Measurement of the cross sections for e+e−→</
Measurement of the cross sections for e+e−→</
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DOI：
10.1103/physrevd.108.l111101
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发表时间：
2023-10
影响因子：
5
通讯作者：
B. C. M. Ablikim;M. Achasov;P. Adlarson;X. Ai;R. Aliberti;A. Amoroso;M. An;Q. An;Y. Bai
中科院分区：
文献类型：
--
作者：
B. C. M. Ablikim;M. Achasov;P. Adlarson;X. Ai;R. Aliberti;A. Amoroso;M. An;Q. An;Y. Bai
使用在北京正负电子对撞机上运行的BESIII探测器在2.000到3.080 GeV的质心能量下收集的数据样本，对e^+e^-to\eta\pi^+\pi^-$过程进行了分波分析。除了占主导地位的$e^+e^-to eta$外，$e^+e^-to a_2(1320)\pi$过程也是相当大的，占总反应的24%。在2.000到2.300 GeV的质心能量范围内，测得的这个过程的截面比BABA系统地高3西格玛以上。在a2(13 2 0)pi$的横截面线形中，观察到一个显著为$5.5\sigma$的共振结构，其中$M=(2 0 44\pm31\pm4)$MeV/$c^2$，$\Gamma=(1 63\pm69\pm2 4)$MeV和$\mathcal{B_{R}}\cdot\Gamma_{e^+e^-}^{R}=(34.6\pm17.1\pm6.0)$eV或$(137.1\pm73.3\pm2.1)$eV。在e^+e^-to Eta$的横截面线形中，观察到在2180 MeV/$c^2$附近存在倾角结构的证据，统计意义为$3.0\sigma$。
Using data samples collected at center-of-mass energies between 2.000 and 3.080 GeV with the BESIII detector operating at the BEPCII collider, a partial-wave analysis is performed on the process $e^+e^-\to\eta\pi^+\pi^-$. In addition to the dominant $e^+e^-\to\rho\eta$ component, the $e^+e^-\to a_2(1320)\pi$ process is also sizeable, contributing up to 24% of the total reaction. The measured cross sections of the process $e^+e^-\to\eta\pi^+\pi^-$ are systematically higher than those of BaBar by more than $3\sigma$ at center-of-mass energies between 2.000 and 2.300 GeV. In the cross section lineshape for $e^+e^-\to a_2(1320)\pi$, a resonant structure is observed with a significance of $5.5\sigma$, with $M=(2044\pm31\pm4)$ MeV/$c^2$, $\Gamma=(163\pm69\pm24)$ MeV and $\mathcal{B_{R}}\cdot\Gamma_{e^+e^-}^{R}=(34.6\pm17.1\pm6.0)$ eV or $(137.1\pm73.3\pm2.1)$ eV. In the cross section lineshape for $e^+e^-\to\rho\eta$, an evidence of a dip structure around 2180 MeV/$c^2$ is observed with statistical significance of $3.0\sigma$.