Study of the χ1 and χ2 charmonium states formed in overlinepp annihilations
Abstract
We report on a study of the χ 1( 3P1) and χ 2( 3P2) states of charmonium formed in antiproton-proton annihilations. An energy scan through the resonances, performed with a very narrow momentum-band beam of antiprotons intersecting a hydrogen jet target, enables us to perform very precise measurements of the mass and the total width of the two resonances. From a sample of 513 χ1 and 585 χ2 events we find M χ1 = (3510.53±0.13) MeV/ c2, M χ2 = (3556.15±0.14) MeV/ c2, Γχ1 = (0.88±0.14) MeV and Γχ2 = (1.98±0.18) MeV. From our measurement of the quantity Γ( R → overlinepp) × BR(R → {J}/{ψ} → e+e-) , using known branching ratios, we obtain Λ(χ 1 → overlinepp) = (69±13) eV and Λ(χ 2 → overlinepp) = (180±31) eV.
- Publication:
-
Nuclear Physics B
- Pub Date:
- March 1992
- DOI:
- 10.1016/0550-3213(92)90448-K
- Bibcode:
- 1992NuPhB.373...35A