Anomalous Sudakov form factors
Abstract
While radiative corrections of infrared origin normally depress high energy amplitudes (Sudakov form factors), we find that in some cases resummation of leading effects produces exponentials with positive exponents, giving rise to amplitudes that grow indefinitely with energy. The effect happens in broken gauge theories like the electroweak sector of the Standard Model, and is related to the existence of amplitudes that do not respect the gauge symmetry, and that contrary to expectations do not vanish in the very high energy limit, but rather become dominant. As a working example we consider a model with two chiral abelian gauge groups U'(1) ⊗ U(1) with large mass splitting M _{ Z'} ≫ M _{ Z }, and we compute leading radiative corrections corrections to the decay of the heavy extra Z' boson into light fermions. For proper fermionic charges, the chirality breaking magnetic dipole moment, although mass suppressed, becomes the dominant contribution to the Z' width at very high energies.
 Publication:

Journal of High Energy Physics
 Pub Date:
 March 2010
 DOI:
 10.1007/JHEP03(2010)072
 arXiv:
 arXiv:0909.1657
 Bibcode:
 2010JHEP...03..072C
 Keywords:

 Spontaneous Symmetry Breaking;
 NLO Computations;
 Standard Model;
 High Energy Physics  Phenomenology;
 High Energy Physics  Theory
 EPrint:
 12 pages