The anti-triplet charmed baryon decays with the light scalar mesons are rarely measured, whereas the recent observation of the Cabibbo-favored $Λ_c^+\to Ληπ^+$ decay hints a possible $Λ_c^+\toΛa_0(980)^+,a_0(980)^+\to ηπ^+$ process. We hence study the $Λ_c^+\toΛa_0(980)^+$ decay. Particularly, it is found that the final state interaction can give a significant contribution, where $Σ^{+}(1385)$ and $η$ in $Λ_c^+\to Σ^{+}(1385)η$ by exchanging a charged pion are transformed as $Λ$ and $a_0(980)^+$, respectively. Accordingly, we predict ${\cal B}(Λ_c^+\toΛa_0(980)^+)=(1.7^{+2.8}_{-1.0}\pm 0.3)\times 10^{-3}$, accessible to the BESIII, BELLEII and LHCb experiments.
A phenomenological analysis of $D\to Kπ$ and $D_s^+\to K K $decays including both Cabibbo-favored and doubly-Cabibbo-suppressed modes have been presented by employing the present experimental data. SU(3) symmetry breaking effects from the decay constants and form factors have been taken into account in the analysis. Three asymmetries, $R(D^0)$, $R(D^+)$, and $R(D_s^+)$, which are generated through interference between Cabbibo-favored and doubly- Cabibbo-suppressed decays, are estimated. Theoretical results agree well with the current measurements.
Model-independent description of nonleptonic decays of charmed mesons is a challenging task due to large nonperturbative effects of strong interactions on the transition amplitudes. We discuss the equivalence of two different flavor-$SU(3)$-based descriptions of Cabibbo-favored non-leptonic decays of charmed mesons to two-pseudoscalars final states including the $η$ and $η^\prime$ mesons.
The parameter $y_{CP}$ is used to characterize mixing in the $D^0$-$\bar{D}{}^0$ meson system. To determine $y_{CP}$, one measures the effective decay width of a $D^0$ or $\bar{D}{}^0$ decaying to a $CP$ eigenstate, relative to the effective width for a decay to a Cabibbo-favored, flavor-specific final state. When using $y_{CP}$ to extract information about $D^0$-$\bar{D}{}^0$ mixing and $CP$ violation, the decay width of the Cabibbo-favored decay is usually assumed to equal $1/τ$, the reciprocal of the $D^0$ lifetime. However, there is a small correction to this that should be taken into acco…
We resume the study of the Cabibbo-favored charmed-meson decays $D^+ \to \bar{K} ππ^+$ in a dispersive framework that satisfies unitarity, analyticity, and crossing symmetry by construction. The formalism explicitly describes the strong final-state interactions between all three decay products and relies on pion-pion and pion-kaon phase shift input. For the first time, we show that the $D^+ \to K_S π^0 π^+$ Dalitz plot obtained by the BESIII collaboration as well as the $D^+ \to K^- π^+ π^+$ Dalitz plot data by CLEO and FOCUS can be described consistently, exploiting the isospin relation betwe…
The current knowledge on the $D^{\ast}$ mesons are still inadequate. Encouraged by the positive development prospects of high-luminosity and high-precision experiments, the Cabibbo-favored nonleptonic $D^{\ast}$ ${\to}$ $\bar{K}π^{+}$, $\bar{K}^{\ast}π^{+}$, $\bar{K}ρ^{+}$ weak decays are studied with the naive factorization approach. It is found that branching ratios of these processes can reach up to ${\cal O}(10^{-10})$ or more, and can be accessible at STCF, CEPC, FCC-ee and LHCb@HL-LHC experiments in the future. It might even be possible to search for the $D^{{\ast}0}$ ${\to}$ $K^{{\ast}-…
A definite relative phase and amplitude exists between the doubly-Cabibbo-% suppressed amplitude for $D^0 \to \ko M^0$ and the Cabibbo-favored amplitude for $D^0 \to \ok M^0$, where $M^0 = (π^0,η,η')$: $A(D^0 \to \ko M^0) = - \tan^2 θ_C A(D^0 \to \ok M^0)$. Here $θ_C$ is the Cabibbo angle. This relation, although previously recognized (for $M^0 = π^0$) as a consequence of the U-spin subgroup of SU(3), is argued to be less sensitive to corrections involving SU(3) breaking than related U-spin relations involving charged kaons or strange $D$ mesons. A corresponding relation between $D^+ \to \ko π…
The two body Cabibbo favored hadronic decays of charmed baryons $Λ^{+}_{c}$, $Ξ^{+}_{c}$ and $Ξ_{c}^{0}$ into an octet or decuplet baryon and a pseudoscalar meson are examined in the SU(3) symmetry scheme. The numerical estimates for decay widths and branching ratios of some of the modes are obtained and are in good agreement with experiment.
