A study of the lineshape of the $\chicone(3872)$ state is made using a data sample corresponding to an integrated luminosity of $3\invfb$ collected in $pp$ collisions at centre-of-mass energies of 7 and 8,TeV with the LHCb detector. Candidate $\chicone(3872)$ and $\psitwos$ mesons from $\bquark$-hadron decays are selected in the $ J/^+ ^-$ decay mode. Describing the {} with a Breit–Wigner function, the mass splitting between the $\chicone(3872)$ and $\psitwos$ states, $\Delta m$, and the width of the $\chicone(3872)$ state, ${\Gamma }_{BW}$, are determined to be $$\begin{eqnarray*} \Delta m & = & 185.598 \pm 0.067 \pm 0.068 \mev \,, \Gamma_{BW} & = & \phantom{00}1.39\phantom{0} \pm 0.24\phantom{0} \pm 0.10\phantom{0} \mev \,, \end{eqnarray*}$$ where the first uncertainty is statistical and the second systematic. Using a Flatt'e-inspired model, the mode and full width at half maximum of the lineshape are determined to be $$\begin{eqnarray*} mode & = 3871.69^{\,+\,0.00\,+\,0.05}_{-0.04\,-\,0.13} &\mev FWHM & = 0.22^{\,+\,0.07\,+\,0.11}_{\,-\,0.06\,-\,0.13}& \mev . \end{eqnarray*}$$ An investigation of the analytic structure of the Flatt'e amplitude reveals a pole structure, which is compatible with a quasi-bound $\Dz\Dstarzb$~state but a quasi-virtual state is still allowed at the level of $2$~standard deviations.

中文翻译：

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xc1（3872）状态的线形研究

使用对应于从中收集的$ 3 \ invfb $的综合亮度的数据样本，对$ \ chicone（3872）$状态的线形进行了研究。$pp$LHCb检测器在7和8 TeV的质心能量上发生碰撞。来自$ \ bquark $-强子衰变的候选$ \ chicone（3872）$和$ \ psitwos $介子在$ J / ^ + ^-$衰变模式中选择。用Breit–Wigner函数描述{}，质量在$ \ chicone（3872）$和$ \ psitwos $状态之间分裂，$\Delta 米$，以及$ \ chicone（3872）$状态的宽度，${\Gamma }_{乙\mathrm{w\; ^}}$，确定为$$ \ begin {eqnarray *} \ Delta m＆=＆185.598 \ pm 0.067 \ pm 0.068 \ mev \ ,, \ Gamma_ {BW}＆=＆\ phantom {00} 1.39 \ phantom {0} \ pm 0.24 \ phantom {0} \ pm 0.10 \ phantom {0} \ mev \，\ end {eqnarray *} $$其中第一个不确定性是统计性的，第二个不确定性是统计性的。使用受Flatt'e启发的模型，线型的模式和半角全宽确定为$$ \ begin {eqnarray *}模式＆= 3871.69 ^ {\，+ \，0.00 \，+ \，0.05 } _ {-0.04 \，-\，0.13}＆\ mev FWHM＆= 0.22 ^ {\，+ \，0.07 \，+ \，0.11} _ {\，-\，0.06 \，-\，0.13}＆ \ mev。\ end {eqnarray *} $$对Flatt'e振幅的解析结构的研究揭示了一个极点结构，$2$〜标准偏差。