Angular analysis of B → K e + e − in the low- q 2 region with new electron identification at Belle

• Published in: Physical review. D 2024-10, Vol.110 (7), Article 072005
• Main Authors: Ferlewicz, D., Urquijo, P., Adachi, I., Adamczyk, K., Aihara, H., Asner, D. M., Atmacan, H., Ayad, R., Babu, V., Banerjee, Sw, Behera, P., Belous, K., Bennett, J., Bessner, M., Bhardwaj, V., Bhuyan, B., Bilka, T., Biswas, D., Bodrov, D., Bračko, M., Branchini, P., Browder, T. E., Budano, A., Campajola, M., Cao, L., Červenkov, D., Chang, M.-C., Cheon, B. G., Chilikin, K., Cho, H. E., Cho, K., Choi, S.-K., Choi, Y., Choudhury, S., Das, S., Dash, N., de Marino, G., De Pietro, G., Dhamija, R., Di Capua, F., Dingfelder, J., Doležal, Z., Dong, T. V., Dubey, S., Ecker, P., Epifanov, D., Ferber, T., Fulsom, B. G., Gaur, V., Garmash, A., Giri, A., Goldenzweig, P., Graziani, E., Gu, T., Guan, Y., Gudkova, K., Hadjivasiliou, C., Hara, T., Hayasaka, K., Hayashii, H., Hazra, S., Hedges, M. T., Herrmann, D., Hou, W.-S., Hsu, C.-L., Iijima, T., Ishikawa, A., Itoh, R., Iwasaki, M., Jacobs, W. W., Jia, S., Jin, Y., Kaliyar, A. B., Kiesling, C., Kim, C. H., Kim, D. Y., Kim, K.-H., Kim, Y.-K., Kinoshita, K., Kodyš, P., Konno, T., Korobov, A., Korpar, S., Kou, E., Kovalenko, E., Križan, P., Krokovny, P., Kuhr, T., Kumar, R., Kumara, K., Kuzmin, A., Kwon, Y.-J., Lai, Y.-T., Lam, T., Lee, S. C., Levit, D., Lewis, P., Li, L. K., Li, Y. B., Li Gioi, L.
• Format: Article
• Language: English
• ISSN: 2470-0010; 2470-0029
• DOI: 10.1103/PhysRevD.110.072005

We perform an angular analysis of the B → K * e + e − decay for the dielectron mass squared, q 2 , range of 0.0008 – 1.1200 GeV 2 / c 4 using the full Belle dataset in the K * 0 → K + π − and K * + → K S 0 π + channels, incorporating new methods of electron identification to improve the statistical power of the dataset. This analysis is sensitive to contributions from right-handed currents from physics beyond the Standard Model by constraining the Wilson coefficients C 7 ( ′ ) . We perform a fit to the B → K * e + e − differential decay rate and measure the imaginary component of the transversality amplitude to be A T Im = − 1.27 ± 0.52 ± 0.12 , and the K * transverse asymmetry to be A T ( 2 ) = 0.52 ± 0.53 ± 0.11 , with F L and A T Re fixed to the Standard Model values. The resulting constraints on the value of C 7 ′ are consistent with the Standard Model within a 2 σ confidence interval.