With the inclusion of nonfactorized amplitudes in a scheme with $N_c=3$, we have studied Cabibbo-favored decays of $D^0$ and $D^+$ into two-body hadronic states involving two isospins in the final state. We have shown that it is possible to understand the measured branching ratios and determined the sizes and signs of nonfactorized amplitudes required.
We assume universal values for the color-singlet ($ε_1$) and color octet ($ε_8$) nonfactorization parameters in B Decays. Two sets of color-favored processes and one set of color-suppressed processes were used to give quantitative estimates of these parameters. It has been found (by calculating the branching ratios for a large number of Cabibbo-favored B Decays) that the values $ε_1(μ_0) = - 0.06 +/- 0.03$ and $ε_8(μ_0) = 0.12 +/- 0.02$ improve significantly the predictions of the factorization model.
According to the standard model, the Cabibbo-favored (CF) decays are $CP$ conserve at tree level. Observation of any finite $CP$ asymmetry can be received as a signal of new physics. In CF charm meson decays, $ D^0 \rightarrow K^- π^+ $ and $ D^+ \rightarrow K_s^0 π^+ $, the following experimental values for their $CP$ asymmetry are reported, respectively: ($0.3 \pm 0.7$) % and ($-0.41 \pm 0.09$) %. The value of the later can be attributed to the mixing of $ K^0 $ and $ \overline{K^0} $, however, its contribution is about ($-0.332 \pm 0.006 $) %. In this paper, we use these experimental result…
Motivated by some new experimental data, we carry out a phenomenological analysis of D --> K pi decays including both Cabibbo favored and doubly Cabibbo suppressed modes. Two asymmetries, R(D^0) and R(D+), which are generated through interference between Cabbibo favored and doubly Cabibbo suppressed D --> K pi transitions, are predicted. The relative strong phase, delta_{K pi}, between D^0 --> K- pi+ and D^0 --> K+ pi- decays, is estimated. The theoretical results agree well with the current measurements.
Within the perturbative QCD approach, we investigated the Cabibbo-Kobayashi-Maskawa-favored $B \to \overline{D} S$ ("$S$" denoting the scalar meson) decays on the basis of the two-quark picture. Supposing the scalar mesons are the ground states or the first excited states, we calculated the the branching ratios of 72 decay modes. Most of the branching ratios are in the range $10^{-4}$ to $10^{-7}$, which can be tested in the ongoing LHCb experiment and the forthcoming Belle-II experiment. Some decays, such as $B^+ \to \overline{D}^{(*)0} a_0^+(980/1450)$ and $B^+ \to D^{(*)-} a_0^+(980/1450)$,…
Since the standard model contribution is virtually absent, any observation of direct CP violation in the Cabibbo-favored charmed meson decays would be evidence of new physics. In this paper, we conduct a quantitative study on direct CP violation in $D^0\to K^-π^+$, $D_s^+\to ηπ^+$ and $D_s^+\to η'π^+$ decays in the $SU(2)_L\times SU(2)_R\times U(1)_{B-L}$ gauge extension of the standard model. In the model, direct CP violation arises mainly from the interference between the decay amplitude coming from the SM left-left current operators and that from the right-right current operators induced by…
A recent update of data on the decays of $D^0$, $D^+$, and $D_s^+$ to pairs of light pseudoscalars calls for a renewed analysis of key decay amplitudes and tests of flavor symmetry. The present data change our previous understanding of relative phases between amplitudes that describe Cabibbo-favored decays of the charmed mesons. The new data also seem to favor a smaller octet-singlet mixing angle for the $η$ and $η'$ mesons when singly-Cabibbo-suppressed processes are taken into account. We also discuss the effects of the new data on interference between Cabibbo-favored and doubly-Cabibbo-supp…
Study on the Cabibbo-favored ${\overline B}_{d,s}$ ${\to}$ $D_{d,s}^{(*)+}S^{-}$ weak decays in QCD factorization
Centre for Theoretical Physics, Henan Normal University（河南师范大学理论物理中心）；School of Physics and Telecommunications Engineering, Zhoukou Normal University（周口师范学院物理与电信工程学院）；School of Physics and Electrical Engineering, Anyang Normal University（安阳师范学院物理与电气工程学院）
Singly-Cabibbo-suppressed decays of charmed particles governed by the quark subprocesses $c \to s u \bar s$ and $c \to d u \bar d$ are analyzed using a flavor-topology approach, based on a previous analysis of the Cabibbo-favored decays governed by $c \to s u \bar d$. Decays to $PP$ and $PV$, where $P$ is a pseudoscalar meson and $V$ is a vector meson, are considered. We include processes in which $η$ and $η'$ are produced.
