IMSc Webinar

Infrared structure of gauge theory : A comparison between N=4 SYM and QCD.

Amlan Chakraborty

Michigen University

We present a detailed study on the infrared structure (IR) of N = 4 SYM and its connection to QCD. Calculation of collinear splitting functions helps to understand the structure and thus one can get IR safe cross sections. We also demonstrate the factorization property that soft plus virtual part of the cross section satisfies in N = 4 SYM and through factorization, we calculate soft distribution function up to third order in perturbation theory. We show that the soft distribution function is process independent that includes operators as well as external legs. In addition to this we compare our findings against the known results in QCD through principle of maximum transcendentality (PMT). We extend our analysis further for the case of four-point form factors (FF) with double composite operator insertion upto 2 loop in N = 4 SYM and find that it violates the PMT while comparing with the corresponding quantity in the standard model, observed for the first time at the level of form factor. We have also analysed the behaviour of different FF at special singular limit (Regge and collinear) N = 4 SYM and it shows universal behaviour of the Leading Transcendental term at that particular singular kinematical point. Also we show that PMT is breaking for 4 point stess tensor Form Factors and try to explain the result in factorisation point of view.