We report a measurement of the ratio R(D*) = B((B) over bar (0) -> D*(+)tau(-)(nu) over bar (tau))/B((B) over bar (0) -> D*(+)l(-)(nu) over bar (l))where l denotes an electron or a muon. The results are based on a data sample containing 772 x 10(6) B (B) over bar pairs recorded at the Upsilon(4S) resonance with the Belle detector at the KEKB e(+)e(-) collider. We select a sample of B-0(B) over bar (0) pairs by reconstructing both B mesons in semileptonic decays to D*(-/+)l(+/-). We measure R(D*) = 0.302 +/- 0.030(stat) +/- 0.011(syst), which is within 1.6 sigma of the Standard Model theoretical expectation, where the standard deviation sigma includes systematic uncertainties. We use this measurement to constrain several scenarios of new physics in a model-independent approach.
Olivier Schneider, Yiming Li, Mingkui Wang, Chao Wang, Sun Hee Kim, Donghyun Kim, Xiao Wang, Lei Li
Olivier Schneider, Yiming Li, Mingkui Wang, Chao Wang, Tagir Aushev, Sun Hee Kim, Donghyun Kim, Xiao Wang, Lei Li
Jian Wang, Olivier Schneider, Yiming Li, Yi Zhang, Aurelio Bay, Guido Haefeli, Christoph Frei, Frédéric Blanc, Tatsuya Nakada, Michel De Cian, Luca Pescatore, François Fleuret, Elena Graverini, Chitsanu Khurewathanakul, Renato Quagliani, Maria Vieites Diaz, Federico Betti, Aravindhan Venkateswaran, Luis Miguel Garcia Martin, Vitalii Lisovskyi, Sebastian Schulte, Veronica Sølund Kirsebom, Mingkui Wang, Zhirui Xu, Lei Zhang, Jessica Prisciandaro, Mark Tobin, Minh Tâm Tran, Niko Neufeld, Matthew Needham, Marc-Olivier Bettler, Greig Alan Cowan, Maurizio Martinelli, Vladislav Balagura, Donal Patrick Hill, Liang Sun, Pietro Marino, Mirco Dorigo, Xiaoxue Han, Liupan An, Federico Leo Redi, Plamen Hristov Hopchev, Thibaud Humair, Maxime Schubiger, Hang Yin, Guido Andreassi, Violaine Bellée, Olivier Göran Girard, Axel Kuonen, Preema Rennee Pais, Pavol Stefko, Tara Nanut, Maria Elena Stramaglia, Tommaso Colombo, Vladimir Macko, Guillaume Max Pietrzyk, Evgenii Shmanin, Dipanwita Dutta, Zheng Wang, Yi Wang, Hans Dijkstra, Gerhard Raven, Peter Clarke, Frédéric Teubert, Giovanni Carboni, Victor Coco, Adam Davis, Paolo Durante, Wenyu Zhang, Yu Zheng, Anton Petrov, Maxim Borisyak, Feng Jiang, Zhipeng Tang