2011/08/31 by Joachim Brod, Martin Gorbahn · 8 citations
Mathematics · Physics and Astronomy · #Charm (quantum number) #Charm quark #Hamiltonian (control theory) #High-Energy Particle Collisions Research #Mathematics #Nuclear physics #Observable #Order (exchange) #Particle physics #Particle physics theoretical and experimental studies #Physics #Physics beyond the Standard Model #Quantum Chromodynamics and Particle Interactions #Quantum chromodynamics #Quantum mechanics #Quark #Standard Model (mathematical formulation) #hep-ph
paper · pdf · doi:10.1103/physrevlett.108.121801
published as Phys.Rev.Lett.108:121801,2012 · 5 pages, 2 figures; typos corrected, references added, extended discussion of results, updated numerics, version as published in PRL
arxiv created 2012/03/19 · openalex publication_date 2012/03/19 · arxiv updated 2012/03/21 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
The observables ϵK and \ensuremathΔMK play a prominent role in particle physics due to their sensitivity to new physics at short distances. To take advantage of this potential, a firm theoretical prediction of the standard-model background is essential. The charm-quark contribution is a major source of theoretical uncertainty. We address this issue by performing a next-to-next-to-leading-order QCD analysis of the charm-quark contribution \ensuremathηcc to the effective |\ensuremathΔS|=2 Hamiltonian in the standard model. We find a large positive shift of 36%, leading to \ensuremathηcc=1.87(76). This result might cast doubt on the validity of the perturbative expansion; we discuss possible solutions. Finally, we give an updated value of the standard-model prediction for |ϵK|=1.81(28)\ifmmode×\else\texttimes\fi10^\ensuremath-3 and \ensuremathΔMKSD=3.1(1.2)\ifmmode×\else\texttimes\fi10^\ensuremath-15 GeV.