CP violation (CPV) in the baryon sectors has not yet been established experimentally. In this work, we propose to search for the hyperon CPV through the Cabibbo-favored charm-baryon decaying processes involving a hyperon in the final states, such as $Λ_c^+\to Λ^0π^+, Λ^0\to pπ^-$. The CPV of the hyperon decays are purely revealed in these chain processes, since the CPV in the Cabibbo-favored charm decays are vanishing in the Standard Model (SM). The hyperons are polarized in the weak charm decays, so that we can measure the Lee-Yang asymmetric parameter $α$ by the angular distributions, and th…
We prove a U-spin amplitude triangle relation among doubly Cabibbo-suppressed (DCS) charmed meson decays, $D^0\to K^+π^-, D^0 \to K^0π^0$ and $D^+_s \to K^0 K^+$, congruent to an isospin relation among corresponding Cabibbo-favored (CF) decays. U-spin breaking in relative phases between CF and DCS amplitudes affects time-dependent studies of $D^0-\od$ mixing. Comparison of final state phase patterns in DCS and CF amplitude triangles, which can shed some light on these phases, is carried out in a phenomenological framework incorporating resonance contributions.
Cabibbo-favored nonleptonic charmed particle decays exhibit large final-state phase differences in $\bar K π$ and $\bar K^* π$ but not $\bar K ρ$ channels. It is of interest to know the corresponding pattern of final-state phases in doubly-Cabibbo-suppressed decays, governed by the $c \to d u \bar s$ subprocess. An experimental program is outlined for determining such phases via measurements of rates for $D \to K^* π$ and $K (ρ, ω,ϕ)$ channels, and determination of interference between bands in Dalitz plots. Such a program is feasible at planned high-intensity sources of charmed particles.
We argue that there could be large, SU(3) violating resonance contributions to D -> K pi decays which would affect the extraction of the D0-anti-D0 mixing parameters from experiment. Such contributions can induce a large strong phase in the interference between the doubly Cabibbo suppressed and the mixing induced Cabibbo favored contributions to the D0 -> K^+ pi^- and anti-D0 -> K^- pi^+ decays. Consequently, the interpretation of a large, CP conserving interference term can involve a large mass difference Delta M rather than a large width difference Delta Gamma.
We analyze various theoretical aspects of CP violation in singly Cabibbo suppressed (SCS) D-meson decays, such as $D \to K K,ππ$. In particular, we explore the possibility that CP asymmetries will be measured close to the present level of experimental sensitivity of $O(10^{-2})$. Such measurements would signal new physics. We make the following points: (i) The mechanism at work in neutral D decays could be indirect or direct CP violation (or both). (ii) One can experimentally distinguish between these possibilities. (iii) If the dominant CP violation is indirect, then there are clear predictio…
Using NLL values for Wilson coefficients and including the contributions from the penguin diagrams, we estimate the amount of nonfactorization in two-body hadronic B decays. Also, we investigate the model dependence of the nonfactorization parameters by performing the calculation using different models for the form factors. The results support the universality of nonfactorizable contributions in both Cabibbo-favored and Cabibbo-suppressed B decays.
In this paper, I report the preliminary results of the strong phase difference $\cosδ_{Kπ}$ between the doubly Cabibbo-suppressed process $\overline{D}{}^0\to K^- π^+$ and Cabibbo-favored $D^0\to K^- π^+$ at BESIII. In addition, the preliminary results of the $D^0$-$\overline{D}{}^0$ mixing parameter $y_\mathrm{CP}$ by analyzing $CP$-tagged semileptonic $D$ decays are presented. These measurements were carried out based on the quantum-correlated technique in studying the process of $D^0\overline{D}{}^0$ pair productions of 2.92 fb$^{-1}$ $e^+e^-$ collision data collected with the BESIII detect…
We report the first observation of the Cabibbo disfavored semileptonic decay mode D+ -> rho0(770) mu+ nu, and measure its decay rate relative to the Cabibbo favored mode D+ -> K*0(892) mu+ nu to be Gamma(D+ -> rho0(770) mu+ nu) / Gamma(D+ -> K*0(892) mu+ nu) = 0.044 +0.031 -0.025 (stat.) +/- 0.014 (sys). The results are compared to theoretical predictions and to previous experimental upper limits.
