Lifetimes and Heavy Quark Expansion

Lenz, Alexander

Lifetimes and Heavy Quark Expansion

Lenz, Alexander

Authors

Alexander Lenz

Contributors

Ikaros Bigi
Editor

Paolo Gambino
Editor

Thomas Mannel
Editor

Abstract

Kolya Uraltsev was one of the inventors of the Heavy Quark Expansion (HQE), that describes inclusive weak decays of hadrons containing heavy quarks and in particular lifetimes. Besides giving a pedagogic introduction into the subject, we review the development and the current status of the HQE, which just recently passed several non-trivial experimental tests with an unprecedented precision. In view of many new experimental results for lifetimes of heavy hadrons, we also update several theory predictions: τ (B+)/τ (Bd) = 1.04+0.05 −0.01 ± 0.02 ± 0.01, τ (Bs)/τ (Bd) = 1.001 ± 0.002, τ (b)/τ (Bd) = 0.935 ± 0.054 and ¯τ (0b )/¯τ (+ b ) = 0.95 ± 0.06. The theoretical precision is currently strongly limited by the unknown size of the nonperturbative matrix elements of four-quark operators, which could be determined with lattice simulations.

Citation

Lenz, A. (2015). Lifetimes and Heavy Quark Expansion. In I. Bigi, P. Gambino, & T. Mannel (Eds.), QCD and heavy quarks : in memoriam Nikolai Uraltsev (63-109). World Scientific Publishing

Publication Date	Jul 1, 2015
Deposit Date	Dec 7, 2015
Publicly Available Date	Jan 28, 2016
Publisher	World Scientific Publishing
Pages	63-109
Book Title	QCD and heavy quarks : in memoriam Nikolai Uraltsev.
Publisher URL	http://www.worldscientific.com/worldscibooks/10.1142/9157

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Copyright Statement
Lifetimes and heavy quark expansion, Alexander Lenz, in QCD and heavy quarks : in memoriam Nikolai Uraltsev, ed. by Ikaros I Bigi, Paolo Gambino, Thomas Mannel Copyright @ 2015 with permission from World Scientific Publishing Co. Pte. Ltd.