Data inizio

23/09/2026 12:00

Data fine

23/09/2026 14:00

Luogo

Dipartimento di Fisica - A502

Relatori

Dr.ssa Elena Mazzeo
CERN

The Higgs boson potential is a cornerstone of particle physics. It encodes the mechanism of electroweak symmetry breaking, through which elementary particles acquire mass, and is also closely connected to fundamental open questions about the evolution of our Universe, from its earliest moments to its long-term destiny. However, its exact shape remains largely unknown experimentally.

The only direct way to probe the Higgs potential is through measurements of the Higgs boson self-interactions, in particular the trilinear Higgs self-coupling, λ₃. A direct measurement of this parameter requires the study of Higgs boson pair (HH) production, an extremely rare process that has not yet been observed. The Large Hadron Collider (LHC) at CERN, the world’s most powerful proton–proton collider, provides the only experimental access to HH production. Following the end of Run 3 in June 2026, the ATLAS and CMS collaborations are now analysing the newly collected data, while also combining them with the Run 2 dataset, hoping to reach the first evidence for HH production.

The extreme rarity of this process makes the search for HH particularly challenging. At the same time, the rich phenomenology of the Higgs boson translates into many possible HH final states, each offering a different way to look for the same process. Combining these different channels is therefore crucial to maximise the sensitivity to HH production.

The next big step for HH will come with Run 4 and the High-Luminosity LHC. Promising ten times more data than those collected so far, the HL-LHC will give us the opportunity not only to establish HH production, but to start answering the bigger question behind these searches: does the trilinear Higgs self-coupling, and ultimately the Higgs potential, behave as we expect?