Turning up and down strong magnetic fields in relativistic nuclear collisions

Abstract

I show that the average transverse momentum, $⟨p_t⟩$, of the hadrons emitted in relativistic nuclear collisions can be used as a ``knob'' to control the strength of the magnetic field induced by the spectator and the participant protons over the overlap region. I thus argue that any observable sensitive to this magnetic field is nontrivially correlated with $⟨p_t⟩$ at a given collision centrality.

Comments: 5 pages, 2 figures; v2: published version