Measurement of the lepton forward-backward asymmetry in $B\to X_s{\ell }^{+}{\ell }^{-}$ decays with a sum of exclusive modes

Journal Article · Mon Feb 01 00:00:00 EST 2016 · Physical Review D

DOI:https://doi.org/10.1103/PhysRevD.93.032008· OSTI ID:1594401

Sato, Y.; Ishikawa, A.; Yamamoto, H.; Abdesselam, A.; Adachi, I.; Adamczyk, K.; Aihara, H.; Asner, D. M.; Aulchenko, V.; Aushev, T.; Ayad, R.; Bakich, A. M.; Bala, A.; Bhardwaj, V.; Bhuyan, B.; Bondar, A.; Bonvicini, G.; Bozek, A.; Bračko, M.; Browder, T. E. ; Červenkov, D.; Chekelian, V.; Chen, A.; Cheon, B. G.; Cho, I. -S.; Cho, K.; Chobanova, V.; Choi, Y.; Cinabro, D.; Dalseno, J.; Danilov, M.; Doležal, Z.; Drásal, Z.; Drutskoy, A.; Dutta, D.; Dutta, K.; Eidelman, S.; Farhat, H.; Fast, J. E.; Ferber, T.; Gaur, V.; Garmash, A.; Gillard, R.; Goh, Y. M.; Golob, B.; Haba, J.; Hara, T.; Hayasaka, K.; Hayashii, H.; He, X. H.; Hoshi, Y.; Hou, W. -S.; Hyun, H. J.; Iijima, T.; Itoh, R.; Iwasaki, Y.; Iwashita, T.; Jaegle, I.; Julius, T.; Kang, J. H.; Kato, E.; Kato, Y.; Kawai, H.; Kawasaki, T.; Kichimi, H.; Kim, D. Y.; Kim, H. J.; Kim, J. B.; Kim, J. H.; Kim, M. J.; Kim, Y. J.; Kinoshita, K.; Klucar, J.; Ko, B. R.; Kodyš, P.; Korpar, S.; Križan, P.; Krokovny, P.; Kuhr, T.; Kumita, T.; Kuzmin, A.; Kwon, Y. -J.; Lee, S. -H.; Li, Y.; Libby, J.; Liu, C.; Liu, Y.; Liu, Z. Q.; Liventsev, D.; Lukin, P.; Miyata, H.; Mizuk, R.; Mohanty, G. B.; Moll, A.; Mussa, R.; Nakao, M.; Natkaniec, Z.; Nayak, M.; Nedelkovska, E.; Nisar, N. K.; Nishida, S.; Nitoh, O.; Ogawa, S.; Pakhlov, P.; Park, H.; Park, H. K.; Pedlar, T. K.; Peng, T.; Pestotnik, R.; Petrič, M.; Piilonen, L. E.; Ribežl, E.; Ritter, M.; Röhrken, M.; Rostomyan, A.; Sahoo, H.; Saito, T.; Sakai, Y.; Sandilya, S.; Santel, D.; Santelj, L.; Sanuki, T.; Savinov, V.; Schneider, O.; Schnell, G.; Schwanda, C.; Schwartz, A. J.; Seidl, R.; Semmler, D.; Senyo, K.; Sevior, M. E.; Shapkin, M.; Shen, C. P.; Shibata, T. -A.; Shiu, J. -G.; Shwartz, B.; Sibidanov, A.; Simon, F.; Sohn, Y. -S.; Sokolov, A.; Solovieva, E.; Stanič, S.; Starič, M.; Sumiyoshi, T.; Tamponi, U.; Tatishvili, G.; Teramoto, Y.; Trabelsi, K.; Uchida, M.; Uehara, S.; Uglov, T.; Unno, Y.; Uno, S.; Urquijo, P.; Ushiroda, Y.; Usov, Y.; Vahsen, S. E.; Van Hulse, C.; Vanhoefer, P.; Varner, G.; Varvell, K. E.; Vorobyev, V.; Wang, C. H.; Wang, M. -Z.; Wang, P.; Wang, X. L.; Watanabe, Y.; Won, E.; Yamaoka, J.; Yamashita, Y.; Yashchenko, S.; Yook, Y.; Zhang, Z. P.; Zhilich, V.; Zhulanov, V.; Zupanc, A.

We report the first measurement of the lepton forward-backward asymmetry $$\mathscr{A}$$_FB as a function of the squared four-momentum of the dilepton system, q², for the electroweak penguin process B→X_sℓ⁺ℓ^- with a sum of exclusive final states, where ℓ is an electron or a muon and X_s is a hadronic recoil system with an s quark. The results are based on a data sample containing 772×10⁶ $$B$$$\bar{B}$$ pairs recorded at the Υ(4S) resonance with the Belle detector at the KEKB e⁺e^- collider. $$\mathscr{A}4_FB for the inclusive B→X_sℓ⁺ℓ^- is extrapolated from the sum of 10 exclusive X_s states whose invariant mass is less than 2 GeV/c². For q²>10.2 GeV²/c², $$\mathscr{A}$_FB<0 is excluded at the 2.3σ level, where σ is the standard deviation. For q²<4.3 GeV²/c², the result is within 1.8σ of the Standard Model theoretical expectation.

• 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)
• Contributing Organization: Belle Collaboration
• Grant/Contract Number: SC0009973
• OSTI ID: 1594401
• Alternate ID(s): OSTI ID: 1238698
• Journal Information: Physical Review D, Vol. 93, Issue 3; ISSN 2470-0010
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

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