Growing excesses of new scalars at the Electro-weak scale at the LHC

30 Apr 2024
Seminars and colloquia
Time
Venue
Dennis Sciama Lecture Theatre
Denys Wilkinson Building, Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH
Speaker(s)

Professor Bruce Mellado
University of the Witwatersrand/iThemba LABS

Seminar series
Experimental particle physics seminar
Knowledge of physics?
Yes, knowledge of physics required

Abstract

With the discovery of a Higgs boson at the Large Hadron Collider (LHC), great deal of attention has shifted towards the search for new bosons. The multi-lepton anomalies at the LHC are a strong indication of underlying new bosons in the data. These include excesses above the Standard Model (SM) predictions two opposite sign and same sign leptons, and three leptons, with and without $b$-jets, far surpassing the 5$\sigma$ mark. The anomalies can be accommodated by the decay of a heavy scalar $H$ into $SS^*, SS^\prime$, where $S$ and $S^\prime$ are Higgs-like bosons. Using the invariant mass of the two opposite sign leptons with Run 1 data, the mass of $S$ was predicted to be $m_S=150\pm5$\,GeV. This estimate was further corroborated with Run 2 data. In this paper we report a large resonant excess in the $\gamma\gamma, Z\gamma$ and $WW$ spectra in associated production with a mass of $152\pm1$\,GeV with a global significance above $5\sigma$. This has the potential to serve as the first evidence of a narrow resonance beyond the SM at the LHC.

Selected articles:

https://inspirehep.net/literature/1467465
https://inspirehep.net/literature/1714045
https://inspirehep.net/literature/1918084
https://inspirehep.net/literature/1814320
https://www.nature.com/articles/s42254-024-00703-6