Probe Chiral Magnetic Effect with Signed Balance Function

Understand

In this paper a pair of observables are proposed as alternative ways, by examining the fluctuation of net momentum-ordering of charged pairs, to study the charge separation induced by the Chiral Magnetic Effect (CME) in relativistic heavy ion collisions.

• They are, the out-of-plane to in-plane ratio of fluctuation of the difference between signed balance functions measured in pair's rest frame, and the ratio of it to similar measurement made in the laboratory frame.
• Both observables have been studied with simulations including flow-related backgrounds, and for the first time, backgrounds that are related to resonance's global spin alignment.
• The two observables have similar positive responses to signal, and opposite, limited responses to identifiable backgrounds arising from resonance flow and spin alignment.