Luminosity Limit from Bound-Free Pair Production in the LHC

The luminosity of the LHC as a lead-ion collider is known to be limited by the large cross-sections for electromagnetic processes in ultra-peripheral collisions. In particular, the process of bound-free e
^-
e
⁺
pair production creates secondary beams of Pb
⁸¹⁺
ions emerging from the collision points and impinging on the vacuum envelope inside superconducting magnets. New Monte-Carlo simulations, exploiting recent implementations of the physics of ion interactions with matter, are helping us to quantify the relationships among luminosity and energy deposition in the magnet coils a view to predicting and alleviating the quench limit on luminosity.