ρ-ω mixing in J/ψ→VP decays

The study of ρ-ω mixing has mainly focused on vector meson decays with isospin I = 1, namely theρ(ω)→π+π- process. In this paper, we present a study of ρ-ω mixing in ρ(ω)→π+π-π0(I = 0) using a flavor parameterization model for the J/ψ→VP process. By fitting a theoretical framework to PDG data, we obtain the SU(3)-breaking effect parameters sV = 0.03±0.12, sP = 0.17±0.17 and the ρ-ω mixing polarization operatorΠρω =(0.006±0.011) GeV2. New values are found for the branching ratios when the mixing effect is incorporated:Br(J/ψ→ωπ0)=(3.64±0.37)×10-4, Br(J/ψ→ωη)=(1.48±0.17)×10-3, Br(J/ψ→ωη)=(1.55±0.56)×10-4, these are different from the corresponding PDG2012 values by 19%, 15% and 15%, respectively.     

Nonfactorization and color-suppressedB →ψ(ψ′)+K(K*) decays

Using a value ofa ₂=0.1±0.03 in a formalism which usesN _c =3, we show that one can define an effectivea ₂, which includes the contribution of nonfactorized effects, for color-suppressed decayB→ψK. We determine the magnitude of this effectivea ₂, which is process-dependent and, in general, complex, in certain commonly used models of form factors. We analyze the color-suppressedB→ψK* branching ratio and longitudinal polarization and demonstrate that nonfactorization effects are needed to understand these data in certain commonly used models of form factors. We extend the analysis to color-suppressed decayB→ψ′K*, whereψ′=ψ(2S), and color-favored decay $\bar B^0 \to D^{* + } \rho ^ - $ where we demonstrate that factorization scheme works well.     

Long distance effects inb→s exclusive decays

We estimate long distance corrections to radiativeB →K ^*γ and to non leptonicB→Kπ,B→K ^*π,B→Kσ,B→K ^*σ,B→KΦ andB→K ^*Φ decays generated by the ( \(\overline b\) c) ( \(\overline c\) s) part of the non leptonic weak Hamiltonian. While vanishing in the vacuum saturation approximation, these corrections are finite if one includes single particle charmed states between the currents in the Hamiltonian. We find small effects in radiative decays, but significant contributions to several non leptonic processes.     

Study of C parity violating and strangeness changing J/ψ→PP weak decays

Although J/ψ weak decays are rare,they are possible within the standard model of elementary particles.Inspired by the potential prospects of the future intensity frontier,the C parity violating J/ψ→πη~((')),ηη' decays and the strangeness changing J/ψ→πK,Kη~((')) decays are studied via the perturbative QCD approach.It is determined that the J/ψ→ηη' decays have relatively large branching ratios,approximately on the order of 10~(-11),which might be within the measurement capability and sensitivity of the future STCF experiment.     

Properties of the coupling constants of J/ψ→VP decays

Based on the branching fractions of J/ψ→VP from different experiments, we investigate the properties of the coupling constants of J/ψ→VP decays using a model-dependent approach. We find that the octet coupling constant, g8, of strong interaction is about twice larger than that of the singlet coupling constant g₁; the electromag- netic breaking parameters g_Eⁱ are larger than the mass breaking parameters g_Mⁱ, moreover, the three parameters of the electromagnetic effect are about equal, but the three parameters of the mass effect are obviously different and their uncertainties are also large; and the phase angle between strong and electromagnetic interactions is in the range of 70°-80°. It deepens our understanding of the coupling constant of J/ψ→VP decays.     

Partial wave analysis ofJ/ψ）→ppπ0 and measurement of J/ψ→ppη,ppη＇

Based on 58 million J/ψ data collected with the BESII detector at the BEPC, Partial Wave Analysis（PWA） is performed on J/ψ→ppπ0. The new excited baryon N（2065） is confirmed. Clear signals for other N＊ states are observed and the corresponding masses, widths and spin-parity are also measured. Processes such as J/ψ→ppη,ppη＇
are also studied and the branching ratios are measured.     

Role of hyperfine mixing in b→c semileptonic decays of doubly-heavy baryons

We analyze the effects of hyperfine mixing in b → c semileptonic decays of doubly heavy baryons.We qualitatively confirm the results by W.Roberts and M.Pervin in Int.J.Mod.Phys.A,2009,24： 2401– 2413,finding that mixing has a great impact on those transitions.However,predictions without mixing differ by a factor of 2 and this discrepancy translates to the mixed case where large differences in decay widths are observed between the two calculations.     

Role of hyperfine mixing in b→c semileptonic decays of doubly-heavy baryons

We analyze the effects of hyperfine mixing in b → c semileptonic decays of doubly heavy baryons.We qualitatively confirm the results by W.Roberts and M.Pervin in Int.J.Mod.Phys.A,2009,24: 2401– 2413,finding that mixing has a great impact on those transitions.However,predictions without mixing differ by a factor of 2 and this discrepancy translates to the mixed case where large differences in decay widths are observed between the two calculations.     

Electromagnetic effects and scattering lengths extraction from experimental data on K → 3π decays

The final state interactions in K ^± → π^±π⁰π⁰ decays are considered using the methods of nonrelativistic quantum mechanics. It is shown how to take into account the largest electromagnetic effect in the analysis of experimental data using the amplitudes calculated earlier. The relevant expressions for amplitude corrections valid both above and below the two charged pions production threshold , including the average effect for the threshold bin, are proposed. These formulae can be used in the procedure of pion scattering lengths measurement from spectrum. The text was submitted by the authors in English.     

