Abstract
Two structures are observed close to the kinematic threshold in the mass spectrum in a sample of proton-proton collision data, corresponding to an integrated luminosity of , recorded by the LHCb experiment. In the quark model, two baryonic resonances with quark content are expected in this mass region: the spin-parity and states, denoted and . Interpreting the structures as these resonances, we measure the mass differences and the width of the heavier state to be , , where the first and second uncertainties are statistical and systematic, respectively. The width of the lighter state is consistent with zero, and we place an upper limit of at 95% confidence level. Relative production rates of these states are also reported.
- Received 18 November 2014
DOI:https://doi.org/10.1103/PhysRevLett.114.062004
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© 2015 CERN, for the LHCb Collaboration
Synopsis
Two New Particles Enter the Fold
Published 10 February 2015
Researchers report the detection of two new subatomic particles made of three quarks from each of the possible quark families.
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