Measurement of branching fractions for B → χc1(2)K (K*) at Belle

N. Soni; K. Abe; K. Abe; I. Adachi; H. Aihara; K. Arinstein; Y. Asano; V. Aulchenko; T. Aushev; A. M. Bakich; E. Barberio; I. Bedny; U. Bitenc; I. Bizjak; S. Blyth; A. Bondar; M. Bračko; T. E. Browder; P. Chang; Y. Chao; A. Chen; K. F. Chen; B. G. Cheon; R. Chistov; S. K. Choi; Y. Choi; A. Chuvikov; J. Dalseno; M. Danilov; M. Dash; L. Y. Dong; S. Eidelman; Y. Enari; D. Epifanov; S. Fratina; N. Gabyshev; A. Garmash; T. Gershon; A. Go; G. Gokhroo; B. Golob; A. Gorišek; J. Haba; T. Hara; K. Hayasaka; H. Hayashii; M. Hazumi; L. Hinz; T. Hokuue; Y. Hoshi; S. Hou; W. S. Hou; T. Iijima; K. Ikado; A. Imoto; K. Inami; A. Ishikawa; R. Itoh; J. H. Kang; J. S. Kang; P. Kapusta; N. Katayama; T. Kawasaki; H. R. Khan; H. Kichimi; H. J. Kim; S. M. Kim; S. Korpar; P. Križan; P. Krokovny; R. Kulasiri; C. C. Kuo; A. Kuzmin; Y. J. Kwon; T. Lesiak; S. W. Lin; D. Liventsev; G. Majumder; F. Mandl; T. Matsumoto; Y. Mikami; W. Mitaroff; K. Miyabayashi; H. Miyake; H. Miyata; Y. Miyazaki; R. Mizuk; D. Mohapatra; T. Nagamine; Z. Natkaniec; S. Nishida; O. Nitoh; S. Ogawa; T. Ohshima; T. Okabe; S. Okuno; S. L. Olsen; Y. Onuki; W. Ostrowicz; H. Ozaki; P. Pakhlov; C. W. Park; R. Pestotnik; M. Peters; L. E. Piilonen; A. Poluektov; Y. Sakai; N. Sato; T. Schietinger; O. Schneider; M. E. Sevior; H. Shibuya; B. Shwartz; V. Sidorov; J. B. Singh; A. Somov; S. Stanič; M. Starič; T. Sumiyoshi; S. Suzuki; S. Y. Suzuki; F. Takasaki; K. Tamai; N. Tamura; M. Tanaka; G. N. Taylor; Y. Teramoto; X. C. Tian; T. Tsuboyama; T. Tsukamoto; S. Uehara; K. Ueno; T. Uglov; S. Uno; P. Urquijo; G. Varner; S. Villa; C. C. Wang; C. H. Wang; Y. Watanabe; E. Won; Q. L. Xie; A. Yamaguchi; Y. Yamashita; M. Yamauchi; J. Ying; Y. Yuan; C. C. Zhang; L. M. Zhang; Z. P. Zhang; V. Zhilich

