Phenomenological study of a gauged ${L_μ-L_τ}$ model with a scalar leptoquark
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arXiv
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| Autores principales: | , , |
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| Formato: | Preprint |
| Publicado: |
2023
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| _version_ | 1866914725349031936 |
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| author | Chen, Chuan-Hung Chiang, Cheng-Wei Su, Chun-Wei |
| author_facet | Chen, Chuan-Hung Chiang, Cheng-Wei Su, Chun-Wei |
| contents | A $Z'$ gauge boson with sub-GeV mass has acquired a significant interest in phenomenology, particularly in view of the muon $g-2$ anomaly and coherent elastic neutrino-nucleon scattering. The latter is challenged by the nuclear recoil energy of a few tens of keV but has been observed by the COHERENT experiment. To further reconcile the observed excesses in $R(D^{(*)})$ from semileptonic charmful $B$ decays and in the $W$ boson mass, we investigate a model with a gauged $U(1)_{L_μ-L_τ}$ symmetry and a scalar leptoquark. In contrast to the mechanism that involves kinetic mixing between the gauge bosons of $U(1)_{\rm em}$ and $U(1)_{L_μ-L_τ}$, we adopt a dynamical symmetry breaking of $U(1)_{L_μ-L_τ}$ by incorporating an additional Higgs doublet. Through mixing with the $U(1)_{L_μ-L_τ}$-charged Higgs doublet, new Higgs decay channels $h\to Z_1 Z_1/Z_1 Z_2$ occur at percent-level branching ratios, which could be accessible at the LHC. The $W$-mass anomaly observed by CDF II can be potentially resolved through the enhancement in the oblique parameter $T$. Due to the flavored gauge symmetry, the introduced scalar leptoquark $S^{\frac{1}{3}}=(\bar{3},1,2/3)$ exhibits a unique coupling to the $τ$-lepton, offering an explanation for the excesses observed in $R(D^{(*)})$. Moreover, $τ\to μ(Z_1\to ) e^- e^+$ via the resonant light gauge boson decay can reach the sensitivity of Belle II at an integrated luminosity of 50 ab$^{-1}$. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2305_09256 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Phenomenological study of a gauged ${L_μ-L_τ}$ model with a scalar leptoquark Chen, Chuan-Hung Chiang, Cheng-Wei Su, Chun-Wei High Energy Physics - Phenomenology High Energy Physics - Experiment A $Z'$ gauge boson with sub-GeV mass has acquired a significant interest in phenomenology, particularly in view of the muon $g-2$ anomaly and coherent elastic neutrino-nucleon scattering. The latter is challenged by the nuclear recoil energy of a few tens of keV but has been observed by the COHERENT experiment. To further reconcile the observed excesses in $R(D^{(*)})$ from semileptonic charmful $B$ decays and in the $W$ boson mass, we investigate a model with a gauged $U(1)_{L_μ-L_τ}$ symmetry and a scalar leptoquark. In contrast to the mechanism that involves kinetic mixing between the gauge bosons of $U(1)_{\rm em}$ and $U(1)_{L_μ-L_τ}$, we adopt a dynamical symmetry breaking of $U(1)_{L_μ-L_τ}$ by incorporating an additional Higgs doublet. Through mixing with the $U(1)_{L_μ-L_τ}$-charged Higgs doublet, new Higgs decay channels $h\to Z_1 Z_1/Z_1 Z_2$ occur at percent-level branching ratios, which could be accessible at the LHC. The $W$-mass anomaly observed by CDF II can be potentially resolved through the enhancement in the oblique parameter $T$. Due to the flavored gauge symmetry, the introduced scalar leptoquark $S^{\frac{1}{3}}=(\bar{3},1,2/3)$ exhibits a unique coupling to the $τ$-lepton, offering an explanation for the excesses observed in $R(D^{(*)})$. Moreover, $τ\to μ(Z_1\to ) e^- e^+$ via the resonant light gauge boson decay can reach the sensitivity of Belle II at an integrated luminosity of 50 ab$^{-1}$. |
| title | Phenomenological study of a gauged ${L_μ-L_τ}$ model with a scalar leptoquark |
| topic | High Energy Physics - Phenomenology High Energy Physics - Experiment |
| url | https://arxiv.org/abs/2305.09256 |