Search

We study $$D_{s}^{+}\rightarrow \rho ^{0(+)}a^{+(0)}_{0}$$ D s + → ρ 0 ( + ) a 0 + ( 0 ) , $$D_{s}^{+}\rightarrow \omega a^{+}_{0}$$ D s + → ω a 0 + , and the resonant $$D_{s}^{+}\rightarrow \rho a_0$$ D s + → ρ a 0 , $$a_{0}\rightarrow \eta \pi (KK)$$ a 0 → η π ( K K ) decays. In the final state interaction, where $$D_s^+\rightarrow (\eta ^{(\prime )}\pi ^+,K^+{{\bar{K}}}^0)$$ D s + → ( η ( ′ ) π + , K + K ¯ 0 ) are followed by the $$(\eta ^{(\prime )}\pi ^+,K^+{{\bar{K}}}^0)$$ ( η ( ′ ) π + , K + K ¯ 0 ) to $$\rho ^{0(+)}a^{+(0)}_{0}$$ ρ 0 ( + ) a 0 + ( 0 ) rescatterings, we predict $$\mathcal{B}(D_{s}^{+}\rightarrow \rho ^{0(+)}a^{+(0)}_{0})=(3.0\pm 0.3\pm 1.0)\times 10^{-3}$$ B ( D s + → ρ 0 ( + ) a 0 + ( 0 ) ) = ( 3.0 ± 0.3 ± 1.0 ) × 10 - 3 . Due to the cancellation of the rescattering effects and the suppressed short-distance W annihilation contribution, we expect that $${{\mathcal {B}}}(D_{s}^{+}\rightarrow \omega a^{+}_{0}) \simeq \mathcal{B}(D_s^+\rightarrow \pi ^+\pi ^0) B ( D s + → ω a 0 + ) ≃ B ( D s + → π + π 0 ) < 3.4 × 10 - 4 . In our calculation, $${{\mathcal {B}}}(D_{s}^{+}\rightarrow \rho ^{0}(a^{+}_{0}\rightarrow )\eta \pi ^{+}) =(1.6^{+0.2}_{-0.3}\pm 0.6)\times 10^{-3}$$ B ( D s + → ρ 0 ( a 0 + → ) η π + ) = ( 1 . 6 - 0.3 + 0.2 ± 0.6 ) × 10 - 3 agrees with the data, whereas $${{\mathcal {B}}}(D_{s}^{+}\rightarrow \rho ^{+}(a^{0}_{0}\rightarrow )K^+K^-)$$ B ( D s + → ρ + ( a 0 0 → ) K + K - ) is 10 times smaller than the observation, which requires a careful examination.

We review the two and three-body baryonic $B$ decays with the dibaryon (${\bf B\bar B'}$) as the final states. Accordingly, we summarize the experimental data of the branching fractions, angular asymmetries, and $CP$ asymmetries. Using the $W$-boson annihilation (exchange) mechanism, the branching fractions of $B\to {\bf B \bf \bar B'}$ are shown to be interpretable. In the approach of perturbative QCD counting rules, we study the three-body decay channels. In particular, we review the $CP$ asymmetries of $B\to {\bf B\bar B'}M$, which are promising to be measured by the LHCb and Belle~II experiments. Finally, we remark the theoretical challenges in interpreting ${\cal B}(B^-\to p\bar p\rho^-)$ and ${\cal B}(B^-\to p\bar p\mu^-\bar \nu_\mu)$., Comment: 15 pages, 3 tables, 2 figures, published version for the special issue "Heavy Flavor Physics and CP Violation" of Advances in High Energy Physics

