Abstract
In the next-to-minimal supersymmetric (NMS) Standard Model (SM), it is possible for either one of the additional singlet-like scalar and pseudoscalar Higgs bosons to be almost degenerate in mass with the sim 125 GeV SM-like Higgs state. In the real NMSSM (rNMSSM), when the mass difference between two scalar states is comparable to their individual total decay widths, the quantum mechanical interference, due to the relevant diagonal as well as off-diagonal terms in the propagator matrix, between them can become sizeable. This possibility invalidates usage of the narrow width approximation (NWA) to compute the cross section for the production of a di-photon pair with a given invariant mass via resonant Higgs boson(s) in the gluon fusion process at the Large Hadron Collider (LHC). When, motivated by the baryon asymmetry of the universe, CP-violating (CPV) phases are explicitly invoked in the Higgs sector of the NMSSM, all the interaction eigenstates mix to give five CP-indefinite physical Higgs bosons. In this scenario, the interference effects due to the off-diagonal terms in the Higgs mass matrix that mix the pseudoscalar-like state with the SM-like one can also become significant, when these two are sufficiently mass-degenerate. We perform a detailed analysis, in both the real and complex NMSSM, of these interference effects, when the full propagator matrix is taken into account, in the production of a photon pair with an invariant mass near 125 GeV through gluon fusion. We find that these effects can account for up to sim 40% of the total cross section for certain model parameter configurations. We also investigate how such mutually interfering states contributing to the sim 125 GeV signal observed at the LHC can be distinguished from a single resonance.
Highlights
The discovery of a Higgs boson [1,2] at the Large Hadron Collider (LHC) provides convincing evidence of spontaneous electro-weak (EW) symmetry breaking (SB) through the Higgs mechanism
We note in the figure that, given the parameter space in Table 1, for the vast majority of points, H1 and H2 tend to lie within 3–4 MeV of each other in the real NMSSM (rNMSSM)
For φκ = 10◦, no points appear along the diagonal for H1/H2 > 6 MeV in the bottom right frame, as the splitting between these two widths starts growing beyond this value
Summary
The discovery of a Higgs boson [1,2] at the LHC provides convincing evidence of spontaneous electro-weak (EW) symmetry breaking (SB) through the Higgs mechanism. The shortcomings of the standard Higgs mechanism, including primarily the stability of the mass of the Higgs boson against large quantum corrections, need to be addressed properly in order to completely understand the dynamics of EWSB. Putting this together with other unresolved issues in the SM, such as its inability to explain the mass of neutrinos, the nature of dark matter (DM) and the large baryon asymmetry of the universe, compel us to believe that the elementary particle spectrum could be richer than the minimal one embedded in the SM. The NMSSM was proposed to take care of this so-called μ-problem through
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
