CERN Accelerating science

Published Articles
Title	Spectroscopy of doubly-heavy baryons at LHCb
Author(s)	Traill, Murdo Thomas (Glasgow U.)
Collaboration	LHCb
Publication	SISSA, 2018
Number of pages	8
In:	PoS Hadron2017 (2018) 067
In:	XVII International Conference on Hadron Spectroscopy and Structure, Salamanca, Spain, 25 - 29 Sep 2017, pp.067
DOI	10.22323/1.310.0067
Subject category	Particle Physics - Experiment
Accelerator/Facility, Experiment	CERN LHC ; LHCb
Abstract	The LHCb detector is ideally designed for studies in hadron spectroscopy. Its capabilities in this area of physics was firmly demonstrated when LHCb announced the discovery of the first ever doubly heavy baryon, $\Xi^{++}_{cc}$, in decays of $\Xi^{++}_{cc} \rightarrow \Lambda^{+}_{c} K^{-} \pi^{+} \pi^{+}$ in 2017. This doubly charmed baryon was observed as a highly significant structure in the $\Lambda^{+}_{c} K^{-} \pi^{+} \pi^{+}$ mass spectrum from proton-proton collision data recorded by the LHCb detector at both 13 TeV and 8 TeV centre-of-mass energies. From the 13 TeV and 8 TeV samples, a yield of 313 $\pm$ 33 and 113 $\pm$ 21 $\Xi^{++}_{cc}$ candidates are measured respectively. The local significances is in excess of 12$\sigma$ in 13 TeV data and above 7$\sigma$ in 8 TeV data. The properties of the peak suggest it is inconsistent with being a strongly decaying state. From the 13 TeV data, the mass is measured to be 3621.40$\pm$ 0.72(stat.)$\pm$ 0.27(syst.)$\pm$ 0.14($\Lambda^{+}_{c}$) MeV/$c^{2}$. More analyses in the double heavy baryon sector using LHCb data are now well advanced. This includes, but is not limited to, searches for the singly charged $\Xi^{+}_{cc}$ state and also charmed-beauty $\Xi_{bc}$ baryons.
Copyright/License	publication: (License: CC-BY-NC-ND 4.0)

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