Charmless 3-body decays of B mesons are studied in a simple model based on the factorization approach. We have identified two distinct sources of nonresonant contributions: a small contribution from the tree transition and a large source of the nonresonant signal in the matrix elements of scalar densities, e.g., $<K\bar K|\bar ss|0>$, induced from the penguin transition. This explains the dominance of the nonresonant background in $B\to KKK$ decays, the sizable nonresonant fraction in $K^-π^+π^-$ and $\bar K^0π^+π^-$ modes and the smallness of nonresonant rates in $B\to πππ$ decays. The seemingly huge discrepancy between BaBar and Belle for the nonresonant contribution in the decay $B^-\to K^-π^+π^-$ is now relieved. We have computed the resonant and nonresonant contributions to charmless 3-body decays and determined the rates for the quasi-two-body decays $B\to VP$ and $B\to SP$. Time-dependent CP asymmetries $\sin2β_{\rm eff}$ and $A_{CP}$ in $K^+K^-K_S,K_SK_SK_S,K_Sπ^+π^-$ and $K_Sπ^0π^0$ modes are estimated.
The hadronic vacuum polarisation contributions to the anomalous magnetic moment of the muon, $a_μ^{\rm had, VP}$ are evaluated dispersively via a combination of experimentally measured $e^+e^-\rightarrow {\rm hadrons}$ cross section data. Many experiments have dedicated programmes to precisely measure these final states, meaning that a vast amount of data is now available and that, in some cases, overall precision has reached the sub-percent level. However, data tensions are evident between measurements of the same hadronic channels from different experiments, which reduces the overall quality…
In the framework of precision experiments, the search for electric dipole moments and the precise determination of magnetic dipole moments (g-2) have since long been of prime interest. Hadronic decays offer the best accuracy, since only the kinematic information carried by a single neutrino per decay is lost. Thus, they reveal more easily precious information on the helicity of the initial tau lepton. However, in contrast to one- or two-body hadronic final states, the description of hadronic multi-body final states depends on the model for the hadronic current. In this work, we determine how t…
A short review of our recent work on amplitude parametrizations of three-body hadronic weak $B$ and $D$ decays is presented. The final states are here composed of three light mesons, namely the various charge $πππ$, $Kππ$ and $KK\bar K$ states. These parametrizations are derived from previous calculations based on a quasi-two-body factorization approach where the two-body hadronic final state interactions are fully taken into account in terms of unitary $S$- and $P$-wave $ππ$, $πK$ and $K \bar K$ form factors. They are an alternative to the isobar-model description and can be useful in the int…
The Hadronic Contribution to the Muon Anomalous Magnetic Moment and to the Running Electromagnetic Fine Structure Constant at MZ - Overview and Latest Results
We introduce parametrizations of hadronic three-body $B$ and $D$ weak decay amplitudes that can be readily implemented in experimental analyses and are a sound alternative to the simplistic and widely used sum of Breit-Wigner type amplitudes, also known as the isobar model. These parametrizations can be particularly useful in the interpretation of CP asymmetries in the Dalitz plots. They are derived from previous calculations based on a quasi-two-body factorization approach in which two-body hadronic final state interactions are fully taken into account in terms of unitary $S$- and $P$-wave $π…
We provide an overview of recent determinations of the strong coupling, $α_s$, from hadronic $τ$ decays. We contrast two analysis methods, the "truncated-OPE approach" and the "DV-model approach," highlighting the assumptions going into each of these. We argue that a detailed study based on ALEPH data shows the truncated-OPE approach to be quantitatively unreliable, while the DV-model approach passes all tests. New data for hadronic $τ$ decays from Belle and Belle-II could provide more stringent tests of the DV-model approach, and thus potentially lead to a more precise value of $α_s$ from had…
Three-body semileptonic $τ$-decays offer a path to understand the properties of light hadronic systems and CP symmetry violations through searches for electric dipole moments. In studies of electro-weak physics, the hadronic part of the final states has traditionally been described using the language of form factors. Spectroscopic information, resolved in terms of orbital angular momentum quantum-numbers, is best being derived from an explicit decomposition of the hadronic current in the orbital angular momentum basis. Motivated by the upcoming large data samples from B factories, we present t…
We study the quasi-two-body $D\to TP$ decays and the three-body $D$ decays proceeding through intermediate tensor resonances, where $T$ and $P$ denote tensor and pseudoscalar mesons, respectively. We employ $D\to T$ transition form factors based upon light-cone sum rules and the covariant light-front quark model to evaluate the decay rates, with the former giving a better agreement with current data. Though the tree amplitudes with the emitted meson being a tensor meson vanish under factorization approximation, contributions proportional to the tensor decay constant $f_T$ can be produced from …
We provide an overview of the latest progress in the study of CP violation and mixing in the $B$ meson decays. Studying the $B^0_d \to J/ψK^0_S$ and $B^0_s \to J/ψϕ$ decays, we focus on the determination of the mixing phases $ϕ_d$ and $ϕ_s$, including hadronic uncertainties with the help of the data. CP violation in the non-leptonic decays $B \to πK$ and $B^0_s \to D_s^{\mp} K^{\pm}$ indicate puzzling patterns. Could these puzzles indicate New Physics?
