Intrinsic Charm at LHCb. 7th Workshop of the APS Topical Group on Hadronic Physics

Transcription

1 Intrinsic Charm at LHCb Philip Ilten on behalf of the LHCb Collaboration Massachusetts Institute of Technoloy February 1, 217 7th Workshop of the APS Topical Group on Hadronic Physics Ilten Intrinsic Charm at LHCb February 1, / 25

2 Introduction Overview detector overview intrinsic charm with Z + c intrinsic charm usin the System for Measurin the Overlap with Gas (SMOG) J/ψ production in jets Ilten Intrinsic Charm at LHCb February 1, / 25

3 Introduction Detector JINST 3 (28) S85 5 m muon system manet ECAL RICH2 OT VELO TT IT SPD/PRS RICH1 T1 T3 y-axis T2 M1 HCAL M2 M3 M4 M5 z-axis 5 m 15 m fully instrumented between 2 < η < 5 momentum resolution between.5% at 5 GeV to 1% at 2 GeV impact parameter resolution of 13 2 µm for tracks secondary vertex precision of.1.5(.1.3) mm in xy(z) Ilten Intrinsic Charm at LHCb February 1, / 25

4 Introduction Trier L HLT1 JINST 8 (213) P422 HLT2 µ: p T > 1.5 GeV 34 khz µµ: p 1 T p2 > 1.3 GeV T 75 khz h: E T > 3.5 GeV 45 khz µ: p T > 4.8(1) GeV.7(5) khz µµ: m > 2.7(1)GeV 1.2(1.3) khz 1 MHz 5 khz track: p T > 1.7 GeV 33 khz µ: p T > 1(4.8) GeV µµ: m > 4.8(3) GeV displaced vertex e: E T > 2.5 GeV 16 khz e: p T > 1 GeV inclusive topoloical beauty BBDT γ: E T > 2.5 GeV 8 khz... inclusive and exclusive charm real-time calibration and full event reconstruction in Run 2 full detector readout in Run 3 15 MHz 5 khz... Ilten Intrinsic Charm at LHCb February 1, / 25

5 Introduction Datasets V. Vanoni (215) HL-LHC projected luminosity per run LHC era HL-LHC era Run 1(a) Run 1(b) Run 2 Run 3 Run 4 Run ? 1 fb 1 2 fb 1 5 fb 1 15 fb 1 23 fb 1 54 fb 1 LHCb uprade durin LS 2 LHCb-PUB replacement of readouts and photo-detectors for the RICHs replacement of trackin detectors full software trier, see LHCb-TDR-16 currently limited by hardware readout at 1 MHz uprade will read out entire detector at 4 MHz Ilten Intrinsic Charm at LHCb February 1, / 25

6 Intrinsic Charm with Z + c Intrinsic Charm with Z + c Ilten Intrinsic Charm at LHCb February 1, / 25

7 Intrinsic Charm with Z + c Bjorken-x Coverae parton distribution function (PDF) parameter space in Q 2 and x Q 2 [GeV 2 ] Tevatron HERA fixed taret GPD 13 TeV LHCb 13 TeV x Ilten Intrinsic Charm at LHCb February 1, / 25

8 Intrinsic Charm with Z + c Intrinsic Charm PDFs Phys. Rev. D 93, no. 3, 336 (216) consider two models from CT14 BHPS: valence-like via the liht-cone picture of nucleon structure SEA: sea-like assumin IC [ū(x, Q ) + d(x, Q )] for Q < m c two normalization points, x IC 1 xic(x, m c)dx 1: x IC =.6% 2: x IC 2% (maximally allowed from lobal fit) xfx(c, x, Q = 91 GeV) CT14NNLO BHPS1 BHPS2 SEA1 SEA2 (xfx xfx CT14 )/xfx CT CT14NNLO BHPS1 BHPS2 SEA1 SEA x x Ilten Intrinsic Charm at LHCb February 1, / 25

9 Intrinsic Charm with Z + c Z Production with Charm measure ratio of Z + c-jet to Z+jet c Z c Z c c not all Z + c-jet final states from intrinsic charm Z Z c c c Z c c c Ilten Intrinsic Charm at LHCb February 1, / 25

10 Intrinsic Charm with Z + c Jet Tain JINST 1 (215) P613 Fr actionbofbsv-taedbcandidates Fraction of SV-Taed Candidates p (SV)/p (jet) T T b c u d s 5 1 SV tracks b c u d s Fraction of SV-Taed Candidates b c u d s SV cor r mass [ GeV ] M cor = M 2 + p 2 sin 2 θ + p sin θ SV PV θ p jet Ilten Intrinsic Charm at LHCb February 1, / 25

11 Intrinsic Charm with Z + c BDT Separation JINST 1 (215) P613 BDT(b c) 1.5 uds-jets BDT(b c) 1.5 c-jets BDT(b c) 1.5 b-jets -.5 LHCb simulation BDT(bc uds) -.5 LHCb simulation BDT(bc uds) -.5 LHCb simulation BDT(bc uds) BDT(bc uds): c and b as sinal, uds as backround BDT(b c): b as sinal c as backround fit 2-dimensional BDT(bc uds) versus BDT(b c) distribution Ilten Intrinsic Charm at LHCb February 1, / 25

12 Intrinsic Charm with Z + c Efficiencies JINST 1 (215) P613 (b,c)-jet ta efficiency LHCb simulation b-jet c-jet 2.2 < η(jet) < < p (jet) < 1 GeV T SV-ta efficiency LHCb b-jet c-jet liht-parton mista probability p (jet) [GeV] T Ilten Intrinsic Charm at LHCb February 1, / 25

