QC QCD @ LH LHC 2019 2019 Bu Buffalo, New Yo York 15 15 – 19 19 Jul uly 2019 2019 Precision PDFs at Future Colliders Claire Gwenlan, Oxford on behalf of the LHeC and FCC-eh WGs
outline • pdfs from future ep high energy colliders, LHeC and FCC-eh summary of ongoing studies towards update of LHeC CDR ( arXiV:1206.2913 ); FCC-eh pdf studies from FCC CDR, volume 1 ( EPJ C79 (2019), no.6, 474 ), plus some ongoing studies on a lower energy FCC configuration • pdfs from the HL-LHC summary of Khalek et al., arXiv:1810.03639; contribution to CERN yellow report on Standard Model Physics at the HL-LHC and HE-LHC, arXiv:1902.04070 2
pdfs: the situation today pdf luminosities (LHC@14TeV) xg(x,Q), NNLO, Q 2 =100 GeV 2 , α s (M Z )=0.118 α xg(x,Q), NNLO, Q^2=100 GeV^2, _s(M_Z)=0.118 Quark-Antiquark, luminosity Quark-Antiquark, luminosity 1.4 1.3 1.5 CT14 CT14 qqbar CT14 CT14 CT14 1.4 MMHT2014 MMHT2014 MMHT2014 MMHT2014 gluinos, KK gravitons, 1.2 NNPDF3.1 NNPDF3.1 MMHT2014 HERAPDF2.0 1.3 NNPDF3.1 1.3 S S = 1.40e+04 GeV = 1.40e+04 GeV boosted top quarks, … NNPDF3.1 HERAPDF2.0 Generated with APFEL 2.7.1 Web 1.2 S = 1.40e+04 GeV Generated with APFEL 2.7.1 Web ABMP16-118 1.1 NNPDF3.1 Q = 1.00e+01 GeV 1.1 Generated with APFEL 2.7.1 Web ABMP16-118 Ratio Ratio Higgs production 1.2 1 1 Q = 1.00e+01 GeV in gluon fusion 0.9 Ratio 0.9 0.8 1.1 0.7 W,Z,VH 0.8 0.6 1 0.7 0.5 3 3 2 2 Gluon-Gluon, luminosity 10 10 Gluon-Gluon, luminosity Gluon-Gluon, luminosity 10 10 10 10 M M [GeV] [GeV] X X 1.3 1.5 1.3 CT14 CT14 CT14 gg CT14 c, b, low mass DY, 0.9 ATLAS-epWZ16 1.4 MMHT2014 MMHT2014 MMHT2014 MMHT2014 1.2 1.2 NNPDF3.1 NNPDF3.1 soft QCD, MC tuning NNPDF3.1 1.3 NNPDF3.1 ABMP16-118 S = 1.40e+04 GeV S = 1.40e+04 GeV S = 1.40e+04 GeV S = 1.40e+04 GeV Generated with APFEL 2.7.1 Web 1.2 Generated with APFEL 2.7.1 Web Generated with APFEL 2.7.1 Web 0.8 1.1 1.1 − − − − − − 6 5 4 3 2 1 1.1 10 10 10 10 10 10 1 Ratio Ratio Ratio x 1 1 1 0.9 current data above x=5.10 -5 , and below x = 0.6–0.7 0.9 0.9 0.8 BSM H,t 0.7 0.8 0.8 0.6 pdfs poorly known at large and small x 0.5 0.7 0.7 3 2 10 10 3 3 10 2 2 10 10 10 10 10 10 M [GeV] M M [GeV] [GeV] X X X higher precision needed also for H, W, t 3
improving knowledge: LHeC and FCC-eh energy recovery LINAC e beam: up to 60 GeV Lint ⟶ 1 ab -1 ( 1000× HERA ; per 10 yrs ) e ERL operating synchronously : • with HL-LHC (or HE-LHC) p: 7 (14) TeV, √s ≈ 1.3 (1.8) TeV • and/or later with an FCC (A) p: 50 (20) TeV, √s ≈ 3.5 (2.2) TeV ☨ FCC (A): a lower energy configuration that could operate earlier in an FCC tunnel, using current magnet technology 4
kinematic coverage opportunity for unprecedented increase in DIS kinematic reach ; ×1000 increase in lumi. 4-momentum transfer squared no higher twist, no nuclear corrections, free of symmetry assumptions, N3LO theory possible, … precision pdfs , and exploration of low x regime; plus extensive ↤ EIC physics program in its own right Max Klein Kobe 17.4.18 ⨉ 15 / 120 extension in Q 2 ,1/x reach vs HERA 5