doi:10.1016/j.physletb.2006.01.013

Measurement of branching fractions for B → χ_c1(2)K (K*) at Belle

N. Soni, K. Abe, K. Abe, I. Adachi, H. Aihara, K. Arinstein, Y. Asano, V. Aulchenko, T. Aushev, A. M. Bakich, E. Barberio, I. Bedny, U. Bitenc, I. Bizjak, S. Blyth, A. Bondar, M. Bračko, T. E. Browder, P. Chang, Y. ChaoA. Chen, K. F. Chen, B. G. Cheon, R. Chistov, S. K. Choi, Y. Choi, A. Chuvikov, J. Dalseno, M. Danilov, M. Dash, L. Y. Dong, S. Eidelman, Y. Enari, D. Epifanov, S. Fratina, N. Gabyshev, A. Garmash, T. Gershon, A. Go, G. Gokhroo, B. Golob, A. Gorišek, J. Haba, T. Hara, K. Hayasaka, H. Hayashii, M. Hazumi, L. Hinz, T. Hokuue, Y. Hoshi, S. Hou, W. S. Hou, T. Iijima, K. Ikado, A. Imoto, K. Inami, A. Ishikawa, R. Itoh, J. H. Kang, J. S. Kang, P. Kapusta, N. Katayama, T. Kawasaki, H. R. Khan, H. Kichimi, H. J. Kim, S. M. Kim, S. Korpar, P. Križan, P. Krokovny, R. Kulasiri, C. C. Kuo, A. Kuzmin, Y. J. Kwon, T. Lesiak, S. W. Lin, D. Liventsev, G. Majumder, F. Mandl, T. Matsumoto, Y. Mikami, W. Mitaroff, K. Miyabayashi, H. Miyake, H. Miyata, Y. Miyazaki, R. Mizuk, D. Mohapatra, T. Nagamine, Z. Natkaniec, S. Nishida, O. Nitoh, S. Ogawa, T. Ohshima, T. Okabe, S. Okuno, S. L. Olsen, Y. Onuki, W. Ostrowicz, H. Ozaki, P. Pakhlov, C. W. Park, R. Pestotnik, M. Peters, L. E. Piilonen, A. Poluektov, Y. Sakai, N. Sato, T. Schietinger, O. Schneider, M. E. Sevior, H. Shibuya, B. Shwartz, V. Sidorov, J. B. Singh, A. Somov, S. Stanič, M. Starič, T. Sumiyoshi, S. Suzuki, S. Y. Suzuki, F. Takasaki, K. Tamai, N. Tamura, M. Tanaka, G. N. Taylor, Y. Teramoto, X. C. Tian, T. Tsuboyama, T. Tsukamoto, S. Uehara, K. Ueno, T. Uglov, S. Uno, P. Urquijo, G. Varner, S. Villa, C. C. Wang, C. H. Wang, Y. Watanabe, E. Won, Q. L. Xie, A. Yamaguchi, Y. Yamashita, M. Yamauchi, J. Ying, Y. Yuan, C. C. Zhang, L. M. Zhang, Z. P. Zhang, V. Zhilich

Department of Physics

Research output: Contribution to journal › Article › peer-review

17 Citations (Scopus)

Abstract

We have measured the branching fractions for the exclusive decay modes B→χ_c1(2)K(K*) using a 140 fb^-1 data sample collected by the Belle detector at the KEKB asymmetric-energy e ⁺e^- collider. The measured branching fractions for B ⁺→χ_c1K⁺, B⁰→χ _c1K⁰, B⁰→χ_c1K* ⁰ and B⁺→χ_c1K*⁺ decay modes are (4.5±0.2±0.5)×10^-4, (3.5±0.3±0.5)×10^-4, (3.1±0.3±0.7) ×10^-4 and (4.1±0.6±0.9)×10^-4, respectively, where the first error is statistical and the second error is systematic. We do not observe statistically significant signals for the B→χ_c2K(K*) decay modes and set upper limits at the 90% confidence level. We also study the helicity distribution for B→χ_c1K* decay mode and show that the longitudinal polarization component is dominant.

Original language	English
Pages (from-to)	155-164
Number of pages	10
Journal	Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Volume	634
Issue number	2-3
DOIs	https://doi.org/10.1016/j.physletb.2006.01.013
Publication status	Published - 2006 Mar 9

Bibliographical note

Funding Information:
We thank the KEKB group for the excellent operation of the accelerator, the KEK cryogenics group for the efficient operation of the solenoid, and the KEK computer group and the National Institute of Informatics for valuable computing and Super-SINET network support. We acknowledge support from the Ministry of Education, Culture, Sports, Science, and Technology of Japan and the Japan Society for the Promotion of Science; the Australian Research Council and the Australian Department of Education, Science and Training; the National Science Foundation of China under contract No. 10175071; the Department of Science and Technology of India; the BK21 program of the Ministry of Education of Korea and the CHEP SRC program of the Korea Science and Engineering Foundation; the Polish State Committee for Scientific Research under contract No. 2P03B 01324; the Ministry of Science and Technology of the Russian Federation; the Ministry of Higher Education, Science and Technology of the Republic of Slovenia; the Swiss National Science Foundation; the National Science Council and the Ministry of Education of Taiwan; and the US Department of Energy.