13 Intrinsic Charm with Z + c Charm-Tain Measurements N(W+b) JINST 1 (215) P613: validation of performance Phys. Rev. D 92 (215): W + c and W + b measurement Phys. Rev. Lett. 115 (215): first forward top measurement arxiv: : t t and W + Q Q 2 1 LHCb Data Wb+top Wb p (µ+b) [GeV] T Chare Asymmetry Data Wb+top Wb LHCb p (µ+b) [GeV] T Ilten Intrinsic Charm at LHCb February 1, / 25

14 Intrinsic Charm with Z + c Expected Sensitivity Phys. Rev. D 93, no. 7, 748 (216) σ(zc)/σ(zj).8 s = 13 TeV Ldt = 5 fb -1 σ(zc)/σ(zj).8 s = 14 TeV Ldt = 15 fb CT14NNLO BHPS1.4 CT14NNLO BHPS1 BHPS2 SEA1 BHPS2 SEA1 SEA2 SEA2 IC CT14NNLO y(z) IC CT14NNLO y(z) Ilten Intrinsic Charm at LHCb February 1, / 25

15 Intrinsic Charm with SMOG Intrinsic Charm with SMOG (not to be confused with Smau) Ilten Intrinsic Charm at LHCb February 1, / 25

16 Intrinsic Charm with SMOG SMOG JINST 9 P125 (214) used for precision luminosity measurements usin beam as imain (uncertainty of 1.16%) at s = 11 GeV y = ycom restriction Ilten type s [GeV] year time pne PbNe pne phe par par PbAr phe phe m 3m 12h 7h 2h 11h 1h 2h 87h Intrinsic Charm at LHCb February 1, / 25

17 Intrinsic Charm with SMOG Bjorken-x Coverae parton distribution function (PDF) parameter space in Q 2 and x Q 2 [GeV 2 ] Tevatron HERA fixed taret GPD 13 TeV LHCb 11 GeV x Ilten Intrinsic Charm at LHCb February 1, / 25

18 Intrinsic Charm with SMOG Intrinsic Charm PDFs Phys. Rev. D 93, no. 3, 336 (216) test with open and hidden-charm production, Q of m(d) xfx(c, x, Q = 2 GeV) CT14NNLO BHPS1 BHPS2 SEA1 SEA x (xfx xfx CT14 )/xfx CT CT14NNLO BHPS1 BHPS2 SEA1 SEA x Ilten Intrinsic Charm at LHCb February 1, / 25

19 Intrinsic Charm with SMOG Measurements JHEP 163, 159 (216) JHEP 151, 172 (215) open and hidden-charm cross-sections with pp data use the J/ψ[µµ], D [K + π ], and D + [K + π π + ] channels (d 2 σ)/(dydpt) [µb/(gevc 1 )] LHCb D 2. < y < 2.5 s = 13 TeV 2.5 < y < < y < < y < < y < 4.5 ) [nb/(gev/c)] T LHCb s = 13 TeV, L int -1 =3.5 pb 1 σ/(dydp 2 d 1 2.< y < < y <3. 3.< y < < y <4. 4.< y < pt [GeV/c] 5 1 p (J/ ψ ) [GeV/c] T (d 2 σ)/(dydpt) [µb/(gevc 1 )] LHCb D + 2. < y < 2.5 s = 13 TeV 2.5 < y < < y < < y < < y < pt [GeV/c] Ilten Intrinsic Charm at LHCb February 1, / 25

20 Intrinsic Charm with SMOG Future Measurements same measurements but with phe and par data rouh predictions in LHCb acceptance from Pythia 8 D at s(par) = 11 GeV D at s(pp) = 13 TeV A.U CT14NNLO BHPS1 BHPS2 SEA1 SEA y + D at s(par) = 11 GeV A.U CT14NNLO BHPS1 BHPS2 SEA1 SEA y + D at s(pp) = 13 TeV A.U CT14NNLO BHPS1.6 BHPS2 SEA1.4 SEA y A.U CT14NNLO BHPS1 BHPS2 SEA1 SEA y Ilten Intrinsic Charm at LHCb February 1, / 25

21 J/ψ Production in Jets J/ψ Production in Jets Ilten Intrinsic Charm at LHCb February 1, / 25

22 J/ψ Production in Jets Two Pictures arxiv: understandin prompt J/ψ critical for intrinsic charm prompt J/ψ calculated with non-relativistic QCD (NRQCD) two pictures on how NRQCD is used NRQCD hard process, octet states showered with QCD splittins shower with NRQCD splittins, match with hard process J/ψ J/ψ utilize J/ψ trier that writes out fully reconstructed event use jets with p T > 2 GeV which contain a J/ψ Ilten Intrinsic Charm at LHCb February 1, / 25

23 J/ψ Production in Jets Results arxiv: measure z p T (J/ψ)/p T (jet) separate into prompt and displaced contributions dσ/σ.3.2 Data (syst) Pythia 8 LHCb s = 13 TeV b J/ψ dσ/σ.3.2 Data (syst) Pythia 8 LHCb s = 13 TeV Prompt z(j/ψ ) z(j/ψ ) Pythia 8 implements the LO hard process picture not the end of the story, need different predictions Ilten Intrinsic Charm at LHCb February 1, / 25

24 Outlook Outlook Ilten Intrinsic Charm at LHCb February 1, / 25

25 Outlook Outlook forward detector with diverse datasets robust and efficient c(b)-tain alorithm validated aainst data intrinsic charm studies underway both with pp and par rule out BHSP models at x IC 1%... or demonstrate IC! Thank you! I discover intrinsic charm where I wish and none dare resist. - SMOG (if SMOG were Smau) Ilten Intrinsic Charm at LHCb February 1, / 25