FCC-ee Higgs Physics

Tuesday 5 May 2026, 14:00 → 15:40 Europe/Zurich

CERN

GMT20260505-120612_Recording_2560x1440.mp4

Intro

• Any study performed within the FCC Higgs group should now be reviewed by the group before publication, particularly true if central samples and framework is used
• How to do it: upload results in form of a note on CDS, reviewer will be assigned (e.g. conveners)
• Instructions: https://docs.google.com/document/d/17pZmNR3ny3yHospsMrQLYkPO6l89Y_zF-SS6OhC-wtI/edit?tab=t.0

 

Electron Yukawa via ee>H>WW>lnu+jj [Apranik Fatehi]

• arXiv:2604.24152 (to be reviewed)
• Do leptons include taus? Yes, but only leptonic taus decays
• Isolation from charged hadrons only
• How are jet flavor tagging score simulated/computed?
• ParticleTransformer FTag algorithm trained at Z pole
• Can we gain something from H->ZZ*->4l?
• Only 1 ab
• Much higher significance from HWW (also including 4j) and Hgg, so probably not worth
• Goal is to achieve 3 sigma with current WP of 10 ab-1 and energy spread 4 MeV: quite optimistic!
• Mostly to stimulate work from accelerator to achieve better beam monochromatisation!

 

The Price of a Large Electron Yukawa Modification [Benjamin Smith]

• Anarchic scenario: any reasons for all C_eH_ij to be the same value?
• UV model matched to SMEFT?
• Yes, so it doesn’t cover all possible sources of NP
• Check other “reasonable” BSM model that could generate this, avoiding existing indirect constraints
• Example: https://arxiv.org/pdf/2311.12112 (light scalar)

 

Dalitz decay of Higgs (H -> llγ) in the 4lγ final state [Shreyas Bakare]

• Why photon E > 20GeV -> ZH production, H slightly boosted, impact on photon minimum p
• Leptons association: plot recoil mass from good Chi2 events
• 4 resolved leptons only? Yes, then no sensitivity to H->gamma*gamma
• Currently using Delphes and from the (tracker) detector resolution one should be able to resolve the individual electrons, but of course this might be studied better in full simulation
• Some contribution to H->gamma*gamma to resolved regime (~1/3 from ATLAS analysis)
• Maybe BDT drive sensitivity to H->Zy phase space? 
• Use m_ll to categorize and improve sensitivity to H->gamma*gamma

 

Higgs plus Photon Production at FCC-ee [Sara Aumiller]

• 1% uncertainty on background normalizations?
• Most background are basically DY-like processes, will be measure to better than 1% uncertainties
• Fully hadronic H->WW*?
• No, background would be harder to constrain 
• Recoil with Z would be a very large background

14:00 → 14:20 Introduction

Speakers: Andrew Mehta (University of Liverpool (GB)), Ang Li (Brookhaven National Laboratory (US)), Giacomo Cacciapaglia, Marco Delmastro (CNRS/IN2P3 LAPP), Ramona Grober (Università di Padova and INFN, Sezione di Padova)

2026_05_05_FCC-Higgs.pdf

14:20 → 14:40 Electron Yukawa via ee>H>WW>lnu+jj

Speakers: Apranik Fatehi (University of Hamburg - CERN), David d'Enterria (CERN), Michele Selvaggi (CERN), Reza Jafari (University of Tehran (IR))

Higgs-Physics-May05-2026.pdf

14:40 → 15:00 The Price of a Large Electron Yukawa Modification

Speaker: Benjamin Smith

higgs_wg_BS.pdf

15:00 → 15:20 Dalitz decay of Higgs (H -> llγ) in the 4lγ final state

Speakers: Aliya Nigamova (Paul Scherrer Institute (CH)), Clemens Lange (Paul Scherrer Institute (CH)), Lea Michaela Caminada (Paul Scherrer Institute (CH)), Shreyas Bakare (Paul Scherrer Institute PSI (CH) | University of Zurich UZH (CH))

Comments_05-05-2026.pdf

SB_Higgs-Dalitz-Decay_4lg_240GeV_FCCee_05-05-2026.pdf

15:20 → 15:40 Higgs plus Photon Production at FCC-ee

Speakers: Ken Mimasu (University of Southampton), Lena Maria Herrmann, Louis Portales (CEA Paris-Saclay, IRFU), Sara Aumiller (University of California Irvine (US))

hgamma_production_Sara_May2026.pdf