We study two-body weak decays of charmed baryons Λ_c and Ξ_c into an octet or decuplet baryon and a pseudoscalar meson employing the SU(3) flavor symmetry. Using certain measured Cabibbo-favored modes, we fix the reduced amplitudes and predict the branching ratios of various decays of charmed baryons in the Cabibbo-enhanced, -suppressed and -doubly suppressed modes.
The $B_{c}^{\ast}$ ${\to}$ $B_{u,d,s}V$, $B_{u,d,s}P$ decays are investigated with the QCD factorization approach, where $V$ and $P$ denote the ground $SU(3)$ vector and pseudoscalar mesons, respectively. The $B_{c}^{\ast}$ ${\to}$ $B_{u,d,s}$ transition form factors are calculated with the Wirbel-Stech-Bauer model. It is found that branching ratios for the color-favored and Cabibbo-favored $B_{c}^{\ast}$ ${\to}$ $B_{s}ρ$, $B_{s}π$ decays can reach up to ${\cal O}(10^{-7})$, which might be measurable in the future LHC experiments.
We find a new $CP$-violation effect in charm decays into neutral kaons, which results from the interference between two tree (Cabibbo-favored and doubly Cabibbo-suppressed) amplitudes with the mixing of final-state mesons. This effect, estimated to be of an order of $10^{-3}$, is much larger than the direct $CP$ asymmetries in these decays, but missed in the literature. It can be revealed by measuring the difference of the time-dependent $CP$ asymmetries in the $D^{+}\toπ^{+}K_S^0$ and $D_{s}^{+}\to K^{+} K_S^0$ modes, which are accessible at the LHCb and Belle II experiments. If confirmed, th…
Decays of neutral D-mesons are considered phenomenologically without invoking any particular models. Special attention is given to cascade decays with intermediate neutral kaons where coherent double-flavor oscillations (CDFO) become possible. We show necessity and unique possibilities of experiments on CDFO. They allow to relate with each other widths and masses of D-meson eigenstates, to separate interference effects due to $D^0 - \bar D^0$ mixing and/or Cabibbo-favored vs. doubly-suppressed transitions. Such experiments provide the only known ways to unambiguous model-independent measuremen…
We point out the $CP$ asymmetry in the chain decay of $Λ_c^+\to Δ^+K(t)(\to π^+π^-)$ is determined by the branching fractions of $Λ^+_c\to Δ^{++} K^-$, $Λ^+_c\to Δ^{+} K^0_{S,L}$ and $Λ^+_c\to Δ^{0} K^+$ modes under the isospin symmetry. The ambiguities from loop-induced quantities and $SU(3)_F$ breaking hadronic effects are avoided. Once the $CP$ asymmetry in the $Λ_c^+$ decays into $Δ^+$ and neutral kaons is confirmed by experiments, we can check if it is beyond the Standard Model, or verify the $CP$-violating effect resulted from the interference between the Cabibbo-favored and the doubly C…
Two-body charmed meson decays $D\to VP$ are studied within the framework of the diagrammatic approach. Under flavor SU(3) symmetry, all the flavor amplitude sizes and their associated strong phases are extracted by performing a $χ^2$ fit. Thanks to the recent measurement of $D_s^+\toπ^+ρ^0$, the magnitudes and the strong phases of the $W$-annihilation amplitudes $A_{P,V}$ have been extracted for the first time. As a consequence, the branching fractions of all the $D\to VP$ decays are predicted, especially those modes that could not be predicted previously due to the unknown $A_{P,V}$. Our work…
We present improved measurements of the branching fractions for the decays B0 --> Ds+pi- and B0-bar --> Ds+K- using a data sample of 657x10^6 BB-bar events collected at the Y(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. The results are BF(B0 --> Ds+pi-) = (1.99 +/- 0.26 +/- 0.18)x10^-5 and BF(B0-bar --> Ds+K-) = (1.91 +/- 0.24 +/- 0.17)x10^-5, where the uncertainties are statistical and systematic, respectively. Based on these results, we determine the ratio between amplitudes of the doubly Cabibbo suppressed decay B0 --> D+pi- and the Cabibbo favored deca…
New data on the decays of the charmed particles $D^0$, $D^+$, and $D_s$ to pairs of light pseudoscalar mesons $P$ allow the testing of flavor symmetry and the extraction of key amplitudes. Information on relative strong phases is obtained. One sees evidence for the expected interference between Cabibbo-favored and doubly-Cabibbo-suppressed decays in the differing patterns of $D^0 \to K_{S,L} π^0$ and $D^+ \to K_{S,L} π^+$ decays.
