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

SLIDE 1

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

SLIDE 2

Analysis Strategy

arXiv: 1811.10021

W → µ ν pµ

T > 26 GeV, |ηµ| < 2.4 *

MT > 50 GeV c → D∗(2010)± → D0 + π±

slow

pD∗

T,reco > 5 GeV

pc

T,gen > 5 GeV *

Differential measurement |ηµ| * Fiducial phase space of the

analysis +c.c.

) [GeV] m(D*,D ∆ 0.14 0.145 0.15 0.155 0.16 0.165 0.17 SS) Events / 1 MeV − (OS 2000 4000 6000 8000 10000 12000

Data W+c c W+c b W+b/W+b Background 0.0001 ± M [ GeV]: 0.1454 ∆ 0.02 ± [MeV]: 0.70 σ 587 ± Data Integral: 19163 679 ± MC Integral: 19594 291 ± MC W+c: 19421 250 ± : 99 c MC W+c 26 ± : 11 b MC W+b/W+b CMS (13 TeV)

1

35.7 fb

Svenja Pflitsch DESY | YSF Associated production of W+charm at 13 TeV | Rencontres de Moriond 2019 2/5

SLIDE 3

Theoretical Predictions

Calculations done with MCFM, W + c available at NLO Scale: µr = µf = MW

1 2µ < µr = µf < 2µ amount to an uncertainty of 3%

Good agreement with all global PDFs

(W+c) [pb] σ

200 400 600 800 1000 1200

Total Uncertainty Statistical Uncertainty

ABMP16 ATLASepWZ16 CT14 MMHT14 NNPDF 3.0 NNPDF 3.1

| < 2.4

µ

η > 26 GeV, |

µ T

p > 5 GeV

c T

p

CMS (13 TeV)

1

35.7 fb

|

µ

η |

0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4

| [pb]

µ

η (W+c)/d| σ d

200 400 600 800 1000

Data ABMP16 ATLASepWZ16 CT14 MMHT14 NNPDF 3.0 NNPDF 3.1 | < 2.4

µ

η > 26 GeV, |

µ T

p > 5 GeV

c T

p

CMS (13 TeV)

1

35.7 fb W + c Svenja Pflitsch DESY | YSF Associated production of W+charm at 13 TeV | Rencontres de Moriond 2019 3/5

SLIDE 4

QCD Analysis: xFitter

Strange Quark Content of the Proton

Input: HERA DIS + CMS W asymm. + CMS W+charm Strangeness suppression : rs = (s + ¯ s)/(¯ u + ¯ d) Results compatible with global PDFs

CMS Hessian uncertainties

µf

2 = 1.9 GeV2

ABMP16nlo ATLASepWZ16nnlo CMS, this analysis

x rs

1 2 10

3

10

2

10

1

1 2 10

3

10

2

10

1

1 2 10

3

10

2

10

1

CMS Hessian uncertainties

µf

2 = mW 2

ABMP16nlo ATLASepWZ16nnlo CMS, this analysis

x rs

0.5 1 1.5 10

3

10

2

10

1

0.5 1 1.5 10

3

10

2

10

1

0.5 1 1.5 10

3

10

2

10

1

Svenja Pflitsch DESY | YSF Associated production of W+charm at 13 TeV | Rencontres de Moriond 2019 4/5

SLIDE 5

Comparison with 7 TeV

In agreement with 7 TeV PDF fits with same parametrization Reduced PDF uncertainties

0.2 0.4 0.6 CMS Hessian uncetainties

µf

2 = 1.9 GeV2

This analysis PRD 90 (2014) 032004 parameterization of PRD 90 (2014) 032004

x • s



x

Fract. uncert.
0.2

0.2 10

3

10

2

10

1
0.2

0.2 10

3

10

2

10

1

1 2 3 CMS Hessian uncetainties

µf

2 = mW 2

This analysis PRD 90 (2014) 032004 parameterization of PRD 90 (2014) 032004

x • s



x

Fract. uncert.
0.1

0.1 10

3

10

2

10

1
0.1

0.1 10

3

10

2

10

1

Svenja Pflitsch DESY | YSF Associated production of W+charm at 13 TeV | Rencontres de Moriond 2019 5/5

