Title: Perspectives on the scale of new physics

Speaker: Dr. Sandeepan Gupta, Durham University

Abstract: So far the Large Hadron Collider (LHC) has discovered the Higgs boson and nothing else, a possibility that had been previously dubbed as ‘the nightmare scenario’. We argue that such a negative attitude is unwarranted and in fact the absence of new physics at the LHC motivates two very concrete research directions depending on our perspective on the question: what is the scale of new physics ? First of all, new physics may be just beyond LHC reach, and then the Standard Model Effective Field Theory (SMEFT) becomes a powerful framework to study indirect deviations. We discuss how the higher accessible centre of mass energy at LHC can potentially compensate for the smaller intrinsic precision of LHC relative to LEP. In the second part of this talk we consider the possibility that there is no new physics close to the TeV scale and view the current situation as an opportunity for a fundamental questioning of the conventionally held rationale for TeV scale physics. More concretely we discuss the recently proposed relaxion models that can accommodate a light Higgs even with a high new physics scale.