arXiv subjects

Dharitree Bezboruah

Publications and source records attributed to Dharitree Bezboruah.

5 recordsLinked to original sources

arXiv2026

Dark NSI & neutrino oscillations : probing via $δ_{CP}$ measurements at DUNE and T2HK

We investigate the possibility of neutrinos interacting with a scalar dark matter field and the resulting implications for neutrino oscillations in the long-baseline sector. As our Universe is predominantly composed of dark matter, neutrinos propagating over astrophysical and terrestrial baselines inevitably traverse a dark matter background. The coherent forward scattering of neutrinos in such a background induces a medium-dependent correction to the mass-squared term in the effective neutrino Hamiltonian having opposing signs for neutrinos and antineutrinos. We study how the elements of this correction matrix, arising from coherent forward scattering of neutrinos with scalar dark matter background referred to as dark non-standard interactions (dark NSI), modify neutrino oscillation probabilities. Furthermore, we also study the effect of the off-diagonal elements and the associated phases on the measurement of leptonic CP violating phase focusing on the upcoming long-baseline superbeam experiments DUNE and T2HK. We show that dark NSI can lead to substantial enhancement or suppression of CP-violation sensitivity, depending on the true values of the dark NSI phases $ϕ_{αβ}$. We further explored how the synergy of DUNE and T2HK can effectively mitigate the degeneracies due to the dark NSI phases, and can restore or even enhance the CP sensitivity as compared to the standard oscillation scenario.

hep-ph↗

arXiv2024

Neutrino mass ordering sensitivities at DUNE, HK and KNO in presence of scalar NSI

The limitations of the Standard Model in explaining neutrino masses and neutrino mixing lead to the exploration of frameworks beyond the Standard Model (BSM). The possibility of neutrinos interacting with fermions via a scalar mediator is one of the interesting prospects. The study of neutrino non-standard interactions (NSI) is a well-motivated phenomenological scenario to explore new physics beyond the Standard Model. These new interactions may alter the standard neutrino oscillation probabilities, potentially leading to observable effects in experiments. It also allows for the exploration of absolute neutrino masses via oscillation experiments. It can modify the oscillation probabilities, which in turn can affect the physics sensitivities in long-baseline experiments. The linear scaling of the effects of scalar NSI with matter density also motivates its exploration in long-baseline (LBL) experiments. We will present our study on the impact of a scalar-mediated NSI on the mass ordering (MO) sensitivities of three long-baseline neutrino experiments, i.e., DUNE, HK and KNO. We study the impact on MO sensitivities at these experiments assuming that scalar NSI parameters are present in nature and are known from other non-LBL experiments. The presence of scalar NSI can notably impact the MO sensitivities of these experiments. Furthermore, we analyze the potential synergy by combining data from DUNE with HK and HK+KNO, thereby exploring a broader parameter space.

hep-ph↗

arXiv2024

Neutrino Oscillations in Presence of Diagonal Elements of Scalar NSI: An Analytic Approach

Scalar Non-Standard Interactions (SNSI) in neutrinos can arise when a scalar mediator couples to both neutrinos and standard model fermions. This beyond the Standard Model (BSM) scenario is particularly interesting as the SNSI contribution appears as a density-dependent perturbation to the neutrino mass, rather than appearing as a matter-induced potential, and the neutrino oscillation probabilities uniquely depend on the absolute neutrino masses. In this work, we show the complex dependence of the SNSI contributions on the neutrino masses and discuss how the mass of the lightest neutrino would regulate any possible SNSI contribution in both mass ordering scenarios. We derive the analytic expressions for neutrino oscillation probabilities, employing the Cayley-Hamilton theorem, in the presence of diagonal elements of SNSI. The expressions are compact and shows explicit dependence on matter effects and the absolute neutrino masses. The analytic expressions calculated here allow us to obtain the dependence of the SNSI contribution on mass terms of the form $m_1 + m_2$, $m_2 - m_1$, $m_1c_{12}^2 + m_2s_{12}^2,$ $ m_1s_{12}^2 + m_2c_{12}^2$, and $m_3$. We then explore the non-trivial impact of neutrino mass ordering on the SNSI contribution. The dependence of the SNSI contribution on the 3$ν$ parameters is then thoroughly explored using our analytic expressions.

hep-ph↗

arXiv2024

Impact of scalar NSI on the neutrino mass ordering sensitivity at DUNE, HK and KNO

The study of neutrino non-standard interactions (NSI) is a well-motivated phenomenological scenario to explore new physics beyond the Standard Model. The possible scalar coupling of neutrinos ($ν$) with matter is one of such new physics scenarios that appears as a sub-dominant effect that can impact the $ν$-oscillations in matter. The presence of scalar NSI introduces an additional contribution directly to the $ν$-mass matrix in the interaction Hamiltonian and subsequently to the $ν$-oscillations. This indicates that scalar NSI may have a significant impact on measurements related to $ν$-oscillations e.g. leptonic CP phase $(δ_{CP})$, $θ_{23}$ octant and neutrino mass ordering (MO). The linear scaling of the effects of scalar NSI with matter density also motivates its exploration in long-baseline (LBL) experiments. In this paper, we study the impact of a scalar-mediated NSI on the MO sensitivity of DUNE, HK and HK+KNO, which are upcoming LBL experiments. We study the impact on MO sensitivities at these experiments assuming that scalar NSI parameters are present in nature and is known from other non-LBL experiments. We observe that the presence of diagonal scalar NSI elements can significantly affect the $ν$-mass ordering sensitivities. We then also combine the data from DUNE with HK and HK+KNO to explore possible synergy among these experiments in a wider parameter space. We also observe a significant enhancement in the MO sensitivities for the combined analysis.

hep-ph↗

arXiv2024

The Sensitivity of DUNE in Presence of Off-Diagonal Scalar NSI Parameters

Scalar non-standard interactions (NSI) presents an exciting pathway for probing potential new physics that extends beyond the Standard Model (BSM). The scalar coupling of neutrinos with matter can appear as a sub-dominant effect that can impact the neutrino oscillation probabilities. The uniqueness of these interactions is that it can directly affect the neutrino mass matrix. This makes oscillations sensitive to the absolute neutrino mass. The effects of scalar NSI scales linearly with matter density which motivates its exploration in long-baseline sector. The presence of scalar NSI can influence the key measurements in the field of neutrino physics, including the precise determination of the leptonic CP phase ($δ_{CP}$), neutrino mass ordering and the octant of $θ_{23}$. The precise determination of $δ_{CP}$ is one of the major goals of DUNE, which is an upcoming long-baseline experiment. A better understanding of the impact of scalar NSI on CP measurement sensitivities is crucial for accurate interpretation of $δ_{CP}$ phase. In this work, we have explored the impact of the complex off-diagonal scalar NSI elements $η_{αβ}$ and their associated phases $ϕ_{αβ}$ on the CP-measurement sensitivities at DUNE. We have explored the impact of the neutrino mass scale on these sensitivities. We look for constraining these off-diagonal elements for different neutrino mass scales. We also explore their correlation with $δ_{CP}$, investigating potential degeneracies that can arise due to additional phases. We also perform a correlation study among different scalar NSI elements. We show that the inclusion of the complex scalar NSI elements can significantly modify the CP phase measurements.

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