Editing LHCb experiment (section)

=== Hadron spectroscopy ===
LHCb is designed to study beauty and charm [[hadron]]s. 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.<ref>{{Cite web|title=59 new hadrons and counting|url=https://home.cern/news/news/physics/59-new-hadrons-and-counting|access-date=2021-03-21|website=CERN|language=en}}</ref> In 2015, analysis of the decay of [[bottom lambda baryon]]s (Λ{{su|p=0|b=b}}) in the LHCb experiment revealed the apparent existence of [[pentaquark]]s,<ref name="LHCb-public">
{{cite web|date=14 July 2015|title=Observation of particles composed of five quarks, pentaquark-charmonium states, seen in Λ{{su|p=0|b=b}}→J/ψpK<sup>−</sup> decays|url=http://lhcb-public.web.cern.ch/lhcb-public/Welcome.html#Penta|access-date=2015-07-14|publisher=[[CERN]]/LHCb}}</ref><ref name="pentaquarkPRL">
{{cite journal|author=R. Aaij et al. (LHCb collaboration)|year=2015|title=Observation of J/ψp resonances consistent with pentaquark states in Λ{{su|p=0|b=b}}→J/ψK<sup>−</sup>p decays|journal=[[Physical Review Letters]]|volume=115|issue=7|pages=072001|arxiv=1507.03414|bibcode=2015PhRvL.115g2001A|doi=10.1103/PhysRevLett.115.072001|pmid=26317714|s2cid=119204136}}</ref> in what was described as an "accidental" discovery.<ref name="NewScientist2015">
{{cite web|author=G. Amit|date=14 July 2015|title=Pentaquark discovery at LHC shows long-sought new form of matter|url=https://www.newscientist.com/article/dn27892-pentaquark-discovery-at-lhc-shows-long-sought-new-form-of-matter/|access-date=2015-07-14|work=[[New Scientist]]}}</ref> Other notable discoveries are those of the "doubly charmed" baryon <math>\Xi_{\rm cc}^{++}</math> in 2017, being a first known [[baryon]] with two heavy quarks; and of the fully-charmed tetraquark <math>\mathrm{T}_{\rm cccc}</math> in 2020, made of two charm quarks and two charm antiquarks.   
{| class="wikitable mw-collapsible"
|+ class="nowrap"| Hadrons discovered at LHCb.<ref>{{Cite web|title=New particles discovered at the LHC|url=https://www.nikhef.nl/~pkoppenb/particles.html|access-date=2021-03-21|website=www.nikhef.nl}}</ref><ref>{{cite web | url=https://lhcb-outreach.web.cern.ch/2022/07/05/observation-of-a-strange-pentaquark-a-doubly-charged-tetraquark-and-its-neutral-partner/ | title=Observation of a strange pentaquark, a doubly charged tetraquark and its neutral partner }}</ref> The term 'excited' for baryons and mesons means existence of a state of lower mass with the same quark content and isospin. 
!
