We report the first search for the flavor-changing neutral-current decays B→Xsνν¯, where Xs is a hadronic system with strangeness equal to 1, in data collected with the Belle II detector at the SuperKEKB asymmetric-energy e+e- collider. The data sample corresponds to an integrated luminosity of 365 fb-1 collected at the δ(4S) resonance and 43 fb-1 collected at a center-of-mass energy 60 MeV below resonance for estimation of e+e-→qq¯ continuum background. One of the B mesons from the δ(4S)→BB¯ decay is fully reconstructed in a hadronic decay mode. The B→Xsνν¯ decay is reconstructed with a sum-of-exclusives approach that uses 30 Xs decay modes. This approach provides high sensitivity to the inclusive decay, despite the presence of two undetected neutrinos. The search is performed in three regions of the Xs mass, MXstrue, chosen to separate contributions from K, K∗(892), and heavier strange final states. We do not observe a significant signal and set upper limits at 90% confidence level on the partial branching fractions for the regions 0.0<0.6 GeV/c2, 0.6<1.0 GeV/c2, and 1.0 GeV/c2

Abumusabh, M., Adachi, I., Adamczyk, K., Aggarwal, L., Ahmed, H., Ahn, Y., et al. (2026). First Search for B →Xsν ν ¯ Decays. PHYSICAL REVIEW LETTERS, 136(23), 1-9 [10.1103/kf73-hw61].

First Search for B →Xsν ν ¯ Decays

Di Canto A.;
2026

Abstract

We report the first search for the flavor-changing neutral-current decays B→Xsνν¯, where Xs is a hadronic system with strangeness equal to 1, in data collected with the Belle II detector at the SuperKEKB asymmetric-energy e+e- collider. The data sample corresponds to an integrated luminosity of 365 fb-1 collected at the δ(4S) resonance and 43 fb-1 collected at a center-of-mass energy 60 MeV below resonance for estimation of e+e-→qq¯ continuum background. One of the B mesons from the δ(4S)→BB¯ decay is fully reconstructed in a hadronic decay mode. The B→Xsνν¯ decay is reconstructed with a sum-of-exclusives approach that uses 30 Xs decay modes. This approach provides high sensitivity to the inclusive decay, despite the presence of two undetected neutrinos. The search is performed in three regions of the Xs mass, MXstrue, chosen to separate contributions from K, K∗(892), and heavier strange final states. We do not observe a significant signal and set upper limits at 90% confidence level on the partial branching fractions for the regions 0.0<0.6 GeV/c2, 0.6<1.0 GeV/c2, and 1.0 GeV/c2
2026
Abumusabh, M., Adachi, I., Adamczyk, K., Aggarwal, L., Ahmed, H., Ahn, Y., et al. (2026). First Search for B →Xsν ν ¯ Decays. PHYSICAL REVIEW LETTERS, 136(23), 1-9 [10.1103/kf73-hw61].
Abumusabh, M.; Adachi, I.; Adamczyk, K.; Aggarwal, L.; Ahmed, H.; Ahn, Y.; Aihara, H.; Akopov, N.; Alghamdi, S.; Alhakami, M.; Aloisio, A.; Althubiti,...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/1084110
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