Exclusive Production at LHCb Philip Ilten on behalf of the LHCb Collaboration Massachusetts Institute of Technology December 1, 2016 Multiple Partonic Interactions at the LHC Ilten Exclusive Production at LHCb December 1, 2016 1 / 20
Introduction Outline • motivation • LHCb detector • datasets • dimuon continuum • χ cJ production • J /ψ and ψ (2 S ) production • double J /ψ and ψ (2 S ) production • J /ψ and ψ (2 S ) production at 13 TeV Ilten Exclusive Production at LHCb December 1, 2016 2 / 20
Introduction Central Exclusive Production pp → pXp γ - γ γ -pomeron pomeron-pomeron p p p γ γ g µ + J/ ψ χ c c c µ - g g g g γ p p p ℓℓ , WW J /ψ , Υ, ρ , Z , . . . χ cJ , χ bJ , gg , . . . photon PDF, QED diffractive PDF, gluon PDF, glueball tests odderon searches searches, QCD tests Ilten Exclusive Production at LHCb December 1, 2016 3 / 20
Introduction Event Signatures inelastic p single diffraction p p double diffraction p p CEP elastic p p CEP inelastic p p elastic p -15 -10 -5 0 5 10 15 η Ilten Exclusive Production at LHCb December 1, 2016 4 / 20
Introduction Detector JINST 3 (2008) S08005 5 m muon system magnet ECAL RICH2 OT TT VELO IT SPD/PRS T1 T3 RICH1 T2 y -axis → M1 HCAL M2 M3 M4 M5 z -axis → 5 m 15 m • fully instrumented between 2 < η < 5 • momentum resolution between 0 . 4% at 5 GeV to 1% at 300 GeV • secondary vertex precision of 0 . 01 − 0 . 05(0 . 1 − 0 . 3) mm in xy ( z ) • dedicated CEP trigger lines Ilten Exclusive Production at LHCb December 1, 2016 5 / 20
Introduction Forward Kinematics √ s = 14 TeV 10 8 LHCb 10 7 ATLAS / CMS Q 2 ( x ) = e ± 2 y x 2 s Tevatron 10 6 HERA 10 5 fixed target Q 2 [GeV 2 ] � xfx ( f 1 , x 1 , Q 2 ) σ = 10 4 10 3 xfx ( f 2 , x 2 , Q 2 )ˆ σ d x 1 d x 2 10 2 10 1 10 0 10 − 6 10 − 5 10 − 4 10 − 3 10 − 2 10 − 1 10 0 x Q ≡ momentum transfer xfx ≡ parton PDF for flavor f x ≡ momentum fraction Ilten Exclusive Production at LHCb December 1, 2016 6 / 20
Introduction Backward Tracks LHCb 10 m 20 m VELO 8.4 cm 1 m Ilten Exclusive Production at LHCb December 1, 2016 7 / 20
Introduction HERSCHEL • high rapidity shower counters for LHCb Ilten Exclusive Production at LHCb December 1, 2016 8 / 20
Introduction LHCb Rapidity Gap LHCb HERSCHEL inelastic p single diffraction p p double diffraction p p CEP elastic p p CEP inelastic p p elastic p -15 -10 -5 0 5 10 15 η Ilten Exclusive Production at LHCb December 1, 2016 9 / 20
Introduction Datasets JINST 9 (2014) 12, P12005 • 36 pb − 1 at √ s = 7 TeV (2010) • 1 fb − 1 at √ s = 7 TeV (2011) • 2 fb − 1 at √ s = 7 TeV (2012) P ( N ) = e µ µ N • 200 pb − 1 at √ s = 13 TeV (2015) N ! • 2010 µ = 1 . 6 P (1) ≈ 21% • 2011 µ = 1 . 4 P (1) ≈ 25% • 2012 µ = 1 . 7 P (1) ≈ 19% • 2015 µ = 1 . 08 P (1) ≈ 35% Ilten Exclusive Production at LHCb December 1, 2016 10 / 20
