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oai:recercat.cat:2445/1315152025-12-05T17:02:51Zcom_2072_1057col_2072_478823col_2072_478917

Measurements of B(¯¯¯B0→Λ+c¯p) and B(B−→Λ+c¯pπ−) and studies of Λ+cπ− resonances Garra Ticó, Jordi Graugés Pous, Eugeni BABAR Collaboration Física de partícules Experiments Particle physics Experiments We present an investigation of the decays ¯¯¯ B 0 → Λ + c ¯ p and B − → Λ + c ¯ p π − based on 383 × 10 6 Υ ( 4 S ) → B ¯¯¯ B decays recorded with the BABAR detector. We measure the branching fractions of these decays; their ratio is B ( B − → Λ + c ¯ p π − ) / B ( ¯¯¯ B 0 → Λ + c ¯ p ) = 15.4 ± 1.8 ± 0.3 . The B − → Λ + c ¯ p π − process exhibits an enhancement at the Λ + c ¯ p threshold and is a laboratory for searches for excited charm baryon states. We observe the resonant decays B − → Σ c ( 2455 ) 0 ¯ p and B − → Σ c ( 2800 ) 0 ¯ p but see no evidence for B − → Σ c ( 2520 ) 0 ¯ p . This is the first observation of the decay B − → Σ c ( 2800 ) 0 ¯ p ; however, the mass of the observed excited Σ 0 c state is ( 2846 ± 8 ± 10 )     MeV / c 2 , which is somewhat inconsistent with previous measurements. Finally, we examine the angular distribution of the B − → Σ c ( 2455 ) 0 ¯ p decays and measure the spin of the Σ c ( 2455 ) 0 baryon to be 1 / 2 , as predicted by the quark model. 2019-04-05T10:14:32Z 2019-04-05T10:14:32Z 2008-12-29 2019-04-05T10:14:32Z info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 1550-7998 https://hdl.handle.net/2445/131515 577668 eng Reproducció del document publicat a: https://doi.org/10.1103/PhysRevD.78.112003 Physical Review D, 2008, vol. 78, num. 11, p. 112003 https://doi.org/10.1103/PhysRevD.78.112003 (c) American Physical Society, 2008 info:eu-repo/semantics/openAccess 18 p. application/pdf American Physical Society Articles publicats en revistes (Física Quàntica i Astrofísica)