Sensitivity of the SHiP experiment to dark photons decaying to a pair of charged particles

TL;DR

This paper reviews the sensitivity of the SHiP experiment to dark photons within a specific mass range, highlighting its potential to explore new parameter space for dark photon detection.

Contribution

It provides a detailed simulation of SHiP's sensitivity to dark photons decaying into charged pairs, expanding the understanding of its detection capabilities in the 0.002 to 10 GeV mass range.

Findings

SHiP can probe dark photon masses between 0.8 and 3.3 GeV.

Sensitivity to mixing parameter squared, ε², ranges from 10⁻¹¹ to 10⁻¹⁷.

Exclusion contours are compared with past experiments.

Abstract

Dark photons are hypothetical massive vector particles that could mix with ordinary photons. The simplest theoretical model is fully characterised by only two parameters: the mass of the dark photon m$_{\gamma^{\mathrm{D}}}$ and its mixing parameter with the photon, $\varepsilon$. The sensitivity of the SHiP detector is reviewed for dark photons in the mass range between 0.002 and 10 GeV. Different production mechanisms are simulated, with the dark photons decaying to pairs of visible fermions, including both leptons and quarks. Exclusion contours are presented and compared with those of past experiments. The SHiP detector is expected to have a unique sensitivity for m$_{\gamma^{\mathrm{D}}}$ ranging between 0.8 and 3.3$^{+0.2}_{-0.5}$ GeV, and $\varepsilon^2$ ranging between $10^{-11}$ and $10^{-17}$.