Two-body hadronic weak decays of the charmed baryon $Ω_c$, including Cabibbo-favored (CF), singly Cabibbo-suppressed (SCS) and doubly Cabibbo-suppressed (DCS) modes, are studied systematically in this work. To estimate nonfactorizable contributions, we work in the pole model for the $P$-wave amplitudes and current algebra for the $S$-wave amplitudes. Among all the channels decaying into a baryon octet and a pseudoscalar meson, $Ω_c\to Ξ^0\overline{K}^0$ is the only allowed CF mode. The predicted branching fraction of order $3.8\%$ and large and positive decay asymmetry of order $0.50$ indicate…
New data on the decays of the charmed particles $D^0$, $D^+$, and $D_s$ to $PV$ final states consisting of a light pseudoscalar meson $P$ and a light vector meson $V$ are analyzed. Following the same methods as in a previous analysis of $D \to PP$ decays, one can test flavor symmetry, extract key key amplitudes, and obtain information on relative strong phases. Analyses are performed for Cabibbo-favored decays and then extended to predict properties of singly- and doubly-Cabibbo-suppressed processes.
Improved $B$ meson decay data have permitted more incisive tests of factorization predictions. A concurrent benefit is the ability to constrain the Cabibbo-Kobayashi-Maskawa matrix element $|V_{cb}|$. Using a simultaneous fit to differential distributions $d Γ(\ob \to D^{*+} l^- \bar ν_l)/ dq^2$ measured by the CLEO and LEP Collaborations, the rates for the color-favored decays $\ob \to D^{(*)+} (π^-,ρ^-,a_1^-)$, and the rate for $\ob \to D^+ l^- \bar ν_l$, we find $|V_{cb}| = 0.0415 \pm 0.0022$. The slope of the universal Isgur-Wise form factor is described by a parameter found to be $\rs = 1…
The LHCb and CDF Collaborations have recently reported evidence for a CP asymmetry around -0.7% in $ΔA_{CP}$, the difference between $A_{CP}(D^0 \to K^+ K^-)$ and $A_{CP}(D^0 \to π^+π^-)$. In the Standard Model this effect may be accounted for by enhanced $1/m_c$ corrections in a CP-violating penguin amplitude governed by a Cabibbo-Kobayashi-Maskawa (CKM) factor $V^*_{cb}V_{ub}$. A consistent scheme based on broken flavor SU(3) is presented relating Cabibbo-favored (CF) and singly-Cabibbo-suppressed (SCS) $D$ meson decay rates into two pseudoscalars. Two important ingredients supporting the ab…
We study the $K^0_S-K^0_L$ asymmetries and $CP$ violations in charm-baryon decays with neutral kaons in the final state. The $K^0_S-K^0_L$ asymmetry can be used to search for two-body doubly Cabibbo-suppressed amplitudes of charm-baryon decays, with the one in $Λ^+_c\to pK^0_{S,L}$ as a promising observable. Besides, it is studied for a new $CP$-violation effect in these processes, induced by the interference between the Cabibbo-favored and doubly Cabibbo-suppressed amplitudes with the neutral kaon mixing. Once the new CP-violation effect is determined by experiments, the direct $CP$ asymmetry…
We investigate nonfactorizable contributions to two-body hadronic decays of the charmed mesons to a pseudoscalar meson and a vector meson in Cabibbo-favored mode. Employing SU(3)-flavor symmetry for the nonfactorizable matrix elements, we obtain branching ratios of the decays in consistent agreement with experiment.
Using the vector meson dominance model we get predictions for the Cabibbo-favored $\tom$ and $\tphi$ decays. We show how the measurements of these two decays can provide information on the nature of the violation of the OZI rule.
