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ISSN - 15507998, Physical Review D - Particles, Fields, Gravitation and Cosmology, 2008, vol. 78, p. -

Measurements of B(B̄0→Λc+p̄) and B(B- →Λc+p̄π-) and studies of Λc+π- resonances

Aubert B., Bona M., Karyotakis Y., Lees J. P., Poireau V., Prencipe E., Prudent X., Tisserand V., Garra Tico J., Grauges E., Lopez L., Palano A., Pappagallo M., Eigen G., Stugu B., Sun L., Abrams G. S., Battaglia M., Brown D. N., Cahn R. N., Jacobsen R. G., Kerth L. T., Kolomensky Yu G., Kukartsev G., Lynch G., Osipenkov I. L., Ronan M. T., Tackmann K., Tanabe T., Hawkes C. M., Soni N., Watson A. T., Koch H., Schroeder T., Walker D., Asgeirsson D. J., Cuhadar-Donszelmann T., Fulsom B. G., Hearty C., Mattison T. S., McKenna J. A., Barrett M., Khan A., Teodorescu L., Blinov V. E., Bukin A. D., Buzykaev A. R., Druzhinin V. P., Golubev V. B., Onuchin A. P., Serednyakov S. I., Skovpen Yu I., Solodov E. P., Todyshev K. Yu, Bondioli M., Curry S., Eschrich I., Kirkby D., Lankford A. J., Lund P., Mandelkern M., Martin E. C., Stoker D. P., Abachi S., Buchanan C., Gary J. W., Liu F., Long O., Shen B. C., Vitug G. M., Yasin Z., Zhang L., Sharma V., Campagnari C., Hong T. M., Kovalskyi D., Mazur M. A., Richman J. D., Beck T. W., Eisner A. M., Flacco C. J., Heusch C. A., Kroseberg J., Lockman W. S., Schalk T., Schumm B. A., Seiden A., Wang L., Wilson M. G., Winstrom L. O., Cheng C. H., Doll D. A., Echenard B., Fang F., Hitlin D. G., Narsky I., Piatenko T.

We present an investigation of the decays B̄0→Λc+p̄ and B-→Λc+p̄π- based on 383×106 Υ(4S) →BB̄ decays recorded with the BABAR detector. We measure the branching fractions of these decays; their ratio is B(B-→Λc+p̄π-)/ B(B̄0→Λc+p̄)=15.4±1.8±0.3. The B-→Λc+p̄π- process exhibits an enhancement at the Λc+p̄ threshold and is a laboratory for searches for excited charm baryon states. We observe the resonant decays B-→Σc(2455)0p̄ and B-→Σc(2800)0p̄ but see no evidence for B-→Σc(2520) 0p̄. This is the first observation of the decay B-→Σc(2800) 0p̄; however, the mass of the observed excited Σc0 state is (2846±8±10)MeV/c2, which is somewhat inconsistent with previous measurements. Finally, we examine the angular distribution of the B-→Σc(2455)0p̄ decays and measure the spin of the Σc(2455)0 baryon to be 1/2, as predicted by the quark model. © 2008 The American Physical Society.