Polarized and unpolarized off-shell H^(*)→ZZ→4■ decay above the 2m_(z) threshold  

作　　者：A.I.Hernandez-Juarez R.Gaitan G.Tavares-Velasco 

机构地区：[1]Departamento de Fisica,FES-Cuautitlan,Universidad Nacional Autonoma de Mexico,C.P.54770,Estado de Mexico,Mexico [2]Facultad de Ciencias Fisico Matematicas,Benemerita Universidad Autonoma de Puebla,Apartado Postal 1152,Puebla,Puebla,Mexico

出　　处：《Chinese Physics C》2024年第11期22-42,共21页中国物理C（英文版）

基　　金：Supported by UNAM Posdoctoral Program (POSDOC);the Sistema Nacional de Investigadores (Mexico)。

摘　　要：An analysis of the off-shell H^(*)→Zz-■_(1)■_(1)■_(2)■_(2) decay width is presented for both unpolarized and polarized Z gauge bosons in the scenario with the most general H^(*)ZZ vertex function,which is expressed in terms of two CP-even(bz and cz)and one CP-odd(bz)anomalous couplings.The SM contributions to the H^(*)ZZ coupling up to the one-loop level are also included.Explicit analytic results for the unpolarized and polarized H^(*)-Zz-■_(1)■_(1)■_(2)■_(2) square amplitudes and the four-body phase space are presented,out of which several obseryable quantities can be obtained straightforwardly.Regarding numerical analysis,a cross-check was performed via MadGraph5_aMC@NLO,where our model was implemented with the aid of FeynRules.We then considered the most stringent bounds on anomalous complex H^(*)ZZ couplings and analyzed the effects of the polarizations of the Z gauge bosons through the polarized H^(*)-ZZ→■_(1)■_(1)■_(2)■_(2) decay width as well as left-right and forward-backward asymmetries,which were found to be sensitive to new-physics effects.Particular focus was put on the effects of the absorptive parts of the anomalous H^(*)ZZ couplings,which have been largely overlooked up to now in LHC analyses.It was found that the studied observable quantities,particularly the left-right asymmetries,can be helpful to search for effects of CP-violation in the H^(*)ZZ coupling and set bounds on the absorptive parts.For completeness,we also analyzed the case of unpolarized Z gauge bosons.

关 键 词：polarization off-shell Higgs anomalous couplings CP violation 

分 类 号：O562[理学—原子与分子物理]