# Sensitivity of the intensity frontier experiments for neutrino and scalar portals: analytic estimates

## TL;DR

This paper provides analytical estimates of the sensitivity regions for intensity-frontier experiments searching for feebly interacting particles, illustrating how experimental parameters influence the maximal mass reach and boundaries, with validation against simulations.

## Contribution

It introduces analytical methods to estimate sensitivity regions of experiments like SHiP and MATHUSLA, enhancing understanding of their capabilities without extensive simulations.

## Key findings

- Analytical estimates match Monte Carlo simulation results.
- Sensitivity boundaries depend on experimental parameters.
- Maximal mass reach can be analytically predicted.

## Abstract

In recent years, a number of intensity-frontier experiments have been proposed to search for feebly interacting particles with a mass in the GeV range. We show analytically how the characteristic shape of the sensitivity regions of such experiments - upper and lower boundaries of the probed region, the maximal mass reach - depends on the parameters of the experiments, taking the SHiP and the MATHUSLA experiments as an example. We find a good agreement of our estimates with the results of the Monte Carlo simulations.