Title: Constraining the SMEFT Extended with Sterile Neutrinos at FCC-ee
报告人：Prof. Frank Deppisch (University College London)
主持人：张永超教授
时间：2025年11月21日（周五）14：00
地点：田家炳楼南楼203报告厅
Abstract
The origin of neutrino masses remains one of the most compelling open questions in particle physics, strongly motivating extensions to the Standard Model (SM) that include right-handed neutrinos, or Heavy Neutral Leptons (HNLs). While minimal Type-I seesaw scenarios are difficult to test at colliders due to small mixing angles, Effective Field Theory (EFT) frameworks allow for a model-independent exploration of heavy new physics that couples the SM to the sterile sector. In this talk, I will present a comprehensive analysis of HNL phenomenology at the Future Circular e^+e^- Collider (FCC-ee), focusing on the SM Effective Field Theory (SMEFT) extended with sterile neutrinos. We investigate a complete set of dimension-6 and dimension-7 operators, as well as effective charged- and neutral-current couplings. I will discuss how these signatures constrain Wilson coefficients of the EFT operators, highlighting the distinct phenomenological differences between Dirac and Majorana HNL scenarios. The results demonstrate that the FCC-ee can significantly extend the reach beyond current LEP and LHC limits, potentially probing the scale of new physics up to the multi-TeV range.
Biography
Prof. Deppisch received his Ph.D. in Theoretical Particle Physics from the University of Wuerzburg (Germany) in 2005. After two postdoctoral positions, at DESY Hamburg (Germany) and the University of Manchester (UK), he has been appointed Professor at University College London (UCL, UK) since 2011. He has been long-term visitor at several institutions world-wide, such as Yale University, HEPHY Vienna, IFIC Valencia and, currently, the Tsung-Dao Lee Institute in Shanghai. His main area of research is neutrino and Beyond-the-SM physics, with a focus on neutrino masses and lepton number violation.
