Combined fit to the and line shape

Jielei Zhang; Limin Yuan

doi:10.1140/epjc/s10052-017-5328-1

EPJ

Combined fit to the $e^+e^-\rightarrow \pi ^{+}\pi ^{-}J/\psi$ and $e^+e^-\rightarrow \pi ^{+}\pi ^{-}\psi (3686)$ line shape

Jielei Zhang^* and Limin Yuan

College of Physics and Electronic Engineering, Xinyang Normal University, Xinyang, 464000, People’s Republic of China

Received: 9 September 2017
Accepted: 20 October 2017
Published online: 31 October 2017

Abstract

We analyze the cross section of $e^+e^-\rightarrow \pi ^{+}\pi ^{-}J/\psi$ measured by Belle, BABAR and BESIII experiments. The parameters of the two resonances Y(4220) and Y(4360) are consistent with that in $e^+e^-\rightarrow \pi ^{+}\pi ^{-}\psi (3686)$ . A combined fit is performed to the two cross sections assuming the two resonances Y(4220) and Y(4360) have the same parameters. The parameters of Y(4220), Y(4360) and Y(4660) are determined to be $M_{Y(4220)}=(4223.3\pm 1.6\pm 2.5)$ MeV/c $^{2}$ , $\Gamma _{Y(4220)}=(54.2\pm 2.6\pm 1.0)$ MeV; $M_{Y(4360)}=(4386.4\pm 2.1\pm 6.4)$ MeV/c $^{2}$ , $\Gamma _{Y(4360)}=(96.0\pm 6.7\pm 2.7)$ MeV; $M_{Y(4660)}=(4646.4\pm 9.7\pm 4.8)$ MeV/c $^{2}$ , $\Gamma _{Y(4660)}=(103.5\pm 15.6\pm 4.0)$ MeV, where the first uncertainties are statistical and the second systematic. The ratios $\frac{\mathcal {B}(Y(4220) \rightarrow \pi ^{+}\pi ^{-}\psi (3686))}{\mathcal {B}(Y(4220) \rightarrow \pi ^{+}\pi ^{-}J/\psi )}$ and $\frac{\mathcal {B}(Y(4360) \rightarrow \pi ^{+}\pi ^{-}\psi (3686))}{\mathcal {B}(Y(4360) \rightarrow \pi ^{+}\pi ^{-}J/\psi )}$ are also obtained, which may help in understanding the nature of these structures.

15th European Conference on Atoms Molecules and Photons (ECAMP)
June 30 to July 4, 2025
Innsbruck, Austria

EPJ

Combined fit to the and line shape

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Combined fit to the $e^+e^-\rightarrow \pi ^{+}\pi ^{-}J/\psi$ and $e^+e^-\rightarrow \pi ^{+}\pi ^{-}\psi (3686)$ line shape