SLIDE 6

Backup:

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

SLIDE 7

D∗(2010)± Reconstruction

D0 → K∓π±

ptrack

T

> 1 GeV,

riginate at fitted secondary vertex

|m(K∓, π±) − m(D0)| < 35 MeV

D∗(2010)± → D0 + π±

slow

ptrack

T

> 0.35 GeV pD∗

T

> 5 GeV ∆R(D0, π±

slow) < 0.15

∆z(π±

slow, µ) < 0.2 cm

pD∗

T / ptrack T

> 0.2

mass [GeV] D 1.6 1.7 1.8 1.9 2 2.1 SS) Events / 11 MeV − (OS 1000 2000 3000 4000 5000

Data W+c c W+c b W+b/W+b Background 0.0005 ± M [ GeV]: 1.8634 0.45 ± [MeV]: 13.87 σ 542 ± Data Integral: 16070 635 ± MC Integral: 16523 278 ± MC W+c: 16434 239 ± : 51 c MC W+c 25 ± : 4 b MC W+b/W+b CMS (13 TeV)

1

35.7 fb

) [GeV] m(D*,D ∆ 0.14 0.145 0.15 0.155 0.16 0.165 0.17 SS) Events / 1 MeV − (OS 2000 4000 6000 8000 10000 12000

Data W+c c W+c b W+b/W+b Background 0.0001 ± M [ GeV]: 0.1454 ∆ 0.02 ± [MeV]: 0.70 σ 587 ± Data Integral: 19163 679 ± MC Integral: 19594 291 ± MC W+c: 19421 250 ± : 99 c MC W+c 26 ± : 11 b MC W+b/W+b CMS (13 TeV)

1

35.7 fb

Svenja Pflitsch DESY | YSF Associated production of W+charm at 13 TeV | Rencontres de Moriond 2019 2/4

SLIDE 8

QCD Analysis: Parametrization

At the starting scale (Q2

0 = 1.9 GeV2):

xuv(x) = Auv xBuv (1 − x)Cuv (1 + Euvx2) xdv(x) = Adv xBdv (1 − x)Cdv xU(x) = AU xBU (1 − x)CU (1 + EUx2) xd(x) = Ad xBd (1 − x)Cd xs(x) = As xBs (1 − x)Cs xg(x) = Ag xBg (1 − x)Cg (1 + Dgx) fs = ¯ s/( ¯ d + ¯ s) released AU = AD(1 − fs) Bu = Bd = Bs 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

SLIDE 9

QCD Analysis: Results

Good agreement among the CMS measurements

Dataset χ2/ndp HERA1+2 CCep 43 / 39 HERA1+2 CCem 57 / 42 HERA1+2 NCem 218 / 159 HERA1+2 NCep 820 69 / 70 HERA1+2 NCep 920 448 / 377 HERA1+2 NCep 460 216 / 204 HERA1+2 NCep 575 220 / 254 CMS W muon charge asym. 7 TeV 13 / 11 CMS W muon charge asym. 8 TeV 4.2 / 11 W+c 7 TeV 2.2 / 5 W+c 13 TeV 2.1 / 5 Correlated χ2 87 Total χ2 / dof 1385 / 1160

0.25 0.5 0.75 1 0.25 0.5 0.75 1 CMS HERA DIS + CMS W + CMS W+c

µf

2 = 1.9 GeV2

MC uncertainties Hessian uncertainties

x • s



x

Fract. uncert.
0.5

0.5 10

3

10

2

10

1
0.5

0.5 10

3

10

2

10

1

1 2 1 2 CMS HERA DIS + CMS W + CMS W+c

µf

2 = 1.9 GeV2

MC uncertainties Hessian uncertainties

rs x

Fract. uncert.
0.5

0.5 10

3

10

2

10

1
0.5

0.5 10

3

10

2

10

1

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