Renormalization of the Cabibbo-Kobayashi-Maskawa Quark Mixing Matrix

We have investigated the present renormalization prescriptions of Cabibbo-Kobayashi-Maskawa (CKM) matrix. When considering the prescription which is formulated with reference to the case of zero mixing we find it doesn't satisfy the unitary condition of the bare CKM matrix. After added a delicate patch this problem can be solved at one-loop level. In this paper We generalize this prescription to all loop levels and keep the unitarity of the bare CKM matrix, simultaneously make the amplitude of an arbitrary physical process involving quark mixing convergent and gauge independent. We also find that in order to keep the CKM counterterms gauge independent the unitarity of the bare CKM matrix must be preserved.Comment: has been revised, 8 pages, 1 figur

Twist-3 distribution amplitudes of scalar mesons from QCD sum rules

We study the twist-3 distribution amplitudes for scalar mesons made up of two valence quarks based on QCD sum rules. By choosing the proper correlation functions, we derive the moments of the scalar mesons up to the first two order. Making use of these moments, we then calculate the first two Gegenbauer coefficients for twist-3 distribution amplitudes of scalar mesons. It is found that the second Gegenbauer coefficients of scalar density twist-3 distribution amplitudes for $K^{*}_0$ and $f_0$ mesons are quite close to that for $a_0$, which indicates that the SU(3) symmetry breaking effect is tiny here. However, this effect could not be neglected for the forth Gegenbauer coefficients of scalar twist-3 distribution amplitudes between $a_0$ and $f_0$. Besides, we also observe that the first two Gegenbauer coefficients corresponding to the tensor current twist-3 distribution amplitudes for all the $a_0$, $K^{*}_0$ and $f_0$ are very small. The renormalization group evolution of condensates, quark masses, decay constants and moments are considered in our calculations. As a byproduct, it is found that the masses for isospin I=1, ${1 \over 2}$ scalar mesons are around $1.27 \sim 1.41$ GeV and $1.44 \sim 1.56$ GeV respectively, while the mass for isospin state composed of $\bar{s} s$ is $1.62 \sim 1.73$ GeV.Comment: replaced with revised version, to be published in Phys. Rev.

Searching for new physics in b→ssdˉb\to s s \bar d decays

For any new physics possibly emerging in the future B experiments, the problem is how to extract the signals from the SM background. We consider the decay $b\to s s\bar d$ which is very small in the SM. In the MSSM this decay is possibly accessible in the future experiments. In the supersymmetric models with R-parity violating couplings, this channel is not strictly constrained, thus being useful in obtaining bounds on the lepton-number violating couplings. A typical candidate for the suggested search is the $B^-\to K^-K^-\pi^+$ mode.Comment: 9 pages, one figure, late

Recalculation of QCD Corrections to b→sγb \to s \gamma Decay

We give a more complete calculation of $b \to s\gamma$ decay, including leading log QCD corrections from $m_{top}$ to $M_W$ in addition to corrections from $M_{W}$ to $m_b$. We have included the full set of dimension-6 operators and corrected numerical mistakes of anomalous dimensions in a previous paper\cite{Cho}. Comparing with the calculations without QCD running from $m_{top}$ to $M_W$\cite{Mis}, the inclusive decay rate is found to be enhanced. At $m_t=150$GeV, it results in 12\% enhancement, and for $m_t=250$GeV, 15\% is found. The total QCD effect makes an enhanced factor of 4.2 at $m_t=150$GeV, and 3.2 for $m_t=250$GeV.Comment: 16 pages, 7 figures (uuencoded ps files), Changes of description. To appear in Phys. Rev.

Constraints on Masses of Charged PGBs in Technicolor Model from Decay b→sγ b \to s \gamma

In this paper we calculate the contributions to the branching ratio of $B\to X_s \gamma$ from the charged Pseudo-Goldstone bosons appeared in one generation Technicolor model. The current $CLEO$ experimental results can eliminate large part of the parameter space in the $m(P^\pm) - m(P_8^\pm)$ plane, and specifically, one can put a strong lower bound on the masses of color octet charged PGBs $P_8^\pm$: $m(P^{\pm}_8) > 400\;GeV$ at $90\%C.L$ for free $m(P^{\pm})$.Comment: 9 pages, 3 figures(uuencoded), Minor changes(Type error), to appear in Phys. Rev.

