Emittance growth from luminosity burn-off in future hadron colliders

Abstract

Future hadron colliders aim at producing larger integrated luminosities by burning-off an increased fraction of the bunch particles. This burn-off removes particles unevenly in the bunch distribution generating an emittance growth. Analytical equations are derived describing the bunch distribution suffering luminosity burn-off and cooling from synchrotron radiation damping, far from the equilibrium emittance, and possibly including transverse collision offsets. This effect is evaluated for HL-LHC [G. Apollinari et al., Report No. CERN-2017-007-M, 2017], HE-LHC [A. Abada et al., Eur. Phys. J. Spec. Top. 228, 1109 (2019)], and FCC-hh [A. Abada et al., Eur. Phys. J. Spec. Top. 228, 755 (2019).] and included into a step-by-step simulation of the physics fill, together with intrabeam scattering, to evaluate impact on performance.