In the ${B}^{+}\ensuremath{\rightarrow}{D}^{+}{D}^{\ensuremath{-}}{K}^{+}$ decay, LHCb has reported the observation of the open-charm exotic states ${X}_{0,1}^{0}\ensuremath{\equiv}{X}_{0,1}(2900{)}^{0}$ with four different quark flavors $(ud\overline{s}\overline{c})$, where the subscripts (0,1) denote the spins. To confirm the discovery, we propose ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Sigma}}}_{c}^{0(++)}{X}_{0,1}^{\ensuremath{'}0(\ensuremath{-}\ensuremath{-})}$ in the final state interaction, where ${X}_{0,1}^{\ensuremath{'}0(\ensuremath{-}\ensuremath{-})}$ with $su\overline{d}\overline{c}$ ($ds\overline{u}\overline{c}$) are the new ${X}_{0,1}$-like exotic states. More specifically, ${\mathrm{\ensuremath{\Lambda}}}_{c}^{+}{D}_{s}^{\ensuremath{-}}$ in ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Lambda}}}_{c}^{+}{D}_{s}^{\ensuremath{-}}$ are transformed as ${\mathrm{\ensuremath{\Sigma}}}_{c}^{0(++)}{X}_{0,1}^{\ensuremath{'}0(\ensuremath{-}\ensuremath{-})}$, by exchanging ${\ensuremath{\pi}}^{+(\ensuremath{-})}$. As the order of magnitude estimates, we calculate $\mathcal{B}({\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Sigma}}}_{c}^{0(++)}{X}_{0,1}^{\ensuremath{'}0(\ensuremath{-}\ensuremath{-})})=(2.3\ifmmode\pm\else\textpm\fi{}0.6,4.3\ifmmode\pm\else\textpm\fi{}0.{8}_{\ensuremath{-}2.5}^{+3.3})\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$. In addition, we estimate other $b$-baryon decays with the ${X}_{0,1}$-like states, such as $\mathcal{B}({\mathrm{\ensuremath{\Xi}}}_{b}^{0(\ensuremath{-})}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Xi}}}_{c}^{0(+)}(2645){X}_{0}^{\ensuremath{'}0(\ensuremath{-}\ensuremath{-})},{\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Xi}}}_{c}^{\ensuremath{'}0}{X}_{0,1}^{0})\ensuremath{\sim}{10}^{\ensuremath{-}5}$. While one needs ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Sigma}}}_{c}^{0(++)}{M}_{c}M$ to observe ${X}_{0,1}^{\ensuremath{'}0(\ensuremath{-}\ensuremath{-})}\ensuremath{\rightarrow}{M}_{c}M$ with ${M}_{c}M={D}_{s}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$, ${\overline{D}}^{0}{\overline{K}}^{0}$ $({D}_{s}^{\ensuremath{-}}{\ensuremath{\pi}}^{\ensuremath{-}}$, ${D}^{\ensuremath{-}}{K}^{\ensuremath{-}})$, $\mathcal{B}({\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Sigma}}}_{c}^{0(++)}{X}_{0,1}^{\ensuremath{'}0(\ensuremath{-}\ensuremath{-})},{X}_{0,1}^{\ensuremath{'}0(\ensuremath{-}\ensuremath{-})}\ensuremath{\rightarrow}{M}_{c}M)\ensuremath{\sim}{10}^{\ensuremath{-}4}$ are accessible to the LHCb experiment.

Baryons with a heavy c-quark or a heavy b-quark and also two c-quarks have been discovered. These states are expected in QCD and therefore provide a test for the theory. There should be double beauty baryons, and also an intriguing possibility that baryons ${\mathbf{B}}_{bc}$ with a c-quark, a b-quark. These states are yet to be discovered. The main decay modes of ${\mathbf{B}}_{bc}$ are expected to be weak processes from theoretical understanding of their mass spectrum. These decay modes can provide crucial information about these heavy baryons ${\mathbf{B}}_{bc}$. We analyze two body hadronic weak decays for ${\mathbf{B}}_{bc}$ using $SU(3)$ flavor symmetry. Any one of the $c$ and $b$ decays will induce ${\mathbf{B}}_{bc}$ to decay. We find that the Cabibbo allowed decays ${\mathbf{B}}_{bc}\ensuremath{\rightarrow}{\mathbf{B}}_{b}+M$ due to $c\ensuremath{\rightarrow}su\overline{d}$ can be crucial for exploration. The LHC may have the sensitivity to discover such decays. Other ${\mathbf{B}}_{bc}$ decays due to $b\ensuremath{\rightarrow}c{q}^{\ensuremath{'}}\overline{q}$ are subleading. Several relations among branching ratios are obtained which can be used to test $SU(3)$ flavor symmetry.