Results Dimuon Continuum LHCb-CONF-2011-022 • uses 36 pb − 1 of 2010 data at √ s = 7 TeV • no backwards tracks, two muons in acceptance, p T ( µ ) > 80 MeV • m ( µµ ) > 2 . 5 GeV and exclude 100 MeV from resonances 2010 Data 50 50 2010 Data Number of events per 100 MeV Number of events per 100 MeV Number of events per 100 MeV Number of events per 100 MeV LPAIR Semi Inelastic Background from 2010 Data LPAIR Fully Inelastic 40 40 LHCb Signal from LPAIR MC Pomwig DPE Preliminary 40 40 35 35 30 30 LHCb 30 30 Preliminary 25 25 20 20 20 20 15 15 10 10 10 10 5 5 0 0 0 0 0.2 0.2 0.4 0.4 0.6 0.6 0.8 0.8 0 0 0.2 0.2 0.4 0.4 0.6 0.6 0.8 0.8 DiMuon Pt (GeV) DiMuon Pt (GeV) DiMuon Pt (GeV) DiMuon Pt (GeV) more than two forward tracks only two forward tracks σ µµ (data) = 67 ± 10 ± 5 ± 15 pb σ µµ (LPAIR) = 42 ± 1 Ilten Exclusive Production at LHCb December 1, 2016 11 / 20
Results χ cJ Production LHCb-CONF-2011-022 • same as dimuon but require exactly two muons and photon in acceptance Events per 5 MeV 2010 Data 180 Number of events per 20 MeV Number of events per 20 MeV ChiC0 from SuperChiC MC LHCb ChiC1 from SuperChiC MC 50 50 160 ChiC2 from SuperChiC MC Preliminary LHCb ChiC from Psi’ Starlight MC 140 Preliminary 40 40 s = 7 TeV 120 s = 7 TeV Data 100 30 30 80 20 20 60 40 10 10 20 0 0 0 2 2.2 2.4 2.6 2.8 3 3.2 3.4 3.6 3.8 4 3.2 3.2 3.4 3.4 3.6 3.6 3.8 3.8 Mass (GeV) 2 2 ChiC Mass (GeV/c ChiC Mass (GeV/c ) ) dimuon invariant mass dimuon+photon invariant mass σ χ c 0 → µµγ = 9.3 ± 2.2 ± 3.5 ± 1.8 pb σ χ c 1 → µµγ = 16.4 ± 5.3 ± 5.8 ± 3.2 σ χ c 2 → µµγ = 28.0 ± 5.4 ± 9.7 ± 5.4 Ilten Exclusive Production at LHCb December 1, 2016 12 / 20
Results J /ψ and ψ (2 S ) Production (1) J. Phys. G 41 (2014) 055002 • uses 930 pb − 1 of 2011 data at √ s = 7 TeV • no backwards tracks, exactly two muons in acceptance, p T ( µ ) > 400 MeV 2 Events per 10 GeV/c 4 10 LHCb 3 10 2 10 10 2500 3000 3500 4000 2 Invariant mass [MeV/c ] Ilten Exclusive Production at LHCb December 1, 2016 13 / 20
Results J /ψ and ψ (2 S ) Production (2) J. Phys. G 41 (2014) 055002 f el e − b el p 2 T + f in e − b in p 2 T + f fd P fd ( p 2 T ) 2 2 /c 4500 /c (a) 450 (b) 2 Signal 2 Signal LHCb LHCb Events per 0.02 GeV Events per 0.1 GeV 4000 400 Inelastic bkg Inelastic bkg 3500 Feed-down bkg 350 Feed-down bkg 3000 300 2500 250 2000 200 1500 150 1000 100 500 50 0 0 0 0.5 1 1.5 2 0 0.5 1 1.5 2 2 2 2 2 p 2 [GeV /c ] p 2 [GeV /c ] T T J /ψ ψ (2 S ) b el = 5 . 70 ± 0 . 11 GeV − 2 b el = 5 . 1 ± 0 . 7 GeV − 2 b in = 0 . 97 ± 0 . 04 GeV − 2 b in = 0 . 8 ± 0 . 2 GeV − 2 • extrapolated from HERA b el ≈ 6 GeV − 2 and b in ≈ 1 GeV − 2 Ilten Exclusive Production at LHCb December 1, 2016 14 / 20
