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Phenomenology of the Fundamental Interactions

Phenomenology of the Fundamental Interactions
This INFN research collaboration focuses on the phenomenology (observable consequences) of several Quantum Field Theory models.
Such models can refer to a subset of the Standard Model of particle physics (SM) and to several extensions beyond it (BSM) which are considered in order to overcome some of its limits. Indeed, in spite of its impressive success, the SM is believed to be an effective theory, i.e. a low energy manifestation of a more fundamental theory.
A wide spectrum of experiments - the Large Hadron Collider (LHC), together with flavor, neutrino and astro-particle experiments - is entering the unexplored territory lying beyond the electroweak scale, with the potential of leading to important breakthroughs in our understanding of fundamental physics.
On the other hand for strong interactions the regime of low energy physics such as hadron spectra, dominated by the confinement phase of QCD, is not yet well understood due to inadequacy of perturbative analysis. Heavy ion collision experiments for the investigation of the quark gluon plasma phase require further theoretical insights.


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Perturbative approaches

- QCD and gauge theories in the Regge limit (small x).
This is a kinematical regime where high density phenomena and nonlinear dynamics are important.
It is reached in hadron collider such as LHC, in Deep Inelastic Scattering experiments and heavy ion collisions.
Theoretically it is a playground where for the first time the notion of integrability in gauge theories appeared.

- Analytic or precise numerical calculation of multi-loop contributions to various processes in QED, QCD and the EW model, by using, in particular, the differential equation approach for the evaluation of the Master Integrals.

- Scattering amplitudes for gauge theories: modern techniques
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Non perturbative analysis for effective and fundamental QFTs

They are studied using the 
approach of Wilsonian renormalization group with functional techniques. The reserch covers any kind of QFT in several dimensions.
Critical and close to critical behavior are essential informations to explore the nature of QFTs. Investigations focus on UV completeness of the theories (asymptotic safety paradigm), constructions of global flow from UV to IR and effective descriptions of “low energy”  of fundamental theories in terms of effective theories.
Applications to gauge theories (QCD, gravity,…) with matter interactions.
These techniques apply as well in condensed matter systems.