English

Unitarity triangle angles explained: a predictive new quark mass matrix texture

High Energy Physics - Phenomenology 2025-06-19 v4

Abstract

We propose a novel quark mass matrix texture-pair with five free parameters, which fits the four quark mass ratios ms/mbm_s/m_b, md/mbm_d/m_b, mc/mtm_c/m_t, mu/mtm_u/m_t, and the four CKM quark mixing observables. The matrices each have one texture zero, but the main innovation here is a ``geometric'' ansatz exploiting a pair of small complex expansion parameters, based on the geometry of the Unitarity Triangle. The fit to the observables is in good agreement with current experimental values renormalised to  ⁣ ⁣104\sim\!\!10^4 TeV, and offers decisive tests against future high-precision measurements of the unitarity triangle angles at the weak scale. We identify two novel symmetries of these mass matrices which explain the phenomenologically-successful relations αϕ2π2\alpha\equiv\phi_2\simeq\tfrac{\pi}{2} and βϕ1π8\beta\equiv\phi_1\simeq\tfrac{\pi}{8}.

Keywords

Cite

@article{arxiv.2501.18508,
  title  = {Unitarity triangle angles explained: a predictive new quark mass matrix texture},
  author = {P. F. Harrison and W. G. Scott},
  journal= {arXiv preprint arXiv:2501.18508},
  year   = {2025}
}

Comments

13 pages, 3 figures, 1 table. V2: Preprint number added, citation added, minor typos corrected. V3: minor formatting changes for journal. Tidied up bibliography. V4: Bibliography re-ordered; Minor clarifications and typos corrected; Tab 1: errors added to UT angle predictions, $\beta_s$ prediction added; Fig 3: improved labeling; Eqs. (A.1)-(A.4) re-expressed in more economical (equivalent) forms

R2 v1 2026-06-28T21:26:00.305Z