Intrinsic Charm at LHCb Philip Ilten on behalf of the LHCb - PowerPoint PPT Presentation

Intrinsic Charm at LHCb Philip Ilten on behalf of the LHCb Collaboration Massachusetts Institute of Technology February 1, 2017 7th Workshop of the APS Topical Group on Hadronic Physics Ilten Intrinsic Charm at LHCb February 1, 2017 1 / 25

Introduction Overview • detector overview • intrinsic charm with Z + c • intrinsic charm using the S ystem for M easuring the O verlap with G as (SMOG) • J /ψ production in jets Ilten Intrinsic Charm at LHCb February 1, 2017 2 / 25

Introduction Detector JINST 3 (2008) S08005 5 m muon system ECAL magnet 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 . 5% at 5 GeV to 1% at 200 GeV • impact parameter resolution of 13 − 20 µ m for tracks • secondary vertex precision of 0 . 01 − 0 . 05(0 . 1 − 0 . 3) mm in xy ( z ) Ilten Intrinsic Charm at LHCb February 1, 2017 3 / 25

Introduction Trigger JINST 8 (2013) P04022 L0 HLT1 HLT2 µ : p T > 1 . 5 GeV µ : p T > 4 . 8(1) GeV µ : p T > 10(4 . 8) GeV 340 kHz 0 . 7(5) kHz µµ : � p 1 T p 2 T > 1 . 3 GeV µµ : m > 2 . 7(1)GeV µµ : m > 4 . 8(3) GeV 75 kHz 1 . 2(1 . 3) kHz 1 MHz 50 kHz h : E T > 3 . 5 GeV track: p T > 1 . 7 GeV displaced vertex 405 kHz 33 kHz e : E T > 2 . 5 GeV inclusive topological e : p T > 10 GeV 160 kHz beauty BBDT γ : E T > 2 . 5 GeV inclusive and . . . 80 kHz 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, 2017 4 / 25

Introduction Datasets V. Vagnoni (2015) HL-LHC • projected luminosity per run LHC era HL-LHC era Run 1(a) Run 1(b) Run 2 Run 3 Run 4 Run 5 2011 2012 2015 - 2019 2021 - 2023 2027 - 2029 2031 - ? 1 fb − 1 2 fb − 1 5 fb − 1 15 fb − 1 23 fb − 1 54 fb − 1 • LHCb upgrade during LS 2 • LHCb-PUB-2014-040 • replacement of readouts and photo-detectors for the RICHs • replacement of tracking detectors • full software trigger , see LHCb-TDR-016 • currently limited by hardware readout at 1 MHz • upgrade will read out entire detector at 40 MHz Ilten Intrinsic Charm at LHCb February 1, 2017 5 / 25

Intrinsic Charm with Z + c Intrinsic Charm with Z + c Ilten Intrinsic Charm at LHCb February 1, 2017 6 / 25

Intrinsic Charm with Z + c Bjorken- x Coverage • parton distribution function (PDF) parameter space in Q 2 and x 10 8 Tevatron 10 7 HERA fixed target 10 6 GPD 13 TeV 10 5 LHCb 13 TeV Q 2 [GeV 2 ] 10 4 10 3 10 2 10 1 10 0 10 − 6 10 − 5 10 − 4 10 − 3 10 − 2 10 − 1 10 0 x Ilten Intrinsic Charm at LHCb February 1, 2017 7 / 25

Intrinsic Charm with Z + c Phys. Rev. D 93 , no. 3, Intrinsic Charm PDFs 033006 (2016) • consider two models from CT14 • BHPS: valence-like via the light-cone picture of nucleon structure u ( x , Q 0 ) + ¯ • SEA: sea-like assuming IC ∝ [¯ d ( x , Q 0 )] for Q 0 < m c � 1 • two normalization points, � x � IC ≡ 0 x IC( x , m c )d x • 1: � x � IC = 0 . 6% • 2: � x � IC ≈ 2% (maximally allowed from global fit) 10 0 10 3 CT14NNLO CT14NNLO BHPS1 BHPS1 10 − 1 10 2 BHPS2 BHPS2 ( xfx − xfx CT14 ) / xfx CT14 xfx ( c, x, Q = 91 GeV) SEA1 SEA1 10 − 2 10 1 SEA2 SEA2 10 − 3 10 0 10 − 4 10 − 1 10 − 5 10 − 2 10 − 6 10 − 3 0 . 0 0 . 2 0 . 4 0 . 6 0 . 8 1 . 0 0 . 0 0 . 2 0 . 4 0 . 6 0 . 8 1 . 0 x x Ilten Intrinsic Charm at LHCb February 1, 2017 8 / 25

