تقرير
Large $t\to cZ$ as a Sign of Vector-Like Quarks in Light of the $W$ Mass
| العنوان: | Large $t\to cZ$ as a Sign of Vector-Like Quarks in Light of the $W$ Mass |
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| المؤلفون: | Crivellin, Andreas, Kirk, Matthew, Kitahara, Teppei, Mescia, Federico |
| المصدر: | Phys. Rev. D 106, L031704 (2022) |
| سنة النشر: | 2022 |
| المجموعة: | High Energy Physics - Experiment High Energy Physics - Phenomenology High Energy Physics - Theory |
| مصطلحات موضوعية: | High Energy Physics - Phenomenology, High Energy Physics - Experiment, High Energy Physics - Theory |
| الوصف: | The rare flavour changing top quark decay $t\to cZ$ is a clear sign of new physics and experimentally very interesting due to the huge number of top quarks produced at the LHC. However, there are few (viable) models which can generate a sizable branching ratio for $t\to cZ$ -- in fact vector-like quarks seem to be the only realistic option. In this paper, we investigate all three representations (under the Standard Model gauge group) of vector-like quarks ($U$, $Q_1$ and $Q_7$) that can generate a sizable branching ratio for $t\to cZ$ without violating bounds from $B$ physics. Importantly, these are exactly the three vector-like quarks which can lead to a sizable positive shift in the prediction for $W$ mass, via the couplings to the top quark also needed for a sizable Br($t\to cZ$). Calculating and using the one-loop matching of vector-like quarks on the Standard Model Effective Field Theory, we find that Br($t\to cZ$) can be of the order of $10^{-6}$, $10^{-5}$ and $10^{-4}$ for $U$, $Q_1$ and $Q_7$, respectively and that in all three cases the large $W$ mass measurement can be accommodated. Comment: 8 pages, 2 figures + supplemental material. v2: Accepted to PRD, discussion of future lepton colliders added, units corrected in eq II.9, further references added |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.1103/PhysRevD.106.L031704 |
| URL الوصول: | http://arxiv.org/abs/2204.05962 |
| رقم الأكسشن: | edsarx.2204.05962 |
| قاعدة البيانات: | arXiv |
| DOI: | 10.1103/PhysRevD.106.L031704 |
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