Keywords

B-meson
Branching fractions
Charmonium
Polarization

ASJC Scopus subject areas

Nuclear and High Energy Physics

Access to Document

10.1016/j.physletb.2006.01.013

Cite this

Soni, N., Abe, K., Abe, K., Adachi, I., Aihara, H., Arinstein, K., Asano, Y., Aulchenko, V., Aushev, T., Bakich, A. M., Barberio, E., Bedny, I., Bitenc, U., Bizjak, I., Blyth, S., Bondar, A., Bračko, M., Browder, T. E., Chang, P., ... Zhilich, V. (2006). Measurement of branching fractions for B → χ_c1(2)K (K*) at Belle. Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 634(2-3), 155-164. https://doi.org/10.1016/j.physletb.2006.01.013

Soni, N, Abe, K, Abe, K, Adachi, I, Aihara, H, Arinstein, K, Asano, Y, Aulchenko, V, Aushev, T, Bakich, AM, Barberio, E, Bedny, I, Bitenc, U, Bizjak, I, Blyth, S, Bondar, A, Bračko, M, Browder, TE, Chang, P, Chao, Y, Chen, A, Chen, KF, Cheon, BG, Chistov, R, Choi, SK, Choi, Y, Chuvikov, A, Dalseno, J, Danilov, M, Dash, M, Dong, LY, Eidelman, S, Enari, Y, Epifanov, D, Fratina, S, Gabyshev, N, Garmash, A, Gershon, T, Go, A, Gokhroo, G, Golob, B, Gorišek, A, Haba, J, Hara, T, Hayasaka, K, Hayashii, H, Hazumi, M, Hinz, L, Hokuue, T, Hoshi, Y, Hou, S, Hou, WS, Iijima, T, Ikado, K, Imoto, A, Inami, K, Ishikawa, A, Itoh, R, Kang, JH, Kang, JS, Kapusta, P, Katayama, N, Kawasaki, T, Khan, HR, Kichimi, H, Kim, HJ, Kim, SM, Korpar, S, Križan, P, Krokovny, P, Kulasiri, R, Kuo, CC, Kuzmin, A, Kwon, YJ, Lesiak, T, Lin, SW, Liventsev, D, Majumder, G, Mandl, F, Matsumoto, T, Mikami, Y, Mitaroff, W, Miyabayashi, K, Miyake, H, Miyata, H, Miyazaki, Y, Mizuk, R, Mohapatra, D, Nagamine, T, Natkaniec, Z, Nishida, S, Nitoh, O, Ogawa, S, Ohshima, T, Okabe, T, Okuno, S, Olsen, SL, Onuki, Y, Ostrowicz, W, Ozaki, H, Pakhlov, P, Park, CW, Pestotnik, R, Peters, M, Piilonen, LE, Poluektov, A, Sakai, Y, Sato, N, Schietinger, T, Schneider, O, Sevior, ME, Shibuya, H, Shwartz, B, Sidorov, V, Singh, JB, Somov, A, Stanič, S, Starič, M, Sumiyoshi, T, Suzuki, S, Suzuki, SY, Takasaki, F, Tamai, K, Tamura, N, Tanaka, M, Taylor, GN, Teramoto, Y, Tian, XC, Tsuboyama, T, Tsukamoto, T, Uehara, S, Ueno, K, Uglov, T, Uno, S, Urquijo, P, Varner, G, Villa, S, Wang, CC, Wang, CH, Watanabe, Y, Won, E, Xie, QL, Yamaguchi, A, Yamashita, Y, Yamauchi, M, Ying, J, Yuan, Y, Zhang, CC, Zhang, LM, Zhang, ZP & Zhilich, V 2006, 'Measurement of branching fractions for B → χ_c1(2)K (K*) at Belle', Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, vol. 634, no. 2-3, pp. 155-164. https://doi.org/10.1016/j.physletb.2006.01.013

