Observation of Two New N* Peaks in J/{psi}{yields}p{pi}{sup -}n and p{pi}{sup +}n Decays

Journal Article · Fri Aug 11 04:00:00 EDT 2006 · Physical Review Letters

DOI:https://doi.org/10.1103/PHYSREVLETT.97.062001· OSTI ID:20860634

Ablikim, M; Bai, J Z; Bian, J G; Cai, X; Chang, J F; Chen, H S; Chen, H X; Chen, J C; Chen, Jin; Chen, M L; Chen, Y B; Chu, Y P; Cui, X Z; Dai, H L; Deng, Z Y; Dong, L Y; Du, S X; Du, Z Z; Fang, J; Fu, C D ^[1]

---

1. Institute of High Energy Physics, Beijing 100039 (China)

The decay J/{psi}{yields}NN{pi} provides an effective isospin 1/2 filter for the {pi}N system due to isospin conservation. Using 58x10{sup 6} J/{psi} decays collected with the Beijing Electromagnetic Spectrometer at the Beijing Electron Positron Collider, more than 100 thousand J/{psi}{yields}p{pi}{sup -}n+c.c. events are obtained. Besides the two well-known N* peaks at around 1500 MeV/c{sup 2} and 1670 MeV/c{sup 2}, there are two new, clear N* peaks in the p{pi} invariant mass spectrum around 1360 MeV/c{sup 2} and 2030 MeV/c{sup 2} with statistical significance of 11{sigma} and 13{sigma}, respectively. We identify these as the first direct observation of the N*(1440) peak and a long-sought missing N* peak above 2 GeV/c{sup 2} in the {pi}N invariant mass spectrum.

• OSTI ID: 20860634
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 6 Vol. 97; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
BEIJING ELECTRON-POSITRON COLLIDER
GEV RANGE 01-10
ISOSPIN
J PSI-3097 MESONS
MASS SPECTRA
PARTICLE DECAY
PIONS MINUS
PROTONS
SCORPIONS
SPECTROMETERS