Search for relativistic fractionally charged particles in space

TL;DR

This study uses five years of DAMPE satellite data to search for relativistic fractionally charged particles in space, setting a new upper flux limit and improving sensitivity over previous experiments.

Contribution

It presents the first space-based search for FCPs using DAMPE data, achieving higher sensitivity and more stringent constraints than prior underground and balloon experiments.

Findings

Set an upper flux limit of 6.2×10⁻¹⁰ cm⁻² sr⁻¹ s⁻¹ for FCPs.

Demonstrated DAMPE's sensitivity is three orders of magnitude higher than similar experiments.

Provided the most stringent constraints on FCP existence in primary cosmic rays to date.

Abstract

More than a century after the performance of the oil drop experiment, the possible existence of fractionally charged particles FCP still remains unsettled. The search for FCPs is crucial for some extensions of the Standard Model in particle physics. Most of the previously conducted searches for FCPs in cosmic rays were based on experiments underground or at high altitudes. However, there have been few searches for FCPs in cosmic rays carried out in orbit other than AMS-01 flown by a space shuttle and BESS by a balloon at the top of the atmosphere. In this study, we conduct an FCP search in space based on on-orbit data obtained using the DArk Matter Particle Explorer (DAMPE) satellite over a period of five years. Unlike underground experiments, which require an FCP energy of the order of hundreds of GeV, our FCP search starts at only a few GeV. An upper limit of $6.2\times 10^{-10}~~\mathrm{cm^{-2}sr^{-1} s^{-1}}$ is obtained for the flux. Our results demonstrate that DAMPE exhibits higher sensitivity than experiments of similar types by three orders of magnitude that more stringently restricts the conditions for the existence of FCP in primary cosmic rays.