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Quarkonium and Charmed Baryon Production at Lhcb Quarkonium and charmed baryon production at LHCb Ronan McNulty (UCD Dublin) on behalf of the LHCb collaboration XIIIth Quark Confinement and the Hadron Spectrum 31 July – 6 August 2018, Maynooth. Quarkonium and double charged baryon production at LHCb 1 ++ 0 LHCb Ξ cc Ω c Inclusive J/ψ , ϒ Exclusive J/ψ Overview • LHCb • Charmed baryons ++ • Observation of Ξ cc. Measurement of branching fractions and lifetime. 0 • Lifetime of Ω c • Quarkonium production • J/ψ and ϒ inclusive in pp • J/ψ and ψ(2S) exclusive in pp, PbPb • Summary Quarkonium and double charged baryon production at LHCb 2 ++ 0 LHCb Ξ cc Ω c Inclusive J/ψ , ϒ Exclusive J/ψ Int. J. Mod. Phys. A 30 (2015) 1530022 The LHCb detector (charged sensitivity -3.5<η<-1.5) Fully instrumented from 2 < η < 5 Trigger on muons pT> 400 MeV, and on J/ψ pT > 0 MeV. Precise vertex reconstruction. Excellent particle identification Quarkonium and double charged baryon production at LHCb 3 ++ 0 LHCb Ξ cc Ω c Inclusive J/ψ , ϒ Exclusive J/ψ Run1 (2010-2012): √s = 7,8 TeV (pp) Data-taking 2010-2018 Run2 (2015-2018) :√s = 13 TeV (pp) Also pA, AA , and fixed target typically 1.1 pp interactions per beam-crossing Quarkonium and double charged baryon production at LHCb 4 ++ 0 LHCb Ξ cc Ω c Inclusive J/ψ , ϒ Exclusive J/ψ Double-charmed Baryons Weak decay expected for ground states P 1 + + ++ + of Ξ ccd Ξ ccu Ω ccs J = 2 Predictions Mass ~ 3500-3700 MeV + ++ Few MeV mass splitting Ξ ccd / Ξ ccu τ(Ξ++) ~ 200-700 fs Ξ+) ~ Ω+) ~ 50-250 fs τ( τ( P 3 + (PRD90, 094007 (2014) J = 2 arXiv:1706.0691, 9807354, 9901323) Strong/EM decays for excited + ++ + Ξ ccd Ξ ccu Ω ccs Quarkonium and double charged baryon production at LHCb 5 ++ 0 LHCb Ξ cc Ω c Inclusive J/ψ , ϒ Exclusive J/ψ + JHEP 12 (2013) 090 Search for Ξ cc History + - + SELEX (2002) observe (6.3σ) in Λc K π (4.8σ in D+K-p+): Mass~3520 MeV, τ< 33fs . FOCUS and BaBar: no evidence. 2013 LHCb (0.65fb-1) no evidence (not inconsistent with SELEX) Quarkonium and double charged baryon production at LHCb 6 ++ 0 LHCb Ξ cc Ω c Inclusive J/ψ , ϒ Exclusive J/ψ ++ PRL 119, 112001 (2017) Search for Ξ cc History SELEX: hep-ex/0702001, Charm 2007 + - + – 6.3σ excess in Λc K π π , Mass~3520 MeV + + + – Candidate in Ξc π π π , Mass~3452 MeV LHCb (1.7fb-1, √s = 13 TeV) • Local significance > 12σ • Resolution 6.6 ± 0.8 MeV (=detector resolution) • Signal yield 313 ± 33 • Mass: 3621.40 ± 0.72(stat) ± 0.31(sys) MeV Quarkonium and double charged baryon production at LHCb 7 ++ 0 LHCb Ξ cc Ω c Inclusive J/ψ , ϒ Exclusive J/ψ ++ arXiv:1807.01919 Other decay modes of Ξ cc LHCb (1.7fb-1, √s = 13 TeV) Search in • Strategy similar to but more efficient due to fewer particles. • Analysis performed blind, using MC and sidebands to optimise selection. • Signal yield 91 ± 20 • Significance: 5.9 σ • Mass: 3620.56 ± 1.45(stat) ± 0.61(sys) MeV • Agrees with