학술논문
Measurements of the branching fractions $\mathcal{B} (\bar{B}{}^0 \to D^{*+} \pi^-)$ and $\mathcal{B} (\bar{B}{}^0 \to D^{*+} K^-)$ and tests of QCD factorization
Document Type
Working Paper
Author
Belle Collaboration; Krohn, J. F.; Ferlewicz, D.; Urquijo, P.; Adachi, I.; Aihara, H.; Said, S. Al; Asner, D. M.; Atmacan, H.; Aushev, T.; Ayad, R.; Babu, V.; Bahinipati, S.; Behera, P.; Belous, K.; Bessner, M.; Bhardwaj, V.; Bhuyan, B.; Bilka, T.; Bodrov, D.; Bonvicini, G.; Borah, J.; Bozek, A.; Bračko, M.; Branchini, P.; Browder, T. E.; Budano, A.; Campajola, M.; Červenkov, D.; Chang, M. -C.; Chang, P.; Chekelian, V.; Chen, A.; Cheon, B. G.; Chilikin, K.; Cho, H. E.; Cho, K.; Cho, S. -J.; Choi, Y.; Choudhury, S.; Cinabro, D.; Cunliffe, S.; Das, S.; Dash, N.; De Nardo, G.; De Pietro, G.; Dhamija, R.; Di Capua, F.; Doležal, Z.; Dong, T. V.; Epifanov, D.; Ferber, T.; Fulsom, B. G.; Garg, R.; Gaur, V.; Gabyshev, N.; Goldenzweig, P.; Golob, B.; Graziani, E.; Gu, T.; Gudkova, K.; Hadjivasiliou, C.; Hara, T.; Hayasaka, K.; Hayashii, H.; Hou, W. -S.; Hsu, C. -L.; Inami, K.; Ishikawa, A.; Iwasaki, M.; Iwasaki, Y.; Jacobs, W. W.; Jang, E. -J.; Jia, S.; Jin, Y.; Joo, K. K.; Kahn, J.; Kaliyar, A. B.; Kang, K. H.; Kawasaki, T.; Kichimi, H.; Kiesling, C.; Kim, C. H.; Kim, D. Y.; Kim, Y. -K.; Kinoshita, K.; Kodyš, P.; Konno, T.; Korobov, A.; Korpar, S.; Kovalenko, E.; Križan, P.; Krokovny, P.; Kumar, M.; Kumar, R.; Kumara, K.; Kwon, Y. -J.; Lam, T.; Laurenza, M.; Lee, S. C.; Li, J.; Li, L. K.; Li, Y. B.; Gioi, L. Li; Libby, J.; Liventsev, D.; Martini, A.; Masuda, M.; Matsuda, T.; Matvienko, D.; Maurya, S. K.; Meier, F.; Merola, M.; Metzner, F.; Miyabayashi, K.; Mizuk, R.; Mohanty, G. B.; Mussa, R.; Nakao, M.; Narwal, D.; Natkaniec, Z.; Natochii, A.; Nayak, L.; Nisar, N. K.; Nishida, S.; Nishimura, K.; Ogawa, K.; Ogawa, S.; Ono, H.; Oskin, P.; Pakhlov, P.; Pakhlova, G.; Pang, T.; Pardi, S.; Park, S. -H.; Patra, S.; Pedlar, T. K.; Pestotnik, R.; Piilonen, L. E.; Podobnik, T.; Popov, V.; Prim, M. T.; Röhrken, M.; Rostomyan, A.; Rout, N.; Russo, G.; Sahoo, D.; Sandilya, S.; Sangal, A.; Santelj, L.; Sanuki, T.; Savinov, V.; Schnell, G.; Schueler, J.; Schwanda, C.; Seino, Y.; Senyo, K.; Sevior, M. E.; Shapkin, M.; Sharma, C.; Shebalin, V.; Shen, C. P.; Shiu, J. -G.; Shwartz, B.; Simon, F.; Solovieva, E.; Stanič, S.; Starič, M.; Stottler, Z. S.; Sumihama, M.; Sumisawa, K.; Sumiyoshi, T.; Sutcliffe, W.; Takizawa, M.; Tamponi, U.; Tanida, K.; Tenchini, F.; Trabelsi, K.; Uchida, M.; Unno, Y.; Uno, K.; Uno, S.; Vahsen, S. E.; van Tonder, R.; Varner, G.; Varvell, K. E.; Vinokurova, A.; Waheed, E.; Wang, E.; Wang, M. -Z.; Wang, X. L.; Watanuki, S.; Won, E.; Yan, W.; Ye, H.; Yelton, J.; Yin, J. H.; Yusa, Y.; Zhai, Y.; Zhilich, V.; Zhukova, V.
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Subject
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Abstract
Using $(771.6 \pm 10.6) \times 10^6$ $B\bar{B}$ meson pairs recorded by the Belle experiment at the KEKB $e^+ e^-$ collider, we report the branching fractions $\mathcal{B}(\bar{B}^0 \to D^{*+} \pi^-) = (2.62 \pm 0.02 \pm 0.09)\times 10^{-3}$ and $\mathcal{B}(\bar{B}^0 \to D^{*+} K^-) = (2.22 \pm 0.06 \pm 0.08)\times 10^{-4}$; the quoted uncertainties are statistical and systematic, respectively. A measurement of the ratio of these branching fractions is also presented, $\mathcal{R}_{K/\pi}=\mathcal{B}(\bar{B} \to D^{*+}K^-) /\mathcal{B}( \bar{B} \to D^{*+}\pi^-) = (8.41 \pm 0.24 \pm 0.13)\times 10^{-2}$, where systematic uncertainties due to the $D^{*+}$ meson reconstruction cancel out. Furthermore, we report a new QCD factorization test based on the measured ratios for $\bar{B} \to D^{*+}h^-$ and $\bar{B} \to D^{*+}\ell^-\nu$ decays at squared momentum transfer values equivalent to the mass of the $h = \pi$ or $K$ hadron. The parameters $|a_1(h)|$ are measured to be $|a_1(\pi)|= 0.884 \pm 0.004 \pm 0.003 \pm 0.016$ and $|a_1(K)|=0.913 \pm 0.019 \pm 0.008 \pm 0.013$, where the last uncertainties account for all external inputs. These values are approximately $15\%$ lower than those expected from theoretical predictions. Subsequently, flavor $SU(3)$ symmetry is tested by measuring the ratios for pions and kaons, $|a_1(K)|^2/ |a_1(\pi)|^2=1.066 \pm 0.042 \pm 0.018 \pm 0.023$, as well as for different particle species. The ratio is consistent with unity and therefore no evidence for $SU(3)$ symmetry breaking effects is found at the $5\%$ precision level.
Comment: 13 pages, 6 figures
Comment: 13 pages, 6 figures