The research efforts of the Physics Beyond the Standard Proton (PBSP) group focus on particle physics phenomenology, which is the field of theoretical particle physics that is mostly interested in the observable consequences of the theoretical understanding of the fundamental building blocks of Nature and of their mutual interactions. The objectives of our research are crucial in order to advance the interpretation of the experimental measurements of the ultra-relativist processes taking place at particle colliders, in particular at the Large Hadron Collider (LHC) at CERN.
The high-energy physics community finds itself at a particularly exciting crossroads, in which hints for new phenomena, such as a new kind of force that features different couplings with the different lepton families (dubbed "fifth force" by the newspapers), have been identified. Such hints have been suggested both by an experiment at Fermilab measuring the anomalous magnetic dipole moment of muons and by the precise flavour measurements performed by the LHCb detector at CERN. It is imperative to make the most of this window of opportunity and to statistically corroborate or falsify the presence of deviations from the Standard Model (SM) predictions coming from possible New Physics effects.
In order to maximise the chances of success, a robust determination of the significance of these signals is paramount. In particular, the outcome of this quest of the whole particle physics community requires the highest possible level of precision in three complementary components: the experimental data, the theoretical predictions and - crucially - a robust framework to globally interpret all subtle deviations from the SM predictions that might arise. Such a framework is crucial in order to confirm and strengthen or, alternatively, weaken and disprove the signals that have been observed so far.
The final outcome of PBSP's research project is the provision of two essential ingredient of such a much-needed statistical framework. On the one hand, PBSP will provide sets of Parton Distribution Functions (PDFs), i.e. the functions that parametrise the protons in terms of their elementary constituents (quarks and gluons), which are free of possible contaminations arising from New Physics. Given that PDFs are a crucial component of any theoretical predictions at the LHC, the delivery of such PDF set is crucial to achieve unbiased interpretation of the experimental observations at CERN. Second, PBSP will yield robust determination of Effective Field Theory (EFT) coefficients that parametrise the effect of heavy new particles at the energies probed by the LHC, in a model-independent way. The final goal of PBSP is to develop a new statistical methodology to devise global fits that are to simultaneously constrain both the proton structure and new physics dynamics from the data collected at the LHC, so that a global interpretation of the LHC data can be achieved.
