Hadron spectroscopy in LHCb

Antimo Palano,P Bühler

doi:10.1051/epjconf/201818101024

Antimo Palano, P Bühler

Open Access

https://doi.org/10.1051/epjconf/201818101024

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Abstract

The LHCb experiment is designed to study the properties and decays of heavy flavored hadrons produced in pp collisions at the LHC. The data collected in the LHC Run I enables precision spectroscopy studies of beauty and charm hadrons. The latest results on spectroscopy of conventional and exotic hadrons are reviewed. In particular the discovery of the first charmonium pentaquark states in theJ/Ψpsystem, the possible existence of four-quark states decaying toJ/ΨΦand the confirmation of resonant nature of theZc(4430)−mesonic state are discussed. In the sector of charmed baryons, the observation of five new Ωcstates, the observation of the Ξcc+and the study of charmed baryons decaying toD0pare presented.

Highlights

The data collected in the LHC Run I enables precision spectroscopy studies of beauty and charm hadrons
In the simple quark model, only two types of quark combinations are required to account for the existing hadrons, i.e. qqcombinations form mesons, while baryons are made up of three quarks
In the quark model proposed by Gell-Mann and Zweig in 1960s [1] other SU(3) colorneutral combinations of quarks and gluons such as gg glueballs, qqg hybrids, qqqqtetraquarks, qqqqq pentaquarks etc. are allowed

Summary

Introduction

In the simple quark model, only two types of quark combinations are required to account for the existing hadrons, i.e. qqcombinations form mesons, while baryons are made up of three quarks. The full amplitude analysis used in the first pentaquark analysis has been applied to this Cabibbo suppressed Λ0b decay Both reduced and extended models of the N∗ contributions have been tested, the latter including a wider set of resonances and allowed couplings. In 2013 Belle collaboration, using more data with about 2000 signal events, performed a full amplitude analysis of the same final state. They obtained a significance of 5.2σ for the Zc(4430)− state, with a mass M(Zc) = 4485±22±28 MeV and width Γ(Zc) = 200 ± 41 ± 26 MeV, favoring the JP = 1+ spin-parity assignment by more than 3.4σ. The interpretation of these states is still an open issue

Observation of five new Ω0c states

Charmed baryon spectroscopy using Λb decays

Findings

Conclusions