We report the observation of the flavor-changing neutral current process b→dγ using a sample of 386×106 B meson pairs accumulated by the Belle detector at the KEKB e+e- collider. We measure branching fractions for the exclusive modes B-→ρ-γ, B̄0→ρ0γ, and B̄0→ωγ. Assuming that these three modes are related by isospin, we find B(B̄→(ρ,ω)γ)=(1.32-0.31+0.34(stat)-0.09+0.10(syst)) ×10-6 with a significance of 5.1σ. This result is used to determine the ratio of Cabibbo-Kobayashi-Maskawa matrix elements |Vtd/Vts| to be 0.199-0.025+0.026(exp)-0.015+0.018(theor). © 2006 The American Physical Society.
Rakesh Chawla, Andrea Rizzi, Matthias Finger, Federica Legger, Matteo Galli, Sun Hee Kim, João Miguel das Neves Duarte, Tagir Aushev, Hua Zhang, Alexis Kalogeropoulos, Yixing Chen, Tian Cheng, Ioannis Papadopoulos, Gabriele Grosso, Valérie Scheurer, Meng Xiao, Qian Wang, Michele Bianco, Varun Sharma, Joao Varela, Marko Stamenkovic, Sourav Sen, Ashish Sharma, Seungkyu Ha, David Vannerom, Csaba Hajdu, Sanjeev Kumar, Sebastiana Gianì, Kun Shi, Abhisek Datta, Siyuan Wang, Anton Petrov, Jian Wang, Yi Zhang, Muhammad Ansar Iqbal, Yong Yang, Xin Sun, Muhammad Ahmad, Donghyun Kim, Matthias Wolf, Anna Mascellani, Paolo Ronchese, , , , , , , , , , , , , , , , , , , , ,
Rakesh Chawla, Arvind Shah, Andrea Rizzi, Matthias Finger, Bandeep Singh, Federica Legger, Thomas Berger, Jian Zhao, João Miguel das Neves Duarte, Tagir Aushev, Hua Zhang, Alexis Kalogeropoulos, Yixing Chen, Tian Cheng, Ioannis Papadopoulos, Valérie Scheurer, Meng Xiao, Wei Sun, Maren Tabea Meinhard, Qian Wang, Michele Bianco, Varun Sharma, Jessica Prisciandaro, Joao Varela, Francesco Fiori, Sourav Sen, Ashish Sharma, Seungkyu Ha, David Vannerom, Csaba Hajdu, Sanjeev Kumar, Sebastiana Gianì, Kun Shi, Abhisek Datta, Miao Hu, Siyuan Wang, Peter Hansen, Muhammad Waqas, Dipanwita Dutta, Anton Petrov, Jian Wang, Yi Zhang, , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,