Calculation of the D- and B-meson lifetimes and the unitarity triangle parameters

Abstract

Using the expansions of the heavy meson decay widths in the heavy quark mass and QCD sum rules for estimates of corresponding matrix elements, we calculate the

Phenomenological analysis ofDmeson lifetimes

“…In Eq. (2.7) the first term proportional to g µν k 2 contributes to the Pauli interference, while the rest to the Wexchange or W -annihilation, where k is the total four-momentum of the integrated quark pair [9]. More specifically, k = p c + p q for the W -exchange and W -annihilation, and k = p c − p q for the Pauli interference.…”

“…As stressed in the Introduction, it is crucial to invoke the effect of the light quark's momentum in the charmed meson in order to properly describe the D lifetimes. For this purpose, the four-quark operators relevant to inclusive nonleptonic D decays are [9] …”

“…However, it is also known that there is a serious problem with the evaluation of the destructive Pauli interference Γ int (D + ) in D + . A direct calculation indicates that Γ int (D + ) overcomes the c quark decay rate so that the resulting nonleptonic decay width of D + becomes negative [8,9]. This certainly does not make sense.…”

“…Consequently, the Pauli effect in D + decay is subject to a large suppression and will not overcome the leading c quark decay width. Based on this observation, in the present paper we will follow [9] to take into account the effects of the spectator quark's momentum consistently. In the framework of heavy quark expansion, this spectator effect can be regarded as higher order 1/m c corrections.…”

“…Since the charmed quark is not heavy enough, it is very important, as stressed by Chernyak [9], for calculations with charmed mesons to account for the nonzero momentum of spectator quarks. It turns out that the Pauli interference in D + decay is suppressed by a factor of (…”