observation in = 0.035 ± 0.008 (stat) ± 0.003 (sys) Quarkonium and double charged baryon production at LHCb 8 ++ 0 LHCb Ξ cc Ω c Inclusive J/ψ , ϒ Exclusive J/ψ PRL 119, 112001 (2017) ++ Lifetime of Ξ cc arXiv: 1806.02744 Peak remains after requiring + − ++ → + − Ξcc Λ c K π π inconsistency with primary vertex. Measure: 0 + − + − Λ b→Λ cπ π π τ ( ++) = 256+22 (stat)±14(sys)fs Ξcc −20 weakly decaying ! Quarkonium and double charged baryon production at LHCb 9 ++ 0 LHCb Ξ cc Ω c Inclusive J/ψ , ϒ Exclusive J/ψ Comparison of theory and experiment various predictions Tricky but possible to reconcile both signals e.g. arXiv:1709.09903 Future for LHCb: Measure other decay modes of Ξ++ and observe Ξ+ Quarkonium and double charged baryon production at LHCb 10 ++ 0 LHCb Ξ cc Ω c Inclusive J/ψ , ϒ Exclusive J/ψ P 1 + Omega Baryon J = 2 Lifetime arXiv: 1807.02024 usc udc ‘Expected’ hierarchy dsc ssc Test of HQE but note spin of spectators and cèWs interference 0 − → + − Ωc pK K π Compare + − + + → D K π π Yield: 978+-60 in b meson/baryon decays Much larger (and cleaner) signal than previous experiments Quarkonium and double charged baryon production at LHCb 11 ++ 0 LHCb Ξ cc Ω c Inclusive J/ψ , ϒ Exclusive J/ψ Omega Baryon Lifetime arXiv: 1807.02024 (old PDG value) Summary of Omega lifetime measurements 0 τ ( ) = 268± 24(stat)±10(sys)± 2(D+) fs Ωc Dominant systematic is MC stats usc udc dsc ssc .... something to understand theoretically in determining hierarchy of lifetimes. Quarkonium and double charged baryon production at LHCb 12 ++ 0 LHCb Ξ cc Ω c Inclusive J/ψ , ϒ Exclusive J/ψ Inclusive quarkonia production Prompt: direct and J/ψ hadroproduction is not completely understood - charmonia feed-down cross-section, pT dependence, polarisation J/ψ from-b (better theoretical agreement) ϒ hadroproduction: heavier mass should give better agreement with NRQCD predictions i j ˆ H dσ[pp → H + X] = ∑ ∫ dx1 dx2GpGp × dσ[ij → (QQ)n X] ϑ n i, j,n intermediary states long-distance matrix elements LHCb: more data at new energies and forward rapidities. Compare ratios to remove experimental and theoretical uncertainties Examine in different productions modes: pPb PbPb and compare to other quarkonia e.g. χc, ηc, J/ψJ/ψ etc (not covered in this talk) Quarkonium and double charged baryon production at LHCb 13 ++ 0 LHCb Ξ cc Ω c Inclusive J/ψ , ϒ Exclusive J/ψ JHEP 1510 (2015) 172, Err. JHEP 1706 (2017) 063 J/Ψ in pp at 13 TeV with 3pb-1 σ ( σ (prompt J/ψ, pT < 14 GeV, 2.0<y<4.5) = 15.03± 0.03± 0.94µb σ (J/ψ-from-b, pT < 14 GeV, 2.0<y<4.5) = 2.25± 0.01± 0.14µb σ (pp → bbX) = 495± 2 ± 52 µb Quarkonium and double charged baryon production at LHCb 14 ++ 0 LHCb Ξ cc Ω c Inclusive J/ψ , ϒ Exclusive J/ψ JHEP 1510 (2015) 172, Err. JHEP 1706 (2017) 063 J/Ψ in pp at 13 TeV with 3pb-1 full double differential distributions as fn of pT and rapidity in paper Prompt J/ψ from b σ ( JHEP 05 (2015) 103 JHEP 05 (1998) 007 Quarkonium and double charged