Final-state interaction andB→KKdecays in perturbative QCD

Abstract

We predict branching ratios and CP asymmetries of the B → KK decays using perturbative QCD factorization theorem, in which tree, penguin, and annihilation contributions, including both factorizable and nonfactorizable ones, are expressed as convolutions of hard six-quark amplitudes with universal meson wave functions. The unitarity angle φ 3 = 90 o and the B and K meson wave functions extracted from experimental data of the B → Kπ and ππ decays are employed. Since the B → KK decays are sensitive to final-state-interaction effects, the comparision of our predictions with future data can test the neglect of these effects in the above formalism. The CP asymmetry in the B ± → K ± K 0 modes and the B 0 d → K ± K ∓ branching ratios depend on annihilation and nonfactorizable amplitudes. The B → KK data can also verify the evaluation of these contributions.

B → K 0 * (1430) K Decays in Perturbative QCD Approach

“…At present, the excellent agreement between the pQCD predictions for the branching ratios and CP violating asymmetries and the precision measurements strongly support the assumption that the FSI effects for B → Kπ decays are not important [7]. For B → KK decays, fortunately, good agreement between the pQCD predictions for the branching ratios of [15,16] and currently available experimental measurements [19] indicates that the FSI effects are most possibly not important also [16]. Of course, more studies are needed about this issue, while further consistency check between the pQCD predictions and the precision data will reveal whether FSI effects are important or not.…”

“…At the same time, the B → K K * decays have been studied before in the GF approach [2] and the QCDF approach [3,4]. The similar decays such as B → KK and K * K * decays have been investigated in the pQCD approach recently [15,16]. On the experimental side, the first measurement of B 0 → (K 0 K * 0 + K 0 K * 0 ) decay has been reported very recently by BaBar collaboration [17] in units of 10 −6 (upper limits at 90% C.L.…”

Revisiting the pure annihilation decaysBs→π+π−andB0→K+

“…(35) is much larger than the previous pQCD prediction as given in Ref. [1]. In order to find the reason for the large difference, we checked the relevant analytical expressions as given in Ref.…”

“…And consequently, they are rare decay modes with a branching ratio (Br) at the level of 10 À7 or less as generally expected. Such decays play a very important role in understanding the annihilation mechanism and determining the strength of the annihilation contribution in B meson charmless hadronic decays, and therefore have been studied intensively by many authors [1][2][3][4][5][6][7][8][9][10] in spite of the great difficulties in both the theoretical calculation and the experimental measurements.…”

B→KK*decays in the perturbative QCD approach

“…− as shown in last three lines of Table I, we find that the leading order pQCD branching ratios from this part can amount to (1 − 4) × 10 −6 , which indicate the large annihilation effects in B → K * 0 K decays in contrast to B → KK [17] and B → KK * [18] decays. The branching ratio in Scenario I is about twice as large as that in Scenario II for B 0 /B 0 → K * 0 + K − while smaller than that in Scenario II for B 0 /B 0 → K + K * 0 − .…”