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ISSN - 03702693, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 2008, vol. 665, p. 9-15

Measurement of masses of the Ξc (2645) and Ξc (2815) baryons and observation of Ξc (2980) → Ξc (2645) π

Lesiak T., Adachi I., Aihara H., Arinstein K., Bakich A. M., Balagura V., Barberio E., Bedny I., Belous K., Bhardwaj V., Bitenc U., Blyth S., Bozek A., Bračko M., Brodzicka J., Browder T. E., Chao Y., Chen A., Chen W. T., Cheon B. G., Chistov R., Cho I. S., Choi S. K., Choi Y., Dalseno J., Dash M., Eidelman S., Gabyshev N., Golob B., Ha H., Haba J., Hayasaka K., Hazumi M., Heffernan D., Hoshi Y., Hou W. S., Hyun H. J., Inami K., Ishikawa A., Ishino H., Itoh R., Iwasaki M., Iwasaki Y., Joshi N. J., Kah D. H., Kaji H., Kang J. H., Kawai H., Kawasaki T., Kichimi H., Kim H. J., Kim S. K., Kim Y. J., Korpar S., Križan P., Krokovny P., Kuo C. C., Kwon Y. J., Lange S., Lee J. S., Lee M. J., Lee S. E., Li J., Lin S. W., Liu C., Liventsev D., Mandl F., McOnie S., Medvedeva T., Miyabayashi K., Miyake H., Miyata H., Miyazaki Y., Mizuk R., Moloney G. R., Nagasaka Y., Nakao M., Natkaniec Z., Nishida S., Nitoh O., Nozaki T., Ogawa S., Ohshima T., Okuno S., Ozaki H., Pakhlova G., Palka H., Park C. W., Park H. K., Peak L. S., Pestotnik R., Piilonen L. E., Sahoo H., Sakai Y.

We report a precise measurement of the masses of the Ξc (2645) and Ξc (2815) baryons using a data sample of 414 fb-1 collected by the Belle Collaboration at the KEKB e+ e- collider. The states Ξc (2645)0, + are observed in the Ξc +, 0 π-, + decay modes, while the Ξc (2815)0, + are reconstructed in the Ξc (2645)+, 0 π-, + decay modes. The following mass splittings are determined: mΞc (2645)+ - mΞc (2645)0 = (- 0.1 ± 0.3 (stat) ± 0.6 (syst)) MeV / c2 and mΞc (2815)+ - mΞc (2815)0 = (- 3.4 ± 1.9 (stat) ± 0.9 (syst)) MeV / c2 with a much better precision than the current world averages. We also observe a new decay mode, Ξc (2980)0, + → Ξc (2645)+, 0 π-, +. © 2008 Elsevier B.V. All rights reserved.