  The Neutrino oscillations have provided an excellent opportunity to study
new-physics beyond the Standard Model, popularly known as BSM. The unknown
couplings involving neutrinos, termed non-standard interactions (NSI), may
appear as `new-physics' in different neutrino experiments. The neutrino NSI
offers significant effects on neutrino oscillations and CP-sensitivity, which
may be probed in various neutrino experiments. The idea of neutrinos coupling
with a scalar has evolved recently and looks promising. The effects of scalar
NSI may appear as a perturbation to the neutrino mass matrix in the neutrino
Hamiltonian. It modifies the neutrino mass matrix and may provide a direct
possibility of probing neutrino mass models. As the scalar NSI affects the
neutrino mass matrix in the Hamiltonian, its effect is energy independent.
Moreover, the matter effects due to scalar NSI scales linearly with the matter
density.
  In this work, we have performed a model-independent study of the effects of
scalar NSI at long baseline neutrino experiments, taking DUNE as a case study.
We have performed such a thorough study for DUNE for the first time. Various
neutrino parameters may get affected due to the inclusion of scalar NSI as it
modifies the effective mass matrix of neutrinos. We have explored the impact of
scalar NSI in neutrino oscillations and its impact on the measurements of
various mixing parameters. We have probed the effects of scalar NSI on
different oscillation channels relevant to the experiment. We have also
explored the impact of various possible elements in the scalar NSI term on the
CP-violation sensitivity at DUNE.
