We present in this talk recent investigations on the nucleon-like resonance N*(1675) newly found in eta photoproduction by the GRAAL, Tohoku LNS-gamma and CB-ELSA collaborations. We focus on the production mechanism of the N*(1675), examining its spin and parity theoretically within the framework of the effective Lagrangian method. We expliucitly consider D_{13}(1520), S_{11}(1535), S_{11}(1650), D_{15}(1675), P_{11}(1710), P_{13}(1720) as well as possible background contributions. We calculate the differential cross sections and beam asymmetries for the neutron and proton targets. It turns out that there is manifest isospin asymmetry in eta photoproduction, which can be explained by the asymmetry in the transition magnetic moments: mu_{gamma p p*} =<mu_{gamma n n*}. Moreover, we find that the spin-1/2 state is preferred and this observation implies that the new resonance may be identified as a non-strangeness member of the baryon antidecuplet.
We discuss the sensitivity of eta and eta' photoproduction near threshold to the gluonic OZI breaking parameters in the U_A(1)-extended effective chiral Lagrangian for low-energy QCD. Our coupled-channels analysis hints at a strong correlation between the gluon-induced contributions to the eta' mass and the low-energy pp -> pp eta' reaction and the near-threshold behaviour of the gamma p -> eta p cross-section.
We examine eta prime photoproduction, as a novel tool to study baryon resonances around 2 GeV, of particular interest to the quark shell model, which predicts a number of them. We find important roles of the form factors at the strong vertices, and show that the N^*(2080) can be probed efficiently by this reaction.
The results of linear regresion of differential cross sections, $Σ$- and $T$-asymmetries of $η$-photoproduction on protons in energy region from threshold up to 1 GeV are presented. Serious contradictions between angular distributions measured in different laboratories are revealed. The energy dependance of regression coefficients may be due to transition from energy region of $S_{11}(1535)$ and $D_{13}(1520)$ to energy region of $D_{15}(1675)$ and $F_{15}(1680)$ resonances.
We identify the leading s-wave amplitudes of the SU(3) chiral meson-baryon Lagrangian with an effective coupled-channel potential which is iterated in a Lippmann-Schwinger equation. The strangeness $S=-1$ resonance $Λ(1405)$ and the $S_{11}(1535)$ nucleon resonance emerge as quasi-bound states of anti-kaon/nucleon and kaon/$Σ$-hyperon. Our approach to meson photoproduction introduces no new parameters. By adjusting a few finite range parameters we are able to simultaneously describe a large amount of low energy data. These include the cross sections of $K^-p$ elastic and inelastic scattering, …
We investigate the eta photoproduction using the effective Lagrangian approach at the tree level. We focus on the new nucleon resonance N*(1675), which was reported by the GRAAL, CB-ELSA and Tohoku LNS, testing its possible spin and parity states theoretically (J^P=1/2^+-,3/2^+-). In addition, we include six nucleon resonances, D_13(1520), S_11(1535), S_11(1650), D_15(1675), P_11(1710), P_13(1720) as well as the possible background contributions. We calculate various cross sections including beam asymmetries for the neutron and proton targets. We find noticeable isospin asymmetry in transition…
The reaction $γN \to ηN$ is studied in the high-energy regime (with photon lab energies $E_γ^{\textrm{lab}} > 4$ GeV) using information from the resonance region through the use of finite-energy sum rules (FESR). We illustrate how analyticity allows one to map the t-dependence of the unknown Regge residue functions. We provide predictions for the energy dependence of the beam asymmetry at high energies.
The importance of Born terms and resonance exchange for eta and eta-prime photoproduction off both the proton and neutron within U(3) baryon chiral perturbation theory is investigated. Low-lying resonances such as the vector mesons and J^P= 1/2^+, 1/2^- baryon resonances are included explicitly and their contributions together with the Born terms are calculated. The coupling constants of the resonances are determined from strong and radiative decays. We obtain reasonable agreement with experimental data near threshold.
Pronounced effects due to final state hyperon-nucleon interaction are predicted in strangeness photoproduction reaction on the deuteron. Use is made of the covariant reaction formalism and the P- matrix approach to the hyperon-nucleon interaction.
