We report a search for a dark vector gauge boson U' that couples to quarks in the decay chain D*(+) -> D-0 pi(+), D-0 -> K-S(0) eta, eta -> U'gamma, U' -> pi(+)pi- No signal is found and we set a mass-dependent limit on the baryonic fine structure constant of 10(-3)-10(-2) in the U' mass range of 290 to 520 MeV/c(2). This analysis is based on a data sample of 976 fb(-1) collected by the Belle experiment at the KEKB asymmetric-energy e(+)e(-) collider.
Jian Wang, Lesya Shchutska, Olivier Schneider, Yiming Li, Yi Zhang, Aurelio Bay, Guido Haefeli, Christoph Frei, Frédéric Blanc, Tatsuya Nakada, Michel De Cian, François Fleuret, Elena Graverini, Renato Quagliani, Federico Betti, Aravindhan Venkateswaran, Luis Miguel Garcia Martin, Vitalii Lisovskyi, Katharina Müller, Sebastian Schulte, Veronica Sølund Kirsebom, Elisabeth Maria Niel, Mingkui Wang, Zhirui Xu, Lei Zhang, Ho Ling Li, Mark Tobin, Minh Tâm Tran, Niko Neufeld, Matthew Needham, Marc-Olivier Bettler, 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, Preema Rennee Pais, Pavol Stefko, Tara Nanut, Maria Elena Stramaglia, Yao Zhou, Tommaso Colombo, Vladimir Macko, Guillaume Max Pietrzyk, Evgenii Shmanin, Simone Meloni, Xiaoqing Zhou, Lino Ferreira Lopes, Surapat Ek-In, Carina Trippl, Sara Celani, Marco Guarise, Serhii Cholak, 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, Xuan Li, Alexey Boldyrev, Almagul Kondybayeva, Hossein Afsharnia