This study explores the diphoton and bb excesses at 95.4 GeV,as well as nano-Hertz gravitational waves originating from domain walls,within the framework of the next-to-two-Higgs-doublet model(N2HDM),which extends the...This study explores the diphoton and bb excesses at 95.4 GeV,as well as nano-Hertz gravitational waves originating from domain walls,within the framework of the next-to-two-Higgs-doublet model(N2HDM),which extends the two-Higgs-doublet model by introducing a real singlet scalar subject to a discrete Z_(2) symmetry.The Z_(2) symmetry is spontaneously broken by the non-zero vacuum expectation value of the singlet scalar,v_(s),which leads to the formation of domain walls.Two different scenarios are discussed:in scenario A,the 95.4 GeV Higgs boson predominantly originates from the singlet field,while in scenario B,it arises mainly from the CP-even components of the Higgs doublets.Accounting for relevant theoretical and experimental constraints,scenario A can fully account for both the diphoton and bb excesses at 95.4 GeV within the 1σrange.In the parameter space accommodating both excesses,scenario A fails to provide a valid explanation for the NANOGrav data up to v_(s)=1000 TeV,and the predicted gravitational wave spectrum can exceed the SKA sensitivity curve in the low frequency region.Scenario B only marginally accounts for the diphoton and bb excesses at the 1σlevel,but can simultaneously explain the NANOGrav data well.展开更多
基金Supported by the Shandong Provincial Natural Science Foundation Projects(ZR2024MA001,ZR2023MA038)the National Natural Science Foundation of China(11975013)。
文摘This study explores the diphoton and bb excesses at 95.4 GeV,as well as nano-Hertz gravitational waves originating from domain walls,within the framework of the next-to-two-Higgs-doublet model(N2HDM),which extends the two-Higgs-doublet model by introducing a real singlet scalar subject to a discrete Z_(2) symmetry.The Z_(2) symmetry is spontaneously broken by the non-zero vacuum expectation value of the singlet scalar,v_(s),which leads to the formation of domain walls.Two different scenarios are discussed:in scenario A,the 95.4 GeV Higgs boson predominantly originates from the singlet field,while in scenario B,it arises mainly from the CP-even components of the Higgs doublets.Accounting for relevant theoretical and experimental constraints,scenario A can fully account for both the diphoton and bb excesses at 95.4 GeV within the 1σrange.In the parameter space accommodating both excesses,scenario A fails to provide a valid explanation for the NANOGrav data up to v_(s)=1000 TeV,and the predicted gravitational wave spectrum can exceed the SKA sensitivity curve in the low frequency region.Scenario B only marginally accounts for the diphoton and bb excesses at the 1σlevel,but can simultaneously explain the NANOGrav data well.
