Measurement of associated production of a W boson and a charm quark - PowerPoint PPT Presentation

Measurement of associated production of a W boson and a charm quark in proton-proton collisions at 13 TeV Svenja Pflitsch for the CMS Collaboration Rencontres de Moriond 2019 - Young Scientist Forum Svenja Pflitsch DESY | YSF Associated production of W+charm at 13 TeV | Rencontres de Moriond 2019 1/5

Analysis Strategy arXiv: 1811.10021 W → µ ν p µ T > 26 GeV, | η µ | < 2.4 * M T > 50 GeV +c.c. c → D ∗ (2010) ± → D 0 + π ± slow -1 CMS 35.7 fb (13 TeV) p D ∗ T,reco > 5 GeV SS) Events / 1 MeV Data 12000 W+c p c W+c c T,gen > 5 GeV * W+b/W+b b 10000 Background ∆ ± M [ GeV]: 0.1454 0.0001 8000 σ ± [MeV]: 0.70 0.02 ± 6000 Data Integral: 19163 587 Differential measurement | η µ | − ± MC Integral: 19594 679 (OS ± MC W+c: 19421 291 4000 ± MC W+c c : 99 250 ± MC W+b/W+b b : 11 26 * Fiducial phase space of the 2000 analysis 0 0.14 0.145 0.15 0.155 0.16 0.165 0.17 ∆ 0 m(D*,D ) [GeV] Svenja Pflitsch DESY | YSF Associated production of W+charm at 13 TeV | Rencontres de Moriond 2019 2/5

Theoretical Predictions Calculations done with MCFM, W + c available at NLO Scale: µ r = µ f = M W 1 2 µ < µ r = µ f < 2 µ amount to an uncertainty of 3% Good agreement with all global PDFs -1 CMS 35.7 fb (13 TeV) -1 CMS 35.7 fb (13 TeV) µ µ η p > 26 GeV, | | < 2.4 Total Uncertainty T | [pb] 1000 c p > 5 GeV Statistical Uncertainty Data T ABMP16 ATLASepWZ16 W + c ABMP16 800 µ CT14 MMHT14 η (W+c)/d| NNPDF 3.0 NNPDF 3.1 ATLASepWZ16 600 CT14 σ 400 d MMHT14 µ µ η p > 26 GeV, | | < 2.4 T 200 c p > 5 GeV NNPDF 3.0 T 0 NNPDF 3.1 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4 µ η | | 0 200 400 600 800 1000 1200 σ (W+c) [pb] Svenja Pflitsch DESY | YSF Associated production of W+charm at 13 TeV | Rencontres de Moriond 2019 3/5

QCD Analysis: xFitter Strange Quark Content of the Proton Input: HERA DIS + CMS W asymm. + CMS W+charm u + ¯ Strangeness suppression : r s = ( s + ¯ s ) / (¯ d ) Results compatible with global PDFs CMS Hessian uncertainties CMS Hessian uncertainties r s r s µ f 2 = 1.9 GeV 2 µ f CMS, this analysis 2 = m W 2 CMS, this analysis 1.5 1.5 1.5 ABMP16nlo ABMP16nlo 2 2 2 ATLASepWZ16nnlo ATLASepWZ16nnlo 1 1 1 1 1 1 0.5 0.5 0.5 -3 -3 -3 -2 -2 -2 -1 -1 -1 -3 -3 -3 -2 -2 -2 -1 -1 -1 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 x x Svenja Pflitsch DESY | YSF Associated production of W+charm at 13 TeV | Rencontres de Moriond 2019 4/5

Comparison with 7 TeV In agreement with 7 TeV PDF fits with same parametrization Reduced PDF uncertainties CMS Hessian uncetainties CMS Hessian uncetainties  x • s  x • s 0.6 2 = 1.9 GeV 2 µ f µ f 2 = m W 2 PRD 90 (2014) 032004 PRD 90 (2014) 032004 3 This analysis This analysis parameterization of PRD 90 (2014) 032004 parameterization of PRD 90 (2014) 032004 0.4 2 0.2 1 0.1 0.1 Fract. uncert. Fract. uncert. 0.2 0.2 0 0 0 0 -0.2 -0.2 -0.1 -0.1 -3 -3 -2 -2 -1 -1 -3 -3 -2 -2 -1 -1 10 10 10 10 10 10 10 10 10 10 10 10 x x Svenja Pflitsch DESY | YSF Associated production of W+charm at 13 TeV | Rencontres de Moriond 2019 5/5

