Patterns of flavour violation in models with vector-like quarks
Abstract We study the patterns of flavour violation in renormalisable extensions of the Standard Model (SM) that contain vector-like quarks (VLQs) in a single complex representation of either the SM gauge group GSM or G SM ′ ≡ GSM ⊗ U(1)L μ − L τ . We first decouple VLQs in the M = (1 − 10) TeV ran...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
SpringerOpen
2017-04-01
|
| Series: | Journal of High Energy Physics |
| Subjects: | |
| Online Access: | http://link.springer.com/article/10.1007/JHEP04(2017)079 |
| _version_ | 1811334810280394752 |
|---|---|
| author | Christoph Bobeth Andrzej J. Buras Alejandro Celis Martin Jung |
| author_facet | Christoph Bobeth Andrzej J. Buras Alejandro Celis Martin Jung |
| author_sort | Christoph Bobeth |
| collection | DOAJ |
| description | Abstract We study the patterns of flavour violation in renormalisable extensions of the Standard Model (SM) that contain vector-like quarks (VLQs) in a single complex representation of either the SM gauge group GSM or G SM ′ ≡ GSM ⊗ U(1)L μ − L τ . We first decouple VLQs in the M = (1 − 10) TeV range and then at the electroweak scale also Z, Z ′ gauge bosons and additional scalars to study the phenomenology. The results depend on the relative size of Z- and Z ′-induced flavour-changing neutral currents, as well as the size of |ΔF | = 2 contributions including the effects of renormalisation group Yukawa evolution from M to the electroweak scale that turn out to be very important for models with right-handed currents through the generation of left-right operators. In addition to rare decays like P → ℓ ℓ ¯ , P → P ′ ℓ ℓ ¯ , P → P ′ ν ν ¯ $$ P\to \ell \overline{\ell},P\to {P}^{\prime}\ell \overline{\ell},P\to {P}^{\prime}\nu \overline{\nu} $$ with P = K, B s , B d and |ΔF | = 2 observables we analyze the ratio ε ′ /ε which appears in the SM to be significantly below the data. We study patterns and correlations between these observables which taken together should in the future allow for differentiating between VLQ models. In particular the patterns in models with left-handed and right-handed currents are markedly different from each other. Among the highlights are large Z-mediated new physics effects in Kaon observables in some of the models and significant effects in B s,d -observables. ε ′ /ε can easily be made consistent with the data, implying then uniquely the suppression of K L → π 0 ν ν ¯ $$ {K}_L\to {\pi}^0\nu\ \overline{\nu} $$ . Significant enhancements of B r K + → π + ν ν ¯ $$ Br\left({K}^{+}\to {\pi}^{+}\nu \overline{\nu}\right) $$ are still possible. We point out that the combination of NP effects to |ΔF | = 2 and |ΔF | = 1 observables in a given meson system generally allows to determine the masses of VLQs in a given representation independently of the size of VLQ couplings. |
| first_indexed | 2024-04-13T17:14:42Z |
| format | Article |
| id | doaj.art-83b7243668b244ed9906975ca77c389e |
| institution | Directory Open Access Journal |
| issn | 1029-8479 |
| language | English |
| last_indexed | 2024-04-13T17:14:42Z |
| publishDate | 2017-04-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Journal of High Energy Physics |
| spelling | doaj.art-83b7243668b244ed9906975ca77c389e2022-12-22T02:38:09ZengSpringerOpenJournal of High Energy Physics1029-84792017-04-012017417210.1007/JHEP04(2017)079Patterns of flavour violation in models with vector-like quarksChristoph Bobeth0Andrzej J. Buras1Alejandro Celis2Martin Jung3TUM Institute for Advanced StudyTUM Institute for Advanced StudyLudwig-Maximilians-Universität München, Fakultät für Physik, Arnold Sommerfeld Center for Theoretical PhysicsTUM Institute for Advanced StudyAbstract We study the patterns of flavour violation in renormalisable extensions of the Standard Model (SM) that contain vector-like quarks (VLQs) in a single complex representation of either the SM gauge group GSM or G SM ′ ≡ GSM ⊗ U(1)L μ − L τ . We first decouple VLQs in the M = (1 − 10) TeV range and then at the electroweak scale also Z, Z ′ gauge bosons and additional scalars to study the phenomenology. The results depend on the relative size of Z- and Z ′-induced flavour-changing neutral currents, as well as the size of |ΔF | = 2 contributions including the effects of renormalisation group Yukawa evolution from M to the electroweak scale that turn out to be very important for models with right-handed currents through the generation of left-right operators. In addition to rare decays like P → ℓ ℓ ¯ , P → P ′ ℓ ℓ ¯ , P → P ′ ν ν ¯ $$ P\to \ell \overline{\ell},P\to {P}^{\prime}\ell \overline{\ell},P\to {P}^{\prime}\nu \overline{\nu} $$ with P = K, B s , B d and |ΔF | = 2 observables we analyze the ratio ε ′ /ε which appears in the SM to be significantly below the data. We study patterns and correlations between these observables which taken together should in the future allow for differentiating between VLQ models. In particular the patterns in models with left-handed and right-handed currents are markedly different from each other. Among the highlights are large Z-mediated new physics effects in Kaon observables in some of the models and significant effects in B s,d -observables. ε ′ /ε can easily be made consistent with the data, implying then uniquely the suppression of K L → π 0 ν ν ¯ $$ {K}_L\to {\pi}^0\nu\ \overline{\nu} $$ . Significant enhancements of B r K + → π + ν ν ¯ $$ Br\left({K}^{+}\to {\pi}^{+}\nu \overline{\nu}\right) $$ are still possible. We point out that the combination of NP effects to |ΔF | = 2 and |ΔF | = 1 observables in a given meson system generally allows to determine the masses of VLQs in a given representation independently of the size of VLQ couplings.http://link.springer.com/article/10.1007/JHEP04(2017)079Beyond Standard ModelCP violationHeavy Quark PhysicsKaon Physics |
| spellingShingle | Christoph Bobeth Andrzej J. Buras Alejandro Celis Martin Jung Patterns of flavour violation in models with vector-like quarks Journal of High Energy Physics Beyond Standard Model CP violation Heavy Quark Physics Kaon Physics |
| title | Patterns of flavour violation in models with vector-like quarks |
| title_full | Patterns of flavour violation in models with vector-like quarks |
| title_fullStr | Patterns of flavour violation in models with vector-like quarks |
| title_full_unstemmed | Patterns of flavour violation in models with vector-like quarks |
| title_short | Patterns of flavour violation in models with vector-like quarks |
| title_sort | patterns of flavour violation in models with vector like quarks |
| topic | Beyond Standard Model CP violation Heavy Quark Physics Kaon Physics |
| url | http://link.springer.com/article/10.1007/JHEP04(2017)079 |
| work_keys_str_mv | AT christophbobeth patternsofflavourviolationinmodelswithvectorlikequarks AT andrzejjburas patternsofflavourviolationinmodelswithvectorlikequarks AT alejandrocelis patternsofflavourviolationinmodelswithvectorlikequarks AT martinjung patternsofflavourviolationinmodelswithvectorlikequarks |