Measurement of CP Asymmetries in B0 → KS0 π0γ Decays at Belle II

I Adachi; L Aggarwal; H Ahmed; H Aihara; N Akopov; A Aloisio; N Anh Ky; DM Asner; H Atmacan; T Aushev; V Aushev; M Aversano; R Ayad; V Babu; H Bae; S Bahinipati; P Bambade; S Banerjee; S Bansal; M Barrett; J Baudot; A Baur; A Beaubien; F Becherer; J Becker; JV Bennett; FU Bernlochner; V Bertacchi; M Bertemes; E Bertholet; M Bessner; S Bettarini; B Bhuyan; F Bianchi; L Bierwirth; T Bilka; S Bilokin; D Biswas; D Bodrov; A Bolz; A Bondar; J Borah; A Boschetti; A Bozek; M Bračko; P Branchini; RA Briere; TE Browder; A Budano; S Bussino; M Campajola; L Cao; G Casarosa; C Cecchi; J Cerasoli; MC Chang; P Chang; R Cheaib; P Cheema; C Chen; BG Cheon; K Chilikin; K Chirapatpimol; HE Cho; K Cho; SJ Cho; SK Choi; S Choudhury; J Cochran; L Corona; JX Cui; S Das; F Dattola; E De La Cruz-Burelo; SA De La Motte; G De Nardo; M De Nuccio; G De Pietro; R De Sangro; M Destefanis; S Dey; R Dhamija; A Di Canto; F Di Capua; J Dingfelder; Z DoleŽal; I Domínguez Jiménez; TV Dong; M Dorigo; D Dorner; K Dort; D Dossett; S Dreyer; S Dubey; K Dugic; G Dujany; P Ecker; M Eliachevitch; P Feichtinger; T Ferber

Journal article

Measurement of CP Asymmetries in B0 → KS0 π0γ Decays at Belle II

I Adachi, L Aggarwal, H Ahmed, H Aihara, N Akopov, A Aloisio, N Anh Ky, DM Asner, H Atmacan, T Aushev, V Aushev, M Aversano, R Ayad, V Babu, H Bae, S Bahinipati, P Bambade, S Banerjee, S Bansal, M Barrett Show all

Physical Review Letters | American Physical Society (APS) | Published : 2025

DOI: 10.1103/PhysRevLett.134.011802

Abstract

We report measurements of time-dependent CP asymmetries in B0→KS0π0γ decays based on a data sample of (388±6)×106 BB¯ events collected at the ϒ(4S) resonance with the Belle II detector. The Belle II experiment operates at the SuperKEKB asymmetric-energy e+e- collider. We measure decay-time distributions to determine CP -violating parameters S and C. We determine these parameters for two ranges of KS0π0 invariant mass: m(KS0π0)(0.8,1.0) GeV/c2, which is dominated by B0→K∗0(→KS0π0)γ decays, and a complementary region m(KS0π0)(0.6,0.8)(1.0,1.8) GeV/c2. Our results have improved precision as compared to previous measurements and are consistent with theory predictions.