We study the Dalitz plot of the Cabibbo-favored charmed-meson decay $D^+\to K^-π^+π^+$ using dispersion theory. The formalism respects all constraints from analyticity and unitarity, and consistently describes final-state interactions between all three decay products. We employ pion-pion and pion-kaon phase shifts as input, and fit the pertinent subtraction constants to Dalitz plot data by the CLEO and FOCUS collaborations. Phase motions of resonant as well as nonresonant amplitudes are discussed, which should provide crucial input for future studies of CP violation in similar three-body charm…
In perturbative QCD approach, we investigate the $B(B_{s})\rightarrow D_{(s)}(\bar{D}_{(s)})\,T$ and $D_{(s)}^{*}(\bar{D}_{(s)}^{*})\,T$ decays, which include the Cabibbo-Kobayashi-Maskawa (CKM) favored decays and the Cabibbo-Kobayashi-Maskawa-suppressed decays, where T denotes a light tensor meson. From our calculation, we find that the nonfactorizable emission diagrams and the annihilation type diagrams are important, especially for those color suppressed channels. For those decays with a tensor meson emitted, the factorizable emission diagrams vanish owing to the fact that a tensor meson ca…
We study the properties of Cabibbo-Kobayashi-Maskawa (CKM) favored semileptonic decays of mesons and baryons containing a heavy quark at the point of no recoil. We first use a diagrammatic analysis to rederive the result observed by earlier authors that at this kinematic point the $B$ meson decays via $b\to c$ transitions can only produce a $D$ or $D^*$ meson. The result is generalized to include photon emissions which violate heavy quark flavor symmetry. We show that photons emitted by the heavy quarks and the charged lepton are the only light particles that can decorate the decays $\bar{B}\t…
The $K_{S}^{0}-K_{L}^{0}$ asymmetries in the $D$ meson decays, induced by the interference between the Cabibbo-favored and the doubly Cabibbo-suppressed amplitudes, can help to understand the dynamics of charm decays. All possible processes of two-body non-leptonic $D$ decays into one neutral kaon and another pseudoscalar or vector meson are considered. We study the $K_{S}^{0}-K_{L}^{0}$ asymmetries and the branching fractions of corresponding processes in the factorization-assisted topological-amplitude approach in which significant flavor $SU(3)$ symmetry breaking effects are included. The b…
We study charm D - meson decays to two pseudoscalar mesons in Cabibbo favored mode employing SU(3)-flavor for the nonfactorizable matrix elements. Using $D\rightarrow \bar K π$ and $D_{s} \rightarrow \bar K K$ to fix the reduced matrix elements, we obtain a consistent fit for $ η$ and $ η'$ emitting decays of $D$ and $ D_{s}$ mesons.
We report on a measurement of CP-violating asymmetries (Acp) in the Cabibbo-suppressed D0 --> pi+ pi- and D0 --> K+K- decays reconstructed in a data sample corresponding to 5.9 fb-1 of integrated luminosity collected by the upgraded Collider Detector at Fermilab. We use the strong decay D*+ --> D0 pi+ to identify the flavor of the charmed meson at production and exploit CP-conserving strong c-cbar pair-production in p-pbar collisions. High-statistics samples of Cabibbo-favored D0 --> K- p+ decays with and without a D* tag are used to correct for instrumental effects and significantly reduce sy…
With the diquark structure of Lambda_c, we investigate the branching ratios of Lambda_c -> n pi^+ and p pi^0. The results show that without considering the final state interaction (FSI), the branching ration of Lambda_c -> p pi^+ is only of order 10^{-6} whereas taking into account the FSI effects, this ratio could reach 10^{-4} and is at the same order as Lambda_c -> n pi^0. Concrete values depend on phenomenological parameters adopted in the calculations. These branching ratios can be measured in the experiments to come.
