Observation of the Ξb0

Primary author: Pat Lukens








CDF observes the production of the Ξb0 through the decay chain
Ξb0 → Ξc+ π-, Ξc+ → Ξ- π+ π+, Ξ- → Λ π-, Λ → p π-. This is the first observation of this particle. The data was collected in 4.2 fb-1 of collisions.
Illustration of the final state
An illustration of the Ξb0 decay chain









In addition, CDF observes the production of the Ξb- through the decay chain
Ξb- → Ξc0 π-, Ξc0 → Ξ- π+, Ξ- → Λ π-, Λ → p π-. This is the first observation of the Ξb- in this final state.
Illustration of the final state
An illustration of the Ξb- decay chain





Ξ- π+ and Ξ- π+ π+ mass distributions. Shaded areas are considered Ξc signal regions
eps version





Ξc0 π- and Ξc+ π- mass distributions. Projections of the unbinned fits to the mass distributions are overlaid in dashed lines.
eps version

The masses of the Ξb- and Ξb0 are measured as follows:


Mass (MeV/c2)
Ξ-b 5796.7 ± 5.1 ± 1.4
Ξ0b 5787.8 ± 5.0 ± 1.3

The mass difference between the two states is found by using the value for the Ξb- from our previous result1. We obtain
M(Ξb-) - M(Ξb0) = 3.1 ± 5.6 ± 1.3 MeV/c2.

The collection of public plots can be found here


The paper is available here

The Joint Experimental-Theoretical Physics Seminar given on 20 July 2011
PDF version
Powerpoint version

1.  T. Aaltonen et al. (CDF Collaboration), Phys. Rev. D 80, 072003 (2009)