@article{1413a7a657ed46528998005a5a634f69,

title = "Measurement of branching fractions for B → χc1(2)K (K*) at Belle",

abstract = "We have measured the branching fractions for the exclusive decay modes B→χc1(2)K(K*) using a 140 fb-1 data sample collected by the Belle detector at the KEKB asymmetric-energy e +e- collider. The measured branching fractions for B +→χc1K+, B0→χ c1K0, B0→χc1K* 0 and B+→χc1K*+ decay modes are (4.5±0.2±0.5)×10-4, (3.5±0.3±0.5)×10-4, (3.1±0.3±0.7) ×10-4 and (4.1±0.6±0.9)×10-4, respectively, where the first error is statistical and the second error is systematic. We do not observe statistically significant signals for the B→χc2K(K*) decay modes and set upper limits at the 90% confidence level. We also study the helicity distribution for B→χc1K* decay mode and show that the longitudinal polarization component is dominant.",

keywords = "B-meson, Branching fractions, Charmonium, Polarization",

author = "N. Soni and K. Abe and K. Abe and I. Adachi and H. Aihara and K. Arinstein and Y. Asano and V. Aulchenko and T. Aushev and Bakich, {A. M.} and E. Barberio and I. Bedny and U. Bitenc and I. Bizjak and S. Blyth and A. Bondar and M. Bra{\v c}ko and Browder, {T. E.} and P. Chang and Y. Chao and A. Chen and Chen, {K. F.} and Cheon, {B. G.} and R. Chistov and Choi, {S. K.} and Y. Choi and A. Chuvikov and J. Dalseno and M. Danilov and M. Dash and Dong, {L. Y.} and S. Eidelman and Y. Enari and D. Epifanov and S. Fratina and N. Gabyshev and A. Garmash and T. Gershon and A. Go and G. Gokhroo and B. Golob and A. Gori{\v s}ek and J. Haba and T. Hara and K. Hayasaka and H. Hayashii and M. Hazumi and L. Hinz and T. Hokuue and Y. Hoshi and S. Hou and Hou, {W. S.} and T. Iijima and K. Ikado and A. Imoto and K. Inami and A. Ishikawa and R. Itoh and Kang, {J. H.} and Kang, {J. S.} and P. Kapusta and N. Katayama and T. Kawasaki and Khan, {H. R.} and H. Kichimi and Kim, {H. J.} and Kim, {S. M.} and S. Korpar and P. Kri{\v z}an and P. Krokovny and R. Kulasiri and Kuo, {C. C.} and A. Kuzmin and Kwon, {Y. J.} and T. Lesiak and Lin, {S. W.} and D. Liventsev and G. Majumder and F. Mandl and T. Matsumoto and Y. Mikami and W. Mitaroff and K. Miyabayashi and H. Miyake and H. Miyata and Y. Miyazaki and R. Mizuk and D. Mohapatra and T. Nagamine and Z. Natkaniec and S. Nishida and O. Nitoh and S. Ogawa and T. Ohshima and T. Okabe and S. Okuno and Olsen, {S. L.} and Y. Onuki and W. Ostrowicz and H. Ozaki and P. Pakhlov and Park, {C. W.} and R. Pestotnik and M. Peters and Piilonen, {L. E.} and A. Poluektov and Y. Sakai and N. Sato and T. Schietinger and O. Schneider and Sevior, {M. E.} and H. Shibuya and B. Shwartz and V. Sidorov and Singh, {J. B.} and A. Somov and S. Stani{\v c} and M. Stari{\v c} and T. Sumiyoshi and S. Suzuki and Suzuki, {S. Y.} and F. Takasaki and K. Tamai and N. Tamura and M. Tanaka and Taylor, {G. N.} and Y. Teramoto and Tian, {X. C.} and T. Tsuboyama and T. Tsukamoto and S. Uehara and K. Ueno and T. Uglov and S. Uno and P. Urquijo and G. Varner and S. Villa and Wang, {C. C.} and Wang, {C. H.} and Y. Watanabe and E. Won and Xie, {Q. L.} and A. Yamaguchi and Y. Yamashita and M. Yamauchi and J. Ying and Y. Yuan and Zhang, {C. C.} and Zhang, {L. M.} and Zhang, {Z. P.} and V. Zhilich",

