Yuma Uematsu ; Yutaka Ushiroda

2023
The University of Tokyo Tokyo

Abstract: We measure the time-dependent CP asymmetries in B0 -> KS0 π0 γ decay using (387.5 ± 5.8) × 10^6 BBbar pairs collected near the Υ(4S) resonance with SuperKEKB and Belle II from 2019 to 2022. For the measurement, we reconstruct one neutral B meson in the B0 -> KS0 π0 γ decay channel, identify the flavor of the accompanying B meson from its decay products, and measure the proper-time difference between the two B mesons. We obtain the following results: for the KS0 π0 invariant mass around K∗(892)0 resonance (0.8 to 1.0 GeV/c2), S_CP(K∗0γ) = 0.00 +0.27−0.26(stat) +0.03−0.04(syst) and A_CP(K∗0γ) = −0.10 ± 0.13(stat) ± 0.03(syst), and for the rest of the mass regions up to 1.8 GeV/c2, S_CP(KS0π0γ) = +0.04 +0.45−0.44(stat) ± 0.10(syst) and A_CP(KS0π0γ) = +0.06 ± 0.25(stat) ± 0.07(syst). These results are the most precise to date as a single measurement.

Note: Presented on 26 07 2023
Note: PhD