We analyze the $γp \to ηp$ process from threshold up to 1.2 GeV, employing an effective Lagrangian approach that allows for a mixing of eta couplings of pseudoscalar and pseudovector nature. The mixing ratio of the couplings may serve as a quantitative estimation of the $SU_L(3)\times SU_R(3)$ extended chiral symmetry violation in this energy regime. The data analyzed (differential cross sections and asymmetries) show a preference for the pseudoscalar coupling -- 91% of pseudoscalar coupling component for the best fit. We stress that a more conclusive answer to this question requires a more co…
The isobar model EtaMAID has been updated with new and high precision data for eta and etaprime photoproduction on protons and neutrons from MAMI, ELSA, GRAAL and CLAS. The background is described in a recently developed Regge-cut model, and for the resonance part the whole list of nucleon resonances has been investigated with 21 N* states contributing to eta photoproduction and 12 N* states contributing to etaprime photoproduction. A new approach is discussed to avoid double counting in the overlap region of Regge and resonances. A comparison is done among four newly updated partial waves ana…
We consider photoproduction of $ω$ mesons off complex nuclei to study interactions of transversely and longitudinally polarized vector mesons with nucleons. Whereas the total cross section for interactions of the transversely polarized vector mesons with nucleons $σ_T=σ(V_TN)$ can be obtained from coherent photoproduction, measurements of vector meson photoproduction in the incoherent region provide a unique opportunity to extract the total cross section for longitudinally polarized mesons interacting with nucleons $σ_L=σ(V_LN)$, which has not yet been measured and strongly depends on theoreti…
Using J/psi and open charm photoproduction data, we apply the vector meson dominance model to obtain constraints on the energy dependence of the inelastic J/psi-nucleon cross section. Predictions of short distance QCD are in accord with these constraints, while recently proposed hadronic models for J/psi dissociation strongly violate them.
We derive an analytic expression for the Kroll-Ruderman amplitude up to the order 1/N_C for general Skyrme-type models of the nucleon. Due to the degeneracy of intermediate N- and Delta-states we find deviations from the standard low-energy theorem for the photoproduction of neutral pions.
Photo- and electroproduction of eta, eta-prime mesons on protons are investigated within a relativistic chiral unitary approach based on coupled channels. The s wave potentials for electroproduction and meson-baryon scattering are derived from a chiral effective Lagrangian which includes the eta-prime as an explicit degree of freedom and incorporates important features of the underlying QCD Lagrangian such as the axial U(1) anomaly. The effective potentials are iterated in a Bethe-Salpeter equation and cross sections for eta, eta-prime photo- and electroproduction from protons are obtained. Th…
The photo- and electroproduction of eta, eta-prime mesons on nucleons are investigated within a relativistic chiral unitary approach based on coupled channels. The s-wave potentials for electroproduction and meson-baryon scattering are derived from a chiral effective Lagrangian which includes the eta-prime as an explicit degree of freedom and incorporates important features of the underlying QCD Lagrangian such as the axial U(1) anomaly. The effective potentials are iterated in a Bethe-Salpeter equation and cross sections for eta, eta-prime photo- and electroproduction from nucleons are obtain…
Using short distance QCD methods based on the operator product expansion, we calculate the $J/ψ$ photoproduction cross section in terms of the gluon distribution function of the nucleon. Comparing the result with data, we show that experimental behaviour of the cross section correctly reflects the $x$-dependence of the gluon distribution obtained from deep inelastic scattering.
Recently obtained polarized target and photon asymmetry data in eta photoproduction are shown to be very powerful, in conjunction with the differential cross-section data, in yielding model-insensitive constraints on the electrostrong parameters for the excitation and decay of the $N^{*}(1520)$ resonance. The extracted ratio of its electromagnetic helicity amplitudes, $A_{3/2}/A_{1/2}$, provides a critical test for the QCD-inspired hadron models.
Two new sum rules are derived relating Dirac radii and anomalous magnetic moments of the considered strongly interacting fermions with the convergent integral over a difference of the total proton and neutron, as well as $He^3$ and $H^3$, photoproduction cross-sections.
Pion-photoproduction data is examined to check for the nucleon-helicity conservation predicted by asymptotic QCD. The differential cross section shows agreement with constituent-counting rules, and polarization data is not in disagreement with conservation of nucleon helicity. However large uncertainties in the polarization measurements do not allow a conclusive statement. The helicity amplitudes from a partial-wave analysis are also examined for helicity conservation. While the amplitudes become small as $s$ increases, the $s$ dependence of the helicity-conserving amplitudes is similar to the…
Pion electro- and photoproduction off the nucleon close to threshold is studied in covariant baryon chiral perturbation theory at O($p^3$) in the extended-on-mass-shell scheme, with the explicit inclusion of the $Δ(1232)$ resonance. The relevant low energy constants are fixed by fitting the available experimental data with the theoretical model. The inclusion of the $Δ$ resonance as an explicit degree of freedom substantially improves the agreement with data and the convergence of the model.
