Search for the decay B0 →γγ using Belle and Belle II data

I Adachi; L Aggarwal; H Aihara; N Akopov; A Aloisio; S Al Said; N Althubiti; 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; K Belous; JV Bennett; FU Bernlochner; V Bertacchi; E Bertholet; M Bessner; S Bettarini; B Bhuyan; F Bianchi; L Bierwirth; T Bilka; D Biswas; A Bobrov; D Bodrov; A Bolz; J Borah; A Boschetti; A Bozek; M Bračko; P Branchini; RA Briere; TE Browder; A Budano; S Bussino; Q Campagna; M Campajola; L Cao; G Casarosa; C Cecchi; J Cerasoli; MC Chang; P Chang; P Cheema; C Chen; BG Cheon; K Chilikin; K Chirapatpimol; HE Cho; K Cho; SJ Cho; SK Choi; S Choudhury; L Corona; JX Cui; 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; D Epifanov; P Feichtinger; T Ferber; T Fillinger

Journal article

Search for the decay B0 →γγ using Belle and Belle II data

I Adachi, L Aggarwal, H Aihara, N Akopov, A Aloisio, S Al Said, N Althubiti, 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 Show all

Physical Review D | Published : 2024

DOI: 10.1103/PhysRevD.110.L031106

Abstract

We report the result of a search for the rare decay B0→γγ using a combined dataset of 753×106 BB¯ pairs collected by the Belle experiment and 387×106 BB¯ pairs collected by the Belle II experiment from decays of the ϒ(4S) resonance produced in e+e- collisions. A simultaneous fit to the Belle and Belle II data sets yields 11.0-5.5+6.5 signal events, corresponding to a 2.5σ significance. We determine the branching fraction B(B0→γγ)=(3.7-1.8+2.2(stat)±0.5(syst))×10-8 and set a 90% credibility level upper limit of B(B0→γγ)<6.4×10-8.