Showing papers by "Y. Ban published in 2000"
01 Dec 2000
81 citations
TL;DR: In this paper, the decay distributions of the dipion system were compared with the general decay amplitude analysis of Cahn, and it was shown that the Dipion system requires some D wave amplitude, as well as S wave.
Abstract: Using a sample of 3.8 M psi(2S) events accumulated with the BES detector, the process psi(2S) --> pi(+) pi(r)-J/psi is studied. The angular distributions are compared with the general decay amplitude analysis of Cahn. We find that the dipion system requires some D wave amplitude, as well as S wave. On the other hand, the J/psi-(pi(+)pi(-)) relative angular momentum is consistent with being pure S wave. The decay distributions have been fit to heavy quarkonium models, including the Novikov-Shifman model. This model, which is written in terms of the parameter kappa, predicts that D wave pions should be present. We determine kappa = 0.183 +/- 0.002 +/- 0.003 based on the joint m(pi pi)-cos theta(pi)* distribution. The fraction of D wave amplitude as a function of m(pi pi) is found to decrease with increasing m(pi pi), in agreement with the model. We have also fit the Mannel-Yan model, which is another model that allows D wave pions.
19 citations
TL;DR: In this paper, a sample of 7.8 million J/{psi} decays collected in the Beijing Spectrometer was used to determine the mass of {eta-sub c} to be 2976.3 MeV.
Abstract: In a sample of 7.8 million J/{psi} decays collected in the Beijing Spectrometer, the process J/{psi}{yields}{gamma}{eta}{sub c} is observed for five different {eta}{sub c} decay channels: K{sup +}K{sup -}{pi}{sup +}{pi}{sup -}, {pi}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -}, K{sup {+-}}K{sub S}{sup 0}{pi}{sup {+-}} (with K{sub S}{sup 0}{yields}{pi}{sup +}{pi}{sup -}), {phi}{phi} (with {phi}{yields}K{sup +}K{sup -}) and K{sup +}K{sup -}{pi}{sup 0}. From these signals, we determine the mass of {eta}{sub c} to be 2976.6{+-}2.9{+-}1.3 MeV. Combining this result with a previously reported result from a similar study using {psi}(2S){yields}{gamma}{eta}{sub c} detected in the same spectrometer gives m{sub {eta}{sub c}}=2976.3{+-}2.3{+-}1.2 MeV. For the combined samples, we obtain {gamma}{sub {eta}{sub c}}=11.0{+-}8.1{+-}4.1 MeV. (c) 2000 The American Physical Society.
14 citations
TL;DR: In this paper, the decay distributions have been fit to heavy quarkonium models, including the Novikov-Shifman model, and they have also fit the Mannel-Yan model which is another model that allows D wave pions.
Abstract: Author(s): Bai, JZ; Ban, Y; Bian, JG; Blum, I; Chen, GP; Chen, HF; Chen, J; Chen, JC; Chen, Y; Chen, YB; Chen, YQ; Cheng, BS; Cui, XZ; Ding, HL; Dong, LY; Du, ZZ; Dunwoodie, W; Gao, CS; Gao, ML; Gao, SQ; Gratton, P; Gu, JH; Gu, SD; Gu, WX; Gu, YF; Guo, ZJ; Guo, YN; Han, SW; Han, Y; Harris, FA; He, J; He, JT; He, KL; He, M; Heng, YK; Hitlin, DG; Hu, GY; Hu, HM; Hu, JL; Hu, QH; Hu, T; Hu, XQ; Huang, GS; Huang, YZ; Izen, JM; Jiang, CH; Jin, Y; Jones, BD; Ju, X; Ke, ZJ; Kelsey, MH; Kim, BK; Kong, D; Lai, YF; Lang, PF; Lankford, A; Li, CG; Li, D; Li, HB; Li, J; Li, JC; Li, PQ; Li, RB; Li, W; Li, WG; Li, XH; Li, XN; Liu, HM; Liu, J; Liu, RG; Liu, Y; Lou, XC; Lowery, B; Lu, F; Lu, JG; Luo, XL; Ma, EC; Ma, JM; Malchow, R; Mao, HS; Mao, ZP; Meng, XC; Nie, J; Olsen, SL; Oyang, J | Abstract: Using a sample of 3.8 M (Formula presented) events accumulated with the BES detector, the process (Formula presented) is studied. The angular distributions are compared with the general decay amplitude analysis of Cahn. We find that the dipion system requires some D wave amplitude, as well as S wave. On the other hand, the (Formula presented) relative angular momentum is consistent with being pure S wave. The decay distributions have been fit to heavy quarkonium models, including the Novikov-Shifman model. This model, which is written in terms of the parameter (Formula presented) predicts that D wave pions should be present. We determine (Formula presented) based on the joint (Formula presented) distribution. The fraction of D wave amplitude as a function of (Formula presented) is found to decrease with increasing (Formula presented) in agreement with the model. We have also fit the Mannel-Yan model, which is another model that allows D wave pions. © 2000 The American Physical Society.
5 citations
TL;DR: In this paper, the first measurement of (Formula presented) and an upper limit for (formulas presented) are determined from 22.3 µm. energy at a c.03 GeV.
Abstract: Author(s): Bai, JZ; Ban, Y; Bian, JG; Blum, I; Chen, GP; Chen, HF; Chen, J; Chen, JC; Chen, Y; Chen, YB; Chen, YQ; Cheng, BS; Cui, XZ; Ding, HL; Dong, LY; Du, ZZ; Dunwoodie, W; Gao, CS; Gao, ML; Gao, SQ; Gratton, P; Gu, JH; Gu, SD; Gu, WX; Gu, YF; Guo, YN; Guo, ZJ; Han, SW; Han, Y; Harris, FA; He, J; He, JT; He, KL; He, M; Heng, YK; Hitlin, DG; Hu, GY; Hu, HM; Hu, JL; Hu, QH; Hu, T; Hu, XQ; Huang, YZ; Huang, GS; Izen, JM; Jiang, CH; Jin, Y; Jones, BD; Ju, X; Ke, ZJ; Kelsey, MH; Kim, BK; Kong, D; Lai, YF; Lang, PF; Lankford, A; Li, CG; Li, D; Li, HB; Li, J; Li, JC; Li, PQ; Li, RB; Li, W; Li, WG; Li, XH; Li, XN; Liu, HM; Liu, J; Liu, RG; Liu, Y; Lou, XC; Lowery, B; Lu, F; Lu, JG; Luo, XL; Ma, EC; Ma, JM; Malchow, R; Mandelkern, M; Mao, HS; Mao, ZP; Meng, XC; Nie, J; Olsen, SL | Abstract: The first measurement of (Formula presented) and an upper limit for (Formula presented) are determined from 22.3 (Formula presented) of (Formula presented) annihilation data at a c.m. energy of 4.03 GeV. The data were recorded by the Beijing Spectrometer (BES) at BEPC. A recoil charge method is applied to charm threshold data to determine the charge of the D meson in the recoil from (Formula presented) reconstructed (Formula presented) (Formula presented) mesons. The branching fractions (Formula presented) and (Formula presented) are determined from 10 events with a reconstructed D and a recoiling (Formula presented) In addition, a 90% C.L. upper limit of (Formula presented) is determined from a search for semileptonic decays of the (Formula presented) © 2000 The American Physical Society.
1 citations