Probing new physics in dimension-8 neutral gauge couplings at e^+e^-colliders

作者：John Ellis,Hong-Jian He,Rui-Qing Xiao

摘要：Neutral triple gauge couplings(nTGCs)are absent in the standard model effective theory up to dimension-6 operators,but could arise from dimension-8 effective operators.In this work,we study the pure gauge operators of dimension-8 that contribute to nTGCs and are independent of the dimension-8 operator involving the Higgs doublet.We show that the pure gauge operators generate both ZγZ^*and Zγγ^*vertices with rapid energy dependence∝E^5,which can be probed sensitively via the reaction e^+e^-→Zγ.We demonstrate that measuring the nTGCs via the reaction e^+e^-→Zγfollowed by Z→qq decays can probe the new physics scales of dimension-8 pure gauge operators up to the range(1-5)TeV at the CEPC,FCC-ee and ILC colliders with s~(1/2)=(0.25-1)TeV,and up to the range(10-16)TeV at CLIC with s~(1/2)=(3-5)TeV,assuming in each case an integrated luminosity of 5 ab~(-1).We compare these sensitivities with the corresponding probes of the dimension-8 nTGC operators involving Higgs doublets and the dimension-8 fermionic contact operators that contribute to the e^+e^-Zγvertex.

发文机构：Department of Physics Theoretical Physics Department NICPB Tsung-Dao Lee Institute&School of Physics and Astronomy Institute of Modern Physics and Department of Physics Center for High Energy Physics

关键词：neutraltriplegaugecouplingsnewphysicsbeyondthestandardmodeleffectivefieldtheorye^+e^-colliders

分类号： O57[理学—粒子物理与原子核物理]