Integrating out heavy particles with functional methods: a simplified framework

• DOI: 10.1007/jhep09(2016)156
• Publication Date: 2016-09-28T05:52:24Z
• Authors: Javier Fuentes-Ma...; Jorge Portolés; Pedro Ruiz-Femenía
• Keywords: High Energy Physics - Theory; Nuclear and High Energy Physics; High Energy Physics - Phenomenology; High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Theory (hep-th); 0103 physical sciences; FOS: Physical sciences; 01 natural sciences

24 pages. Uses feynMF package<br/>We present a systematic procedure to obtain the one-loop low-energy effective Lagrangian resulting from integrating out the heavy fields of a given ultraviolet theory. We show that the matching coefficients are determined entirely by the hard region of the functional determinant involving the heavy fields. This represents an important simplification with respect the conventional matching approach, where the full and effective theory contributions have to be computed separately and a cancellation of the infrared divergent parts has to take place. We illustrate the method with a descriptive toy model and with an extension of the Standard Model with a heavy real scalar triplet. A comparison with other schemes that have been put forward recently is also provided.<br/>