Neutrino and The Standard Model

TL;DR

This paper discusses how the Standard Model, especially with the inclusion of neutrinos, is shaped by fundamental principles and how future discoveries like neutrinoless double beta decay could confirm the role of neutrinos as Majorana particles.

Contribution

It proposes that the simplest possibilities consistent with gauge symmetry and symmetry breaking influence the Standard Model's structure, emphasizing the importance of neutrino properties beyond the Standard Model.

Findings

Massless left-handed neutrinos are crucial in the charged current structure.

Neutrino properties are likely determined by physics beyond the Standard Model.

Detection of neutrinoless double beta decay would support neutrinos being Majorana particles.

Abstract

After discovery of the Higgs boson at CERN the Standard Model acquired a status of the full, correct theory of the elementary particles in the electroweak range. What general conclusions can be inferred from the SM? I am suggesting here that in the framework of such general principles as local gauge symmetry, unification of the weak and electromagnetic interactions and Brout-Englert-Higgs spontaneous breaking of the electroweak symmetry nature chooses the simplest possibilities. It is very plausible that massless left-handed neutrinos (simplest, most economical possibility) play crucial role in the determination of the charged current structure of the Standard Model and that neutrino properties (masses and nature) are determined by a beyond the Standard Model physics. The discovery of the neutrinoless double $\beta$-decay and proof that neutrinos with definite masses are Majorana particles would be an important evidence in favor of the considered scenario.