Aligned yet large dipoles: a SMEFT study

Journal Article · 06 November 2024 · Journal of High Energy Physics (Online)

DOI: https://doi.org/10.1007/jhep11(2024)046 · OSTI ID:2481718

Bonnefoy, Quentin  ^[1]; Kley, Jonathan  ^[2]; Liu, Di  ^[3]; Rossia, Alejo N.  ^[4]; Yao, Chang-Yuan  ^[5]

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1. Université de Strasbourg (France); University of California, Berkeley, CA (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany)
2. Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany); Humboldt-Universität zu Berlin (Germany)
3. Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany); Annecy-le-Vieux (France)
4. University of Manchester (United Kingdom)
5. Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany); Nankai University, Tianjin (China)

We study a non-universal flavor scenario at the level of the Standard Model Effective Field Theory, according to which the matrix of Wilson coefficients cuW of an up-type electroweak quark dipole operator is aligned with the up-type Yukawa coupling. Such an alignment usually follows from the assumption of Minimal Flavor Violation (MFV), away from which we step by allowing the entries of cuW to be sizable along the first quark generations. A particular example, which we refer to as “inverse hierarchy MFV”, features Wilson coefficients inversely proportional to quark masses, and arises from BSM models respecting MFV and containing heavy fields that replicate the mass hierarchy of SM quarks. We then analyze the phenomenology driven by cuW at colliders and at lower-energy flavor experiments. We show that precision measurements of the process pp → Wh → γγℓν at FCC-hh could set an upper bound on |cuW| ≲ O (10^-2)(Λ/TeV)², with Λ the cutoff of the effective field theory. This bound is an order of magnitude stronger than the existing LHC bounds. Moreover, we estimate that Wh → b$$\overline{b}$$ℓν at HL-LHC could also give competitive bounds. In the low-energy regime, we consider bounds arising from rare kaon decays, which turn out to be loose, |c$$_{uW}^{11}$$ | < O (1)(Λ/TeV)². We finally demonstrate that our flavor and operator assumptions can be derived from a weakly-coupled UV model, which we choose to simultaneously illustrate the UV origin of inverse hierarchy MFV.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: China Postdoctoral Science Foundation; Deutsche Forschungsgemeinschaft; European Research Council (ERC); European Union’s Horizon Europe research and innovation programme; National Key Research and Development Program of China; USDOE Office of Science (SC), High Energy Physics (HEP)
• Grant/Contract Number: AC02-05CH11231; SC0019225
• OSTI ID: 2481718
• Journal Information: Journal of High Energy Physics (Online), Journal Name: Journal of High Energy Physics (Online) Journal Issue: 11 Vol. 2024; ISSN 1029-8479
• Publisher: Springer NatureCopyright Statement
• Country of Publication: United States
• Language: English