We study the process e+e− → psi(2s)pi+pi- with initial-state-radiation events produced at the PEP-II asymmetric-energy collider. The data were recorded with the BABAR detector at center-of-mass energies at and near the Upsilon(nS) (n = 2; 3; 4) resonances and correspond to an integrated luminosity of 520 fb−1 . We investigate the psi(2S)pi+pi- mass distribution from 3.95 to 5.95 GeV/c^2, and measure the center-of-mass energy dependence of the associated e+e- ->psi(2S)pi+pi- cross section. The mass distribution exhibits evidence of two resonant structures. A fit to the psi(2S)pi+pi- mass distribution corresponding to the decay mode psi(2S)-> j/psi pi+pi- yields a mass value of 4340 \pm 16 \pm 9 MeV/c^2 and a width of 94 \pm 32 \pm 13 MeV for the first resonance, and for the second a mass value of 4669 \pm 21 \pm 3 \pm MeV/c^2 and a width of 104 \pm 48 \pm 10 \pm MeV. In addition, we show the pi+pi- mass distributions for these resonant regions.
Study of the reaction e+e- -> psi(2s)pi+pi- via initial-state radiation at BaBar
BETTONI, Diego;BOZZI, Concezio;CALABRESE, Roberto;CIBINETTO, Gianluigi;FIORAVANTI, Elisa;GARZIA, Isabella;LUPPI, Eleonora;SANTORO, Valentina;
2014
Abstract
We study the process e+e− → psi(2s)pi+pi- with initial-state-radiation events produced at the PEP-II asymmetric-energy collider. The data were recorded with the BABAR detector at center-of-mass energies at and near the Upsilon(nS) (n = 2; 3; 4) resonances and correspond to an integrated luminosity of 520 fb−1 . We investigate the psi(2S)pi+pi- mass distribution from 3.95 to 5.95 GeV/c^2, and measure the center-of-mass energy dependence of the associated e+e- ->psi(2S)pi+pi- cross section. The mass distribution exhibits evidence of two resonant structures. A fit to the psi(2S)pi+pi- mass distribution corresponding to the decay mode psi(2S)-> j/psi pi+pi- yields a mass value of 4340 \pm 16 \pm 9 MeV/c^2 and a width of 94 \pm 32 \pm 13 MeV for the first resonance, and for the second a mass value of 4669 \pm 21 \pm 3 \pm MeV/c^2 and a width of 104 \pm 48 \pm 10 \pm MeV. In addition, we show the pi+pi- mass distributions for these resonant regions.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.