$R$ measurement and QCD studies at future super $\tau-c$ factory

TL;DR

This paper discusses the potential of a future super tau-charm factory to significantly improve measurements of R, QCD parameters, and hadronic structures using high-luminosity e+e- collisions in the 2-7 GeV range.

Contribution

It outlines the prospects and scientific opportunities of a super tau-charm factory for precision QCD studies and hadron spectroscopy, emphasizing the expected improvements in measurement accuracy.

Findings

Achieving 2% or better precision in R measurements.

Enhanced determination of QCD parameters like alpha_s and charm quark mass.

Detailed studies of charmonium resonances and exotic states.

Abstract

We review status of $R$ measurement and QCD studies at low energy range, discuss prospects for a super $\tau-$charm factory in $2-7$ GeV. With a high-luminosity $e^+e^-$ collider, statistics are no longer problem for $R$ measurement and a precision of $2\%$ or even better is foreseen, that will lead to bring down the uncertainty of hadronic contribution to the QED running coupling constant $\Delta\alpha_{had}$ and the anomalous magnetic moment of the muon ($a_{\mu}$); measure the strong coupling constant $\alpha_s$ and the charm quark mass; improve the measurement of the resonance parameters of heavy charmonia. Huge data samples in $2-3$ GeV will make it possible to study excited states of $\rho$, $\omega$ and $\phi$, or exotic $Y(2175)$; measure electromagnetic form factor of mesons and baryons; and measure fragmentation functions of hadrons.