2025/11/21 by Hovhannisyan, Artyom, Nierste, Ulrich · 1 citation
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 · doi:10.48550/arxiv.2511.17759
openalex publication_date 2025/11/21 · openalex created_date 2025/11/27 · openalex updated_date 2026/07/28
The precise measurement of the width difference ΔΓs among the mass eigenstates of the Bs-Bs system requires the calculation of the corresponding decay matrix to order αs/mb. QCD corrections to power-suppressed terms in the Heavy Quark Expansion involve the renormalization of dimension-7 four-quark operators for which no general methodology is available yet. In the MS scheme one-loop corrections to matrix elements of dimension-7 operators violate the power counting, but we find the responsible terms to be infrared-finite and show that they can be absorbed into finite counterterms proportional to dimension-6 operators. We calculate all these counterterms and subsequently verify the consistency of our results with hadronic matrix elements calculated in the limit of a large number Nc of colours. The condition of correct power counting implies constraints on the possible definitions of evanescent operators.