Correlation between the scaling factor of the yukawa coupling and cross section for the $e^{+}{e}^{-}\to hhf\overline{f}$ ($f\ne t$) in type-I 2HD

Abstract

The objective of this study is to correlate the scaling factor of the Standard Model (SM) like Higgs boson and the cross section ratio of the process $e^{+}{e}^{-}\to hhf\overline{f}$ where $f\ne t$, normalized to SM predictions in the type I of the Two Higgs Doublet Model. All calculations have been performed at $\sqrt{s}=500$ GeV and $1\le \tan \beta \le 30$ for masses $m_H=m_A=m_{H^{\pm }}=300GeV$ and $m_H=300$ GeV, $m_A=m_{H^{\pm }}=500$ GeV. The working scenario is by taking without alignment limit, that is $s_{\beta -\alpha }=0.98$ and $s_{\beta -\alpha }=0.99,$ $0.995$, which gives the enhancement in the cross section, particularly a few times greater than the predictions of the SM due to resonant-impacts of the additional heavy neutral Higgs bosons. This shows that enhancement in cross section occurs on leaving the alignment i.e., $s_{\beta -\alpha }=1$, at which all the higgs that couple to vector bosons and fermions have the same values as in SM at tree level. A large value of enhancement factor is obtained at $s_{\beta -\alpha }=0.98$ compared to $s_{\beta -\alpha }=0.99,$ $0.995$. Furthermore, the decrease in the enhancement factor is observed for the case when $m_H=300$ GeV, $m_A=m_{H^{\pm }}=500$ GeV. The behavior of the scaling factor with $\tan \beta$ is also studied, which shows that for large values of $\tan \beta$, the scaling factor becomes equal to $s_{\beta -\alpha }$. Finally a convincing correlation is achieved by taking into account, the experimental and theoretical constraints e.g, perturbative unitarity, vacuum stability and electroweak oblique parameters.

Comments: 17 pages, 17 figures. International Journal of Theoretical Physics, 2021