decays, chiral dynamics and OZI violation (original) (raw)

J/\Psi \to \phi \pi \pi (K \bar{K}) decays, chiral dynamcis and OZI violation

arXiv: High Energy Physics - Phenomenology, 2000

We have studied the invariant mass distributions of the \pi\pi and K \bar{K} systems for invariant masses up to 1.2 GeV from the J/\Psi \to \phi \pi\pi(K\bar{K}) decays. The approach exploits the connection between these processes and the \pi\pi and K\bar{K} strange and non-strange scalar form factors by considering the \phi meson as a spectator. The calculated scalar form factors are then matched with the ones from next-to-leading order chiral perturbation theory, including the calculation of the the K\bar{K} scalar form factors. Final state interactions in the J/\Psi \to \phi \pi\pi (K\bar{K}) processes are taken into account as rescattering effects in the system of the two pseudoscalar mesons. A very good agreement with the experimental data from DM2 and MARK-III is achieved. Furthermore, making use of SU(3) symmetry, the S-wave contribution to the \pi^+\pi^- event distribution in the J/\Psi \to \omega \pi^+\pi^- reaction is also given and the data up to energies of about 0.7 GeV...

Improved analysis of J/ψ decays into a vector meson and two pseudoscalars

2006

Recently, the BES collaboration has published an extensive partial wave analysis of experimental data on J/ψ → φπ + π − , J/ψ → ωπ + π − , J/ψ → φK + K − and J/ψ → ωK + K −. These new results are analyzed here, with full account of detection efficiencies, in the framework of a chiral unitary description with coupled-channel final state interactions between ππ and KK pairs. The emission of a dimeson pair is described in terms of the strange and nonstrange scalar form factors of the pion and the kaon, which include the final state interaction and are constrained by unitarity and by matching to the next-to-leading-order chiral expressions. This procedure allows for a calculation of the S-wave component of the dimeson spectrum including the f0(980) resonance, and for an estimation of the low-energy constants of Chiral Perturbation Theory, in particular the large Nc suppressed constants L r 4 and L r 6. The decays in question are also sensitive to physics associated with OZI violation in the 0 ++ channel. It is found that the S-wave contributions to φπ + π − , φK + K − and ωπ + π − given by the BES partial-wave analysis may be very well fitted up to a dimeson center-of-mass energy of ∼ 1.2 GeV, for a large and positive value of L r 4 and a value of L r 6 compatible with zero. An accurate determination of the amount of OZI violation in the J/ψ → φπ + π − decay is achieved, and the S-wave contribution to ωK + K − near threshold is predicted.

Chiral dynamics and the reactions pp↦dK+ and pp↦dπ+η

The European Physical Journal A, 2001

We perform a study of the final-state interactions of the K +K 0 and theK 0 d systems in the reactions pp → dK +K 0 and pp → dπ + η. Since the two-meson system couples strongly to the a0(980) resonance, these reactions are expected to be an additional source of information about the controversial scalar sector. We also show that these reactions present peculiar features which can shed additional light on the much debated meson-baryon scalar sector with strangeness −1. We deduce the general structure of the amplitudes close to the dK +K 0 threshold, allowing for primary K +K 0 as well as π + η production with the two mesons in relative Sor P-wave. The interactions of the mesons are accounted for by using chiral unitary techniques, which generate dynamically the a0(980) resonance, and theK 0 d interaction is also taken into account. General formulae are derived that allow to incorporate the final-state interactions in these systems for any model of the production mechanism. We illustrate this approach by considering two specific production mechanisms based on three flavor meson-baryon chiral perturbation theory. It is demonstrated that in this scenario theK 0 d interactions are very important and can change the crosssection by as much as one order of magnitude. The amount of π + η versus K +K 0 production is shown to depend critically on the primary mixture of the two mechanisms, with large interference effects due to final-state interactions. These effects are also shown to occur in the event distributions of invariant masses which are drastically modified by the final-state interactions of the two-meson or theKd system.

The phi to pi+ pi- decay within a chiral unitary approach

2000

Starting from the Chiral Perturbation Theory Lagrangian, but keeping different masses for the charged and neutral mesons, and using a previously developed non-perturbative unitary scheme that generates the lightest meson-meson resonances, we construct K Kbar to K Kbar and K Kbar to pi+ pi- in the vector channel. This allows us to obtain the kaon-loop contribution to the phi-rho mixing and study the phi to pi+pi- decay. The dominant contribution to this decay comes from the phi to gamma to pi+pi- process. However, there can be large interferences with the subdominant contributions coming from phi-rho and phi-omega mixing, or of these two contributions among themselves. As a consequence, a reliable measurement of phi to pi+pi- decay could be used to differentiate between some phi-omega mixing scenarios proposed in the literature.