Branching ratio and CP asymmetry of Bs→π+π−B_s \to \pi^+ \pi^- decays in the perturbative QCD approach

In this paper, we calculate the decay rate and CP asymmetry of the $B_s \to \pi^+\pi^-$ decay in perturbative QCD approach with Sudakov resummation. Since none of the quarks in final states is the same as those of the initial $B_s$ meson, this decay can occur only via annihilation diagrams in the standard model. Besides the current-current operators, the contributions from the QCD and electroweak penguin operators are also taken into account. We find that (a) the branching ratio is about $4 \times 10^{-7}$; (b) the penguin diagrams dominate the total contribution; and (c) the direct CP asymmetry is small in size: no more than $3$; but the mixing-induced CP asymmetry can be as large as ten percent testable in the near future LHC-b experiments.Comment: 12 pages, 4 figures included, RevTe

Exclusive semileptonic decays of Λb→Λl+l−\Lambda_b \to \Lambda l^{+} l^{-} in supersymmetric theories

The weak decays of $\Lambda_b \to \Lambda l^{+} l^{-}$ ($l=e, \mu$) are investigated in Minimal Supersymmetric Standard Model (MSSM) and also in Supersymmetric (SUSY) SO(10) Grand Unified Models. In MSSM the special attention is paid to the Neutral Higgs Bosons (NHBs) as they make quite a large contribution in exclusive $B \to X_{s} l^{+} l^{-}$ decays at large $\tan{\beta}$ regions of parameter space of SUSY models, since part of SUSY contributions is proportional to $\tan^{3}{\beta}$. The analysis of decay rate, forward-backward asymmetries, lepton polarization asymmetries and the polarization asymmetries of $\Lambda$ baryon in $\Lambda_b \to \Lambda l^{+} l^{-}$ show that the values of these physical observables are greatly modified by the effects of NHBs. In SUSY SO(10) GUT model, the new physics contribution comes from the operators which are induced by the NHBs penguins and also from the operators having chirality opposite to that of the corresponding SM operators. SUSY SO(10) effects show up only in the decay $\Lambda_b \to \Lambda +\tau^{+} \tau^{-}$ where the longitudinal and transverse lepton polarization asymmetries are deviate significantly from the SM value while the effects in the decay rate, forward-backward asymmetries and polarization asymmetries of final state $\Lambda$ baryon are very mild. The transverse lepton polarization asymmetry in $\Lambda_b \to \Lambda +\tau^{+} \tau^{-}$ is almost zero in SM and in MSSM model. However, it can reach to -0.1 in SUSY SO(10) GUT model and could be seen at the future colliders; hence this asymmetry observable will provide us useful information to probe new physics and discriminate between different models.Comment: 26 pages, 8 figure

Branching Ratio and CP Violation of B to pi pi Decays in Perturbative QCD Approach

We calculate the branching ratios and CP asymmetries for B^0 to pi^+pi^-, B^+ to pi^+pi^0 and B^0 to pi^0pi^0 decays, in a perturbative QCD approach. In this approach, we calculate non-factorizable and annihilation type contributions, in addition to the usual factorizable contributions. We found that the annihilation diagram contributions are not very small as previous argument. Our result is in agreement with the measured branching ratio of B to pi^+pi^- by CLEO collaboration. With a non-negligible contribution from annihilation diagrams and a large strong phase, we predict a large direct CP asymmetry in B^0 to pi^+pi^-, and pi^0pi^0, which can be tested by the current running B factories.Comment: Latex, 28 pages including 11 figures; added contents and figures, corrected typo

b→sγb \to s \gamma Decay and Right-handed Top-bottom Charged Current

We introduce an anomalous top quark coupling (right-handed current) into Standard Model Lagrangian. Based on this, a more complete calculation of $b \to s\gamma$ decay including leading log QCD corrections from $m_{top}$ to $M_W$ in addition to corrections from $M_{W}$ to $m_b$ is given. The inclusive decay rate is found to be suppressed comparing with the case without QCD running from $m_t$ to $M_W$ except at the time of small values of $|f_R^{tb}|$. e.g. when $f_R^{tb}=-0.08$, it is only $1/10$ of the value given before. As $|f_R^{tb}|$ goes smaller, this contribution is an enhancement like standard model case. From the newly experiment of CLEO Collaboration, strict restrictions to parameters of this top-bottom quark coupling are found.Comment: 20 Pages, 2 figures( ps file uuencoded)

Study of pure annihilation type decays B→Ds∗KB \to D_s^{*} K

In this work, we calculate the rare decays $B^0 \to D_s^{*-} K^+$ and $B^+ \to D_s^{*+} \bar{K}^0$ in perturbative QCD approach with Sudakov resummation. We give the branching ratio of $10^{-5}$ for $B^0 \to D_s^{*-}K^+$, which will be tested soon in $B$ factories. The decay $B^+ \to D_s^{*+} \bar{K}^0$ has a very small branching ratio at ${\cal O}(10^{-8})$, due to the suppression from CKM matrix elements $|V_{ub}^* V_{cd}|$. It may be sensitive to new physics contributions.Comment: 14 pages, 1 figur