LHCb

Hadron spectroscopy

LHCb is designed to study beauty and charm hadrons. In addition to precision studies of the known particles such as mysterious X(3872), a number of new hadrons have been discovered by the experiment. As of 2021, all four LHC experiments have discovered about 60 new hadrons in total, vast majority of which by LHCb. In 2015, analysis of the decay of bottom lambda baryons (Λ
_b) in the LHCb experiment revealed the apparent existence of pentaquarks, in what was described as an "accidental" discovery. Other notable discoveries are those of the "doubly charmed" baryon ${\displaystyle \Xi _{\rm {cc}}^{++}}$ in 2017, being a first known baryon with two heavy quarks; and of the fully-charmed tetraquark ${\displaystyle \mathrm {T} _{\rm {cccc}}}$ in 2020, made of two charm quarks and two charm antiquarks.