We study the three-body anti-triplet ${\bf B_c}\to {\bf B_n}MM'$ decays with the $SU(3)$ flavor ($SU(3)_f$) symmetry, where ${\bf B_c}$ denotes the charmed baryon anti-triplet of $(\Xi_c^0,-\Xi_c^+,\Lambda_c^+)$, and ${\bf B_n}$ and $M(M')$ represent baryon and meson octets, respectively. By considering only the S-wave $MM'$-pair contributions without resonance effects, the decays of ${\bf B_c}\to {\bf B_n}MM'$ can be decomposed into irreducible forms with 11 parameters under $SU(3)_f$, which are fitted by the 14 existing data, resulting in a reasonable value of $\chi^2/d.o.f=2.8$ for the fit. Consequently, we find that the triangle sum rule of ${\cal A}(\Lambda_c^+\to n\bar K^0 \pi^+)-{\cal A}(\Lambda_c^+\to pK^- \pi^+)-\sqrt 2 {\cal A}(\Lambda_c^+\to p\bar K^0 \pi^0)=0$ given by the isospin symmetry holds under $SU(3)_f$, where ${\cal A}$ stands for the decay amplitude. In addition, we predict that ${\cal B}(\Lambda_c^+\to n \pi^{+} \bar{K}^{0})=(0.9\pm 0.8)\times 10^{-2}$, which is $3-4$ times smaller than the BESIII observation, indicating the existence of the resonant states. For the to-be-observed ${\bf B_c}\to {\bf B_n}MM'$ decays, we compute the branching fractions with the $SU(3)_f$ amplitudes to be compared to the BESIII and LHCb measurements in the future., Comment: 14 pages, no figure, revised version accepted by PRD

A large number of new experimental data on $B$ decay into two light pesudoscalar ($P$) mesons have been collected by the LHCb collaboration. Besides confirming information on ${B}_{u,d}\ensuremath{\rightarrow}PP$ decays obtained earlier by B-factories at KEK and SLAC, new information on ${B}_{s}\ensuremath{\rightarrow}PP$ and also more decay modes with $P$ being $\ensuremath{\eta}$ or ${\ensuremath{\eta}}^{\ensuremath{'}}$ have been obtained. Using these new data, we perform a global fit for $B\ensuremath{\rightarrow}PP$ to determine decay amplitudes in the framework of $SU(3)/U(3)$ flavor symmetry. We find that $SU(3)$ flavor symmetry can explain data well. The annihilation amplitudes are found to be small as expected. Several $CP$ violating relations predicted by $SU(3)$ flavor symmetry are in good agreement with data. Current available data can give constraints on the amplitudes which induce $P=\ensuremath{\eta},{\ensuremath{\eta}}^{\ensuremath{'}}$ decays in the framework of $U(3)$ flavor symmetry, and can also determine the $\ensuremath{\eta}\ensuremath{-}{\ensuremath{\eta}}^{\ensuremath{'}}$ mixing angle $\ensuremath{\theta}$ with $\ensuremath{\theta}=(\ensuremath{-}18.4\ifmmode\pm\else\textpm\fi{}1.2)\ifmmode^\circ\else\textdegree\fi{}$. Several $B\ensuremath{\rightarrow}PP$ decay modes which have not been measured are predicted with branching ratios accessible at the LHCb. These decays can provide further tests for the framework of $SU(3)/U(3)$ flavor symmetry for $B$ decays.

The channel D s + → p n ¯ is the only kinematically allowed baryonic D decay. It proceeds solely through the W -annihilation topology. Hence, a recent observation of this mode by CLEO will shed light on the dynamics of W -annihilation. At the short-distance level, its branching ratio is very small, of order 10 −6 , owing to chiral suppression. It receives long-distance contributions through final-state scattering of the leading tree and color-suppressed amplitudes. Assuming that the long-distance enhancement of W -annihilation in the baryonic D decay is similar to that in the mesonic D s + decay, where the latter can be obtained from the analysis of the diagrammatic approach, we find that D s + → p n ¯ becomes visible. The observation of this baryonic D decay implies the dynamical enhancement of the W -annihilation topology in the D s + decay.

We study the charmful three-body baryonic B decays with $D^{(*)}$ or $J/\Psi$ in the final state. We explain the measured rates of $\bar B^0\to n\bar p D^{*+}$, $\bar B^0\to p\bar p D^{(*)0}$, and $B^-\to \Lambda \bar p J/\Psi$. In particular, the branching fraction of $\bar B^0\to\Lambda\bar \Lambda D^0$ predicted to be of order $2.3\times 10^{-6}$ is in accordance with the Belle measurement, $(1.05^{+0.57}_{-0.44}\pm 0.14)\times 10^{-5}, Comment: 7 pages, 2 figures, 2 tables; parallel talk given at at "Particle Physics, Astrophysics and Quantum Field Theory: 75 Years since Solvay", November 27-29, 2008, Singapore

