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Measurement of psi2S radiative decays
1Institute of High Energy Physics, Beijing 100049, People's Republic of China.
Physical Review Letters
|August 7, 2007
Summary
This study reports the first measurements of psi(2S) particle decays into various final states, including gammapp and gamma2(pi+pi-). These findings provide new insights into the decay properties of psi(2S) mesons.
Area of Science:
- Particle Physics
- High-Energy Physics
- Quantum Chromodynamics
Background:
- The psi(2S) meson is an excited state of the J/psi meson, crucial for understanding quarkonium physics.
- Previous studies have explored various psi(2S) decays, but comprehensive measurements of specific channels are limited.
Purpose of the Study:
- To report the first measurements of branching fractions and upper limits for numerous psi(2S) decays.
- To investigate psi(2S) decays into final states involving photons, pions, kaons, and other mesons.
- To contribute to a more complete understanding of psi(2S) meson properties and decay dynamics.
Main Methods:
- Analysis of 14 x 10^6 psi(2S) events collected by the BESII detector.
- Measurement of branching fractions and upper limits for specific decay channels with hadron invariant mass below 2.9 GeV/c^2.
- Utilized invariant mass reconstruction and event selection techniques to identify decay products.
Main Results:
- Reported first measurements of branching fractions or upper limits for psi(2S) decays into gammapp, gamma2(pi+pi-), gammaKS0K+pi-+c.c., gammaK+K-pi+pi-, gammaK*0K-pi++c.c., gammaK*0K*0, gammapi+pi-pp, gamma2(K+K-), gamma3(pi+pi-), and gamma2(pi+pi-)K+K-.
- Presented branching fractions for psi(2S) decays into 2(pi+pi-)pi0, omegapi+pi-, omegaf2(1270), b1+/-pi-/+, and pi02(pi+pi-)K+K-.
- These results provide crucial data for theoretical models of meson decays.
Conclusions:
- The study provides the first experimental data for a significant number of psi(2S) decay channels.
- These measurements will help refine theoretical predictions and improve our understanding of the strong interaction.
- The comprehensive dataset from BESII enhances the exploration of psi(2S) properties.
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