Why is SUSY Breaking so Difficult?! - Institute for Particle Physics ...
Why is SUSY Breaking so Difficult?! - Institute for Particle Physics ...
Why is SUSY Breaking so Difficult?! - Institute for Particle Physics ...
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Witten Index<strong>SUSY</strong> vacua are easy to findConsider W = Tr (−1) F = ∑ B〈B|B〉 − ∑ F〈F|F〉As H <strong>is</strong> positive definite: H|B〉 = 0 =⇒ Q|B〉 = 0whereas <strong>for</strong> H|B〉 ̸= 0 we are guaranteed a state |F〉 = Q|B〉with the same energy but opposite stat<strong>is</strong>tics.◮ W counts the number of zero energy states ◭If W <strong>is</strong> non-zero, there must ex<strong>is</strong>t a susy vacuum.Independent of couplings — “topological”Non-zero <strong>for</strong> vector-like theories ⇒ complicates models(I.P.P.P. — Durham University) <strong>SUSY</strong> <strong>Breaking</strong> Heidelberg 16 / 27