Complex Singularity and Unitarity

Mishima, Nobuhiko; Yamazaki, Motoyoshi

doi:10.1143/ptp.33.500

Cited by 8 publications

(11 citation statements)

References 2 publications

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“…(2) The currently known NLO contributions to hard kernel H (1) (α 2 s ) include [4,5,15]: (a) The vertex correction (VC)from the Feynman diagrams Fig.2(a)-2(d);…”

Section: B Nlo Contributionsmentioning

confidence: 99%

Revisiting the Kπ puzzle in the pQCD factorization approach

Bai¹,

Liu²,

Fan³

et al. 2014

Chinese Phys. C

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In this paper, we calculated the branching ratios and direct CP violation of the four B → Kπ decays with the inclusion of all currently known next-to-leading order (NLO) contributions by employing the perturbative QCD (pQCD) factorization approach. We found that (a) Besides the 10% enhancement from the NLO vertex corrections, the quark-loops and magnetic penguins, the NLO contributions to the form factors can provide an additional ∼ 15% enhancement to the branching ratios, and lead to a very good agreement with the data; (b) The NLO pQCD predictions are A dir CP (B 0 → K + π − ) = (−6.5 ± 3.1)% and A dir CP (B + → K + π 0 ) = (2.2 ± 2.0)%, become well consistent with the data due to the inclusion of the NLO contributions.

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“…(2) The currently known NLO contributions to hard kernel H (1) (α 2 s ) include [4,5,15]: (a) The vertex correction (VC)from the Feynman diagrams Fig.2(a)-2(d);…”

Section: B Nlo Contributionsmentioning

confidence: 99%

Revisiting the Kπ puzzle in the pQCD factorization approach

Bai¹,

Liu²,

Fan³

et al. 2014

Chinese Phys. C

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“…The NLO contributions from the Feynman diagrams in Fig. 3 − the vertex corrections, the quark-loops and chromo-magnetic penguins − were evaluated several years ago [21,36,38], and taken into account in our previous studies for the B → Kη (′) decay in Ref. [12].…”

Section: A General Analysis Of the Nlo Contributions In The Pqcd Appmentioning

confidence: 99%

Anatomy ofB→Kη(′)decays in different mixing schemes and effects of next-to-leading order contributions in the perturbative QCD approach

et al. 2013

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In this paper we perform a comprehensive study of the four B → Kη (′) decays in the perturbative QCD (pQCD) factorization approach. We calculate the CP-averaged branching ratios and CP-violating asymmetries of B → Kη (′) decays in the ordinary η-η ′ , the η-η ′ -G, and the ηη ′ -G-η c mixing schemes. Besides the full leading order (LO) contributions, all currently known next-to-leading order (NLO) contributions to B → Kη (′) decays in the pQCD approach are taken into account. From our calculations and phenomenological analysis, we find the following. (a) The NLO contributions in general can provide significant enhancements to the LO pQCD predictions for the decay rates of the two B → Kη ′ decays, around 70%−89% in magnitude, but result in relatively small changes to Br(B → Kη). (b) Although the NLO pQCD predictions in all three considered mixing schemes agree well with the data within one standard deviation, those pQCD predictions in the η-η ′ -G mixing scheme provide the best interpretation for the measured pattern of Br(B → Kη (′) ): Br(B 0 → K 0 η) ≈ 1.13 × 10 −6 , Br(B 0 → K 0 η ′ ) ≈ 66.5 × 10 −6 , Br(B ± → K ± η) ≈ 2.36 × 10 −6 , and Br(B ± → K ± η ′ ) ≈ 67.3 × 10 −6 , which agree perfectly with the measured values. (c) The NLO pQCD predictions for the CP-violating asymmetries for the four considered decays are also in good consistent with the data. (d) The newly known NLO contribution to the relevant form factors M F F can produce about a 20% enhancement to the branching ratios Br(B → Kη ′ ), which plays an important role in closing the gap between the pQCD predictions and the relevant data. (e) The general expectations about the relative strength of the LO and NLO contributions from different sources are examined and confirmed by explicit numerical calculations.

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“…(2) The Feynman diagrams contributing to the hard kernel H (1) (α 2 s ) at the NLO level in the pQCD approach include: (a) the Vertex Correction (VC) [35]; (b) the Quark-Loop (QL) contributions [35,36]; (c) the magnetic penguins (MG) contributions [35,37]; and (d) the NLO part of the form factors (FF) as given in Ref. [38].…”

Section: A Nlo Contributions In the Pqcd Approachmentioning

confidence: 99%

B → Kη ^(′) decays in the SM with fourth generation fermions

Cheng¹,

Fan²,

Xiao³

2014

Chinese Phys. C

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By employing the perturbative QCD (pQCD) factorization approach, we calculate the new physics contributions to the four B → Kη (′) decays in the Standard Model (SM) with a fourth generation of fermions (SM4), induced by the loop diagrams involving t ′ quark. Within the considered parameter space of the SM4 we find that (a) the next-to-leading order (NLO) pQCD predictions for the branching ratios and CP-violating asymmetries in both the SM and SM4 generally agree with the data within one standard deviation; (b) for Br(B → Kη), the inclusion of the fourth generation contributions can improve the agreement between the theoretical predictions and the data effectively; (c) for Br(B → Kη ′ ), however, the decrease due to t ′ loops is disfavored by the data; and (d) the new physics corrections to the CP-violating asymmetries of the considered decays are about 10% only.

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Complex Singularity and Unitarity

Cited by 8 publications

References 2 publications

Revisiting the Kπ puzzle in the pQCD factorization approach

Revisiting the Kπ puzzle in the pQCD factorization approach

Anatomy ofB→Kη(′)decays in different mixing schemes and effects of next-to-leading order contributions in the perturbative QCD approach

B → Kη ^(′) decays in the SM with fourth generation fermions

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Complex Singularity and Unitarity

Cited by 8 publications

References 2 publications

Revisiting the Kπ puzzle in the pQCD factorization approach

Revisiting the Kπ puzzle in the pQCD factorization approach

Anatomy ofB→Kη(′)decays in different mixing schemes and effects of next-to-leading order contributions in the perturbative QCD approach

B → Kη (′) decays in the SM with fourth generation fermions

Contact Info

Product

Resources

About

B → Kη ^(′) decays in the SM with fourth generation fermions