"SPECIAL PARTICLE SEMINAR: Higgs to Two Photons, Gauge Invariance, and the Hierarchy Problem"

Speaker: 
Jennifer Kile
Institution: 
Univ. of Florida
Date: 
Friday, April 18, 2014
Time: 
3:00 pm
Location: 
FRH 4135

 

ABSTRACT:

The Standard Model calculation of the two-photon decay of the Higgs boson has the curious feature of being finite but regulator-dependent.  While dimensional regularization yields a result which respects the electromagnetic Ward identities, additional terms which violate gauge invariance arise if the calculation is done setting d=4.  This discrepancy between the dimensional-regularization and d=4 results is recognized as a true ambiguity which must be resolved using physics input; as dimensional regularization respects gauge invariance, the calculation using dimensional regularization is accepted as the correct SM result.  However, here we point out another possibility, namely, that it is possible that the individual diagrams do violate the electromagnetic Ward identities, but that the gauge-invariance-violating terms cancel when all contributions, both from the SM and from new physics, are included.  We derive the conditions under which such a cancellation occurs, and find consequences for solutions to the hierarchy problem.  In particular, we find that supersymmetry obeys these conditions, even if it is softly broken at an arbitrarily high scale.


 

Host: 
Flip Tanedo