Doctoral contract for Belle 2 experience (M/F)

Job Description

Thesis Subject

Activities:

Data analysis, participation to data taking, participation to Belle II service tasks, activities of outreach and dissemination.


Processes involving Flavor Changing Neutral Currents (FCNC), where a B meson undergoes decay into a pair of oppositely charged leptons, serve as potent avenues in the exploration of physics beyond the Standard Model (SM). Notably, the decay B0s → μ+μ− has been observed by LHC experiments, and its measured branching fraction (BF) aligns with the SM prediction, thereby imposing rigorous constraints on theories extending beyond the SM. Investigations into the tauonic modes B → τ+τ−, where B can be either a B0 or B0s meson, become particularly compelling due to indications of lepton flavor nonuniversality hinted from several experiments in b → s l l and b → c l nu processes. Models elucidating these anomalies propose that the BF of B → τ+τ− modes could exhibit significant enhancements compared to SM predictions, potentially by several orders of magnitude. Only few measurements have been performed on those modes so far, Belle II is expected to improve them significantly. The Belle II experiment, located at KEK in Japan, began data collection in 2019 with the goal of accumulating the largest statistics of B mesons ever recorded at an e+e- collider.

Your Work Environment

This PhD will take place at CPPM, Marseille (https://www.cppm.in2p3.fr/web/en/index.html). Extended stays at the IRL of KEK (Toshiko Yuasa Laboratory) are to be foreseen as well as shorter stays for collaboration meetings and participation to the data taking.

References:

Search for the decays B0s→τ+τ− and B0→τ+τ−, Phys. Rev. Lett. 118, 251802 (2017), arXiv:1703.02508.

C. Bobeth et al., Bs,d → τ+τ− in the Standard Model with reduced theoretical uncertainty, Phys. Rev. Lett. 112 (2014) 101801, arXiv:1311.0903.

B.Capdevila et al., Searching for New Physics with b→sτ+τ− processes, Phys. Rev. Lett. 120 (2018) 181802, arXiv:1712.01919.

Compensation and benefits

Compensation

2300 € gross monthly

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

CNRS

The research professions