Effects of the supersymmetric phases on the neutral Higgs sector

TL;DR

This work investigates how supersymmetric CP-violating phases affect the neutral Higgs sector of the MSSM by computing one-loop radiative corrections from top/stop loops using the effective potential. The analysis reveals that a nonzero CP-violating phase gamma = $\varphi_{\mu}+\varphi_{A_t}$ induces mixing between CP-even and CP-odd Higgs components, with the lightest Higgs remaining predominantly CP-even while the heavier Higgs states acquire substantial CP admixtures, especially at large $\tan\beta$. These mixings alter Higgs masses and their couplings to fermions, leading to significant changes in decay rates such as $H_i\to \bar f f$, and potentially observable collider signatures. The study emphasizes that CP phases can act as a diagnostic tool for supersymmetry, offering distinctive phenomenology beyond the CP-conserving MSSM and motivating collider probes of CP-violating Higgs sector dynamics.

Abstract

By using the effective potential approximation and taking into account the dominant top quark and scalar top quark loops, radiative corrections to MSSM Higgs potential are computed in the presence of the supersymmetric CP-violating phases. It is found that, the lightest Higgs scalar remains essentially CP-even as in the CP-invariant theory whereas the other two scalars are heavy and do not have definite CP properties. The supersymmetric CP-violating phases are shown to modify significantly the decay rates of the scalars to fermion pairs.

Figures (8)

• Figure 1: Variation of $M^{2}_{13}/|M^{2}_{12}|$ (solid curve) and $M^{2}_{23}/|M^{2}_{12}|$ (dashed curve) with $\tan\beta$ for $M_{\tilde{L}}=M_{\tilde{R}}=|A_{t}|=10\cdot M_{Z}$, $|\mu|=2.5\cdot M_{Z}$ and $\tilde{M}_{A}=2\cdot M_{Z}$ with $\gamma=\pi/4$. The CP-- violating mixings become important for large $\tan\beta$.
• Figure 2: Percentage composition of $H_{1}$ as a function of $\gamma$ for $\tan\beta=4$ (left panel) and $\tan\beta=30$ (right panel). Here $\phi_{1}$, $\phi_{2}$ and $\sin\beta\varphi_{1}+\cos\beta\varphi_{2}$ contributions are $|{\cal{R}}_{11}|^{2}$ (solid curve), $|{\cal{R}}_{12}|^{2}$ (dashed curve) and $|{\cal{R}}_{13}|^{2}$ (short-dashed curve), in percents. Values of the parameters are given in (29).
• Figure 3: Percentage composition of $H_{2}$ as a function of $\gamma$ for $\tan\beta=4$ (left panel) and $\tan\beta=30$ (right panel). Here $\phi_{1}$, $\phi_{2}$ and $\sin\beta\varphi_{1}+\cos\beta\varphi_{2}$ contributions are $|{\cal{R}}_{21}|^{2}$ (solid curve), $|{\cal{R}}_{22}|^{2}$ (dashed curve) and $|{\cal{R}}_{23}|^{2}$ (short-dashed curve), in percents.
• Figure 4: Percentage composition of $H_{3}$ as a function of $\gamma$ for $\tan\beta=4$ (left panel) and $\tan\beta=30$ (right panel). Here $\phi_{1}$, $\phi_{2}$ and $\sin\beta\varphi_{1}+\cos\beta\varphi_{2}$ contributions are $|{\cal{R}}_{31}|^{2}$ (solid curve), $|{\cal{R}}_{32}|^{2}$ (dashed curve) and $|{\cal{R}}_{33}|^{2}$ (short-dashed curve), in percents.
• Figure 5: Masses of the scalars $H_{i}$ as a function of $\gamma$ for $\tan\beta=4$ (left panel) and $\tan\beta=30$ (right panel). Here $M_{H_{1}}$, $M_{H_{2}}$ and $M_{H_{3}}$ are shown by solid, dashed, and short-dashed curves, respectively. In both panels $H_{1}$ is the lightest scalar whose composition is shown in Fig. 2.