The singular behavior of massive QCD amplitudes

By Alexander Mitov, Sven-Olaf Moch. 2006

152 citations recorded by the source corpus.

We discuss the structure of infrared singularities in on-shell QCD amplitudes with massive partons and present a general factorization formula in the limit of small parton masses. The factorization formula gives rise to an all-order exponentiation of both, the soft poles in dimensional regularization and the large collinear logarithms of the parton masses. Moreover, it provides a universal relation between any on-shell amplitude with massive external partons and its corresponding massless amplitude. For the form factor of a heavy quark we present explicit results including the fixed-order expansion up to three loops in the small mass limit. For general scattering processes we show how our constructive method applies to the computation of all singularities as well as the constant (mass-independent) terms of a generic massive n-parton QCD amplitude up to the next-to-next-to-leading order corrections.

Subfields: Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/4639eb3a2cb9daba5be8582932979f14f9c92582

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Nuclear and High Energy Physics

1. A. Broggio
2. A. Ferroglia
3. T. Becher
4. M. Neubert
5. R. Britto
6. Chris D. White
7. M. Schwartz
8. F. Cachazo

Citations in the corpus

• Introduction to Soft-Collinear Effective Theory (2014, result): “Both functions are found to be suppressed like O(m4/s2) in the limit in which the parton mass m is much smaller than the hard scale(s) s, in accordance with mass factorization theorems proposed in the literature [125,126].”
• Erratum: On the structure of infrared singularities of gauge-theory amplitudes (2009, methodology): “Furthermore, by combining our results with methods developed in [86–90], which relate the singularities of massive and massless amplitudes, our formalism can be generalized to the massive case.”
• Loop amplitudes in gauge theories: modern analytic approaches (2010, background): “The coefficients of the cut-free integrals can, in some cases, be completely fixed by the universal ultraviolet and infrared divergent behavior [60, 61, 50, 62, 63].”