A Phenomenological Model for π and K Meson Decays

Progress of Theoretical Physics, 1968

A Phenolucnological Model for 71: and K Meson Decays !(im iaki KONNO lJejJ(lrtmCJI[ oj Physics ([}ld llfolJlic EJlcrp,'Y Research Institute lVi/IOJl Un i'vcrsify, T()/~:vo (!\.(:~ceivl'd September :25, 1~)(;7) j\ phenomenological model for Te-ancll(-meson semi-leptonic decays is proposed. An effective Lagrangian is constructed. This structure i:.; expressed by the effective strong interaction Lagrangian except for one overall coupling constant which characterizes weak interaction. It is found that the strength of weak interaction is smaller than that of strong interacj'ion by an order 10-7 and is also found that the two Cabibbo angles characteristic of the vector (0 f') and axial vector (0. 1) currents arc determined by the pseudovector coupling constants ('" and If(anel ,(j,d[Jv ratios for 7UV and ICV scattering, namely and Ix tan Oel = In-, Ill", lIZ r-c , (II') \ ~A 1{Y tan Uv = tan 0.1' / rJv \ Y~i These relations are cumparecl favorably with experiment. It is predicted that the probability of the strangeness conserving neutral K-l11eson decay, Ko >K-+c: +-J.i e , is two orclers of magnitude lower than that of the Cabihbo theory. Finally, relation of ic-and K-l11eson masses to the coupling constants of strong and weak in teractions is also discussed.

The phi--> pi^+ pi^-and phi radiative decays within a chiral unitary approach

2000

We report on recent results on the decay of the φ into π + π − and φ radiative decays into π 0 π 0 γ and π 0 ηγ, which require the consideration of the final state interaction of a pair of mesons in a region inaccessible to Chiral Perturbation Theory. By using nonperturbative chiral unitary methods for the meson meson interaction we can obtain the corresponding decay widths and the results are compared with recent experimental data. 1 The φ → π + π − decay The φ decay into π + π − is an example of isospin violation. The φ has isospin I = 0, spin J = 1, and hence it does not couple to the π + π − system in the isospin limit, which implies the rule I + J = even. The experimental situation on this decay is rather confusing. There are two older results whose central

Φ→π+π- Decay Within a Chiral Unitary Approach

Physical Review D, 2000

Starting from the Chiral Perturbation Theory Lagrangian, but keeping different masses for the charged and neutral mesons (mu = m d ), and using a previously developed non-perturbative unitary scheme that generates the lightest meson-meson resonances, we construct KK → KK and KK → π + π − in the vector channel. This allows us to obtain the kaon-loop contribution to the φ−ρ mixing and study the φ → π + π − decay. The dominant contribution to this decay comes from the φ → γ → π + π − process. However, there can be large interferences with the subdominant contributions coming from φ − ρ and φ − ω mixing, or of these two contributions among themselves. As a consequence, a reliable measurement of φ → π + π − decay could be used to differentiate between some φ − ω mixing scenarios proposed in the literature.

Towards an effective description for the J/ψ decays

In this work we propose a phenomenological Resonance Chiral Theory inspired vertex J/ψρπ, which is a basic ingredient for a description of the J/ψ phenomenology. This vertex is characterized by only one coupling constant which is computed through the analysis of the J/ψ → γπ 0 decay. Assuming ρ meson dominance we compute the BR(J/ψ → π 0 π + π −), finding a good agreement with the experimental measurement.

Decays KL,S → π0π0γ and KL,S → π0π0e+e− as probes of chiral dynamics

Physics Letters B, 1993

The decays KL,S → π0π0γ are examples of quadrupole transitions (E2 and M2 respectively) which are forbidden in chiral perturbation theory (ChPT) at ). At the same time, the virtual photon amplitude is calculable in ChPT. Using a plausible estimate for the real photon amplitude KL → π0π0γ, we show that the decay rate of KL → π0π0e+e− contains comparable contributions from the E2 and virtual photon mechanisms, and that the two components can be clearly distinguished in the invariant mass spectrum of the e+e− pair.

K+→π+π0 decays on finite volumes and at next-to-leading order in the chiral expansion

Nuclear Physics B, 2003

We present the ingredients necessary for the determination of physical K → ππ decay amplitudes for ∆I = 3/2 transitions, from lattice simulations at unphysical kinematics and the use of chiral perturbation theory at next-to-leading order. In particular we derive the expressions for the matrix elements I=2 ππ|O W |K , where O W is one of the operators appearing in the ∆S = 1 weak Hamiltonian, in terms of low-energy constants at next-toleading order in the chiral expansion. The one-loop chiral corrections are evaluated for arbitrary masses and momenta, both in full QCD and in the quenched approximation. We also investigate the finite-volume effects in this procedure.