Falsifying high-scale leptogenesis at the LHC.

Area of Science:

• Particle Physics
• Cosmology
• Astroparticle Physics

Background:

• The observed baryon asymmetry in the Universe is a key cosmological puzzle.
• Lepton number violating (LNV) processes are crucial for baryogenesis models.
• High-scale leptogenesis (LG) models propose mechanisms for generating this asymmetry.

Purpose of the Study:

• To investigate the implications of observing LNV processes for high-scale LG models.
• To determine the constraints imposed by LNV processes on early Universe cosmology.
• To analyze the impact of LNV on the washout factor and equilibrium conditions.

Main Methods:

• Theoretical analysis of LNV processes and their connection to baryon asymmetry.
• Examination of leptogenesis models with heavy right-handed neutrinos.
• Assessment of the out-of-equilibrium condition in the early Universe.

Main Results:

• A nonzero cross section for LNV processes would strongly constrain washout factors.
• This would violate the out-of-equilibrium condition in high-scale LG models.
• Observation of LNV processes would falsify high-scale LG models.

Conclusions:

• The detection of LNV processes at the LHC would rule out specific high-scale leptogenesis scenarios.
• Non-observation of LNV processes does not exclude the viability of all leptogenesis models.
• Constraints on early Universe physics are derived from LNV process measurements.