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.
基金
supported in part by United Kingdom STFC(Grant No.ST/P000258/1)
in part by the Estonian Research Council via a Mobilitas Pluss grant
in part by the TDLI distinguished visiting fellow programme
supported in part by the National Natural Science Foundation of China(Grant Nos.11675086,and 11835005)
supported in part by the CAS Center for Excellence in Particle Physics(CCEPP)
the National Key R&D Program of China(Grant No.2017YFA0402204)
the Key Laboratory for Particle Physics,Astrophysics and Cosmology(Ministry of Education)
the Office of Science and Technology,Shanghai Municipal Government(Grant No.16DZ2260200)。
