Constituent-counting rule in photoproduction of hyperon resonances

Abstract

We analyze the CLAS data on the photoproduction of hyperon resonances, as well as the available data for the ground state $\Lambda$ and ${\Sigma }^0$ of the CLAS and SLAC-E84 collaborations, by considering constituent-counting rule suggested by perturbative QCD. The counting rule emerges as a scaling behavior of cross sections in hard exclusive reactions with large scattering angles, and it enables us to determine the number of elementary constituents inside hadrons. Therefore, it could be used as a new method for identifying internal constituents of exotic-hadron candidates. From the analyses of the $\gamma p\to K^{+}\Lambda$ and $K^{+}{\Sigma }^0$ reactions, we find that the number of the elementary constituents is consistent with $n_{\gamma }=1$, $n_p=3$, $n_{K^{+}}=2$, and $n_{\Lambda }=n_{{\Sigma }^0}=3$. Then, the analysis is made for the photoproductions of the hyperon resonances $\Lambda (1405)$, $\Sigma (1385{)}^0$, and $\Lambda (1520)$, where $\Lambda (1405)$ is considered to be a $\bar{K}N$ molecule and hence its constituent number could be five. However, we find that the current data are not enough to conclude the numbers of their constituent. It is necessary to investigate the higher-energy region at $\sqrt{s}>2.8$ GeV experimentally beyond the energy of the available CLAS data for counting the number of constituents clearly. We also mention that our results indicate energy dependence in the constituent number, especially for $\Lambda (1405)$. If an excited hyperon is a mixture of three-quark and five-quark states, the energy dependence of the scaling behavior could be valuable for finding its composition and mixture.

7 pages, 9 eps figures, version accepted for publication in PRD, discussions improved

References in corpus (6)

• Measurement of gamma gamma* --> pi0 transition form factor at Belle
• Lattice QCD Evidence that the Lambda(1405) Resonance is an Antikaon-Nucleon Molecule
• Comprehensive analysis of the wave function of a hadronic resonance and its compositeness
• Tetraquark Cusp Effects from Diquark Pair Production
• Scaling and Resonances in Elementary K^+ Lambda Photoproduction
• The composite nature of the $\Lambda (1520)$ resonance

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• Photoproduction of $\Lambda (1405)$ with the $N^{\ast }$ and $t$-channel Regge contributions
• Exploring Baryon Resonances with Transition Generalized Parton Distributions: Status and Perspectives
• QCD Constituent Counting Rules for Neutral Vector Mesons
• Photo- and electroproduction of $\Lambda (1405)$ via ${\gamma }^{(\ast )}p\to K^{+}{\pi }^{+}{\Sigma }^{-}$
• Constituent counting rule for exclusive production of heavy quarkoniumlike exotic resonance and a light hadron
• High Energy Behaviour of Light Meson Photoproduction
• Hadron tomography and its application to gravitational radii of hadrons
• Exotic-Hadron Signature by Constituent-Counting Rule in Perturbative QCD
• Conference Summary of QNP2018
• Hadron tomography studies by generalized parton distributions and distribution amplitudes
• Exclusive Hard Processes for Studying Hadron Structures at J-PARC