Scholarlink

<p>We build upon a simple U(2)<sub><i>F</i></sub> model of flavor, in which all fermion masses and mixing hierarchies arise from powers of two small parameters controlling U(2)<sub><i>F</i></sub> breaking. In the original formulation, an isomorphism to the discrete <i>D</i><sub>6</sub> × U(1)<sub><i>F</i></sub> symmetry was invoked to generate a Majorana neutrino mass term. Here, we retain the successful features of that model for the charged leptons and quarks, while exploring alternative neutrino charge assignments within the U(2)<sub><i>F</i></sub> framework. This approach allows us to generate Majorana neutrino masses via the see-saw mechanism without introducing any additional symmetries nor invoking any isomorphism. We further examine the implications of our models for Lepton Flavor Violating (LFV) decays, analyzing the processes <i>μ</i> → <i>eγ</i>, <i>τ</i> → <i>μγ</i> and <i>τ</i> → <i>eγ</i> and their connection with the leptonic anomalous magnetic moments. We show that within the Standard Model Effective Field Theory (SMEFT) approach the current limits on the branching ratios of <i>μ</i> → <i>eγ</i> LFV decays obtained in our U(2)<sub><i>F</i></sub> models are not compatible with the central value of the recent measurement of the (<i>g</i> − 2)<sub><i>μ</i></sub>, thereby suggesting that either (<i>g</i> − 2)<sub><i>μ</i></sub> must be very close to the Standard Model predictions, as the latest experimental and theoretical results seem to suggest, or the invoked flavor symmetry is not appropriate to describe an anomalous muon magnetic moment.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

A roadmap for neutrino charge assignments in U(2)F flavor models: implications for LFV processes and leptonic anomalous magnetic moments

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2026年2月20日

查看全文
  • Alessio Giarnetti,
  • Simone Marciano,
  • Davide Meloni,
  • Mirko Rettaroli

摘要

We build upon a simple U(2)F model of flavor, in which all fermion masses and mixing hierarchies arise from powers of two small parameters controlling U(2)F breaking. In the original formulation, an isomorphism to the discrete D6 × U(1)F symmetry was invoked to generate a Majorana neutrino mass term. Here, we retain the successful features of that model for the charged leptons and quarks, while exploring alternative neutrino charge assignments within the U(2)F framework. This approach allows us to generate Majorana neutrino masses via the see-saw mechanism without introducing any additional symmetries nor invoking any isomorphism. We further examine the implications of our models for Lepton Flavor Violating (LFV) decays, analyzing the processes μ → eγ, τ → μγ and τ → eγ and their connection with the leptonic anomalous magnetic moments. We show that within the Standard Model Effective Field Theory (SMEFT) approach the current limits on the branching ratios of μ → eγ LFV decays obtained in our U(2)F models are not compatible with the central value of the recent measurement of the (g − 2)μ, thereby suggesting that either (g − 2)μ must be very close to the Standard Model predictions, as the latest experimental and theoretical results seem to suggest, or the invoked flavor symmetry is not appropriate to describe an anomalous muon magnetic moment.