Intrinsic Charm with Z + c Z Production with Charm • measure ratio of Z + c -jet to Z +jet c Z c Z g c g c • not all Z + c -jet final states from intrinsic charm g g g Z Z c ¯ c ¯ ¯ c Z g c g c g c Ilten Intrinsic Charm at LHCb February 1, 2017 9 / 25

Intrinsic Charm with Z + c Jet Tagging JINST 10 (2015) P06013 0.4 FractionbofbSV-TaggedbCandidates Fraction of SV-Tagged Candidates 0.18 b 0.35 b 0.16 c 0.3 c 0.14 0.12 u d s g 0.25 u d s g 0.1 0.2 0.08 0.15 0.06 0.1 0.04 0.05 0.02 0 0 0 0.2 0.4 0.6 0.8 1 0 2 4 6 8 10 p (SV)/p (jet) SV corr mass [ GeV ] T T � M 2 + p 2 sin 2 θ + p sin θ M cor = 0.7 Fraction of SV-Tagged Candidates b 0.6 c 0.5 u d s g 0.4 p jet 0.3 0.2 θ 0.1 SV 0 0 5 10 PV SV tracks Ilten Intrinsic Charm at LHCb February 1, 2017 10 / 25

Intrinsic Charm with Z + c BDT Separation JINST 10 (2015) P06013 1 1 1 ) ) ) c c c | udsg -jets | c -jets | b -jets b b b BDT( BDT( BDT( 0.5 0.5 0.5 0 0 0 -0.5 -0.5 -0.5 LHCb simulation LHCb simulation LHCb simulation -1 -1 -1 -1 -0.5 0 0.5 1 -1 -0.5 0 0.5 1 -1 -0.5 0 0.5 1 BDT( | ) BDT( | ) BDT( | ) bc udsg bc udsg bc udsg • BDT( bc | udsg ): c and b as signal, udsg as background • BDT( b | c ): b as signal c as background • fit 2-dimensional BDT( bc | udsg ) versus BDT( b | c ) distribution Ilten Intrinsic Charm at LHCb February 1, 2017 11 / 25

Intrinsic Charm with Z + c Efficiencies JINST 10 (2015) P06013 LHCb simulation 1 1 (b,c)-jet tag efficiency SV-tag efficiency LHCb η 2.2 < (jet) < 4.2 -jet b -jet b 0.8 20 < p (jet) < 100 GeV 0.8 -jet T -jet c c 0.6 0.6 0.4 0.4 0.2 0.2 0 0 20 40 60 80 100 0.001 0.002 0.003 0.004 0.005 p (jet) [GeV] light-parton mistag probability T Ilten Intrinsic Charm at LHCb February 1, 2017 12 / 25

Intrinsic Charm with Z + c Charm-Tagging Measurements • JINST 10 (2015) P06013: validation of performance • Phys. Rev. D 92 (2015): W + c and W + b measurement • Phys. Rev. Lett. 115 (2015): first forward top measurement • arXiv:1610.08142: t ¯ t and W + Q ¯ Q 200 ) Charge Asymmetry W+b LHCb Data 0.4 Wb +top ( N 0.2 Wb 100 0 Data -0.2 LHCb Wb +top -0.4 Wb 0 ∞ ∞ 20 45 70 95 20 45 70 95 µ µ p ( + b ) [GeV] p ( + b ) [GeV] T T Ilten Intrinsic Charm at LHCb February 1, 2017 13 / 25

Intrinsic Charm with Z + c Phys. Rev. D 93 , no. 7, Expected Sensitivity 074008 (2016) ) ) Zj s = 13 TeV Zj s = 14 TeV ∫ ∫ ( ( σ -1 σ -1 Ldt = 5 fb Ldt = 15 fb )/ )/ 0.08 0.08 Zc Zc ( ( σ σ 0.06 0.06 0.04 CT14NNLO BHPS1 0.04 CT14NNLO BHPS1 BHPS2 SEA1 BHPS2 SEA1 SEA2 SEA2 CT14NNLO CT14NNLO 3 2 2.5 3 3.5 4 4.5 3 2 2.5 3 3.5 4 4.5 2 2 IC IC 1 1 2 2.5 3 3.5 4 4.5 2 2.5 3 3.5 4 4.5 ( ) ( ) y Z y Z Ilten Intrinsic Charm at LHCb February 1, 2017 14 / 25

