Probing the ∆U = 0 rule in three body charm decays

CP violation in charm decay was observed in the decays D0→ P±P∓ of a D0 meson to two pseudoscalars. When interpreted within the SM, the results imply that the ratio of the relevant rescattering amplitudes has a magnitude and phase that are both of O(1). We discuss ways to probe similar ratios in D0→ V±P∓ decays, where V is a vector that decays to two pseudoscalars, from the Dalitz-plot analysis of time-integrated three-body decays. Compared to two-body decays, three-body decays have the advantage that the complete system can be solved without the need for time-dependent CP violation measurements or use of correlated $$ {D}^0-{\overline{D}}^0 $$ D 0 − D ¯ 0 production. We discuss the decays D0→ π+π−π0 and D0→ K+K−π0 as examples by considering a toy model of only two overlapping charged resonances, treating the underlying pseudo two-body decays in full generality.

A phenomenological analysis on isospin-violating decay of X(3872)

In a molecular scenario, we investigate the isospin-breaking hidden charm decay processes of X(3872), i.e., $$X(3872) \rightarrow \pi ^+ \pi ^- J/\psi $$ X ( 3872 ) → π + π - J / ψ , $$X(3872) \rightarrow \pi ^+ \pi ^- \pi ^0 J/\psi $$ X ( 3872 ) → π + π - π 0 J / ψ , and $$X(3872)\rightarrow \pi ^0\chi _{cJ}$$ X ( 3872 ) → π 0 χ cJ . We assume that the source of the strong isospin violation comes from the different coupling strengths of X(3872) to its charged components $$D^{*+} D^-$$ D ∗ + D - and neutral components $$D^{*0 } {\bar{D}}^0$$ D ∗ 0 D ¯ 0 as well as the interference between the charged meson loops and neutral meson loops. The former effect could fix our parameters by using the measurement of the ratio $$\Gamma [X(3872) \rightarrow \pi ^+ \pi ^- \pi ^0 J/\psi ]/\Gamma [X(3872) \rightarrow \pi ^+ \pi ^- J/\psi ]$$ Γ [ X ( 3872 ) → π + π - π 0 J / ψ ] / Γ [ X ( 3872 ) → π + π - J / ψ ] . With the determined parameter range, we find that the estimated ratio $$\Gamma [X(3872) \rightarrow \pi ^0 \chi _{c1}/\Gamma [X(3872) \rightarrow \pi ^+ \pi ^- J/\psi ]$$ Γ [ X ( 3872 ) → π 0 χ c 1 / Γ [ X ( 3872 ) → π + π - J / ψ ] is well consistent with the experimental measurement from the BESIII collaboration. Moreover, the partial width ratio of $$\pi ^0 \chi _{cJ}$$ π 0 χ cJ for $$J=0,1,2$$ J = 0 , 1 , 2 is estimated to be $$1.77{-}1.65:1:1.09{-}1.43$$ 1.77 - 1.65 : 1 : 1.09 - 1.43 , which could be tested by further precise measurements of BESIII and Belle II.

Toward charged $$Z_{cs}(3985)$$ structure under a reflection mechanism

Very recently, the BESIII Collaboration reported a charged hidden-charm structure with strangeness in the recoil mass of $$K^+$$ K + of a process $$e^+e^-\rightarrow D_s^{*-}D^0K^+$$ e + e - → D s ∗ - D 0 K + or $$D_s^{-}D^{*0}K^+$$ D s - D ∗ 0 K + , which is named as $$Z_{cs}(3985)^{-}$$ Z cs ( 3985 ) - . The newly observed charged structure can be treated as a partner structure with strangeness of well-known $$Z_{c}(3885)^{-}$$ Z c ( 3885 ) - reported in a process $$e^+e^-\rightarrow D^{*-}D^0\pi ^+$$ e + e - → D ∗ - D 0 π + . In this work, we propose a reflection picture to understand the nature of $$Z_{cs}(3985)$$ Z cs ( 3985 ) . By performing a combined analysis for the line shape of the recoil mass distribution of $$K^+$$ K + at five energy points $$\sqrt{s}=4.628, 4.641, 4.661, 4.681, 4.698$$ s = 4.628 , 4.641 , 4.661 , 4.681 , 4.698 GeV, we find that the $$Z_{cs}(3985)$$ Z cs ( 3985 ) can be explained as a reflection structure of charmed-strange meson $$D_{s2}^{*}(2573)$$ D s 2 ∗ ( 2573 ) , which is produced from the open-charm decay of Y(4660) with a $$D_s^*$$ D s ∗ meson. Furthermore, we predicted the angular distribution of final state $$D_s^{*-}$$ D s ∗ - in process $$e^+e^-\rightarrow D_s^{*-}D^0K^+$$ e + e - → D s ∗ - D 0 K + based on our proposed reaction mechanism, which may be an essential criterion to test the non-resonant nature of $$Z_{cs}(3985)$$ Z cs ( 3985 ) further.

ON THE SEARCH FOR HADRON MODES OF HIDDEN CHARM MESONS DECAY

From the results obtained in publication [1] as well percentage between decay modes of exitated states of mesons, cited in reference book “Particle Data Group” became possible to evaluate the number of hadron final states on which the meson with hidden charm decay. In the paper is shown a rough estimate of final states number for hadron decays of mesons with hidden charm. The most statistically secured are the final states for ηс (1 S), 2 (π+π-) and π+π- K+K- for χс0 (1P) mesons.