Charge-asymmetry dependence of kaon elliptic flow in Au$+$Au collisions at $\sqrt{s_{\mathrm{NN}}} = $ 27 GeV from STAR

Theory predicts that a chiral magnetic wave (CMW) at finite baryon density can induce a charge-asymmetry dependence of elliptic flow (v$_{\mathrm{2}})$ of particles produced in heavy-ion collisions [1]. In the case of pions, STAR has observed that v$_{\mathrm{2}}(\pi ^{\mathrm{-}})$-v$_{\mathrm{2}}(\pi^{\mathrm{+}})$ exhibits a linear dependence on charge asymmetry with a positive slope in Au$+$Au collisions from 27 to 200 GeV [2]. This is consistent with the CMW picture. At lower collision energies, it was found that the charge-asymmetry integrated v$_{\mathrm{2}}$ for negative pions is higher while for kaons, the positive charge is favored. Therefore, an observation of the same positive linear dependence of kaon v$_{\mathrm{2}}$ difference on charge asymmetry will provide a further test on the CMW predictions in heavy-ion collisions. In this work, we will present the status of our kaon elliptic flow measurements as a function of charge asymmetry for Au$+$Au collisions at $\sqrt{s_{\mathrm{NN}}} = $ 27 GeV. \\[4pt] [1] Y. Burnier, D. Kharzeev, J. Liao, and H. Yee, Phys.Rev.Lett. 107 (2011) 052303.\\[0pt] [2] L. Adamczyk et al [STAR Collaboration], Phys.Rev.Lett. 114 (2015) 252302.\\[0pt] [3] L. Adamczyk et al [STAR Collaboration], Phys.Rev.Lett. 110 (2013) 142301.