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Lifetimes and heavy quark expansion.

Lenz, Alexander (2015) 'Lifetimes and heavy quark expansion.', in QCD and heavy quarks : in memoriam Nikolai Uraltsev. New Jersey: World Scientific, pp. 63-109.


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.

Item Type:Book chapter
Full text:(AM) Accepted Manuscript
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Publisher 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.
Date accepted:No date available
Date deposited:28 January 2016
Date of first online publication:July 2015
Date first made open access:No date available

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