note = "Funding Information: We thank the KEKB group for the excellent operation of the accelerator, the KEK cryogenics group for the efficient operation of the solenoid, and the KEK computer group and the National Institute of Informatics for valuable computing and Super-SINET network support. We acknowledge support from the Ministry of Education, Culture, Sports, Science, and Technology of Japan and the Japan Society for the Promotion of Science; the Australian Research Council and the Australian Department of Education, Science and Training; the National Science Foundation of China under contract No. 10175071; the Department of Science and Technology of India; the BK21 program of the Ministry of Education of Korea and the CHEP SRC program of the Korea Science and Engineering Foundation; the Polish State Committee for Scientific Research under contract No. 2P03B 01324; the Ministry of Science and Technology of the Russian Federation; the Ministry of Higher Education, Science and Technology of the Republic of Slovenia; the Swiss National Science Foundation; the National Science Council and the Ministry of Education of Taiwan; and the US Department of Energy.",

year = "2006",

month = mar,

day = "9",

doi = "10.1016/j.physletb.2006.01.013",

language = "English",

volume = "634",

pages = "155--164",

journal = "Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics",

issn = "0370-2693",

publisher = "Elsevier B.V.",

number = "2-3",

}

TY - JOUR

T1 - Measurement of branching fractions for B → χc1(2)K (K*) at Belle

AU - Soni, N.

AU - Abe, K.

AU - Adachi, I.

AU - Aihara, H.

AU - Arinstein, K.

AU - Asano, Y.

AU - Aulchenko, V.

AU - Aushev, T.

AU - Bakich, A. M.

AU - Barberio, E.

AU - Bedny, I.

AU - Bitenc, U.

AU - Bizjak, I.

AU - Blyth, S.

AU - Bondar, A.

AU - Bračko, M.

AU - Browder, T. E.

AU - Chang, P.

AU - Chao, Y.

AU - Chen, A.

AU - Chen, K. F.

AU - Cheon, B. G.

AU - Chistov, R.

AU - Choi, S. K.

AU - Choi, Y.

AU - Chuvikov, A.

AU - Dalseno, J.

AU - Danilov, M.

AU - Dash, M.

AU - Dong, L. Y.

AU - Eidelman, S.

AU - Enari, Y.

AU - Epifanov, D.

AU - Fratina, S.

AU - Gabyshev, N.

AU - Garmash, A.

AU - Gershon, T.

AU - Go, A.

AU - Gokhroo, G.

AU - Golob, B.

AU - Gorišek, A.

AU - Haba, J.

AU - Hara, T.

AU - Hayasaka, K.

AU - Hayashii, H.

AU - Hazumi, M.

AU - Hinz, L.

AU - Hokuue, T.

AU - Hoshi, Y.

AU - Hou, S.

AU - Hou, W. S.

AU - Iijima, T.

AU - Ikado, K.

AU - Imoto, A.

AU - Inami, K.

AU - Ishikawa, A.

AU - Itoh, R.

AU - Kang, J. H.

AU - Kang, J. S.

AU - Kapusta, P.

AU - Katayama, N.

AU - Kawasaki, T.

AU - Khan, H. R.

AU - Kichimi, H.

AU - Kim, H. J.

AU - Kim, S. M.

AU - Korpar, S.

AU - Križan, P.

AU - Krokovny, P.

AU - Kulasiri, R.

AU - Kuo, C. C.

AU - Kuzmin, A.

AU - Kwon, Y. J.

AU - Lesiak, T.

AU - Lin, S. W.

AU - Liventsev, D.

AU - Majumder, G.

AU - Mandl, F.

AU - Matsumoto, T.

AU - Mikami, Y.

AU - Mitaroff, W.

AU - Miyabayashi, K.

AU - Miyake, H.

AU - Miyata, H.

AU - Miyazaki, Y.

AU - Mizuk, R.

AU - Mohapatra, D.

AU - Nagamine, T.

AU - Natkaniec, Z.

AU - Nishida, S.

AU - Nitoh, O.

AU - Ogawa, S.

AU - Ohshima, T.

AU - Okabe, T.

AU - Okuno, S.

AU - Olsen, S. L.

AU - Onuki, Y.

AU - Ostrowicz, W.

AU - Ozaki, H.

AU - Pakhlov, P.

AU - Park, C. W.

AU - Pestotnik, R.

AU - Peters, M.

AU - Piilonen, L. E.

AU - Poluektov, A.

AU - Sakai, Y.

AU - Sato, N.

AU - Schietinger, T.

AU - Schneider, O.

AU - Sevior, M. E.

AU - Shibuya, H.

AU - Shwartz, B.