HL-LHC pdfs BUT can’t we get precision pdfs from the LHC itself? HL-LHC projections suggest it can go quite some way! arXiv:1810.03639 gluon down BUT projections are in an ideal world, where many different types of LHC measurements have well understood systematics, correlations, ubar strange and no data inconsistencies single, consistent DIS data set is a tried and tested reliable way to achieve precision also, possible issues of timing … 6
− − − A final LHeC run in dedicated operat −1 timelines LHeC 1 st run, Lint approx. 50 fb -1 total Lint ⟶ 1 ab -1 LHeC projected Integrated Luminosity: F. Bordry , arXiv:1810.13022 circa 2030 end of HL-LHC today 50 fb -1 could be achieved in 3 years before LS5 and long before the end of HL-LHC running 7
pdfs from ep colliders Low Q Low Q 2 NC NC CC CC ν ( γ exchange ) e e ± W ± e γ d , u d , u 4-momentum transfer squared q fl fl avour composition F 2 ~ �� ( q + qbar bar ) e + : d e : d e - : u : u �� �� �� dF dF 2/ 2/ dlnQ dlnQ 2 ~ α s · g �� High Q 2 NC High Q NC e Final States: Final States: ( Jets , C Charm , … ) e γ , Z q σ ~ α s ⋅ g ↤ EIC �� Z P Parity Violation �� �� �� xF 3 ~ �� ( q - qbar xF qbar ) valence Max Klein Kobe 17.4.18 6 ⨉ 15 / 120 extension in Q 2 ,1/x reach vs HERA 8
simulation and LHeC pdf programme pdf fit studies: M. Klein, CG completely resolve all proton pdfs , and α s to permille precision → ubar, uv, dbar, dv, s, c, b, t, xg and α s NEW LHeC simulations (e: 50 GeV , p: 7TeV) dataset e charge e pol. lumi (fb-1) uncert. assumptions: luminosity NC/CC – –0.8 5,50,1000 elec. scale: 0.1%; hadr. scale 0.5% NC/CC + 0 1,10 positron radcor: 0.3%; 𝝳 p at high y: 1% polarisation NC/CC – 0 50 uncorrelated extra eff.: 0.5% (important for EW NC/CC – +0.8 10,50 CC syst: 1.5% physics) luminosity: 0.5% NB, I will frequently refer to the following: LHeC 1 st Run (e-, 50 fb-1, P=-0.8) LHeC full inclusive (e-, 1000 fb-1, P=-0.8) + (e-, 50 fb-1, P=+0.8) + (e+,10 fb-1) QCD analysis a la HERAPDF , BUT no constraint that dbar=ubar at small x; 4+1 xuv, xdv, xUbar, xDbar and xg 9
gluon at large x 2 2 gluon distribution at Q = 1.9 GeV gluon at large x is small and currently 10 ) 2 = 1.9 GeV very poorly known; PDF (68% C.L.) CT14 NNPDF3.0 crucial for new physics searches MMHT2014 1 HERAPDF2.0_EIG LHeC 50fb-1 e-, P=-0.8 LHeC full inclusive LHeC sensitivity at large x comes as 2 xg(x, Q part of overall package -1 10 high luminosity (×50–1000 HERA); fully constrained quark pdfs; small x; -2 momentum sum rule 10 LHeC -3 10 gluon and sea intimately related LHeC can disentangle sea from valence quarks at large x, with precision -4 10 measurements of CC and NC F2 γZ , xF3 γZ 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 x 10
