Higgs Boson and Supersymmetry?

[Johnleprekan]

Can someone explain to me in layman's terms why the Higgs Boson needs to be less than 130 GeV to prove Supersymmetry exists?

 

[fzero]

Can someone explain to me in layman's terms why the Higgs Boson needs to be less than 130 GeV to prove Supersymmetry exists?

It is not true that a Higgs boson with mass less than 130 GeV proves the existence of supersymmetry.

What is true is that the simplest supersymmetric extension of the Standard Model, known as the Minimal Supersymmetric Standard Model, or MSSM, predicts that the lightest Higgs has a mass that is not too much above 125 GeV or so. The argument is outlined at http://en.wikipedia.org/wiki/MSSM_Higgs_Mass.

Even though the Higgs boson seems to be just within the range allowed by the MSSM does not mean that supersymmetry is correct. To address that we need additional data on the nature of the Higgs, but, more importantly, on the superpartner particles predicted by supersymmetry.

 

[Johnleprekan]

Why does it predict it to be this low though?

Why does it need to be sufficiently heavy? To do what?

 

[Bill_K]

It's the other way around - not that supersymmetry requires a light Higgs, rather a light Higgs suggests supersymmetry.

The Higgs potential V(φ) is typically written as a quartic polynomial, which is sufficient to describe the vacuum expectation value of the Higgs field and the Higgs mass. However when radiative corrections are included, the parameters become energy dependent. At very high energy, the curve may turn over and even become negative. If the vacuum we presently live in is not the lowest energy state, it would be metastable and subject to catastrophic change.

This situation becomes more likely for light Higgs masses, and 125 GeV is dangerously light. But supersymmetry tends to reduce the effect and stabilize the vacuum. So a light Higgs suggests supersymmetry.