baryon production at LHCb 15 ++ 0 LHCb Ξ cc Ω c Inclusive J/ψ , ϒ Exclusive J/ψ ϒ in pp at 13 TeV with 277pb-1 JHEP 07(2018)134 full double differential distributions in paper Chinese Physics C 39 (2015) 12. Quarkonium and double charged baryon production at LHCb 16 ++ 0 LHCb Ξ cc Ω c Inclusive J/ψ , ϒ Exclusive J/ψ JHEP 1510 (2015) 172, Err. JHEP 1706 (2017) 063 JHEP 07(2018)134 J/Ψ and ϒ in pp: ratio of 13/8 TeV σ ( Quarkonium and double charged baryon production at LHCb 17 ++ 0 LHCb Ξ cc Ω c Inclusive J/ψ , ϒ Exclusive J/ψ Motivation: Photo-production of vector mesons (at HERA) Here QCD works nicely! Note: • soft/hard transition • σ ~ xλ • g(x,Q2) (down to x=2E-6) JHEP 11 (2013) 085 10.3204/DESY-PROC-2012-03/58 Quarkonium and double charged baryon production at LHCb 18 ++ 0 LHCb Ξ cc Ω c Inclusive J/ψ , ϒ Exclusive J/ψ Central Exclusive Production (CEP) QED Photo-production Double pomeron exchange Laboratory to study • physics of the vacuum • soft/hard QCD • saturation • exotics (tetraquarks, glueballs, hybrids) Experimentally: Reconstruct central system and identify rapidity gaps Quarkonium and double charged baryon production at LHCb 19 ++ 0 LHCb Ξ cc Ω c Inclusive J/ψ , ϒ Exclusive J/ψ Veto (Run 2) Rough LHCb coverage y=-10 y=-2 y=0 y=2 y=10 13 TeV Elastic Scattering Single Diffraction Double Diffraction Central Exclusive Production (elastic) Central Exclusive Production (inelastic) Quarkonium and double charged baryon production at LHCb 20 ++ 0 LHCb Ξ cc Ω c Inclusive J/ψ , ϒ Exclusive J/ψ High Rapidity Shower Counters at LHCb (HeRSCheL) arXiv:1806.04079 JINST 13 (2018) P04017 “Activity in HeRSCheL” Quarkonium and double charged baryon production at LHCb 21 ++ 0 LHCb Ξ cc Ω c Inclusive J/ψ , ϒ Exclusive J/ψ J/ψ and ψ(2S) candidate arXiv:1806.04079 Tag with Herschel Anti-Tag with Herschel dσ dσ ~ exp(b t) ~ exp(b t) dt sig dt bkg 2 −2 − bbkg ~ 1 GeV bsig ~ 6 GeV Quarkonium and double charged baryon production at LHCb 22 ++ 0 LHCb Ξ cc Ω c Inclusive J/ψ , ϒ Exclusive J/ψ pp and γp cross-sections arXiv:1806.04079 JHEP 1311 (2013) 085. JPG41 (2014) 055009 J/ψ ψ(2S) Quarkonium and double charged baryon production at LHCb 23 ++ 0 LHCb Ξ cc Ω c Inclusive J/ψ , ϒ Exclusive J/ψ Pb-Pb collisions LHCb-CONF-2018-003 The photon comes from the (coherent) Pb nucleus The pomeron comes from the nucleus -> Nuclear PDFs Quarkonium and double charged baryon production at LHCb 24 ++ 0 LHCb Ξ cc Ω c Inclusive J/ψ , ϒ Exclusive J/ψ Pb-Pb collisions LHCb-CONF-2018-003 Coherent HeRSCheL suppresses Incoherent incoherent events Quarkonium and double charged baryon production at LHCb 25 ++ 0 LHCb Ξ cc Ω c Inclusive J/ψ , ϒ Exclusive J/ψ Pb-Pb collisions LHCb-CONF-2018-003 Quarkonium and double charged baryon production at LHCb 26 ++ 0 LHCb Ξ cc Ω c Inclusive J/ψ , ϒ Exclusive J/ψ Summary • A small selection of recent results • Charmed baryons ++ • Observation of Ξ cc.
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