Chiral perturbative solution for the type-I seesaw mechanism in next-to-leading order

Fuente: arXiv
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Main Author: Yang, Masaki J. S.
Format: Preprint
Published: 2024
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author Yang, Masaki J. S.
author_facet Yang, Masaki J. S.
contents In this letter, we perform chiral perturbative diagonalization of the type-I seesaw mechanism by hierarchical singular values $λ_{i}$ of the Dirac mass matrix $m_{D}$ up to the next-to-leading order (NLO). Since the mass matrix of right-handed neutrinos $M_{R}$ has parity symmetries under $λ_{i} \leftrightarrow - λ_{i}$, the singular values $M_{i}$ and mixing angles of diagonalization of $M_{R}$ are written by only even and odd orders of $λ_{i}$ respectively. We confirm this fact by specific perturbative expansions of the third- and the fourth-order by $λ_{i}$. As a result, as long as the chiral perturbation theory is valid, the NLO contributions are generally suppressed by $O(λ_{i}^{2} / \labmda_{j}^{2}) \lesssim 1\%$ compared to the leading-order expressions that have sufficient accuracies.
format Preprint
id arxiv_https___arxiv_org_abs_2402_02767
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Chiral perturbative solution for the type-I seesaw mechanism in next-to-leading order
Yang, Masaki J. S.
High Energy Physics - Phenomenology
In this letter, we perform chiral perturbative diagonalization of the type-I seesaw mechanism by hierarchical singular values $λ_{i}$ of the Dirac mass matrix $m_{D}$ up to the next-to-leading order (NLO). Since the mass matrix of right-handed neutrinos $M_{R}$ has parity symmetries under $λ_{i} \leftrightarrow - λ_{i}$, the singular values $M_{i}$ and mixing angles of diagonalization of $M_{R}$ are written by only even and odd orders of $λ_{i}$ respectively. We confirm this fact by specific perturbative expansions of the third- and the fourth-order by $λ_{i}$. As a result, as long as the chiral perturbation theory is valid, the NLO contributions are generally suppressed by $O(λ_{i}^{2} / \labmda_{j}^{2}) \lesssim 1\%$ compared to the leading-order expressions that have sufficient accuracies.
title Chiral perturbative solution for the type-I seesaw mechanism in next-to-leading order
topic High Energy Physics - Phenomenology
url https://arxiv.org/abs/2402.02767