impact of luminosity on LHeC pdfs 1.1 Fractional uncertainty Fractional uncertainty 1.08 1.6 LHeC all inclusive HERA 1.06 1.4 LHeC e-, P=-0.8 1.04 1.2 1.02 1 1 0.98 0.8 0.96 0.6 0.94 dv uv 0.92 0.4 0.9 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 x x LHeC e-, P=-0.8 1.15 Fractional uncertainty 5 fb-1 Fractional uncertainty ( 1 st Run ) 50 fb-1 2 1.1 1000 fb-1 1.5 1.05 1 1 0.95 0.5 sea quarks gluon 0.9 0 0.85 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 -6 -5 -4 -3 -2 -1 10 10 10 10 10 10 x x small and medium x quickly constrained ( 5 fb-1 ≡ ×5 HERA ≡ 1st year LHeC ) large x ( ≡ large Q2 ), gain from increased Lint 11
impact of positrons on LHeC pdfs 1.1 Fractional uncertainty Fractional uncertainty 1.08 1.6 LHeC all inclusive HERA 1.06 1.4 LHeC e-, P=-0.8 1.04 1.2 1.02 1 1 0.98 0.8 0.96 0.6 0.94 dv uv 0.92 0.4 0.9 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 x x LHeC 50fb-1 e-, P=-0.8 1.15 Fractional uncertainty Fractional uncertainty plus e+, P=0 1 fb-1 2 1.1 10 fb-1 50 fb-1 1.5 1.05 1 1 0.95 0.5 sea quarks gluon 0.9 0 0.85 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 -6 -5 -4 -3 -2 -1 10 10 10 10 10 10 x x CC : e+ sensitive to d; NC : e± asymmetry gives xF3 γZ , sensitive to valence 12
collider configurations 1.1 1.1 Fractional uncertainty Fractional uncertainty Fractional uncertainty Fractional uncertainty 1.08 1.08 1.6 1.6 LHeC all inclusive HERA 1.06 1.06 1.4 1.4 LHeC e-, P=-0.8 1.04 1.04 1.2 1.2 1.02 1.02 1 1 1 1 0.98 0.98 0.8 0.8 0.96 0.96 0.6 0.6 0.94 0.94 uv dv 0.92 0.92 0.4 0.4 0.9 0.9 0.1 0.1 0.2 0.2 0.3 0.3 0.4 0.4 0.5 0.5 0.6 0.6 0.7 0.7 0.8 0.8 0.9 0.9 0.1 0.1 0.2 0.2 0.3 0.3 0.4 0.4 0.5 0.5 0.6 0.6 0.7 0.7 0.8 0.8 0.9 0.9 x x x x p: 20 TeV FCC-eh (A) FCC-eh (A) 1.15 1.15 Fractional uncertainty Fractional uncertainty Fractional uncertainty Fractional uncertainty FCC-eh p: 50 TeV 2 2 FCC-eh 1.1 1.1 1.5 1.5 1.05 1.05 1 1 1 1 0.95 0.95 0.5 0.5 sea quarks gluon 0.9 0.9 0 0 0.85 0.85 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 -6 -5 -4 -3 -2 -1 -6 -5 -4 -3 -2 -1 10 10 10 10 10 10 10 10 10 10 10 10 x x x x FCC-eh (A) : new preliminary simulation with 2 ab -1 polarised e– ( NB, NO e+ yet; impact especially in dv ) FCC-eh: CDR, volume 1, EPJ C79 (2019), no.6, 474 13
empowering LHC searches external , reliable pdfs needed for range extension and interpretation gluons quarks SUSY (RPC, RPV), LQs, … exotic and extra boson searches at high mass W (combined +/-) W (combined +/-) E. Kay & U. Klein using VRAP v0.9 250 PDF w.r.t CT14nnlo [%] NNPDF 3.0 (90% CL) 200 NNPDF 3.0 (68% CL) MMHT14 (68% CL) 150 ABM16 (68% CL) JR14 (68% CL) 100 CT14 NNLO (90% CL) d 50 LHeC-13p LL (68% CL) 0 - 50 - 100 arXiv:1211.5102 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 m [GeV] inv 14
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