Intrinsic Charm with SMOG Intrinsic Charm with SMOG (not to be confused with Smaug) Ilten Intrinsic Charm at LHCb February 1, 2017 15 / 25

Intrinsic Charm with SMOG SMOG JINST 9 P12005 (2014) • used for precision luminosity measurements using beam gas imaging (uncertainty of 1 . 16%) • at √ s = 110 GeV y = y com + 4 . 77 type √ s [GeV] year time p Ne 87 2012 30m PbNe 54 2013 30m p Ne 110 2015 12h p He 110 2015 7h p Ar 110 2015 20h restriction p Ar 69 2015 11h PbAr 69 2015 100h p He 110 2016 20h p He 87 2016 87h Ilten Intrinsic Charm at LHCb February 1, 2017 16 / 25

Intrinsic Charm with SMOG Bjorken- x Coverage • parton distribution function (PDF) parameter space in Q 2 and x 10 8 Tevatron 10 7 HERA fixed target 10 6 GPD 13 TeV 10 5 LHCb 110 GeV Q 2 [GeV 2 ] 10 4 10 3 10 2 10 1 10 0 10 − 6 10 − 5 10 − 4 10 − 3 10 − 2 10 − 1 10 0 x Ilten Intrinsic Charm at LHCb February 1, 2017 17 / 25

Intrinsic Charm with SMOG Phys. Rev. D 93 , no. 3, Intrinsic Charm PDFs 033006 (2016) • test with open and hidden-charm production, Q of m ( D ) 10 0 10 3 CT14NNLO 10 2 BHPS1 10 − 1 BHPS2 10 1 ( xfx − xfx CT14 ) / xfx CT14 SEA1 xfx ( c, x, Q = 2 GeV) 10 − 2 SEA2 10 0 10 − 3 10 − 1 CT14NNLO 10 − 4 BHPS1 10 − 2 BHPS2 10 − 5 SEA1 10 − 3 SEA2 10 − 6 10 − 4 0 . 0 0 . 2 0 . 4 0 . 6 0 . 8 1 . 0 0 . 0 0 . 2 0 . 4 0 . 6 0 . 8 1 . 0 x x Ilten Intrinsic Charm at LHCb February 1, 2017 18 / 25

Intrinsic Charm with SMOG JHEP 1603 , 159 (2016) Measurements JHEP 1510 , 172 (2015) • open and hidden-charm cross-sections with pp data • use the J /ψ [ µµ ], D 0 [ K + π − ], and D + [ K + π − π + ] channels ( d 2 σ ) / ( d y d p T ) [ µ b / ( GeV c − 1 )] LHCb D 0 2 . 0 < y < 2 . 5 )] √ s = 13 TeV 2 . 5 < y < 3 . 0 c 3 . 0 < y < 3 . 5 LHCb ) [nb/(GeV/ 3 . 5 < y < 4 . 0 -1 10 2 3 s = 13 TeV, L =3.05 pb 10 4 . 0 < y < 4 . 5 int 2 10 10 1 T p d 2.0< <2.5 y y 2.5< y <3.0 /(d 10 3.0< y <3.5 σ 10 0 3.5< y <4.0 2 d 4.0< y <4.5 0 5 10 ψ p ( J/ ) [GeV/ c ] 0 2 4 6 8 10 12 14 p T [ GeV / c ] T ( d 2 σ ) / ( d y d p T ) [ µ b / ( GeV c − 1 )] LHCb D + 2 . 0 < y < 2 . 5 √ s = 13 TeV 2 . 5 < y < 3 . 0 10 2 3 . 0 < y < 3 . 5 3 . 5 < y < 4 . 0 4 . 0 < y < 4 . 5 10 1 10 0 10 − 1 0 2 4 6 8 10 12 14 p T [ GeV / c ] Ilten Intrinsic Charm at LHCb February 1, 2017 19 / 25