[Paper Review] Dark Matter in Lepto-Baryonic Left-Right Theories

Sudhanwa Patra|arXiv (Cornell University)|Dec 15, 2015

Computational Physics and Python Applications3 citations

TL;DR

This paper proposes a Lepto-Baryonic Left-Right symmetric gauge theory where lepton and baryon number symmetries are local, and identifies viable dark matter candidates arising from the neutral components of fermion triplets. Gauge anomaly cancellation necessitates these states, which naturally emerge as dark matter when the theory breaks down to the Standard Model via the Higgs mechanism.

ABSTRACT

A Lepto-Baryonic Left-Right symmetric theory is considered where leptons and baryons are local gauge symmetries. These theories are generally anomalous and the possible gauge anomaly free solutions for these theories are presented here. This paper also shows different ways in which Lepto-Baryonic Left-Right theories are broken down to Standard Model gauge group which further breaks down to low energy by SM Higgs boson. It is found that the neutral component of fermion triplets can be a viable dark matter candidate originally introduced for gauge anomaly cancellation. The other dark matter possibilities within this Lepto-Baryonic Left-Right symmetric theories are also presented.

Motivation & Objective

• To construct a gauge-invariant Lepto-Baryonic Left-Right theory with local symmetries for leptons and baryons.
• To resolve gauge anomalies in such theories by identifying consistent anomaly-free solutions.
• To explore symmetry breaking patterns leading from the Left-Right gauge group down to the Standard Model gauge group.
• To identify viable dark matter candidates within the model, particularly from neutral fermion triplet components.

Proposed method

• Formulate a non-Abelian gauge theory with local lepton and baryon number symmetries.
• Analyze gauge anomalies using anomaly cancellation conditions for U(1) and non-Abelian gauge groups.
• Construct symmetry breaking chains from the Left-Right gauge group to the Standard Model group via Higgs mechanisms.
• Identify neutral fermion states from triplet representations as potential dark matter candidates.
• Evaluate the viability of these states as dark matter by examining their quantum numbers and couplings.

Experimental results

Research questions

• RQ1 Which anomaly-free configurations exist in Lepto-Baryonic Left-Right theories with local lepton and baryon number symmetries?
• RQ2 How can the Left-Right gauge symmetry break down to the Standard Model gauge group through Higgs mechanisms?
• RQ3 Can the neutral component of fermion triplets serve as a viable dark matter candidate due to gauge anomaly cancellation?
• RQ4 What other dark matter candidates arise in this theoretical framework beyond the neutral triplet?

Key findings

• The neutral component of fermion triplets emerges as a viable dark matter candidate due to its origin in gauge anomaly cancellation.
• Anomaly-free solutions in the theory require specific fermion representations, including those that include the dark matter candidate.
• The theory allows for multiple symmetry breaking paths from the Left-Right group down to the Standard Model group.
• The dark matter candidate is stable due to its quantum numbers and does not decay via gauge interactions.
• Other dark matter possibilities exist within the model, though the neutral triplet is highlighted as particularly natural.
• The model realizes dark matter without introducing additional global symmetries, relying instead on gauge structure and anomaly cancellation.