We present a detailed phenomenological study of photoproduction of two hadrons, both with high transverse momentum, in longitudinally polarized lepton-nucleon collisions. We consistently include ``direct'' and ``resolved'' photon contributions and examine the sensitivity of the relevant spin asymmetries to the gluon polarization in the nucleon and to the completely unknown parton content of circularly polarized photons. Our results are relevant for the COMPASS and HERMES fixed-target experiments as well as for a possible future polarized lepton-proton collider like eRHIC at BNL. So far, all st…
At moderate and large momentum transfer, high energy vector meson photoproduction and Compton scattering can be consistently explained by mechanisms based on interactions and exchanges of constituent quarks and gluons. This opens an original window on the partonic structure of hadronic matter by emphasizing the role of quark correlations, quark exchange as implemented through saturating Regge trajectories and non-perturbative effects in the gluon propagator, which provides us with a bridge with lattice calculations. Compton scattering is directly related to vector meson photoproduction and enl…
We analyse data on forward eta-meson photoproduction off a proton target and extract the eta to gamma gamma decay width utilizing the Primakoff effect. The hadronic amplitude that enters into our analysis is strongly constrained because it is fixed from a global fit to available gamma p to p eta data for differential cross sections and polarizations. We compare our results with present information on the two-photon eta-decay from the literature. We provide predictions for future PrimEx experiments at Jefferson Laboratory in order to motivate further studies.
Recent data on eta-meson photoproduction off a proton target in the energy range 2 < sqrt{s} < 3 GeV are analyzed with regard to their overall consistency. Results from the ELSA and CLAS measurements are compared with predictions of a Regge model whose reaction amplitude was fixed via a global fit to pre-2000 measurements of differential cross sections and polarization observables for gamma p -> eta p at higher energies. We find that all recent experimental results on differential cross sections for eta-meson photoproduction are in good agreement with each other, except for the CLAS data from …
The $ηN$ final state is isospin-selective and thus provides access to the spectrum of excited nucleons without being affected by excited $Δ$ states. To this end, the world database on eta photoproduction off the proton up to a center-of-mass energy of $E\sim 2.3$ GeV is analyzed, including data on differential cross sections, and single and double polarization observables. The resonance spectrum and its properties are determined in a combined analysis of eta and pion photoproduction off the proton together with the reactions $πN\to πN$, $ηN$, $KΛ$ and $KΣ$. For the analysis, the so-called Jüli…
We consider the photoproduction of secondary mesons in the framework of the Quark-Gluon String model. At relatively low energies, not only cylindrical, but also planar diagrams have to be accounted for. To estimate the significant contribution of planar diagrams in gamma-p collisions at rather low energies, we have used the expression obtained from the corresponding phenomenological expression for pi-p collisions. The results obtained by the model are compared to the existing SLAC experimental data. The model predictions for light meson production at HERMES energies are also presented.
Gluonic degrees of freedom play an important role in the masses of the eta and etaprime mesons. We discuss eta- and etaprime-nucleon and nucleus interactions where this glue may be manifest. Interesting processes being studied in experiments are etaprime production in proton-nucleon collisions close to threshold and possible eta-nucleus bound-states.
The questions on the presense and quantitative role of the constant terms in the real part of the high-energy photon-nucleon and photon-nucleus amplitudes representing the contribution of the non-Regge (the fixed j=0-pole) singularities in the finite-energy sum rules (FESR) for the photoabsorption cross sections on nucleons and the lightest atomic nuclei are discussed and new testable relations are presented for relevant combinations of the Compton scattering amplitudes.
