Polarized dissociation and spin alignment of moving quarkonia in a quark-gluon plasma

Recent experiments have found spin alignment of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mi>J</a:mi><a:mo>/</a:mo><a:mi>ψ</a:mi></a:mrow></a:math> with respect to the event plane in heavy ion collisions, suggesting a medium effect that is spin dependent. We propose a possible mechanism with polarized dissociation from the motion of <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mi>J</c:mi><c:mo>/</c:mo><c:mi>ψ</c:mi></c:math> with respect to the medium. We calculate the polarized dissociation rate for a quarkonium spin triplet state from spin chromomagnetic coupling in the potential nonrelativistic QCD framework. This is done for the leading order gluo-dissociation process and the next to leading order inelastic Coulomb scattering process. The polarized dissociation rate is expressed as a function of relative velocity between quarkonium and quark-gluon plasma and the quantization axis. Applying the polarized dissociation rate to quarkonium evolution with a dissociation effect only in a Bjorken flow, we find the spin 0 state to dissociate less than the other spin states, leading to positive <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:mrow><e:msub><e:mrow><e:mi>ρ</e:mi></e:mrow><e:mrow><e:mn>00</e:mn></e:mrow></e:msub><e:mo>−</e:mo><e:mn>1</e:mn><e:mo>/</e:mo><e:mn>3</e:mn></e:mrow></e:math>. The regeneration contribution is expected to give a contribution with the opposite sign.