interaction in a torsion-free background. The new interaction modifies the behaviour of the neutrinos passing through matter by introducing additional coupling terms, resulting in a new component in the effective potential. As a result, the neutrino oscillation probabilities in matter are altered. The relevant probabilities are computed using the Cayley-Hamilton formalism. We then numerically explore the potential to probe these torsion-induced NSI in the DUNE experiment. We obtain the bounds on the parameters characterizing the torsional effects. By selecting representative values of torsion parameters to which the DUNE experiment is sensitive, we analyse how these geometric interactions affect the experiment's sensitivity to determine neutrino mass hierarchy, the octant of the 2-3 leptonic mixing angle, and the CP phase. We also examine the new parameter degeneracies introduced by torsion effects and assess their impact on the overall sensitivities of DUNE. We find that the additional parameter degeneracies in the presence of torsion significantly affect the octant sensitivity.

hep-ph↗

arXiv2025

Torsional modulation of atmospheric neutrino oscillation

Fermions act as sources of spacetime torsion. However, this torsion is non-dynamical and can be eliminated using its equations of motion. The resulting theory features an effective four-fermion interaction in a torsion-free background. Generically this interaction is non-universal and violates parity. When neutrinos propagate through matter, they experience the effect of this geometrical interaction, which is similar to the MSW effect, but diagonal in the mass basis. Since this quartic interaction term varies linearly with matter density, its effect will be more prominent for atmospheric neutrinos specially for upward going atmospheric neutrinos. We investigate the effect of spacetime geometry on $\nu_\mu \to \nu_\tau$ and $\nu_\mu \to \nu_e$ conversion probability and $\nu_\mu$ survival probability, by solving the Schr\"odinger equation using the {Preliminary Reference Earth Model (PREM)} density profile of the Earth. We also study the dependence of atmospheric neutrino oscillation probability on the CP phase angle in presence of this effect. We further provide a discussion of the MSW and parametric resonances in presence of the geometrical interaction.

hep-ph↗

arXiv2025

Exploring the Effect of Chiral Torsion on Neutrino Oscillation in Long Baseline Experiments

In curved spacetime, neutrinos experience an extra contribution to their effective Hamiltonian coming from a torsion-induced four-fermion interaction that is diagonal in mass basis and also causes neutrino mixing while propagating through fermionic matter. This geometrical quartic interaction term appears as the modification to the neutrino mass term and significantly influences both neutrino conversion and survival probabilities. Since this term varies linearly with matter density, long baseline (LBL) experiments would be a good choice to probe this effect. We put bounds on torsional coupling parameters and also see the impact of torsion on physics sensitivities in the DUNE experiment.

hep-ph↗

arXiv2023

Neutrino oscillations induced by chiral torsion

Neutrino mixing is caused by the fact that neutrino flavors are not eigenstates of the free Hamiltonian. This causes oscillations among different neutrino flavors. When neutrinos pass through a medium, weak interactions produce different effective masses for neutrinos of different flavors, leading to a modification of the mixing parameters. In curved spacetime there is an additional contribution to neutrino Hamiltonian from a torsion-induced four-fermion interaction, which also causes neutrino mixing while propagating through fermionic matter. We provide an outline of the calculation of this effect on neutrino oscillation.

hep-ph↗

arXiv2023

Effect of spacetime geometry on neutrino oscillations

Propagation of fermions in spacetime requires a spin connection, which can be split into a universal gravitational part and a non-universal ``contorsion'' part. The latter is non-dynamical and can be eliminated from the theory, leaving an effective four-fermion interaction with unknown coupling constants. The generic form of the contorsion-fermion coupling, and thus the four-fermion interaction, breaks chiral symmetry. This interaction affects all fermions -- in particular neutrinos passing through matter will notice a contribution to their effective Hamiltonian, just like the MSW effect coming from weak interactions, but diagonal in the mass basis rather than the flavor basis. Then there is a possibility that this geometrical contribution is not negligible for neutrinos passing through normal matter, provided the coupling constants are not too small. We calculate the matter potential due to this interaction and thus write the conversion and survival probabilities including its effect. We plot conversion probabilities of $\nu_\mu$ to $\nu_e$ and $\nu_\tau$ for a baseline of 1300 km, as well as their dependence on the CP phase, with and without the geometrical interaction. We also plot the survival probability of reactor $\bar{\nu}_e$ for different baselines.

hep-ph↗

arXiv2023

Neutrino oscillation caused by spacetime geometry

Effects of gravitational interaction are generally neglected in particle physics. A first order formulation of gravity is presented to include gravity in Quantum Mechanical Lagrangian of fermions. It is seen that fermions minimally coupled to gravity gives rise to a torsionless effective theory with a quartic interaction. After passing through a thermal background the most generic form of contortion contributes to neutrino effective mass. This effective mass can change the current oscillation parameters.

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