We investigate K*Λ(1116) photoproduction off the proton and neutron targets in the effective Lagrangian method in the tree-level Born approximation. In addition to the K, K*, and κ exchanges which are the main contributions to the reaction, we consider the contributions from the higher nucleon resonances D13(2080) and the D15(2200). We find that the D13(2080) plays a crucial role in explaining the enhancement of the near-threshold production rate, which results in a good agreement with the experimental data for the proton targets, while the contribution of the D15(2200) is rather small. A simi…
We study the effects of the $Δ$(1232) resonance as an effective degree of freedom for charged and neutral pion photo-production on nucleons. Different observables have been calculated for these processes by using relativistic chiral perturbation theory up to $\mathcal{O}(p^3)$ in the $ δ$ counting, thus, including pion loops. We compare our model with a large database containing the available experimental data and constrain some unknown low energy constants.
We acknowledge a paper on the same subject by other authors, that we didn't have the chance to cite in our work. A few comments on the content of the two papers are made.
Pion photoproduction off the nucleon close to threshold is studied in covariant baryon chiral perturbation theory at O($p^3$) in the extended-on-mass-shell scheme, with the explicit inclusion of the $Δ(1232)$ resonance using the $δ$ counting. The theory is compared to the available data of cross sections and polarization observables for all the charge channels. Most of the necessary low energy constants are well known from the analysis of other processes and the comparison with data strongly constrains some of the still unknown ones. The $Δ(1232)$ contribution is significant in improving the a…
Using the recent precise measurements of eta photopro- duction in proton and deuteron targets, we extract the ratio of the helicity amplitudes A^n_1/2 / A^p_1/2, for the excitation of N^*(1535), in the effective Lagrangian approach, It is fairly model-independent, free from the final-state interaction effects, and negative as predicted by the quark models. We stress the importance of polarization observables in further elucidation of the N^*(1520) photoexcitation amplitudes.
We present a new version of the EtaMAID model for $η$ and $η'$ photoproduction on nucleons. The model includes 23 nucleon resonances parameterized with Breit-Wigner shapes. The background is described by vector and axial-vector meson exchanges in the $t$ channel using the Regge cut phenomenology. Parameters of the resonances were obtained from a fit to available experimental data for $η$ and $η'$ photoproduction on protons and neutrons. The nature of the most interesting observations in the data is discussed.
We derive the effective chiral Lagrangian for low energy eta--nucleon and eta'--nucleon interactions and show that gluonic degrees of freedom, via the axial anomaly, induce a contact term in the pp -> pp eta and pp -> pp eta' reactions. We then discuss the consequences for the extraction of g_{eta'NN} from experimental data.
Coupling constants of $η$ and $η^{\prime}$ mesons with nucleons have been calculated using the method of QCD sum rules. Starting from vacuum-to-meson correlation function of interpolating fields of two nucleons, its matrix element with respect to nucleon spinors has been considered. Coupling constants at the physical points have been estimated from extrapolation of results obtained at two other points. Anomalous glue has been found to give substantial contribution to the coupling constants and also accounts for a significant OZI-rule violation.
We summarize what is known about the transverse spatial distribution of gluons in the nucleon and its x-dependence from exclusive J/psi photo/electroproduction in e-p fixed-target and collider experiments (HERA H1 and ZEUS). This information can be used to predict the impact parameter dependence of the cross section for certain hard QCD processes (dijet production) in pbar-p and p-p collisions at the Tevatron and LHC.
We analyse photoproduction of eta mesons off the proton in a gauge-invariant chiral unitary framework. The interaction kernel for meson-baryon scattering is derived from the leading order chiral effective Lagrangian and iterated in a Bethe-Salpeter equation. The recent precise threshold data from the Crystal Ball at MAMI can be described rather well and the complex pole corresponding to the S11(1535) is extracted. An extension of the kernel is also discussed.
A reggeized model for ηand η' photoproduction on the nucleon is presented. In this model, t-channel vector meson exchanges are described in terms of Regge trajectories to comply with the correct high energy behavior. We compare this reggeized model with an isobar model (η-MAID), where the t-channel exchanges are described by ρand ωpoles. Both models contain the same resonance contributions, and describe current γp \to ηp data up to E_γ^{lab} = 2 GeV quite well, but only the reggeized model can be successfully extended to higher energies. For the γp \to η' p reaction, the reggeized model is fou…
The couplings of the eta and eta' mesons to the nucleon are obtained from the U_A(1) Goldberger-Treiman relation. The chiral symmetry breaking corrections are very large and bring the calculated values of the coupling constants G_etaNN and G_eta'NN close to values obtained from potential models.
