# Why must SUSY be broken in SUGRA inflation?

Why must supersymmetry be broken during the inflation in supergravity models? How does adding supersymmetry to power-law or Starobinsky models spoil inflation?

And is breaking of SUSY needed for both F-term and D-term inflations?

• Do you have a reference? I'm not sure exactly what scenario you're describing – innisfree Mar 16 '16 at 11:43
• You can see here for example - "arxiv.org/pdf/1101.2488v2.pdf", for general cases. – Kosm Mar 16 '16 at 11:48

For inflation we need to have a positive energy density $V>0$, which drives inflation. If [the VEV of] the F-term potential $V_F>0$, then we necessarily have F-term SUSY breaking. (Text in [] should be removed, see discussion below.)
• I don't get what you mean. Let $\phi$ be the inflaton. Then, during inflation we necessarily have $V(\phi)>0$ and SUSY is (spontaneously) broken. – psm Mar 17 '16 at 13:00
• Oh, sorry. I should edit that. During inflation we have $V>0$, that's it. – psm Mar 17 '16 at 13:32