!Quark content{{efn-lr|1=Abbreviations are the first letter of the quark name ([[up quark|up]]='u', [[down quark|down]]='d', [[top quark|top]]='t', [[bottom quark|bottom]]='b', [[charmed quark|charmed]]='c', [[strange quark|strange]]='s'). [[Antiquark]]s have overbars.}}
!Particle name
!Type
!Year of discovery
|-
|1
|<math>\rm bud</math>
|<math>\Lambda_{\rm b}(5912)^0</math>
|Excited baryon
|2012
|-
|2
|<math>\rm bud</math>
|<math>\Lambda_{\rm b}(5920)^0</math>
|Excited baryon
|2012
|-
|3
|<math>\rm c\bar{u}</math>
|<math>\rm D_J(2580)^0</math>
|Excited meson
|2013
|-
|4
|<math>\rm c\bar{u}</math>
|<math>\rm D_J(2740)^0</math>
|Excited meson
|2013
|-
|5
|<math>\rm c\bar{d}</math>
|<math>\rm D_J^*(2760)^+</math>
|Excited meson
|2013
|-
|6
|<math>\rm c\bar{u}</math>
|<math>\rm D_J(3000)^0</math>
|Excited meson
|2013
|-
|7
|<math>\rm c\bar{u}</math>
|<math>\rm D_J^*(3000)^0</math>
|Excited meson
|2013
|-
|8
|<math>\rm c\bar{d}</math>
|<math>\rm D_J^*(3000)^+</math>
|Excited meson
|2013
|-
|9
|<math>\rm c\bar{s}</math>
|<math>\rm D_{s1}^*(2860)^+</math>
|Excited meson
|2014
|-
|10
|<math>\rm bsd</math>
|<math>\Xi^{'-}_{\rm b}</math>
|Excited baryon
|2014
|-
|11
|<math>\rm bsd</math>
|<math>\Xi^{*-}_{\rm b}</math>
|Excited baryon
|2014
|-
|12
|<math>\rm \bar{b}u</math>
|<math>\rm B_J(5840)^+</math>
|Excited meson
|2015
|-
|13
|<math>\rm \bar{b}d</math>
|<math>\rm B_J(5840)^0</math>
|Excited meson
|2015
|-
|14
|<math>\rm \bar{b}u</math>
|<math>\rm B_J(5970)^+</math>
|Excited meson
|2015
|-
|15
|<math>\rm \bar{b}d</math>
|<math>\rm B_J(5970)^+</math>
|Excited meson
|2015
|-
|16{{efn-lr|Previously unknown combination of quarks}}
|<math>\rm c\bar{c}uud</math>
|<math>\rm P_c(4380)^+</math>
|Pentaquark
|2015
|-
|17
|<math>\rm c\bar{c}s\bar{s}</math>
|<math>\rm X(4274)</math>
|Tetraquark
|2016
|-
|18
|<math>\rm c\bar{c}s\bar{s}</math>
|<math>\rm X(4500)</math>
|Tetraquark
|2016
|-
|19
|<math>\rm c\bar{c}s\bar{s}</math>
|<math>\rm X(4700)</math>
|Tetraquark
|2016
|-
|20
|<math>\rm c\bar{u}</math>
|<math>\rm D_3^*(2760)^0</math>
|Excited meson
|2016
|-
|21
|<math>\rm cud</math>
|<math>\Lambda_{\rm c}(2860)^+</math>
|Excited baryon
|2017
|-
|22
|<math>\rm css</math>
|<math>\Omega_{\rm c}(3000)^0</math>
|Excited baryon
|2017
|-
|23
|<math>\rm css</math>
|<math>\Omega_{\rm c}(3050)^0</math>
|Excited baryon
|2017
|-
|24
|<math>\rm css</math>
|<math>\Omega_{\rm c}(3066)^0</math>
|Excited baryon
|2017
|-
|25
|<math>\rm css</math>
|<math>\Omega_{\rm c}(3090)^0</math>
|Excited baryon
|2017
|-
|26
|<math>\rm css</math>
|<math>\Omega_{\rm c}(3119)^0</math>
|Excited baryon
|2017
|-
|27{{efn-lr|Previously unknown combination of quarks; first baryon with two charm quarks, 
and the only [[Weak interaction|weakly]]-decaying particle discovered so far at the LHC.}}
