Abstract
We present a measurement of the mass difference between and quarks in final states of events in of data collected with the D0 detector from Fermilab Tevatron Collider collisions at . The measured mass difference of is consistent with the equality of and masses. This is the first direct measurement of a mass difference between a quark and its antiquark partner.
- Received 5 June 2009
DOI:https://doi.org/10.1103/PhysRevLett.103.132001
©2009 American Physical Society