ATLAS calorimeter capabilities for B-physics studies: the $B_{s}^{0} \to J/\psi \eta$ example

This paper presents an example of the utilisation of ATLAS calorimeters for B-physics analysis. We show that, using the ATLAS electromagnetic calorimeter and the appropriate cuts, a 2.3% eta reconstruction efficiency could be reached in the eta to gamma gamma channel with a background fraction of 24%. This makes possible the extension of the ATLAS B-physics programme to interesting channels such as B/sub s//sup 0/ to J/ psi eta , and demonstrates that ATLAS calorimeters perform for soft-particle measurement. (8 refs).