The implication of $J/\psi\to (\gamma + ){\rm invisible}$ for the effective field theories of neutrino and dark matter

TL;DR

This paper investigates how $J/ar{ ext{psi}}$ decays into invisible particles constrain effective field theories of neutrinos and dark matter, providing bounds on new physics scales and dark matter interactions.

Contribution

It introduces a comprehensive analysis of $J/ar{ ext{psi}}$ decay data to set limits on EFT operators for neutrinos and dark matter, including projections for future experiments.

Findings

Most stringent bounds on new physics scales are 12.8 GeV for neutrinos and 11.6 GeV for dark matter.

$J/ar{ ext{psi}}$ invisible decay data constrain light dark matter mass range beyond direct detection.

Future Super Tau Charm Factory can improve limits by two orders of magnitude.

Abstract

We study the implication of $J/\psi$ decay into invisible particles for light sterile neutrino and sub-GeV dark matter (DM). The low-energy effective field theories (EFTs) are used for the description of general neutrino interactions and the Dirac fermion DM coupled to charm quark. For $J/\psi\to \gamma+{\rm invisible}$, we perform the likelihood fits for the individual neutrino and DM operators with distinct Lorentz structures and photon spectra. The limits on the decay branching fractions are obtained for different neutrino or DM scenarios and then converted to the lower bounds on the new energy scales. The most stringent bounds on the energy scale in neutrino and DM EFTs are 12.8 GeV and 11.6 GeV, respectively. The purely invisible decay $J/\psi\to {\rm invisible}$ provides complementary constraints on the effective operators. The relevant bound on the energy scale is above 100 GeV for the dipole operators. We also evaluate the limit on the DM-nucleon scattering cross section converted from $J/\psi$ data. The data of $J/\psi$ invisible decays are sensitive to the light DM mass range where the DM direct detection experiments cannot probe yet. The future Super Tau Charm Factory after one year run can push the limits down by two orders of magnitude.