arXiv subjects

Yasuhiro Okada

Publications and source records attributed to Yasuhiro Okada.

75 records · Page 5Linked to original sources

arXiv1994

Charged Higgs mass bound from the $b\rightarrow sγ$ process in the minimal supergravity model

We study the constraint on the mass of the charged Higgs boson in the minimal supergravity model based on the recent measurement of the inclusive $b\rightarrow sγ$ decay. It is shown that the lower bound for the charged Higgs mass crucially depends on the sign of the higgsino mass parameter ($μ$). For $μ<0$, the bound exceeds 400 GeV when the ratio of two Higgs vacuum expectation values ($\tanβ$) is larger than 10. No strong bound is obtained for $μ>0$ due to cancellations between charged Higgs and supersymmetric particle contributions. For $3\lsim\tanβ\lsim5$, a charged Higgs lighter than 180 GeV is excluded by this process irrespective of the sign of $μ$.

hep-ph↗

arXiv1994

Neutral Scalar Higgs Masses and Production Cross Sections in an Extended Supersymmetric Standard Model

Upper bounds on the three neutral scalar Higgs masses are considered in the supersymmetric standard model with a gauge singlet Higgs field. When the lightest Higgs is singlet-dominated the second lightest Higgs is shown to lie near or below the theoretical upper bound on the lightest Higgs mass. We also consider detectability of these Higgs bosons at a future $e^+ e^-$ linear collider with $\sqrt{s}\sim 300 $ GeV and show that at least one of the neutral scalar Higgs has a production cross section larger than 0.04~pb.

hep-ph↗

arXiv1993

Light Stop and the $b\rightarrow sγ$ Process

A constraint from $b\rightarrow sγ$ process to the minimal supersymmetric standard model is derived in the light stop region where the coupling between the lighter stop and the $Z^0$ boson vanishes due to the left-right mixing of the stop states. It is pointed out that although some region in the parameter space is excluded from this process there remains a large parameter space where the amplitude of the $b\rightarrow sγ$ is suppressed due to partial cancellation between different diagrams. Stop as light as 20 GeV is still viable from the $b\rightarrow sγ$ constraint.

hep-ph↗