Study of exclusive $B\to X_u\ell \nu$ decays and extraction of $\left|V_{ub}\right|$ using full reconstruction tagging at the Belle experiment

Journal Article · Wed Aug 07 00:00:00 EDT 2013 · Physical Review. D, Particles, Fields, Gravitation and Cosmology

DOI:https://doi.org/10.1103/PhysRevD.88.032005· OSTI ID:1594532

Sibidanov, A.; Varvell, K. E.; Adachi, I.; Aihara, H.; Asner, D. M.; Aulchenko, V.; Aushev, T.; Bakich, A. M.; Bala, A.; Bozek, A.; Bračko, M.; Browder, T. E.; Chekelian, V.; Chen, P.; Cheon, B. G.; Chilikin, K.; Chistov, R.; Cho, I. -S.; Cho, K.; Chobanova, V. ; Choi, Y.; Cinabro, D.; Dalseno, J.; Danilov, M.; Dingfelder, J.; Doležal, Z.; Drásal, Z.; Drutskoy, A.; Dutta, D.; Eidelman, S.; Epifanov, D.; Farhat, H.; Fast, J. E.; Ferber, T.; Frey, A.; Gaur, V.; Ganguly, S.; Gillard, R.; Goh, Y. M.; Golob, B.; Haba, J.; Hayashii, H.; Hoshi, Y.; Hou, W. -S.; Hyun, H. J.; Iijima, T.; Ishikawa, A.; Itoh, R.; Iwasaki, Y.; Julius, T.; Kah, D. H.; Kang, J. H.; Kawasaki, T.; Kiesling, C.; Kim, D. Y.; Kim, H. J.; Kim, J. B.; Kim, J. H.; Kim, K. T.; Kim, Y. J.; Klucar, J.; Ko, B. R.; Kodyš, P.; Korpar, S.; Križan, P.; Krokovny, P.; Kronenbitter, B.; Kuhr, T.; Kuzmin, A.; Kwon, Y. -J.; Lee, S. -H.; Li, J.; Li, Y.; Libby, J.; Liu, Y.; Liventsev, D.; Lukin, P.; Matvienko, D.; Miyabayashi, K.; Miyata, H.; Mohanty, G. B.; Moll, A.; Mussa, R.; Nagasaka, Y.; Nakano, E.; Nakao, M.; Natkaniec, Z.; Nayak, M.; Nedelkovska, E.; Ng, C.; Nisar, N. K.; Nishida, S.; Nitoh, O.; Nozaki, T.; Ogawa, S.; Okuno, S.; Olsen, S. L.; Oswald, C.; Park, H.; Park, H. K.; Pedlar, T. K.; Pestotnik, R.; Petrič, M.; Piilonen, L. E.; Ritter, M.; Röhrken, M.; Rostomyan, A.; Ryu, S.; Sahoo, H.; Saito, T.; Sakai, Y.; Sandilya, S.; Santelj, L.; Sanuki, T.; Sato, Y.; Savinov, V.; Schneider, O.; Schnell, G.; Schwanda, C.; Senyo, K.; Seon, O.; Sevior, M. E.; Shapkin, M.; Shebalin, V.; Shen, C. P.; Shibata, T. -A.; Shiu, J. -G.; Simon, F.; Smerkol, P.; Sohn, Y. -S.; Solovieva, E.; Stanič, S.; Starič, M.; Steder, M.; Sumihama, M.; Sumisawa, K.; Sumiyoshi, T.; Tatishvili, G.; Teramoto, Y.; Trabelsi, K.; Tsuboyama, T.; Uchida, M.; Uehara, S.; Uglov, T.; Unno, Y.; Uno, S.; Urquijo, P.; Ushiroda, Y.; Vahsen, S. E.; Van Hulse, C.; Vanhoefer, P.; Varner, G.; Vorobyev, V.; Wagner, M. N.; Wang, C. H.; Wang, P.; Watanabe, M.; Watanabe, Y.; Williams, K. M.; Won, E.; Yabsley, B. D.; Yamashita, Y.; Yashchenko, S.; Yook, Y.; Zhang, Z. P.; Zhilich, V.; Zhulanov, V.; Zupanc, A.

Here, we report the results of a study of the exclusive semileptonic decays $B^{-}\to {\pi }^0{\ell }^{-}{\overline{\nu }}_{\ell }$, ${\overline{B}}^0\to {\pi }^{+}{\ell }^{-}{\overline{\nu }}_{\ell }$, $B^{-}\to {\rho }^0{\ell }^{-}{\overline{\nu }}_{\ell }$, ${\overline{B}}^0\to {\rho }^{+}{\ell }^{-}{\overline{\nu }}_{\ell }$ and $B^{-}\to \omega {\ell }^{-}{\overline{\nu }}_{\ell }$, where $\ell$ represents an electron or a muon. The events are tagged by fully reconstructing a second $B$ meson in the event in a hadronic decay mode. The measured branching fractions are $\mathcal{B}(B^{-}\to {\pi }^0{\ell }^{-}{\overline{\nu }}_{\ell })=(0.80\pm 0.08\pm 0.04)\times {10}^{-4}$, $\mathcal{B}({\overline{B}}^0\to {\pi }^{+}{\ell }^{-}{\overline{\nu }}_{\ell })=(1.49\pm 0.09\pm 0.07)\times {10}^{-4}$, $\mathcal{B}(B^{-}\to {\rho }^0{\ell }^{-}{\overline{\nu }}_{\ell })=(1.83\pm 0.10\pm 0.10)\times {10}^{-4}$, $\mathcal{B}({\overline{B}}^0\to {\rho }^{+}{\ell }^{-}{\overline{\nu }}_{\ell })=(3.22\pm 0.27\pm 0.24)\times {10}^{-4}$, and $\mathcal{B}(B^{-}\to \omega {\ell }^{-}{\overline{\nu }}_{\ell })=(1.07\pm 0.16\pm 0.07)\times {10}^{-4}$, where the first error is statistical and the second one is systematic. The obtained branching fractions are inclusive of soft photon emission. Furthermore, we determine the branching fractions as a function of the 4-momentum transfer squared to the leptonic system $q^2=(p_{\ell }+p_{\nu }{)}^2$, where $p_{\ell }$ and $p_{\nu }$ are the lepton and neutrino 4-momenta, respectively. Using the pion modes, a recent light cone sum rule calculation, lattice QCD results and a model-independent description of the hadronic form factor, a value of the Cabibbo-Kobayashi-Maskawa matrix element $\left|V_{ub}\right|=(3.52\pm 0.29)\times {10}^{-3}$ is extracted. A structure in the two-pion invariant mass distribution near $1.3\mathrm{GeV}/c^2$, which might be dominated by the decay $B^{-}\to f_2\left(1270\right){\ell }^{-}{\overline{\nu }}_{\ell }$, $f_2\to {\pi }^{+}{\pi }^{-}$, is seen. These results are obtained from a $711{\mathrm{fb}}^{-1}$ data sample that contains $772\times {10}^6$ $B\overline{B}$ pairs, collected near the ${\rm Y}\left(4S\right)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider.

• Research Organization: Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), High Energy Physics (HEP); National Natural Science Foundation of China (NSFC)
• Contributing Organization: Belle Collaboration
• Grant/Contract Number: SC0009973
• OSTI ID: 1594532
• Journal Information: Physical Review. D, Particles, Fields, Gravitation and Cosmology, Vol. 88, Issue 3; ISSN 1550-7998
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

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