Investigating luminosity optimization in STCF with crab waist scheme by beam–beam simulation

To achieve the design luminosity of [Formula: see text], the Super Tau-Charm Facility (STCF) adopts an extremely low [Formula: see text] and a crab waist (CW) collision design. The extremely small vertical beam size at the interaction point and low vertical emittance required to achieve a beam–beam parameter of around 0.1 make the CW colliders highly susceptible to beam instabilities arising from beam–beam interactions. Some of these instabilities need to be carefully assessed and optimized through strong–strong beam–beam simulations. In this paper, we investigate the luminosity stability of the STCF design parameters using both weak–strong and strong–strong simulations. We also explore the influence of the CW scheme and various beam parameters on luminosity. These findings offer valuable insight to guide lattice design and optimize global parameters for STCF.