Phenomenology Study Of The Lightest CP-even Higgs In Nmssm

Particle physics is a basic theoretical science that studies the composition of matter and its interaction.In July 2012,the discovery of the Higgs boson(the so-called “God particle”),which is one of the most important events in the history of human science,completes the Standard Model(SM)of particle physics.The standard model(SM)has made significant achievements in describing the interaction between quarks and leptons in the cases without gravity.However,there still exist some problems unsolved.Such as: the standard model does not include gravity,electroweak breaking problem,the neutrino mass problem,the Higgs mass problem,the unity of forces,and so on.In order to solve the Higgs mass problem,a new symmetry-supersymmetry is introduced.Supersymmetry establishes the symmetry between fermions and bosons.All the particles in the SM have a superpartner in the supersymmetry.The contributions of the loops between fermions and bosons can be offset at all orders due to the introduction of supersymmetry.Over the past two years,the Minimal Supersymmetric Standard Model(MSSM)is difficult to explain the galactic center gamma-ray excess revealed by the Fermi-LAT data and Z-peak excess reported by the ATLAS collaboration at the LHC,while the Next-to-Minimal Supersymmetric Standard Model(NMSSM)can be used to explain these experiments.As the simplest extension of MSSM,the NMSSM adds one more Higgs singlet field.Due to the introduction of Higgs singlet field,the mass of Higgs boson has a great enhancement at tree level,and does not need large contributions from loop corrections.Therefore,compared to the MSSM,NMSSM is even more natural to explain the 125 GeV Higgs data.NMSSM predicts that there are three CP-even Higgs particles,two CP-odd Higgs particles and a pair of charged Higgs particles,which enlarges Higgs spectrum.Thus,it is very important to study the properties of Higgs boson in NMSSM at future Higgs factory ILC,Which provides theoretical guidance for the accurate examination of the properties of Higgs boson and NMSSM.In this paper,we study the production of the lightest CP-even Higgs boson at ILC in natural NMSSM.Considering various experimental constraints,we scan over the parameter space of the NMSSM by requiring the fine tuning measures ?z and ?h are less than 50.Then in the allowed parameter space we investigate the Higgs-strahlung production of the lightest CP-even Higgs boson h1 at ILC assuming the next-to-lightest CP-even Higgs boson acts as SM-like.We calculate the cross section of the process e+e-?Zh1 at ILC with center-of-mass energy of 250 GeV,and also discuss the decay patterns of h1.We find that the cross section of the process e+e-? Zh1 can reach about 84 fb.Moreover,the cross section increases with the mass of h1 and strongly depends on the Higgs doublet-component of h1.For most of the surviving samples,h1 mainly decays to b(?) .However,for certain regions of the surviving samples,the branching ratio of h1??? can maximally reach 2%,which can be used to discriminate the NMSSM from MSSM.