We exploit the angular and quantum correlations in the $D\bar{D}$ pairs produced through the decay of the $ψ(3770)$ resonance in a charm factory to investigate CP-violation in two different ways. We consider the case of $ψ(3770)\rightarrow D\bar{D}\rightarrow (V_1V_2)(Kπ)$ decays, which provide a new way to measure the strong phase difference $δ$ between Cabibbo-favored and doubly-Cabibbo suppressed $D$ decays required in the determination of the CKM angle $γ$. We also build CP-violating observables in $ψ(3770)\rightarrow D\bar{D}\rightarrow (V_1V_2)(V_3 V_4)$ to isolate specific new physics e…
We find a new $CP$ violating effect in charmed hadron decays into neutral kaons, which is induced by the interference between the Cabibbo-favored and doubly Cabibbo-suppressed amplitudes with the $K^{0}-\overline K^{0}$ mixing. It is estimated to be of order of $\mathcal{O}(10^{-3})$, much larger than the direct $CP$ asymmetry, but missed in the literature. To reveal this new $CP$ violation effect, we propose a new observable, the difference of the $CP$ asymmetries in the $D^{+}\to π^{+}K_S^0$ and $D_{s}^{+}\to K^{+} K_S^0$ modes. Once the new effect is determined by experiments, the direct $C…
We study Cabibbo-Kobayashi-Maskawa (CKM) favored weak decays of Bc mesons in the Isgur-Scora-Grinstein-Wise (ISGW) quark model. We present a detailed analysis of the Bc meson decaying to a pseudoscalar meson (P) and an axial-vector meson (A). We also give the form factors involving transition in the ISGW II framework and consequently, predict the branching ratios of decays.
The charm quark offers interesting opportunities to cross-check the mechanism of CP violation precisely tested in the strange and beauty sectors. In this paper, we exploit the angular and quantum correlations in the D\bar{D} pairs produced through the decay of the psi(3770) resonance in a charm factory to investigate CP-violation in two different ways. We build CP-violating observables in psi(3770) -> D\bar{D} -> (V_1V_2)(V_3 V_4) to isolate specific New Physics effects in the charm sector. We also consider the case of psi(3770) -> D\bar{D} -> (V_1V_2)(Kπ) decays, which provide a new way to me…
We studied the nonleptonic $B_{c}$ ${\to}$ $BP$, $BV$ decay with the QCD factorization approach. It is found that the Cabibbo favored processes of $B_{c}$ ${\to}$ $B_{s}π$, $B_{s}ρ$, $B_{u}\bar{K}$ are the promising decay channels with branching ratio larger than 1\%, which should be observed earlier by the LHCb Collaboration.
We obtain the first estimates of branching ratios for the weak decays of $B_c$ meson decaying to two orbitally excited mesons namely, axial-vector meson ($A$) and tensor meson ($T$), in the final state. We calculate $B_c \to T$ transition form factors using the Isgur-Scora-Grinstein-Wise II framework and consequently predict branching ratios of $ B_c \to AT $ decays in Cabibbo-Kobayashi-Maskawa favored and suppressed modes.
The Cabibbo allowed non-leptonic $B$-decays in two hadrons are studied, within the factorization hypothesis, in the framework of Isgur and Wise theory for the matrix elements of the $ΔB=-ΔC=\pm 1$ weak currents. The $SU(2)_{HF}$ symmetry relates $|ΔB|=1$ to $|ΔC|=1$ currents, which have been measured in the semileptonic strange decays of charmed particles. By assuming colour screening and allowing for $SU(3)$ invariant contributions from the annihilation terms with charmed final states one is able to comply with the present experimental knowledge.\\ The $CP$ violating asymmetries in neutral $B…
Motivated by the recent evidence for direct CP-violation in D0 -> h+h- decays, we provide an exhaustive study of both Cabibbo-favored and Cabibbo-suppressed (singly and doubly) D0 -> h1+h2-l+l- decays. In particular, we study the Dalitz plot for the long-distance contributions in the (m_{ll}^2,m_{hh}^2) parameter space. We find that near-resonant effects, i.e., D0 -> V(h1+h2-)l+l- with V=ρ,K*,ϕ, are sizeable and even dominant (over Bremsstrahlung) for the μ+μ- decay modes, bringing the branching ratios close to the LHCb reach. We also provide a detailed study of the angular asymmetries for suc…
We study the decays of heavy chiral (t', b') quarks in a four-generation extension of the Standard Model. If the difference between the t' and b' masses is smaller than the W mass, as favored by precision electroweak measurements, then the Cabibbo-Kobayashi-Maskawa favored, on-shell decay t'-->b'W is forbidden. As a result, other t' decays have substantial branching fractions, which are highly sensitive to the magnitude of the diagonal CKM matrix element V_{t'b'}. We show that |V_{t'b'}| can be determined from the ratio of the two-body and three-body t'-decay branching fractions and estimate t…