|<math>\rm ccu</math>
|<math>\Xi_{\rm cc}^{++}</math>
|Baryon
|2017
|-
|28
|<math>\rm bsd</math>
|<math>\Xi_{\rm b}(6227)^-</math>
|Excited baryon
|2018
|-
|29
|<math>\rm buu</math>
|<math>\Sigma_{\rm b}(6097)^+</math>
|Excited baryon
|2018
|-
|30
|<math>\rm bdd</math>
|<math>\Sigma_{\rm b}(6097)^-</math>
|Excited baryon
|2018
|-
|31
|<math>\rm c\bar{c}</math>
|<math>\psi_3 (3842)</math><ref>{{Cite web|title=pdgLive|url=https://pdglive.lbl.gov/Particle.action?init=0&node=M241&home=MXXX025|access-date=2021-03-21|website=pdglive.lbl.gov}}</ref>
|Excited meson
|2019
|-
|32
|<math>\rm c\bar{c}uud</math>
|<math>\rm P_c(4312)^+</math>
|Pentaquark
|2019
|-
|33
|<math>\rm c\bar{c}uud</math>
|<math>\rm P_c(4440)^+</math>
|Pentaquark
|2019
|-
|34
|<math>\rm c\bar{c}uud</math>
|<math>\rm P_c(4457)^+</math>
|Pentaquark
|2019
|-
|35
|<math>\rm bud</math>
|<math>\Lambda_{\rm b}(6146)^0</math>
|Excited baryon
|2019
|-
|36
|<math>\rm bud</math>
|<math>\Lambda_{\rm b}(6152)^0</math>
|Excited baryon
|2019
|-
|37
|<math>\rm bss</math>
|<math>\Omega_{\rm b}(6340)^-</math>
|Excited baryon
|2020
|-
|38
|<math>\rm bss</math>
|<math>\Omega_{\rm b}(6350)^-</math>
|Excited baryon
|2020
|-
|39{{efn-lr|Simultaneous with [[Compact Muon Solenoid|CMS]]; CMS had not enough data to claim the discovery.}}
|<math>\rm bud</math>
|<math>\Lambda_{\rm b}(6070)^0</math>
|Excited baryon
|2020
|-
|40
|<math>\rm csd</math>
|<math>\Xi_{\rm c}(2923)^0</math>
|Excited baryon
|2020
|-
|41
|<math>\rm csd</math>
|<math>\Xi_{\rm c}(2939)^0</math>
|Excited baryon
|2020
|-
|42{{efn-lr|Previously unknown combination of quarks; first tetraquark made exclusively of charm quarks}}
|<math>\rm cc\bar{c}\bar{c}</math>
|<math>\rm T_{cccc}</math>
|Tetraquark
|2020
|-
|43{{efn-lr|Previously unknown combination of quarks; first tetraquark with all quarks being different}}
|<math>\rm \bar{c}d\bar{s}u</math>
|<math>\rm X_0(2900)</math>
|Tetraquark
|2020
|-
|44
|<math>\rm \bar{c}d\bar{s}u</math>
|<math>\rm X_1(2900)</math>
|Tetraquark
|2020
|-
|45
|<math>\rm bsu</math>
|<math>\Xi_{\rm b}(6227)^0</math>
|Excited baryon
|2020
|-
|46
|<math>\rm \bar{b}s</math>
|<math>\rm B_s(6063)^0</math>
|Excited meson
|2020
|-
|47
|<math>\rm \bar{b}s</math>
|<math>\rm B_s(6114)^0</math>
|Excited meson
|2020
|-
|48
|<math>\rm c\bar{s}</math>
|<math>\rm D_{s0}(2590)^+</math>
|Excited meson
|2020
|-
|49
|<math>\rm c\bar{c}s\bar{s}</math>
|<math>\rm X(4630)</math>
|Tetraquark
|2021
|-
|50
|<math>\rm c\bar{c}s\bar{s}</math>
|<math>\rm X(4685)</math>
|Tetraquark
|2021
|-
|51
|<math>\rm c\bar{c}u\bar{s}</math>
|<math>\rm Z_{cs}(4000)^+</math>
|Tetraquark
|2021
|-
|52
|<math>\rm c\bar{c}u\bar{s}</math>
|<math>\rm Z_{cs}(4220)^+</math>
|Tetraquark
|2021
|}
{{notelist-lr}}