The S-D mixing and dielectron widths of higher charmonium 1−− states

The dielectron widths of ψ(4040), ψ(4160), and ψ(4415), and their ratios are shown to be in good agreement with experiment, if in all cases the S-D mixing with a large mixing angle θ ≅ 34° is taken. Arguments are presented why continuum states give small contributions to the wave functions at the origin. We find that the Y (4360) resonance, considered as a pure 3 ³ D ₁ state, would have very small dielectron width, Γ _ee (Y (4360)) = 0.060 keV. On the contrary, for large mixing between the 4 ³ S ₁ and 3 ³ D ₁ states with the mixing angle θ = 34.8°, Γ _ee (ψ(4415)) = 0.57 keV coincides with the experimental number, while a second physical resonance, probably Y (4360), has also a rather large Γ _ee (Y (∼4400)) = 0.61 keV. For the higher Y (4660) resonance, considered as a pure 5 ³ S ₁ state, we predict the dielectron width Γ _ee (Y (4660)) = 0.70 keV, but it becomes significantly smaller, namely 0.31 keV, if the mixing angle between the 5 ³ S ₁ and 4 ³ D ₁ states has the characteristic value θ = 34°. The mass and dielectron width of the 6 ³ S ₁ charmonium state are calculated. The text was submitted by the authors in English.     

General properties of the polarization effects in the decays A→B+ℓ++ℓ−

The general structure is obtained of the polarization effects for the single-photon mechanism in the decays AB+⁺+^–.This structure takes into account possible violations of the P- and T-invariances in the electromagnetic interaction of hadrons. Use is made only of the principal properties of the electrodynamics of hadrons, such as the conservation of the hadronic electromagnetic current and the symmetry properties of the current under spatial and temporal reflections.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 87–91, April, 1987.     

Cabibbo-angle-favored decays:D→SP

We have studiedD→K ₀ ^* π andD→Ka ₀ decays in the factorization approximation. The spectator model leads to a color-suppression of \(D^0 \to \bar K_0^{*0} \pi ^0 \) . However, due to the smallness off _{a 0}, a similar suppression does not occur for \(D^0 \to \bar K^0 a_0^0 \) . We show that the inclusion of annihilation contribution can lift the color-suppression of \(D^0 \to \bar K_0^{*0} \pi ^0 \) . We also include final state interactions in a dynamical model whereK (1830) pole in the direct channel dominates the annihilation process.     

Rescattering and electroweak penguin effects in strategies to constrain and determine the CKM angle γ from B → πK decays

A general parametrization of the B ⁺ → π ⁺ K ⁰ and B _d ⁰ → π ⁻ K ⁺ decay amplitudes is presented. It relies only on the isospin symmetry of strong interactions and the phase structure of the Standard Model and involves no approximations. In particular, this parametrization takes into account both rescattering and electroweak penguin effects, which limit the theoretical accuracy of bounds on γ arising from the combined B ^+- → π ^+- K, B _d → π ^∓ K ^± branching ratios. Generalized bounds making also use of the CP asymmetry in the latter decay are derived, and their sensitivity to possible rescattering and electroweak penguin effects is investigated. It is pointed out that experimental data on B ^± → K ^± K allow us to include rescattering processes in these bounds completely, and an improved theoretical treatment of electroweak penguins is presented. It is argued that rescattering effects may enhance the combined B ^± → K ^± K branching ratio by a factor of O(10) to the 10⁻⁵ level, and that they may be responsible for the small present central value of the ratio of the combined B _d → π ^∓ K ^± and B ^± → π ^± K branching ratios, which has recently been reported by the CLEO collaboration and, if confirmed, would exclude values of γ within a large region around 90°.     

D~0-~0 mixing and other charm decays at Belle

The D0-0 mixing at Belle in different modes with corresponding methods is reported in this paper,there is a clear evidence for non-zero y D0 mixing parameter,and the measurement of D0 mixing parameter x is still a challenge.CP violation in the decays is not observed.Branching fractions of other charm decays are presented.     

B→（J/ψ,η_c）K decays in the perturbative QCD approach

In this paper,we calculated the B →（J/ψ,ηc） K decays in the perturbative QCD（pQCD） factorization approach with the inclusion of the partial next-to-leading order（NLO） contributions. With the inclusion of the significant enhancement from the NLO vertex corrections,the NLO pQCD predictions for the branching ratios agree with the data within 2σ errors：Br（B0 → J/ψK0） = 5.2-＋32..58×10-4,Br（B＋ → J/ψK＋） = 5.6-＋32..79×10-4,Br（B0 →ηcK0） = 5.5-＋22..30 × 10-4,Br（B＋ →ηcK＋） = 5.9-＋22..51 × 10-4.     

CP violation and strong phases from penguins in B±→PP and B±→VP decays

We calculate direct CP-violating rate asymmetries in chargedB→PP andB→VP decays arising from the interference of amplitudes with different strong and CKM phases. The perturbative strong phases develop at order α _s from absorptive parts of one-loop matrix elements of the next-to-leading logarithm corrected effective Hamiltonian. CPT constraints are maintained. Based on this model, we find that partial rate asymmetries between charge conjugateB ^± decays can be as high as 20% for certain channels with branching ratios in the 10^?6 range. Because the $c\bar c$ threshold lies so close to the physical momentum scale, the asymmetries depend sensitively on the model assumptions used to evaluate the imaginary parts of the matrix elements, in particular, on the internal momentum transfer. The charge asymmetries of partial rates would provide unambiguous evidence for direct CP violation.