AFFINITY · Amplitudes and form factors via integrability

Amplitudes and form factors via integrability

The idea that our understanding of physical reality should be phrased in a mathematical language goes back to G. Galilei and it is still the common thread throughout several research directions in theoretical physics. The quantum theory of fields is the framework we currently use to encode a variety of physical phenomena, ranging from the interactions among fundamental particles to the description of statistical systems, such as a gas or a magnet. The canonical approach to the study of quantum field theories consists in computing physical observables in the approximation of weak interactions. In this context physical observables are expressed as power series expansions in the coupling constant, the small parameter governing the strength of the interaction. A concrete example of physical observable that can be measured at colliders, such as the Large Hadron Collider (LHC), is the differential cross section, whose computation involves different ingredients. This project focuses on two crucial ones, i.e. scattering amplitudes, describing the evolution between the initial and the final state of a scattering process, and form factors, describing the production or annihilation of fundamental particles by the action of some external energetic probe – as in Drell-Yan (DY) or Deep Inelastic Scattering (DIS) processes. The standard technique for computing such quantities has a graphic interpretation in terms of Feynman diagrams, for which the number of loops is related to the order in the perturbative expansion. However one important drawback of the method is that the complexity of the computation grows quickly (more precisely factorially) with the number of particles and standard techniques soon cease to be a viable path. Improving the currently known computational methods and understanding quantum field theories at finite value of the coupling are two of the main challenges of current research in theoretical physics. This proposal aims to give a contribution in both of these directions through the study of amplitudes and form factors in the context of the AdS/CFT correspondence. This duality established a remarkable relation between very different theories and it allows to access the strong coupling regime of quantum field theories by studying the weak coupling regime of a string moving in a particular geometry called Anti de Sitter (AdS) space. Furthermore, the emergent integrability of the model allows to hope for an exact solution which would yield an unprecedented example of quantum field theory which can be solved exactly.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз