# $\chi_{c1}$ and $\chi_{c2}$ resonance parameters with the decays $\chi_{c1,c2} \to J/\psi\mu^+\mu^-$

LHCb Collaboration; Bernet, R; Müller, K; Serra, N; Steinkamp, O; Straumann, U; Vollhardt, A; et al (2017). $\chi_{c1}$ and $\chi_{c2}$ resonance parameters with the decays $\chi_{c1,c2} \to J/\psi\mu^+\mu^-$. Physical Review Letters, 119(22):221801.

## Abstract

The decays $\chi_{c1} \to J/\psi\mu^+\mu^-$ and $\chi_{c2} \to J/\psi\mu^+\mu^-$ are observed and used to study the resonance parameters of the $\chi_{c1}$ and $\chi_{c2}$ mesons. The masses of these states are measured to be
$m(\chi_{c1}) = 3510.71 \pm 0.04(stat) \pm 0.09(syst) MeV$ and
$m(\chi_{c2}) = 3556.10 \pm 0.06(stat) \pm 0.11(syst) MeV$, where the knowledge of the momentum scale for charged particles dominates the systematic uncertainty. The momentum-scale uncertainties largely cancel in the mass difference $m(\chi_{c2}) − m(\chi_{c1}) = 45.39 \pm 0.07(stat) \pm 0.03(syst) MeV$. The natural width of the $\chi_{c2}$ meson is measured to be $\Gamma(\chi_{c2}) = 2.10 \pm 0.20(stat) \pm 0.02(syst) MeV$. These results are in good agreement with and have comparable precision to the current world averages.

## Abstract

The decays $\chi_{c1} \to J/\psi\mu^+\mu^-$ and $\chi_{c2} \to J/\psi\mu^+\mu^-$ are observed and used to study the resonance parameters of the $\chi_{c1}$ and $\chi_{c2}$ mesons. The masses of these states are measured to be
$m(\chi_{c1}) = 3510.71 \pm 0.04(stat) \pm 0.09(syst) MeV$ and
$m(\chi_{c2}) = 3556.10 \pm 0.06(stat) \pm 0.11(syst) MeV$, where the knowledge of the momentum scale for charged particles dominates the systematic uncertainty. The momentum-scale uncertainties largely cancel in the mass difference $m(\chi_{c2}) − m(\chi_{c1}) = 45.39 \pm 0.07(stat) \pm 0.03(syst) MeV$. The natural width of the $\chi_{c2}$ meson is measured to be $\Gamma(\chi_{c2}) = 2.10 \pm 0.20(stat) \pm 0.02(syst) MeV$. These results are in good agreement with and have comparable precision to the current world averages.

## Statistics

### Citations

Dimensions.ai Metrics

### Altmetrics

Detailed statistics