In this study, we have investigated the two-body hadronic decay of the charged kaon, $ K^{+}\rightarrowπ^{+}+π^{0} $, in the presence of a laser field with circular polarization. We have derived, by analytical techniques, the laser-assisted decay width and the branching ratio of the charged kaon decay via the two-body hadronic channel. We have also taken into consideration the impressive results obtained for the laser-assisted charged kaon decay via the leptonic mode in order to understand more clearly the effect of the laser field on the quantities related to the charged kaon decay such as th…
Within the framework of perturbative QCD factorization, we investigate the nonfactorizable contributions to these factorization-forbidden Quasi-two-body decays $B_{(s)}\rightarrow hχ_{c0}\rightarrow hπ^+π^-(K^+K^-)$ with $ h=π, K$. We compare our predicted branching ratios for the $B_{(s)}\rightarrow Kχ_{c0}\rightarrow Kπ^+π^-(K^+K^-)$ decay with available experiment data as well as predictions by other theoretical studies. The branching ratios of these decays are consistent with data and other theoretical predictions. In the Cabibbo-suppressed decays $B_{(s)}\rightarrow hχ_{c0}\rightarrow hπ^…
We construct the theoretical framework for quasi-two-body $D$ meson decays with the help of pion and kaon electromagnetic form factors, and with which we study the contributions of the subprocesses $ρ(770,1450)\to K\bar{K}$ for the three-body $D$ decays within the flavour $SU(3)$ symmetry. Because of the limitations imposed by phase space and strong coupling, the contributions for kaon pair from the virtual bound state $ρ(770)$ are channel-dependent and generally small for the concerned three-body $D$ decays. But some quasi-two-body processes could still be observed in the Dalitz plot analyses…
Recently Belle collaboration reported new measurements for the branching fractions with the first observing two processes of $\mathcal{B}(Ξ_c^0\toΛK^0_S)$, $\mathcal{B}(Ξ_c^0\toΣ^0 K^0_S)$ and updating data for $\mathcal{B}(Ξ_c^0\toΣ^+ K^-)$. Combined with other known data on charmless two body decays of anti-triplet charmed baryons, a lot of information can be derived with the assistance of $SU(3)$ flavour symmetry. Using $SU(3)$ relations between different decay modes, we can give some predictions based on the new measurements which can be tested with the high luminosity experiments in the f…
The dispersive approach to QCD is briefly overviewed and its application to the assessment of hadronic contributions to electroweak observables is discussed.
Strong two- and three-body decays of the new excited hyperon $Ω^*(2012)$ are discussed in the hadronic molecular approach. The $Ω^*(2012)$ state is considered to contain the mixed $Ξ\bar K$ and $Ωη$ hadronic components. In our calculations we use a phenomenological hadronic Lagrangian describing the coupling of the bound states to its constituents and of the constituents to other hadrons occurring in the final state. Our results show that the decay widths of the two-body decay modes $Ω^*(2012) \to Ξ\bar K$ lie in the few MeV region and are compatible with or dominate over the rates of the thre…
A dispersive method to study CP asymmetries in hadronic multi-body $B$ decays
Universität Bonn（波恩大学）；Universidad Complutense de Madrid（马德里康普顿斯大学）；Forschungszentrum Jülich（于利希研究中心）；Universidade Estadual de Campinas（坎皮纳斯州立大学）；Universität Siegen（锡根大学）
We construct hadronic amplitudes for the three-body decays $η^{(\prime)}\toπ^+π^-π^0$ and $η'\toηπ^+π^-$ in a non-perturbative fashion, allowing for $C$- and $CP$-violating asymmetries in the $π^+π^-$ distributions. These amplitudes are consistent with the constraints of analyticity and unitarity. We find that the currently most accurate Dalitz-plot distributions taken by the KLOE-2 and BESIII collaborations confine the patterns of these asymmetries to a relative per mille level. Our dispersive representation allows us to extract the individual coupling strengths of the $C$- and $CP$-violating…
Probing the three-body force in hadronic systems with specific charge parity
Beihang University（北京航空航天大学）；Lanzhou University（兰州大学）；École Centrale de Pékin/School of General Engineering, Beihang University（北京航空航天大学中法工程师学院/通用工程学院）；Peng Huanwu Collaborative Center for Research and Education, Beihang University（北京航空航天大学彭桓武研究中心）；Beijing Key Laboratory of Advanced Nuclear Materials and Physics, Beihang University（北京航空航天大学先进核材料物理北京市重点实验室）；Southern Center for Nuclear-Science Theory (SCNT), Institute of Modern Physics, Chinese Academy of Sciences（中国科学院近代物理研究所南方核科学理论中心）
We analyze, in a fully model-independent manner, the effects of new physics on a few semi-hadronic three-body meson decays of the type $P_i \to P_f f_1 f_2$, where $P_i$, $P_f$ are well chosen pseudo-scalar mesons and $f_{1,2}$ denote fermions out of which at least one gets detected in experiments. We find that the angular distribution of events of these decays can probe many interesting new physics, such as the nature of the intermediate particle that can cause lepton-flavor violation, or presence of heavy sterile neutrino, or new intermediate particles, or new interactions. We also provide a…
We study Cabibbo-favored (CF) and singly Cabibbo-suppressed (SCS) two-body hadronic weak decays of the antitriplet charmed baryons $Λ_c^+$, $Ξ_c^0$ and $Ξ_c^+$ with more focus on the last two. Both factorizable and nonfactorizable contributions are considered in the topologic diagram approach. The estimation of nonfactorizable contributions from $W$-exchange and inner $W$-emission diagrams relies on the pole model and current algebra. The non-perturbative parameters in both factorizable and nonfactorizable parts are calculated in the MIT bag model. Branching fractions and up-down decay asymmet…
