baryogenesis via leptogenesis

baryogenesis via leptogenesis
Name	baryogenesis via leptogenesis
Field	Particle physics, Cosmology, Astroparticle physics
Introduced	1986
Key figures	Mikhail Shaposhnikov, Tsutomu Yanagida, Goran Senjanović, Alexander Sakharov, Andrei Dolgov
Related	Big Bang cosmology, Neutrino mass, CP violation, Standard Model, Grand Unified Theory

baryogenesis via leptogenesis. Baryogenesis via leptogenesis is a cosmological scenario that links the origin of the Baryon asymmetry of the Universe to lepton-number–violating processes in the early Universe, proposing that an initial lepton asymmetry is converted into a baryon excess by sphaleron processes during the Electroweak epoch. The idea builds on foundational work by Andrei Sakharov on the conditions for matter–antimatter asymmetry and was developed in influential papers by Tsutomu Yanagida and others in the context of GUT-scale physics and sees strong connections to models proposed by Goran Senjanović and Mikhail Shaposhnikov.

Introduction

Leptogenesis situates itself at the intersection of Big Bang nucleosynthesis, Cosmic microwave background, Standard Model extensions, and mechanisms for generating small neutrino masses such as the seesaw mechanism proposed in frameworks related to SO(10), SU(5), and Left-right symmetric model. It addresses the observed baryon-to-photon ratio measured by the Planck and Wilkinson Microwave Anisotropy Probe collaborations, while relying on theoretical ingredients considered in works by Alexander Sakharov, Andrei Dolgov, and model-building by Tsutomu Yanagida and Goran Senjanović.

Theoretical Framework

The theoretical framework combines elements of Thermal field theory, Finite-temperature field theory, and nonperturbative processes like sphalerons studied in contexts developed by Edward Witten, Nikolai Kuznetsov, and groups building on Lattice gauge theory methods. It embeds lepton number violation and CP violation within extensions of the Standard Model, frequently invoking heavy singlet right-handed neutrinos from seesaw constructions motivated by SO(10), SU(5), Pati–Salam model, and scenarios influenced by Grand Unified Theory proposals. Boltzmann-equation treatments draw on formalism from Sakharov criteria analyses and techniques advanced in studies by John Ellis, Steven Weinberg, and Andrei Linde.

Mechanisms of Leptogenesis

Leptogenesis mechanisms include Thermal leptogenesis initiated after reheating in inflationary models by groups around Goran Senjanović and Tsutomu Yanagida, Nonthermal leptogenesis in inflaton decay scenarios studied by Andrei Linde and Alan Guth, and resonant enhancements known from the work of A. Pilaftsis and collaborators. These mechanisms often rely on CP-asymmetric decays of heavy Majorana states, interference effects computed in perturbative frameworks related to methods by Gerard 't Hooft and Martinus Veltman, and flavor effects analyzed with inputs from Bruno Pontecorvo and Ziro Maki studies on neutrino mixing.

Connections to Neutrino Physics

Leptogenesis tightly connects to experimental and theoretical developments in Neutrino oscillation experiments such as Super-Kamiokande, SNO, Daya Bay, T2K, NOvA, and proposed facilities like DUNE and Hyper-Kamiokande. Models map the heavy-sector parameters to low-energy observables including PMNS matrix phases associated with work by Bruno Pontecorvo and Ziro Maki, while constraints on absolute neutrino mass scale relate to searches by KATRIN and cosmological limits from Planck and Large Scale Structure surveys championed by collaborations including SDSS and DESI.

Cosmological Implications and Constraints

Cosmological implications span impacts on Big Bang nucleosynthesis predictions tested by groups working on primordial element abundances, limits from the Cosmic microwave background anisotropy measurements by COBE, WMAP, and Planck, and bounds from Large Scale Structure data used by collaborations like SDSS and Euclid teams. Thermal histories invoking high reheating temperatures face constraints from gravitino problem analyses in Supersymmetry contexts explored by Howard Haber and Steven Weinberg, while low-scale or resonant scenarios are evaluated in frameworks related to Lepton flavor violation limits from experiments such as MEG and Mu2e.

Experimental Tests and Observational Signatures

Direct tests include searches for Neutrinoless double beta decay at collaborations like GERDA, EXO, and CUORE, which probe Majorana masses relevant to leptogenesis models advocated by Goran Senjanović and Tsutomu Yanagida. Collider signatures at Large Hadron Collider experiments ATLAS and CMS can probe extended gauge sectors from Left-right symmetric model constructions similar to proposals by Mohapatra and Pati–Salam model proponents, while indirect signatures appear in precision measurements by KOTO and Belle II collaborations addressing CP violation patterns related to leptogenesis dynamics.

Alternatives and Extensions

Alternative baryogenesis frameworks include Electroweak baryogenesis studied by Michael Trodden, Affleck–Dine baryogenesis developed in supersymmetric contexts by Ian Affleck and Michael Dine, and mechanisms from GUT baryogenesis in models by Howard Georgi. Extensions of leptogenesis incorporate Low-scale leptogenesis proposals, Sterile neutrino scenarios connected to Dark matter candidates explored by Asaka and Shaposhnikov, and connections to String theory or Extra dimensions considered in works by Edward Witten and Joseph Polchinski.

Open Questions and Future Directions

Open questions include precise mapping between high-energy CP phases and low-energy observables pursued by collaborations at DUNE and Hyper-Kamiokande, the viability of low-reheating-temperature scenarios in inflationary models from groups like those led by Andrei Linde and Alan Guth, and the role of quantum transport theory refined by researchers such as Wilhelm Heisenberg-influenced formalism developers. Future directions emphasize synergy among Cosmic microwave background experiments, Neutrinoless double beta decay searches, Large Hadron Collider upgrades, and astrophysical surveys like Euclid and Vera C. Rubin Observatory to further constrain leptogenesis parameter space.

Category:Baryogenesis