Anomalies in particle physics and their implications for physics beyond the standard model

The 2HDM+a model is one of the main models used in the interpretations of dark matter searches at the LHC. So far, all the 2HDM+a benchmarks considered by the ATLAS and CMS experiments are limited to a type-II Yukawa sector, in which the Higgs bosons A, H, and H± are all constrained to be mass-degenerate and heavier than around 600 GeV. In this work, we present the first detailed study of 2HDM+a models with a type-I Yukawa sector, which, for moderate values of tan β, lift the constraints from flavour physics, allowing the extra Higgs bosons to be even lighter than the 125 GeV Higgs boson discovered at the LHC. We discuss several benchmarks where the A, H, and H± states are not necessarily mass-degenerate and the signatures that arise in these models, some of which have not yet been explored at the LHC. We present the dominant channels in the studied benchmarks and the expected sensitivity in Run 2 data using truth-level analyses and discuss potential improvements in the experimental searches for Run 3.

Novel collider signatures in the type-I 2HDM+a model

Argyropoulos,

Haisch,

Kalaitzidou

2024

Anomalous thresholds in B → (P, V)γ* form factors

Mutke,

Hoferichter,

Kubis

2024

We study the effects of anomalous thresholds on the non-local form factors describing the hadronization of the light-quark contribution to B → (P, V)γ* transitions. Starting from a comprehensive discussion of anomalous thresholds in the triangle loop function for different mass configurations, we detail how the dispersion relation for ππ intermediate states is affected by contour deformations mandated by the anomalous branch points. Phenomenological estimates of the size of the anomalous contributions to the form factors are provided with couplings determined from measured branching fractions and Dalitz plot distributions. Our key finding is that anomalous effects are suppressed on the ρ(770) resonance, while off-peak the effects can become as large as $$ \mathcal{O} $$ O (10%) of the full (light-quark-loop induced) non-local form factors. We comment on future generalizations towards higher intermediate states and the charm loop, outlining how the dispersive framework established in this work could help improve the non-local form factors needed as input for a robust interpretation of B → (P, V)ℓ+ℓ− decays.

Global fit to the 2HDM with generic sources of flavour violation using GAMBIT

Athron,

Crivellin,

Gonzalo

et al. 2024

We perform a global statistical analysis of the two-Higgs-doublet model with generic sources of flavour violation using GAMBIT. This is particularly interesting in light of deviations from the Standard Model predictions observed in $$ b\to c\tau \overline{\nu} $$ b → cτ ν ¯ and b → sℓ+ℓ− transitions as well as the indications for a charged Higgs with a mass of 130 GeV in top quark decays. Including all relevant constraints from precision, flavour and collider observables, we find that it is possible to simultaneously explain both the charged and neutral current B anomalies. We study the impact of using different values for the W mass and the Standard Model prediction for the anomalous magnetic moment of the muon and provide predictions for observables that can probe our model in the future such as lepton flavour violation searches at Belle II and Higgs coupling strength measurements at the high-luminosity LHC.