Physics of leptoquarks in precision experiments and at particle colliders

By I. Doršner, S. Fajfer, Admir Greljo, Jernej F. Kamenik, Nejc Kosnik. 2016

637 citations recorded by the source corpus.

We present a comprehensive review of physics effects generated by leptoquarks (LQs), i.e., hypothetical particles that can turn quarks into leptons and vice versa, of either scalar or vector nature. These considerations include discussion of possible completions of the Standard Model that contain LQ fields. The main focus of the review is on those LQ scenarios that are not problematic with regard to proton stability. We accordingly concentrate on the phenomenology of light leptoquarks that is relevant for precision experiments and particle colliders. Important constraints on LQ interactions with matter are derived from precision low-energy observables such as electric dipole moments, (g-2) of charged leptons, atomic parity violation, neutral meson mixing, Kaon, B, and D meson decays, etc. We provide a general analysis of indirect constraints on the strength of LQ interactions with the quarks and leptons to make statements that are as model independent as possible. We address complementary constraints that originate from electroweak precision measurements, top, and Higgs physics. The Higgs physics analysis we present covers not only the most recent but also expected results from the Large Hadron Collider (LHC). We finally discuss direct LQ searches. Current experimental situation is summarized and self-consistency of assumptions that go into existing accelerator-based searches is discussed. A progress in making next-to-leading order predictions for both pair and single LQ productions at colliders is also outlined.

Subfields: Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/117cb69b35644f83d5fb90ec46c6608e09216f05

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Citations in the corpus

Review of lepton universality tests in B decays (2018, background): “Leptoquark models provide a larger set of possibilities, with six different type of representations (lumping together representations differing only through hypercharge) [140,167,202]: three are scalar leptoquarks (S1, R2, S3) and three are vector leptoquarks (U1, V2, U3).”
Charged Lepton Flavour Violation: An Experimental and Theoretical Introduction (2017, background): “Detailed discussions of the LQ models with a particular focus on their implications for CLFV observables are presented in [233, 234, 235, 236] (for a general review on LQs see [237]), in particular [236] considers the consequences for μ→ e observables of introducing LQs with sizeable couplings to bo”
Baryon number and lepton universality violation in leptoquark and diquark models (2017, background): “For an excellent review and many references see [12], which is focused primarily on light leptoquarks.”
What is the scale of new physics behind the B-flavour anomalies? (2017, neutral): “[45] we have: • S1 ∼ (3, 1, 1/3): LS1 ⊃ y QLQi,aǫLj,b S1 + h.”
Opportunities in Flavour Physics at the HL-LHC and HE-LHC (2018, background): “An example are leptoquark mediators [264], which are well motivated as the NP explanations of the B-meson anomalies, see, e.”
Flavour anomalies after the RK∗ measurement (2017, methodology): “In parenthesis we reported the SU(3)× SU(2)L× U(1)Y gauge quantum numbers, and we followed the notations and conventions from [52] for LQ names.”
From the Trees to the Forest: A Review of Radiative Neutrino Mass Models (2017, background): “[543, 638] for the names of the leptoquarks, where subscripts indicate dimension of the SU(2)L representations.”
Vector boson fusion at multi-TeV muon colliders (2020, background): “Though not conclusively established [114, 132], the possibility of leptoquarks is a viable solution to longstanding anomalies observed across several flavor experiments [133–138].”