Coordinatori
Light baryon spectroscopy: Session 1
- David Ireland (University of Glasgow)
Light baryon spectroscopy: Session 2
- Marco Ripani (Istituto Nazionale di Fisica Nucleare)
Light baryon spectroscopy: Session 3
- Maxim Mai
The existence of hexaquark states has far-reaching consequences, such as our understanding of quark structure, and the mechanisms involved inside neutron stars[1]. Predicted in 1964[2], and recently discovered, the simplest non-trivial hexaquark, is the d*(2380), an “excited deuteron” state. The deuteron, comprised of a proton and neutron, can be excited to this state during deuteron...
The exclusive double pion electromagnetic production is an important tool for the study of N and 𝛥 excitations and for the search of missing baryonic resonances. In fact, in photoproduction reactions the two pion channel represents the dominant contribution to the total cross section, therefore favoring, especially in the second resonant region, the observation of intermediate states whose...
One important step in understanding the baryon spectrum is a precise knowledge of the excited states and their decays. In order to extract the contributing resonances from experimental data a partial wave analysis needs to be performed. To resolve ambiguities, the measurement of polarization observables is indispensable. In the regime of high mass baryon resonances multi-meson final states are...
Recent results studying the masses and widths of low-lying baryon resonances in lattice QCD are presented. The $s$-wave scattering lengths with both total isospins $I=1/2$ and $I=3/2$ are inferred from the finite-volume spectrum below the inelastic threshold together with the $I=3/2$ $p$-wave containing the $\Delta(1232)$ resonance. A lattice QCD computation employing a combined basis of...
At SPring-8 LEPS2 beamline, a linearly polarized photon beam is available in the tagged energy range of 1.3–2.4 GeV. In this facility, the BGOegg experiment has been carried out using a detector setup with a large-acceptance electromagnetic calorimeter, which has the world’s best resolution in the energy range around 1 GeV. A main physics subject in this experiment is the spectroscopy of...
The study of the excited states of the nucleon is a powerful tool for the understanding of its structure in the non-perturbative regime of QCD, which is one of the major challenges of modern physics.
Meson photoproduction, as well as other photon-induced reactions, allow to study the excitation spectra of the nucleons and, in combination with the use of a polarized beam and/or target, allow...
Data on the photo- and electroproduction of different hadrons provide access to the spectrum of excited baryons. The amplitudes and resonance properties obtained through this phenomenological analysis can serve as a point of comparison for theories and models of excited baryons and their dynamics. Recent results from the Julich-Bonn-Washington model will be presented, including extensions to...
In this presentation we would like to determine the properties of the lightest resonance in the baryonic sector of QCD: the Delta(1232) resonance. We determine the finite volume energy spectrum of $\pi-N$ system. Using Luescher formalism we can predict the mass and the width of the delta resonance. In our analysis we include ensembles with the same pion mass at different spatial volume...
An experimental program has been approved at the Thomas Jefferson National Accelerator Facility to measure the (ep,e’K+)Y reactions using the CLAS12 setup in Hall B.
Data have been obtained using electron beams with energies of 6.5, 7.5, and 10.2 GeV, impinging upon a liquid hydrogen target in the CLAS12 center. Scattered electrons have been detected in a polar angle range of 2.5° to 4.5° by...
The world’s largest samples of $J/\psi$ and $\psi(3686)$ events produced in $e^+e^-$ annihilation provide a clean source of baryon excitations, allowing for a rich baryon spectroscopy programme at BESIII. Based on the large data samples collected by BESIII experiment, the baryon spectroscopy has been studied through decays J/psi -> omega p anti-p, psi(3686) -> Lambda anti-Lambda eta, psi(3686)...
The discovery of the X, Y, Z states in the (hidden) charm meson sector first by Belle, and the PC baryon states by LHCb revealed the existence of multi-quark objects beyond the simple quarkantiquark or 3-quark valence configurations. If the emergence of such multi-quark structures was a general feature of QCD, then related structures should appear in the uds-sector as well. The BGOOD...
The BGOOD photoproduction experiment at the ELSA facility is uniquely designed to explore kinematics where a charged particle is identified in a forward spectrometer and a recoiling hadronic system is reconstructed in the central calorimeter at low momentum transfer. Typically used to study strangeness photoproduction at low $t$, the setup also enables studies of coherent reactions off the...
Hadron mass spectra have been a topic of investigation since long so as to explore the unknown degrees of freedom of quarks inside a composite system. The non-relativistic approach backed by constituent quark model alongwith hypercentral potential term has been used to obtain a number of excited resonance masses for light, strange baryons. The $\Xi$ and $\Omega$ baryons are known with very...
