In this paper, we study scalar mediator induced nonstandard interactions (SNSIs) in the context of the ESSnuSB experiment. In particular, we study the capability of ESSnuSB to put bounds on the SNSI parameters and also study the impact of SNSIs in the measurement of the leptonic
CP phase
δCP. Existence of SNSIs modifies the neutrino mass matrix and this modification can be expressed in terms of three diagonal real parameters (
ηee,
ημμ, and
ηττ) and three off-diagonal complex parameters (
ηeμ,
ηeτ, and
ημτ). Our study shows that the upper bounds on the parameters
ημμ and
ηττ depend upon how
Δm312 is minimized in the theory. However, this is not the case when one tries to measure the impact of SNSIs on
δCP. Further, we show that the
CP sensitivity of ESSnuSB can be completely lost for certain values of
ηee and
ημτ for which the appearance channel probability becomes independent of
δCP. Published by the American Physical Society 2024