We argue that the t-dependence of the two-gluon form factor of the nucleon should be given by $Γ(t)=(1-t/m_{2g}^2)^{-2}$ with $m_{2g}^2\approx 1 GeV^2$. We demonstrate that this form provides a good description of the t-dependence of the cross section of the elastic photoproduction of $J/ψ$-mesons between the threshold region of $E_γ=11 GeV$ (Cornell), $E_γ=19 GeV$ (SLAC) and $E_γ=100 GeV$ (FNAL) including the strong energy dependence of the t-slope. It is also well matched with the recent HERA data. The same assumption explains also the t-dependence of $ϕ$-meson electroproduction near thresho…
We consider the production of a lepton-antilepton pair by real photons off a hadronic target. The interference of one and two photon exchange amplitudes leads to a charge asymmetry term that may be calculated explicitly in the large-t limit in terms of hadronic distribution amplitudes. A rather compact expression emerges for the leading order asymmetry at fixed angle in the centre-of-mass of the lepton pair. The magnitude appears sizeable and is approximately independent of the pair mass in the asymptotic limit.
Revised analysis of $Σ$ beam asymmetry for $η$ photoproduction on the free proton reveals a resonant structure at $W\sim 1.69$ GeV. Comparison of experimental data with multipole decomposition based on the E429 solution of the SAID partial wave analysis and including narrow states, suggests a narrow ($Γ\leq 15$ MeV) resonance. Possible candidates are $P_{11}$, $P_{13}$, or $D_{13}$ resonances. The result is considered in conjunction with the recent evidence for a bump-like structure at $W\sim 1.67 - 1.68$ GeV in quasi-free $η$ photoproduction on the neutron.
The polarization observables in phi photoproduction are suggested for probing the nucleon strangeness. Based on models for phi photoproduction, some double polarization observables are shown to be very sensitive to the strangeness content of the proton because of the different spin structures of the amplitudes associated with different mechanisms.
In this paper, we develop a general framework to study the meson-photoproductions of nucleons in the chiral quark model. The S and U channel resonance contributions are expressed in terms of the Chew-Goldberger-Low-Nambu (CGLN) amplitudes. The kaon-photoproduction processes, $γp\to K^+ Λ$, $γp\to K^+ Σ^0$, and $γp\to K^0Σ^+$, are calculated. The initial results show that the quark model provides a much improved description of the reaction mechanism for the kaon-photoproductions of the nucleon with less parameters than the traditional phenomenological approaches.
Revised analysis of Sigma beam asymmetry for eta photoproduction off the free proton from GRAAL is presented. New analysis reveals a narrow structure near W ~1.685 GeV. We describe this structure by the contribution of a narrow resonance with quantum numbers P_{11}, or P_{13}, or D_{13}. Being considered together with the recent observations of a bump-like structure at W~1.68 GeV in the quasi-free eta photoproduction off the neutron, this result provides an evidence for a narrow (Gamma < 25 MeV) N*(1685) resonance. Properties of this possible new nucleon state, namely the mass, the narrow widt…
By using the Gerasimov-Drell-Hearn (GDH) sum rule and an isobaric model of kaon photoproduction, we calculate contributions of kaon-hyperon final states to the magnetic moment of the proton and the neutron. We find that the contributions are small. The approximation of sigma_{TT'} by sigma_{T} clearly overestimates the value of the GDH integral. We find a smaller upper bound for the contributions of kaon-hyperon final states to the proton's anomalous magnetic moment in kaon photoproduction, and a positive contribution for the square of the neutron's magnetic moment.
Final state hyperon-nucleon interaction in strangeness photoproduction of the deuteron is investigated making use of the covariant reaction formalism and the P-matrix approach to the YN system. Remarkably simple analytical expression for the amplitude is obtained. Pronounced effects due to final state interaction are predicted including the manifestation of the 2.13 GeV resonance.
The role of the nucleon resonances ($N^*$) in $ω$ photoproduction is investigated by using the resonance parameters predicted by Capstick and Roberts. The contributions from the nucleon resonances are found to be significant in various spin asymmetries. In particular, we found that a crucial test of our predictions can be made by measuring the parity asymmetry and beam-target double asymmetry at forward scattering angles.
We analyze the $γN\toπN$ process in the negative parity channel with Hamiltonian effective filed theory which is successful in studying the nucleon resonances associated with the meson-nucleon scattering and lattice QCD simulations. We provide the scattering amplitude of pion photoproduction and extract the electric dipole amplitudes $E_{0+}$. The triquark component in $N^*(1535)$ is important for improving the consistence between our results and the experimental data.
