| Title: | TeV scale quark-lepton unification |
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| Authors: | ID Babu, K. S. (Author)
ID Biswas, Sumit (Author)
ID Saad, Shaikh, Institut "Jožef Stefan" (Author) |
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| Files: |  URL - Source URL, visit https://link.springer.com/article/10.1007/JHEP06(2026)023
 PDF - Presentation file, download (4,65 MB)
MD5: 04385F34418F75F081C8FE0107EEC0A6
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| Language: | English |
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| Typology: | 1.01 - Original Scientific Article |
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| Organization: |  IJS - Jožef Stefan Institute
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| Abstract: | We propose a quark-lepton symmetric Pati-Salam (PS) model based on the gauge group SU(2)L × SU(2)R × SU(4)C with an E6-inspired particle spectrum which naturally accommodates a multi-TeV leptoquark gauge boson . A softly broken Z2 symmetry plays a crucial role in realizing this scenario, under which the Standard Model (SM) fermions are even, while new vector-like fermions present in the model are odd. A notable feature of this model is that the PS gauge boson Xμ itself is Z2-odd, causing it to couple exclusively between SM fermions and the vector-like fermions, except in the right-handed down-quark sector, where mixing is induced by the soft breaking of Z2. This structure leads to helicity suppression of tree-level meson decays mediated by Xμ, with Z2-unsuppressed contributions arising only via one-loop diagrams. We show that Xμ can be as light as 1.1 TeV while being compatible with all flavor-violating constraints. However, mass relations among the gauge bosons push the Xμ mass limit up to 4.3 TeV from the stringent LHC bounds on the Z′ mass. This comparatively low PS-breaking scale opens up promising collider opportunities for probing the leptoquark gauge boson, as well as the distinctive signature of vector-like down-type quarks carrying an unusual baryon number of 2/3. The model can be further tested via lepton flavor-violating processes induced by the leptoquark gauge boson, such as μ → eγ, μ → eee, and μ-e conversion in nuclei. Neutrino masses arise in the model through dimension-seven operators at tree-level, as well as from dimension-five operators via one-loop diagrams. |
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| Keywords: | new gauge interactions, specific BSM phenomenology, theories of flavour |
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| Publication status: | Published |
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| Publication version: | Version of Record |
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| Submitted for review: | 27.12.2025 |
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| Article acceptance date: | 10.04.2026 |
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| Publication date: | 03.06.2026 |
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| Publisher: | Published for SISSA by Springer. |
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| Year of publishing: | 2026 |
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| Number of pages: | str. 1-67 |
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| Numbering: | Vol. 2026, article no. 23 (2026) |
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| Source: | Italija |
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| PID: | 20.500.12556/DiRROS-30358  |
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| UDC: | 539.1 |
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| ISSN on article: | 1029-8479 |
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| DOI: | 10.1007/JHEP06(2026)023 |
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| COBISS.SI-ID: | 282398979 |
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| Copyright: | © The Authors. |
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| Note: | Nasl. z nasl. zaslona;
Opis vira z dne 22. 6. 2026;
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| Publication date in DiRROS: | 23.06.2026 |
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| Views: | 107 |
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| Downloads: | 95 |
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