We present an analysis of the processes e+e- → ηΥ(1S), ηΥ(2S), and γXb with Xb → π+ π- χbJ, χbJ → γΥ(1S) (J = 1, 2) reconstructed from γγπ+π- ℓ+ℓ- (ℓ = e, μ) final states in 19.6 fb-1 of Belle II data collected at four energy points near the peak of the Υ(10753) resonance. Here, Xb is a hypothetical bottomonium-sector partner of the X(3872). In the process e+e- → ηΥ(2S), we observe a signal with a significance that exceeds 6.0σ when all energy points are combined. A signal with a significance of 4.2σ is observed at a center-of-mass energy of 10.653 GeV, close to the B*B* threshold. At this energy, we measure σ(ηΥ(2S))/σ(π+π- Υ(2S)) > 23 at the 90% confidence level, indicating a strong violation of heavy-quark spin symmetry. No significant signal is observed for e+e- → ηΥ(1S) or γXb. Upper limits on the Born cross sections for the processes e+e- → ηΥ(1S) and e+e- → γXb with Xb → π+ π- χbJ are determined.

Adachi, I., Aggarwal, L., Ahmed, H., Ahn, Y., Aihara, H., Akopov, N., et al. (2026). Observation of 𝑒+⁢𝑒− →𝜂⁢ϒ⁡(2⁢𝑆) and search for 𝑒+⁢𝑒−→𝜂⁢ϒ⁡(1⁢𝑆), 𝛾⁢𝑋𝑏 at √𝑠 near 10.75 GeV. PHYSICAL REVIEW D, 113(5), 1-8 [10.1103/9f61-rmvx].

Observation of 𝑒+⁢𝑒− →𝜂⁢ϒ⁡(2⁢𝑆) and search for 𝑒+⁢𝑒−→𝜂⁢ϒ⁡(1⁢𝑆), 𝛾⁢𝑋𝑏 at √𝑠 near 10.75 GeV

Di Canto, A.;
2026

Abstract

We present an analysis of the processes e+e- → ηΥ(1S), ηΥ(2S), and γXb with Xb → π+ π- χbJ, χbJ → γΥ(1S) (J = 1, 2) reconstructed from γγπ+π- ℓ+ℓ- (ℓ = e, μ) final states in 19.6 fb-1 of Belle II data collected at four energy points near the peak of the Υ(10753) resonance. Here, Xb is a hypothetical bottomonium-sector partner of the X(3872). In the process e+e- → ηΥ(2S), we observe a signal with a significance that exceeds 6.0σ when all energy points are combined. A signal with a significance of 4.2σ is observed at a center-of-mass energy of 10.653 GeV, close to the B*B* threshold. At this energy, we measure σ(ηΥ(2S))/σ(π+π- Υ(2S)) > 23 at the 90% confidence level, indicating a strong violation of heavy-quark spin symmetry. No significant signal is observed for e+e- → ηΥ(1S) or γXb. Upper limits on the Born cross sections for the processes e+e- → ηΥ(1S) and e+e- → γXb with Xb → π+ π- χbJ are determined.
2026
Adachi, I., Aggarwal, L., Ahmed, H., Ahn, Y., Aihara, H., Akopov, N., et al. (2026). Observation of ��+⁢��− →��⁢ϒ⁡(2⁢��) and search for ��+⁢��−→��⁢ϒ⁡(1⁢��), ��⁢���� at √�� near 10.75 GeV. PHYSICAL REVIEW D, 113(5), 1-8 [10.1103/9f61-rmvx].
Adachi, I.; Aggarwal, L.; Ahmed, H.; Ahn, Y.; Aihara, H.; Akopov, N.; Alghamdi, S.; Alhakami, M.; Aloisio, A.; Althubiti, N.; Amos, K.; Angelsmark, M....espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/1083635
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