Longitudinal weak gauge boson scattering has been well known as a powerful method to probe the underlying mechanism of the electroweak symmetry breaking sector of the Standard Model. We point out that longitudinal weak gauge boson scattering is also sensitive to the gauge sector when the non-Abelian trilinear and quartic couplings of the Standard Model Z boson are modified due to the general mixings with another Z' boson in the hidden sector and possibly with the photon as well. In particular, these mixings can lead to a partially strong scattering effect in the channels of W^\pm_L W^\pm_L \to W^\pm_L W^\pm_L and W^\pm_L W^\mp_L \to W^\pm_L W^\mp_L which can be probed at the Large Hadron Collider. We study this effect in a simple U(1) extension of the Standard Model recently suggested in the literature that includes both the symmetry breaking Higgs mechanism as well as the gauge invariant Stueckelberg mass terms for the two Abelian groups. Other types of Z' models are also briefly discussed., Comment: 18 pages, 4 figures, and 2 tables, version to appear in PRD

We study the charmful three-body baryonic B decays with $D^{(*)}$ or $J/\Psi$ in the final state. We explain the measured rates of $\bar B^0\to n\bar p D^{*+}$, $\bar B^0\to p\bar p D^{(*)0}$, and $B^-\to \Lambda \bar p J/\Psi$ and predict the branching fractions of $\bar B^0\to \Lambda\bar p D^{*+}$, $\bar B^0\to \Sigma^0\bar p D^{*+}$, $B^-\to\Lambda \bar p D^{0}$, and $B^-\to\Lambda \bar p D^{*0}$ to be of order $(1.2, 1.1, 1.1, 3.9)\times 10^{-5}$, respectively. They are readily accessible to the $B$ factories., Comment: 21 pages, 5 figures, version to appear in PRD

The observed branching ratios for $B\to K \eta'$ decays are much larger than factorization predictions in the Standard Model (SM). Many proposals have been made to reconcile the data and theoretical predictions. In this paper we study these decays within the SM using flavor U(3) symmetry. If small annihilation amplitudes are neglected, one needs 11 hadronic parameters to describe $B\to PP$ decays where $P$ can be one of the $\pi$, $K$, $\eta$ and $\eta'$ nonet mesons. We find that existing data are consistent with SM with flavor U(3) symmetry. We also predict several measurable branching ratios and CP asymmetries for $B \to K (\pi) \eta(\eta')$, $\eta(\eta')\eta(\eta')$ decays. Near future experiments can provide important tests for the Standard Model with flavor U(3) symmetry.

With SU(3) symmetry one only needs 13 hadronic parameters to describe $B\to PP$ decays in the Standard Model. When annihilation contributions are neglected, only 7 hadronic parameters are needed. These parameters can be determined from existing experimental data and some unmeasured branching ratios and CP asymmetries of the type $B\to PP$ can be predicted. In this talk we present SU(3) predictions of branching ratios and CP asymmetries for $B\to PP$ decays in the Standard Model., Comment: 4 pages, no figure. Talk present at the 5th International Conference on Hyperons, Charm and Beauty Hadrons, Vancouver, June 2002

We study the constraints on the CP violating phase gamma in the Kobayashi-Maskawa model using available experimental data. We first follow the conventional method to update the constraint on gamma by performing a chi (2) analysis using data from \epsilon (K)\, Deltam(Bd,s), and \V-ub\V-cb\. We also include the recent information on sin 2 beta in the analysis. We obtain the best fit for gamma to be 66 degrees and the 95% C.L. allowed range to be 42 degrees -87 degrees. We then develop a method to carry out a chi (2) analysis based on SU(3) symmetry using data from B-->pi pi and B -->K pi. We also discuss SU(3) breaking effects from a model estimate. We find that the present data on B -->pi pi ,K pi can also give some constraint on gamma although weaker than the earlier method limited by the present experimental errors. Future improved data will provide a more stringent constraint. Finally we perform a combined fit using data from \epsilon (K)/, Delta mB(d,s)' \V-ub/V-cb\, sin 2 beta, and rare charmless hadronic B decays. The combined analysis gives gamma =67 degrees for the best-fit value and 43 degrees -87 degrees as the 95% C.L. allowed range. Several comments on other methods to determine gamma based on SU(3) symmetry are also provided.