Backup: Svenja Pflitsch DESY | YSF Associated production of W+charm at 13 TeV | Rencontres de Moriond 2019 1/4

D ∗ (2010) ± Reconstruction -1 CMS 35.7 fb (13 TeV) SS) Events / 11 MeV Data D 0 → K ∓ π ± 5000 W+c W+c c W+b/W+b b Background 4000 p track > 1 GeV, M [ GeV]: 1.8634 ± 0.0005 σ ± T [MeV]: 13.87 0.45 3000 ± originate at fitted secondary vertex Data Integral: 16070 542 ± MC Integral: 16523 635 − (OS 2000 MC W+c: 16434 ± 278 ± | m (K ∓ , π ± ) − m (D 0 ) | < 35 MeV MC W+c c : 51 239 ± MC W+b/W+b b : 4 25 1000 0 1.6 1.7 1.8 1.9 2 2.1 D ∗ (2010) ± → D 0 + π ± 0 D mass [GeV] slow CMS 35.7 fb -1 (13 TeV) SS) Events / 1 MeV Data p track 12000 W+c > 0.35 GeV W+c c T W+b/W+b b 10000 Background p D ∗ > 5 GeV ∆ ± T M [ GeV]: 0.1454 0.0001 8000 σ ± [MeV]: 0.70 0.02 ∆ R (D 0 , π ± slow ) < 0.15 ± Data Integral: 19163 587 6000 − ± (OS MC Integral: 19594 679 ± ∆ z ( π ± MC W+c: 19421 291 slow , µ ) < 0.2 cm 4000 ± MC W+c c : 99 250 ± T / � p track MC W+b/W+b b : 11 26 p D ∗ 2000 > 0.2 T 0 0.14 0.145 0.15 0.155 0.16 0.165 0.17 ∆ 0 m(D*,D ) [GeV] Svenja Pflitsch DESY | YSF Associated production of W+charm at 13 TeV | Rencontres de Moriond 2019 2/4

QCD Analysis: Parametrization At the starting scale ( Q 2 0 = 1.9 GeV 2 ): xu v ( x ) = A u v x B u v (1 − x ) C u v (1 + E u v x 2 ) xd v ( x ) = A d v x B d v (1 − x ) C d v x U( x ) = A U x B U (1 − x ) C U (1 + E U x 2 ) xd ( x ) = A d x B d (1 − x ) C d xs ( x ) = A s x B s (1 − x ) C s xg ( x ) = A g x B g (1 − x ) C g (1 + D g x ) s/ ( ¯ f s = ¯ d + ¯ s ) released A U = A D (1 − f s ) B u = B d = B s released [arXiv:1708.01067] xs = x ¯ s Svenja Pflitsch DESY | YSF Associated production of W+charm at 13 TeV | Rencontres de Moriond 2019 3/4

QCD Analysis: Results CMS HERA DIS + CMS W + CMS W+c  x • s µ f 2 = 1.9 GeV 2 Hessian uncertainties 1 1 Good agreement among the CMS MC uncertainties 0.75 0.75 measurements 0.5 0.5 0.25 0.25 χ 2 /n dp Dataset Fract. uncert. HERA1+2 CCep 43 / 39 0.5 0.5 HERA1+2 CCem 57 / 42 0 0 HERA1+2 NCem 218 / 159 -0.5 -0.5 HERA1+2 NCep 820 69 / 70 -3 -3 -2 -2 -1 -1 10 10 10 10 10 10 x HERA1+2 NCep 920 448 / 377 CMS HERA DIS + CMS W + CMS W+c HERA1+2 NCep 460 216 / 204 r s µ f 2 = 1.9 GeV 2 Hessian uncertainties HERA1+2 NCep 575 220 / 254 MC uncertainties CMS W muon charge asym. 7 TeV 13 / 11 2 2 CMS W muon charge asym. 8 TeV 4.2 / 11 W+c 7 TeV 2.2 / 5 1 1 W+c 13 TeV 2.1 / 5 Correlated χ 2 87 Fract. uncert. 0.5 0.5 Total χ 2 / dof 1385 / 1160 0 0 -0.5 -0.5 -3 -3 -2 -2 -1 -1 10 10 10 10 10 10 x Svenja Pflitsch DESY | YSF Associated production of W+charm at 13 TeV | Rencontres de Moriond 2019 4/4