### Speaker

### Description

We examine the impact of Lorentz Invariance Violation (LIV) in measuring the octant of $\theta_{23}$ and CP phases at DUNE. We consider the LIV parameters $a_{e\mu}$ and $a_{e\tau}$, which induce an additional interference term in oscillation probabilities. Taking one LIV parameter at-a-time ($|a_{e\mu}| = |a_{e\tau}| = 5 \times 10^{-24}$ GeV), we find that the octant discovery potential of DUNE gets substantially deteriorated for unfavorable combinations of $\delta$ and $\varphi_{e\mu}$/$\varphi_{e\tau}$. The octant can only be resolved at $3\sigma$ if the true value of $\sin^2\theta_{23}<0.42$ or $>0.62$ for any choices of $\delta$ and $\varphi$. Interestingly, we also observe that when both $a_{e\mu}$ and $a_{e\tau}$ are present together, they significantly cancel the impact of each other and DUNE largely regains its octant resolution capability. We also reconstruct the CP phases $\delta$ and $\varphi_{e\mu}$/$\varphi_{e\tau}$. The typical $1\sigma$ uncertainty on $\delta$ is $10^{\circ}$ to $15^{\circ}$ and the same on $\varphi_{e\mu}$/$\varphi_{e\tau}$ is $25^{\circ}$ to $30^{\circ}$.

### Mini-abstract

Measuring 2-3 mixing angle and CP phases at DUNE in the presence of Lorentz Invariance Violation