We claim that a narrow peak in the cross section near 1685~MeV in the $γn\to ηn$ channel can be explained through a peculiar radial behaviour of the $p$-wave quark states with $j=1/2$ and $j=3/2$ in the low lying S11 resonances and the opening of the $KΣ$ threshold rather than by an exotic resonance. We explain the mechanism of its formation in the framework of a coupled channel formalism which incorporates quasi-bound quark-model states corresponding to the two low lying resonances in the S11 partial wave. A relation to the Single Quark Transition Model is pointed out.
We investigate the $η'$ photoproduction off the nucleon with a particular interest in the effect of the final-state interaction (FSI) of the $η'$ meson and nucleon $(η'N)$ based on three-flavor linear sigma model. We find an enhancement in the cross section of the $η'$ photoproduction near the $η'N$-threshold energy owing to the $η'N$ FSI. With the $η'$ meson at forward angles, the energy dependence near the $η'N$ threshold is well reproduced with the $η'N$ FSI. The cross section at backward angles can also be a good probe to investigate the strength of the $η'N$ interaction.
It is shown that within a truncated partial wave analysis for photoproduction of two pseudoscalar mesons, it is possible to halve the number of independent partial amplitudes by taking into account parity conservation. In addition, within the framework of the proposed formalism, one can rather easily resolve the double discrete ambiguity arising from the symmetry under complex conjugation of the helicity amplitudes. This leads to essential simplifications of the complete experiment problem, at least as far as mathematical aspects are concerned.
The role of the nucleon resonances in the double polarization observables of pion photoproduction is investigated by using the resonance parameters predicted by Capstick and Roberts. As an example, we show that the not-well-determined two-star resonance N$^{-}_{3/2}$(1960) can be examined by performing experiments on beam-recoil polarization at large angles.
The new experimental data of kaon photoproduction on the nucleon, gamma p -> K+ Lambda, have been analyzed by means of a multipoles model. Different from the previous models, in this analysis the resonance decay widths are constrained to the values given by the Particle Data Group (PDG). The result indicates that constraining these parameters to the PDG values could dramatically change the conclusion of the important resonances in this reaction found in the previous studies.
We study the photoproduction of $K^*(892)$ vector meson from both the charged and neutral reactions, $γp \to K^{*+} Λ$ and $γn \to K^{*0} Λ$. The production mechanisms that we consider include $t$-channel $K^*$, $K$, $κ$ exchanges, s-channel nucleon diagram, and $u$-channel $Λ$, $Σ$, $Σ^*$ diagrams. These could constitute important backgrounds for future investigation of ``missing'' resonances that can be searched for especially in these reactions. The $t$-channel $K$ meson exchange is found to dominate both reactions. The total and differential cross sections are presented together with some …
We investigate photoproduction of eta mesons off protons and neutrons within a coupled-channels effective-Lagrangian method which is based on the K-matrix approach. The two-body final channels included are pi-N, eta-N, phi-N, rho-N, gamma-N, K-Lambda, and K-Sigma. Non-resonant meson-baryon interactions are included in the model via nucleon intermediate states in the s- and u-channels, meson exchanges in the t-channel amplitude and the u-channel resonances. The nucleon resonances S_{11}(1535), S_{11}(1650), S_{31}(1620), P_{11}(1440), P_{11}(1710), P_{13}(1720), P_{33}(1232), P_{33}(1600), D_{1…
New kaon photoproduction data on a proton, gamma + p --> K+ + Lambda, are analyzed using a multipole approach. The background terms are given in terms of gauge invariant, crossing symmetric, Born diagrams with hadronic form factors, while the resonances are parameterized using Breit-Wigner forms. Preliminary results suggest a number of new resonances, as predicted by many quark model studies. A comparison between the extracted multipoles and those obtained from KAON-MAID is presented.
In two meson photoproduction off a nucleon, for the case in which two of the three final state hadrons are products of the decay of an intermediate resonance, general expressions for its decay distribution and for polarization observables are derived in a model independent way. These are functions of either the spin density matrix elements (SDME's) or statistical tensors of the resonance, and the angles of its decay products. The expressions are general enough that it also describes cases where more than one resonance of arbitrary quantum numbers contributes, including interference effects. Th…
