论文标题
$ e^{+} e^{ - } \rightarrowμ^+μ^ - $从3.80到4.60 GEV处的横截面的测量
Measurement of cross sections for $e^{+}e^{-} \rightarrow μ^+μ^-$ at center-of-mass energies from 3.80 to 4.60 GeV
论文作者
论文摘要
使用在BEPCII对撞机上操作的BESIII检测器进行的数据样本测量了$ e^+e^ - \rightArrowμ^+μ^ - $的$ e^+e^ - \rightArrowμ^+μ^ - $的横截面。我们测量了Muonic宽度，并确定Charmonium状态$ψ（4040）$，$ψ（4160）$和$ψ（4415）$衰减至$μ^+μ^ - $的分支分数，以及对放大器的阶段的首次确定。此外，我们观察到在4.220 GEV/$ C^2 $附近的Dimuon横截面中的结构的证据，我们将其表示为$ s（4220）$。分析一致的振幅总和产生了八种解决方案，其中一种解决方案的质量为$ {m} _ {s（4220）} = 4216.7 \ pm 8.9 \ pm 4.1 $ 〜mev/$ 〜mev/$ c^2 $ \ pm 22.8 \ pm 10.5 $〜meV，以及$ {\rmγ}^{μμμ} _ {s（4220）} = 1.53 \ pm1.26 \ pm0.54 $ 〜kev的muonic宽度= 1.53 \ pm1.26 \ pm1.26 \ kev，第一个不确定性是统计的，是第二个系统的。八个解决方案给出了质量，总宽度，muonic宽度的中心值，分别为4212.8至4219.4 MEV/$ C^2 $，从36.4至49.6 MeV，从1.09到1.53 KEV。 $ s（4220）$信号的统计意义为$3.9σ$。校正辐射效果的总二酮横截面具有超过$7σ$的结构的统计意义。
The observed cross sections for $e^+e^-\rightarrow μ^+μ^-$ at energies from 3.8 to 4.6 GeV are measured using data samples taken with the BESIII detector operated at the BEPCII collider. We measure the muonic widths and determine the branching fractions of the charmonium states $ψ(4040)$, $ψ(4160)$, and $ψ(4415)$ decaying to $μ^+μ^-$, as well as making a first determination of the phase of the amplitudes. In addition, we observe evidence for a structure in the dimuon cross section near 4.220 GeV/$c^2$, which we denote as $S(4220)$. Analyzing a coherent sum of amplitudes yields eight solutions, one of which gives a mass of ${M}_{S(4220)}=4216.7 \pm 8.9 \pm 4.1$~MeV/$c^2$, a total width of ${\rm Γ^{\rm tot}_{S(4220)}}=47.2 \pm 22.8 \pm 10.5$~MeV, and a muonic width of ${\rm Γ}^{μμ}_{S(4220)}=1.53\pm1.26\pm0.54$~keV, where the first uncertainties are statistical and the second systematic. The eight solutions give the central values of the mass, total width, muonic width to be, respectively, in the range from 4212.8 to 4219.4 MeV/$c^2$, from 36.4 to 49.6 MeV, and from 1.09 to 1.53 keV. The statistical significance of the $S(4220)$ signal is $3.9σ$. Correcting the total dimuon cross section for radiative effects yields a statistical significance for this structure of more than $7σ$.
