2023/11/01 by Arianna Tinari, Tinari, Arianna
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.2311.00782
openalex publication_date 2023/11/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The rare B → K(*) ℓ ℓ decays exhibit a long-standing tension with Standard Model (SM) predictions, which can be attributed to a lepton-universal short-distance b → s ℓ ℓ interaction. We present two novel methods to disentangle this effect from long-distance dynamics: one based on the determination of the inclusive b → s ℓ ℓ rate at high dilepton invariant mass (q2≥ 15~\rm GeV2), the other based on the analysis of the q2 spectrum of the exclusive modes B → K(*) ℓ ℓ (in the entire q2 range). Using the first method, we show that the SM prediction for the inclusive b → s ℓ ℓ rate at high dilepton invariant mass is in good agreement with the result obtained summing the SM predictions for one- and two-body modes (K, K^*, Kπ). This observation allows us to perform a direct comparison of the inclusive b → s ℓ ℓ rate with data. This comparison shows a significant deficit (∼ 2σ) in the data, fully compatible with the deficit observed at low-q2 on the exclusive modes. This provides independent evidence of an anomalous b → s ℓ ℓ short-distance interaction, free from uncertainties on the hadronic form factors. To test the short-distance nature of this effect we use a second method, where we analyze the exclusive B → K(*) ℓ ℓ data in the entire q2 region. Here, after using a dispersive parametrization of the charmonia resonances, we extract the non-SM contribution to the universal Wilson coefficient C9 for every bin in q2 and for every polarization. The q2- and polarization-independence of the result, and its compatibility with the inclusive determination, provide a consistency check of the short-distance nature of this effect.