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D. Ryabchikov

Publications and source records attributed to D. Ryabchikov.

4 recordsLinked to original sources

Resolving ambiguities in model-independent partial-wave analysis of three-body decay

Partial wave analysis is an important tool for analyzing large data sets in hadronic decays of light and heavy mesons. It commonly relies on the isobar model, which assumes multihadron final states originate from successive two-body decays of well-known undisturbed intermediate states. Recently, analyses of heavy-meson decays and diffractively produced states have attempted to overcome the strong model dependences of the isobar model. These analyses have overlooked that model-independent, or freed-isobar, partial-wave analysis can break the orthogonality of partial waves and introduce mathematical ambiguities into results. We show how these ambiguities arise and present general techniques for identifying their presence and for correcting for them. We demonstrate these techniques with specific examples in both heavy-meson decay and pion--proton scattering.

hep-ph

Resonances of the systems π-ηand π-η' in the reactions π-p --> π-ηp and π-p --> π-η' p at COMPASS

We describe partial-wave analyses of the systems π-ηand π-η' produced in interactions of a π- beam (190 GeV/c) with a liquid hydrogen target. The data were recorded during the 2008 COMPASS run, where a slow recoiling proton (|t|>0.1 GeV^2) was required by the trigger. We compare analyses of the π-ηand π-η' data. Significant contributions can be attributed to the resonances a_2(1320), observed in the D_+-wave, and a_4(2040), observed in the G_+-wave. Between the two systems, we find similar compositions of the even partial waves D_+ and G_+ after taking phase-space factors into account, but a much enhanced P_+-wave in π-η'. Relative phase-differences indicate a large incoherent contribution of in the P_+-wave of the η'π- system, but other interpretations are not excluded. The known resonances a_2(1320), a_4(2040) and their parameters could be extracted from the data; their branchings are found to roughly agree with predictions from ηη' mixing.

hep-ex

Search for $f_1(1285) \to π^+π^-π^0$ decay with VES detector

The isospin violating decay $f_1(1285)\toπ^+π^-π^0$ has been studied at VES facility. This study is based at the statistics acquired in $π^- Be$ interactions at 27, 36.6 and 41 GeV/c in diffractive reaction $π^- N \to (f_1 π^-) N$. The $f_1(1285) \to π^+π^-π^0$ decay is observed. The ratio of decay probabilities $BR(f_1(1285) \to π^+π^-π^0)$ to $BR(f_1(1285) \to ηπ^+π^-) \cdot BR(η\to γγ)$ is $\sim\:1.4%$.

hep-ex

Study of $η'\toηπ^+π^-$ Dalitz plot

Dalitz plot of the $η' \to ηπ^+π^-$ decay is studied using the data collected with the VES spectrometer in two different exclusive reactions. The coefficients for the matrix element squared decomposition are measured on the largest statistics of $η'$ decays reported so far.

hep-ph