Primary Observables for Indirect Searches at Colliders

Abstract

We consider the complete set of observables for collider searches for indirect effects of new heavy physics. They consist of $SU(3{)}_{\mathrm{C}}\times U(1{)}_{\mathrm{EM}}$ invariant interaction terms/operators that parameterize deviations from the Standard Model. We show that, under very general assumptions, the leading deviations from the Standard Model are given by a finite number of `primary' operators, with the remaining operators given by `Mandelstam descendants' whose effects are suppressed by powers of Mandelstam variables divided by the mass scale $M$ of the heavy physics. We explicitly determine all 3 and 4-point primary operators relevant for Higgs signals at colliders by using the correspondence between on-shell amplitudes and independent operators. We give a detailed discussion of the methods used to obtain this result, including a new analytical method for determining the independent operators. The results are checked using the Hilbert series that counts independent operators. We also give a rough sketch of the phenomenology, including unitarity bounds on the interaction strengths and rough estimates of their importance for Higgs decays at the HL-LHC. These results motivate further exploration of Higgs decays to $Z\bar{f}f$, $W\bar{f}{f}^{\prime }$, $\gamma \bar{f}f$, and $Z\gamma \gamma$.

46 pages, 2 figures, 13 tables. Final published version in JHEP

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Cited by in corpus (7)

• EFT matching from analyticity and unitarity
• Dimension-8 SMEFT contact-terms for vector-pair production via on-shell Higgsing
• Primary Observables for Electroweak Gauge Boson Collider Signals
• Multi-Higgs Amplitudes Bootstrapped: Dissecting SMEFT and HEFT
• General Signals for Charged Lepton Flavor Violating Decays
• Quantifying EFT Uncertainties in LHC Searches
• Scalar leptoquark contributions to the $gg\to Zh$ process