Jet-Origin Identification and Its Application at an Electron-Positron Higgs Factory

TL;DR

This paper introduces a jet origin identification method for categorizing jets into specific quark flavors and gluons, demonstrating its effectiveness at an electron-positron Higgs factory and applying it to Higgs decay measurements.

Contribution

The paper presents a novel jet origin identification technique with high flavor tagging efficiency and low charge flip rates, applied to Higgs decay analysis at a future collider.

Findings

Jet flavor tagging efficiencies range from 67% to 92%.

Charge flip rates are between 7% and 24%.

Upper limits on rare Higgs decay branching ratios are established.

Abstract

To enhance the scientific discovery power of high-energy collider experiments, we propose and realize the concept of jet origin identification that categorizes jets into 5 quark species $(b,c,s,u,d)$, 5 anti-quarks $(\bar{b},\bar{c},\bar{s},\bar{u},\bar{d})$, and the gluon. Using state-of-the-art algorithms and simulated $\nu\bar{\nu}H, H\rightarrow jj$ events at 240 GeV center-of-mass energy at the electron-positron Higgs factory, the jet origin identification simultaneously reaches jet flavor tagging efficiencies ranging from 67% to 92% for bottom, charm, and strange quarks, and jet charge flip rates of 7% to 24% for all quark species. We apply the jet origin identification to Higgs rare and exotic decay measurements at the nominal luminosity of the Circular Electron Positron Collider (CEPC), and conclude that the upper limits on the branching ratios of $H\rightarrow s \bar{s}, u\bar{u}, d\bar{d}$, and $H\rightarrow sb, db, uc, ds$ can be determined to $2\!\!\times\!\!10^{-4}$ to $1\!\!\times\!\!10^{-3}$ at 95% confidence level. The derived upper limit for $H\rightarrow s \bar{s}$ decay is approximately three times the prediction of the Standard Model.