Precision Physics in the Higgs Sector

Monday 3 Mar 2025, 14:00 → 17:00 Europe/Rome

Conversi (Dipartimento di Fisica-Ed. G.Marconi)

Laura Reina (Florida State University), Nicholas Wardle (CMS), Paolo Francavilla (Istituto Nazionale di Fisica Nucleare)

Thematic afternoon on Precision Physics in the Higgs sector.

The event will feature three speakers:

• Laura Reina (theoretical contribution, 40'+10')
• Nicholas Wardle (experimental contribution from CMS, 40'+10')
• Paolo Francavilla (experimental contribution from ATLAS, 40'+10')

 

Organizers: Francesco Pandolfi, Mauro Valli, Valerio Ippolito

Zoom link: https://uniroma1.zoom.us/j/87038625161?pwd=cEtGRjZNT2VWSlJIWmxaYmxSMDhRZz09

1 Enabling the LHC Higgs precision program: a theory perspective

Understanding the deep origin of the electroweak symmetry breaking is at the core of some of the remaining fundamental questions in particle physics and cosmology. The discovery of the Standard-Model (SM) Higgs boson at the Large Hadron Collider (LHC) has been a milestone achievement in this quest and made this connection even more compelling and intriguing. The incredible performance of the LHC in measuring the properties of the discovered Higgs boson and the projected reach of its High-Luminosity upgrade (HL-LHC) will allow us to build a full-fledged Higgs-boson precision program and extract indirect information on physics beyond the SM. Higgs-boson precision physics is indeed at the core of the (HL-)LHC physics program, but to fully enable this program we need theoretical predictions to match the accuracy of experimental measurements. This can become a multi-component challenging task when the experimental precision reaches percent level or below. In this talk I will discuss how this challenge is being addressed and also point to possible questions that
should be discussed in moving forward.

Speaker: Laura Reina (Florida State University)

roma25-higgs.pdf

2 Over 10 years of measurements in the Higgs Sector with CMS

The Higgs discovery in 2012 marked a milestone achievement of the LHC. Since the discovery, measuring the properties of the Higgs boson and characterising its role in electroweak symmetry breaking has become a key tool in the search for physics beyond the standard model. The CMS experiment at CERN is one of the key players in making precision measurements of Higgs boson properties. As the dataset increases, CMS is using ever increasing levels of sophistication to collect, analyse and interpret Higgs boson data, making use of advanced tool-kits like machine learning. As we move towards the high-luminosity (HL) running of the LHC, ensuring the continued success of the precision Higgs measurement programme at CMS poses a significant challenge, that require new analysis ideas and techniques to overcome. By exploiting the data that we will have in this way, Higgs boson precision measurements will complement existing searches for new particles, hopefully leading to discovery of new physics at he HL-LHC or beyond it.

Speaker: Nicholas Wardle (Imperial College London)

roma25-higgs-CMS.pdf

3 Higgs Physics with ATLAS: From Discovery to Precision

Since its discovery in 2012, the Higgs boson has become a cornerstone of the Standard Model (SM), yet many of its properties remain under investigation. The ATLAS experiment at the Large Hadron Collider (LHC) is playing a crucial role in advancing our understanding of the Higgs sector through increasingly sophisticated analysis techniques. In this seminar, we will explore the precise measurement of Higgs boson properties and the impact of state-of-the-art analysis methods, including machine learning techniques, on these measurements. We will discuss strategies for determining key observables—such as mass, width, production cross-sections, decay branching ratios, and couplings to SM particles—emphasizing the role of differential kinematic distributions. These distributions not only provide stringent tests of the SM but also serve as a powerful tool to probe potential signs of new physics, such as anomalous Higgs interactions or contributions from undiscovered particles. By leveraging high-precision measurements and innovative statistical techniques, the LHC experiments continue to push the boundaries of Higgs physics, paving the way for future discoveries at the LHC and beyond.

Speaker: Paolo Francavilla (INFN Pisa)

FrancavillaRoma2025Short.pdf

16:30 Coffee Break