Observation of the {sup 1}P{sub 1} state of charmonium

Journal Article · Tue Nov 01 00:00:00 EST 2005 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PhysRevD.72.092004· OSTI ID:20713805

Rubin, P ^[1]; Cawlfield, C; Eisenstein, B I; Gollin, G D; Karliner, I; Kim, D; Lowrey, N; Naik, P; Sedlack, C; Selen, M; White, E J; Williams, J; Wiss, J ^[2]; Edwards, K W ^[3]; Besson, D ^[4]; Pedlar, T K ^[5]; Cronin-Hennessy, D; Gao, K Y; Gong, D T; Hietala, J ^[6]

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1. George Mason University, Fairfax, Virginia 22030 (United States)
2. University of Illinois, Urbana-Champaign, Illinois 61801 (United States)
3. Carleton University, Ottawa, Ontario, K1S 5B6 (Canada)
4. University of Kansas, Lawrence, Kansas 66045 (United States)
5. Luther College, Decorah, Iowa 52101 (United States)
6. University of Minnesota, Minneapolis, Minnesota 55455 (United States); and others

The spin-singlet P-wave state of charmonium, h{sub c}({sup 1}P{sub 1}), has been observed in the decay {psi}(2S){yields}{pi}{sup 0}h{sub c} followed by h{sub c}{yields}{gamma}{eta}{sub c}. Inclusive and exclusive analyses of the M(h{sub c}) spectrum have been performed. Two complementary inclusive analyses select either a range of energies for the photon emitted in h{sub c}{yields}{gamma}{eta}{sub c} or a range of values of M({eta}{sub c}). These analyses, consistent with one another within statistics, yield M(h{sub c})=[3524.9{+-}0.7 (stat){+-}0.4 (sys)] MeV/c{sup 2} and a product of the branching ratios B{sub {psi}}({psi}(2S){yields}{pi}{sup 0}h{sub c})xB{sub h}(h{sub c}{yields}{gamma}{eta}{sub c})=[3.5{+-}1.0 (stat){+-}0.7 (sys)]x10{sup -4}. When the {eta}{sub c} is reconstructed in seven exclusive decay modes, 17.5{+-}4.5 h{sub c} events are seen with an average mass M(h{sub c})=[3523.6{+-}0.9 (stat){+-}0.5 (sys)] MeV/c{sup 2}, and B{sub {psi}}B{sub h}=[5.3{+-}1.5 (stat){+-}1.0 (sys)]x10{sup -4}. If combined, the inclusive and exclusive data samples yield an overall mass M(h{sub c})=[3524.4{+-}0.6 (stat){+-}0.4 (sys)] MeV/c{sup 2} and product of branching ratios B{sub {psi}}B{sub h}=[4.0{+-}0.8 (stat){+-}0.7 (sys)]x10{sup -4}. The h{sub c} mass implies a P-wave hyperfine splitting {delta}M{sub HF}(1P){identical_to}<M(1{sup 3}P)>-M(1{sup 1}P{sub 1})=[1.0{+-}0.6 (stat){+-}0.4 (sys)] MeV/c{sup 2}.

• OSTI ID: 20713805
• Journal Information: Physical Review. D, Particles Fields, Vol. 72, Issue 9; Other Information: DOI: 10.1103/PhysRevD.72.092004; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA). CLEO Collaboration; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
BRANCHING RATIO
EMISSION
ETA C-2980 MESONS
HADRONIC PARTICLE DECAY
MEV RANGE
NUCLEAR REACTION YIELD
P WAVES
PHOTONS
PIONS NEUTRAL
PSI-3770 MESONS
REST MASS
SPIN
STATISTICS