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Importance of vector leptoquark-scalar box diagrams in Pati-Salam unification with vector-like families

Iguro, Syuhei 1,2; Kawamura, Junichiro; Okawa, Shohei; Omura, Yuji
1 Institut für Theoretische Teilchenphysik (TTP), Karlsruher Institut für Technologie (KIT)
2 Institut für Astroteilchenphysik (IAP), Karlsruher Institut für Technologie (KIT)

Abstract:

We study lepton flavor violation (LFV) induced by one-loop box diagrams in Pati-Salam (PS) unification with vector-like families. The vector leptoquark (LQ) associated with the PS gauge symmetry breaking generally causes various LFV processes such as KL → μe and μ → e conversion at the tree-level, thereby driving its mass scale to be higher than PeV scale. The vector-like families are introduced to suppress such tree-level LFV processes, allowing the LQ to have TeV scale mass. In this paper, we point out that there are inevitable one-loop contributions to those LFV processes from the box diagrams mediated by both one LQ and one scalar field, even if the tree-level contributions are suppressed. We consider a concrete model for demonstration, and show that the vector-like fermion masses have an upper bound for a given LQ mass when the one-loop induced processes are consistent with the experimental limits. The vector-like fermion mass should be lighter than 3 TeV for 20 TeV LQ, if a combination of the couplings does not suppress KL → μe decay. Our findings would illustrate importance of the box diagrams involving both LQ and physical modes of symmetry breaking scalars in TeV scale vector LQ models.

Zugehörige Institution(en) am KIT Institut für Astroteilchenphysik (IAP)
Institut für Theoretische Teilchenphysik (TTP)
Publikationstyp Zeitschriftenaufsatz
Publikationsmonat/-jahr 07.2022
Sprache Englisch
Identifikator ISSN: 1029-8479, 1126-6708, 1127-2236
KITopen-ID: 1000149055
HGF-Programm 51.11.01 (POF IV, LK 01) Teilchenphysik
Erschienen in Journal of High Energy Physics
Verlag Scuola Internazionale Superiore di Studi Avanzati (SISSA)
Band 2022
Heft 7
Seiten Art.-Nr.: 22
Vorab online veröffentlicht am 04.07.2022
Nachgewiesen in Web of Science
Scopus
Dimensions
Relationen in KITopen

Verlagsausgabe §
DOI: 10.5445/IR/1000149055
Veröffentlicht am 27.07.2022
Originalveröffentlichung
DOI: 10.1007/JHEP07(2022)022
Scopus
Zitationen: 4
Web of Science
Zitationen: 2
Dimensions
Zitationen: 5
Seitenaufrufe: 62
seit 28.07.2022
Downloads: 15
seit 31.07.2022
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