AU - Sidorov, V.

AU - Singh, J. B.

AU - Somov, A.

AU - Stanič, S.

AU - Starič, M.

AU - Sumiyoshi, T.

AU - Suzuki, S.

AU - Suzuki, S. Y.

AU - Takasaki, F.

AU - Tamai, K.

AU - Tamura, N.

AU - Tanaka, M.

AU - Taylor, G. N.

AU - Teramoto, Y.

AU - Tian, X. C.

AU - Tsuboyama, T.

AU - Tsukamoto, T.

AU - Uehara, S.

AU - Ueno, K.

AU - Uglov, T.

AU - Uno, S.

AU - Urquijo, P.

AU - Varner, G.

AU - Villa, S.

AU - Wang, C. C.

AU - Wang, C. H.

AU - Watanabe, Y.

AU - Won, E.

AU - Xie, Q. L.

AU - Yamaguchi, A.

AU - Yamashita, Y.

AU - Yamauchi, M.

AU - Ying, J.

AU - Yuan, Y.

AU - Zhang, C. C.

AU - Zhang, L. M.

AU - Zhang, Z. P.

AU - Zhilich, V.

N1 - Funding Information: We thank the KEKB group for the excellent operation of the accelerator, the KEK cryogenics group for the efficient operation of the solenoid, and the KEK computer group and the National Institute of Informatics for valuable computing and Super-SINET network support. We acknowledge support from the Ministry of Education, Culture, Sports, Science, and Technology of Japan and the Japan Society for the Promotion of Science; the Australian Research Council and the Australian Department of Education, Science and Training; the National Science Foundation of China under contract No. 10175071; the Department of Science and Technology of India; the BK21 program of the Ministry of Education of Korea and the CHEP SRC program of the Korea Science and Engineering Foundation; the Polish State Committee for Scientific Research under contract No. 2P03B 01324; the Ministry of Science and Technology of the Russian Federation; the Ministry of Higher Education, Science and Technology of the Republic of Slovenia; the Swiss National Science Foundation; the National Science Council and the Ministry of Education of Taiwan; and the US Department of Energy.

PY - 2006/3/9

Y1 - 2006/3/9

N2 - We have measured the branching fractions for the exclusive decay modes B→χc1(2)K(K*) using a 140 fb-1 data sample collected by the Belle detector at the KEKB asymmetric-energy e +e- collider. The measured branching fractions for B +→χc1K+, B0→χ c1K0, B0→χc1K* 0 and B+→χc1K*+ decay modes are (4.5±0.2±0.5)×10-4, (3.5±0.3±0.5)×10-4, (3.1±0.3±0.7) ×10-4 and (4.1±0.6±0.9)×10-4, respectively, where the first error is statistical and the second error is systematic. We do not observe statistically significant signals for the B→χc2K(K*) decay modes and set upper limits at the 90% confidence level. We also study the helicity distribution for B→χc1K* decay mode and show that the longitudinal polarization component is dominant.

AB - We have measured the branching fractions for the exclusive decay modes B→χc1(2)K(K*) using a 140 fb-1 data sample collected by the Belle detector at the KEKB asymmetric-energy e +e- collider. The measured branching fractions for B +→χc1K+, B0→χ c1K0, B0→χc1K* 0 and B+→χc1K*+ decay modes are (4.5±0.2±0.5)×10-4, (3.5±0.3±0.5)×10-4, (3.1±0.3±0.7) ×10-4 and (4.1±0.6±0.9)×10-4, respectively, where the first error is statistical and the second error is systematic. We do not observe statistically significant signals for the B→χc2K(K*) decay modes and set upper limits at the 90% confidence level. We also study the helicity distribution for B→χc1K* decay mode and show that the longitudinal polarization component is dominant.

KW - B-meson

KW - Branching fractions

KW - Charmonium

KW - Polarization

UR - http://www.scopus.com/inward/record.url?scp=33244489388&partnerID=8YFLogxK

U2 - 10.1016/j.physletb.2006.01.013

DO - 10.1016/j.physletb.2006.01.013

M3 - Article

AN - SCOPUS:33244489388

SN - 0370-2693

VL - 634

SP - 155

EP - 164

JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

IS - 2-3

ER -