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Register a new userProperties of baryon resonances from a multichannel partial wave analysis
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Properties of nucleon and $Delta$ resonances are derived from a multichannel partial wave analysis. The statistical significance of pion and photo-induced inelastic reactions off protons are studied in a multichannel partial-wave analysis.
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We study charmed baryon resonances that are generated dynamically from a coupled-channel unitary approach that implements heavy-quark symmetry. Some states can already be identified with experimental observations, such as $Lambda_c(2595)$, $Lambda_c(2660)$, $Sigma_c(2902)$ or $Lambda_c(2941)$, while others need a compilation of more experimental data as well as an extension of the model to include higher order contributions. We also compare our model to previous SU(4) schemes.
Results from a partial-wave analysis of the reaction $gamma p rightarrow K^+ Lambda$ are presented. The reaction is dominated by the $S_{11}(1650)$ and $P_{13}(1720)$ resonances at low energies and by $P_{13}(1900)$ at higher energies. There are small contributions from all amplitudes up to and including $G_{17}$, with $F_{17}$ necessary for obtaining a good fit of several of the spin observables. We find evidence for $P_{11}$(1880), $D_{13}$(2120), and $D_{15}$(2080) resonances, as well as a possible $F_{17}$ resonance near 2300 MeV, which is expected from quark-model predictions. Some predictions for $gamma n to K^0 Lambda$ are also included.
The BESIII experiment in Beijing takes data in $tau$-charm domain since 2009. For the moment the world largest samples of $J/psi$, $psi(3686)$, $psi(3770)$ and $psi(4040)$ data have been collected. Hadron spectroscopy is a unique way to access QCD, which is one of the most important physics goals of BESIII. Experimental search of new forms of hadrons and subsequent investigation of their properties would provide validation of and valuable input to the quantitative understanding of QCD. The key to success lies in high levels of precision during the measurement and high statistics in the recorded data set complemented with sophisticated analysis methods. Partial wave analysis (PWA) is a powerful tool to study the hadron spectroscopy, that allows one to extract the resonances spin-parity, mass, width and decay properties with high sensitivity and accuracy. In this poster, we present the working PWA framework of BESIII -- GPUPWA and the recent results of PWA of $J/psitogammaetaeta$. GPUPWA is a PWA framework for high statistics partial wave analyses harnessing the GPU parallel computing.
Understanding the properties of the strange $Lambda^*$ baryon resonances is a long-standing and fascinating problem. $Lambda_c$ charm-baryon semileptonic weak decays to these resonances are highly sensitive to their internal structure and can be used to test theoretical models. We have performed the first lattice-QCD computation of the form factors governing $Lambda_c$ semileptonic decays to a $Lambda^*$ resonance: the $Lambda^*(1520)$, which has negative parity and spin $3/2$. Here we present the resulting Standard-Model predictions of the $Lambda_ctoLambda^*(1520)ell^+ u_ell$ differential and integrated decay rates as well as angular observables. Furthermore, by combining the recent BESIII measurement of the $Lambda_c to X e^+ u_e$ inclusive semipositronic branching fraction [Phys. Rev. Lett. 121, 251801 (2018)] with lattice-QCD predictions of the $Lambda_c to Lambda e^+ u_e$, $Lambda_c to n e^+ u_e$, and $Lambda_c to Lambda^*(1520) e^+ u_e$ decay rates, we obtain an upper limit on the sum of the branching fractions to all other semipositronic final states. In particular, this upper limit constrains the $Lambda_ctoLambda^*(1405)e^+ u_e$ branching fraction to be very small, which may be another hint for a molecular structure of the $Lambda^*(1405)$.
We study charmed baryon resonances which are generated dynamically within a unitary meson-baryon coupled channel model that treats the heavy pseudoscalar and vector mesons on equal footing as required by heavy-quark symmetry. It is an extension of recent SU(4) models with t-channel vector meson exchanges to a SU(8) spin-flavor scheme, but differs considerably from the SU(4) approach in how the strong breaking of the flavor symmetry is implemented. Some of our dynamically generated states can be readily assigned to recently observed baryon resonances, while others do not have a straightforward identification and require the compilation of more data as well as an extension of the model to d-wave meson-baryon interactions and p-wave coupling in the neglected s- and u-channel diagrams. Of several novelties, we find that the Lambda_c(2595), which emerged as a ND quasi-bound state within the SU(4) approaches, becomes predominantly a ND* quasi-bound state in the present SU(8) scheme.
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