Effects of quark gluon plasma droplet evolution on charge separation in small collision systems within a multiphase transport model

In relativistic high-energy heavy-ion collisions, the chiral magnetic effect (CME) could produce a charge separation in quark gluon plasma (QGP) and remain in the final hadron system during evolution, observed as the correlator <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:mi mathvariant="normal">Δ</a:mi><a:mi>γ</a:mi></a:mrow></a:math>. This physics procedure could also occur in small collision systems if the CME were to emerge in the QGP droplet. In this paper, we study the effects of QGP droplet evolution on charge separation in small collision systems, based on a multiphase transport model. Our calculations indicate that, with given initial charge separation, the effects of parton level evolution and hadron level evolution weaken the charge separation indeed, but there are still enough signals that could survive to the final hadron system. Furthermore, we found that, the contribution of background to <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"><c:mrow><c:mi mathvariant="normal">Δ</c:mi><c:mi>γ</c:mi></c:mrow></c:math> is negligible in small collision systems. So, we propose the small collision system is a good place to check the contribution of the CME.