Results J /ψ and ψ (2 S ) Production (3) J. Phys. G 41 (2014) 055002 6 1.4 /dy [nb] /dy [nb] LHCb LHCb 1.2 5 σ σ d d 1 4 0.8 3 0.6 2 0.4 Data with uncorrelated uncertainty Data with uncorrelated uncertainty Data total uncertainty Data total uncertainty 1 0.2 LO prediction (JMRT) LO prediction (JMRT) (a) (b) NLO prediction (JMRT) NLO prediction (JMRT) 0 0 2 2.5 3 3.5 4 4.5 2 2.5 3 3.5 4 4.5 Rapidity Rapidity J /ψ ψ (2 S ) 6 1.4 /dy [nb] /dy [nb] LHCb LHCb 1.2 5 σ σ d d 1 4 0.8 3 0.6 Data with uncorrelated uncertainty 2 Data total uncertainty 0.4 Data with uncorrelated uncertainty Saturation model of Gay Ducati, Griep & Machado Data total uncertainty 1 Saturation model of Motyka & Watt Saturation model of Gay Ducati, Griep & Machado 0.2 (a) (b) 0 0 2 2.5 3 3.5 4 4.5 2 2.5 3 3.5 4 4.5 Rapidity Rapidity Ilten Exclusive Production at LHCb December 1, 2016 15 / 20
Results J /ψ and ψ (2 S ) Production (4) J. Phys. G 41 (2014) 055002 d σ pp → pJ /ψ p dn dn = r + k + σ γ p → J /ψ p ( W + ) + r − k − σ γ p → J /ψ p ( W − ) dy dk + dk − 3 10 (nb) dn • dk ± are photon LHCb σ fluxes, k ≈ m ( J /ψ ) / 2 e ±| y | √ s • W ± 2 = 2 k ± 2 10 LHCb (W+ solutions) • W + is photon emitter LHCb (W- solutions) H1 • W − is photon target ZEUS Fixed target experiments 10 • r ± are absorptive Power law fit to H1 data corrections 3 2 10 10 W (GeV) Ilten Exclusive Production at LHCb December 1, 2016 16 / 20
Results J /ψ and ψ (2 S ) at 13 TeV (1) LHCb-CONF-2016-007 • uses 204 pb − 1 of 2015 data at √ s = 13 TeV • HERSCHEL veto in place and used signal background without HERSCHEL with HERSCHEL Ilten Exclusive Production at LHCb December 1, 2016 17 / 20
Results J /ψ and ψ (2 S ) at 13 TeV (2) LHCb-CONF-2016-007 9 /dy (nb) /dy (nb) 2.2 LHCb Preliminary LHCb Preliminary 8 2 7 1.8 σ σ 1.6 6 d d 1.4 5 1.2 4 1 3 0.8 0.6 JMRT 'LO' JMRT 'LO' 2 0.4 JMRT 'NLO' JMRT 'NLO' 1 0.2 0 2 3 4 2 3 4 ψ ψ J/ rapidity (2S) rapidity J /ψ ψ (2 S ) (nb) (nb) 3 10 LHCb ( s = 13 TeV) 2 10 LHCb ( s = 7 TeV) L H C b p r e l i m i n a r y ALICE p (2S) p ψ H1 J/ ZEUS → ψ Fixed target experiments p → Power law fit to H1 data p γ σ JMRT NLO prediction γ σ 10 LHCb ( s = 13 TeV) LHCb preliminary LHCb ( s = 7 TeV) 2 10 H1 ψ H1 J/ power law scaled by 0.166 3 3 2 2 10 10 10 10 W (GeV) W (GeV) Ilten Exclusive Production at LHCb December 1, 2016 18 / 20
Results Double ψ Production J. Phys. G 41 (2014) 15002 • uses 1 fb − 1 of 2011 data at √ s = 7 TeV • uses 2 fb − 1 of 2012 data at √ s = 8 TeV p p c c J/ψ J/ψ c c c c J/ψ J/ψ c c p p σ J /ψ, J /ψ = 58 ± 6 pb J /ψ ψ(2S) σ J /ψ,ψ (2 S ) = 63 +27 − 18 ± 10 pb σ χ c 0 χ c 0 < 69 nb J /ψ σ χ c 1 χ c 1 < 45 nb σ χ c 2 χ c 2 < 141 nb Ilten Exclusive Production at LHCb December 1, 2016 19 / 20
Conclusions Outlook • comprehensive exclusive production program at LHCb • important for odderon and glueball searches • provides data for understanding PDFs • HERSCHEL performing well • more results using final states other than muons and photons underway! Thank you! Ilten Exclusive Production at LHCb December 1, 2016 20 / 20
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