2012/11/27 by Felix Bahr, Bahr, F., Fabio Bernardoni +23 · 1 citation
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Lattice (hep-lat) #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions
paper · doi:10.48550/arxiv.1211.6327
openalex publication_date 2012/11/27 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The 2012 PDG reports a tension at the level of 3 σ between two exclusive determinations of |Vub|. They are obtained by combining the experimental branching ratios of B → τν and B → πl ν (respectively) with a theoretical computation of the hadronic matrix elements \fB and the B → π form factor f+(q2). To understand the tension, improved precision and a careful analysis of the systematics involved are necessary. We report the results of the ALPHA collaboration for \fB from the lattice with 2 flavors of O(a) improved Wilson fermions. We employ HQET, including 1/mb corrections, with pion masses ranging down to ≈ 190 MeV. Renormalization and matching were performed non-perturbatively, and three lattice spacings reaching a-1≈ 4.1 GeV are used in the continuum extrapolation. We also present progress towards a computation of f+(q2), to directly compare two independent exclusive determinations of |Vub| with each other and with inclusive determinations. Additionally, we report on preliminary results for \fBqs, needed for the analysis of Bs → μ+μ-.