1 fromDeep-InelasticScattering sblumlein/Talks/ALPH1.pdf · 1 αs fromDeep-InelasticScattering J....

33
1 α s from Deep-Inelastic Scattering J. Bl ¨ umlein, DESY in collaboration with S. Alekhin and S.O. Moch, U. Hamburg Introduction Valence Non-Singlet Analysis Combined NS+S Analyses, Inclusion of Collider Data Comparison of Results Conclusions J. Bl ¨ umlein α s -Workshop Geneva, Oct. 2015

Transcript of 1 fromDeep-InelasticScattering sblumlein/Talks/ALPH1.pdf · 1 αs fromDeep-InelasticScattering J....

Page 1: 1 fromDeep-InelasticScattering sblumlein/Talks/ALPH1.pdf · 1 αs fromDeep-InelasticScattering J. Bl¨umlein, DESY in collaboration with S. Alekhin and S.O. Moch, U. Hamburg • Introduction

1

αs from Deep-Inelastic Scattering

J. Blumlein, DESY

in collaboration with S. Alekhin and S.O. Moch, U. Hamburg

• Introduction

• Valence Non-Singlet Analysis

• Combined NS+S Analyses, Inclusion of Collider Data

• Comparison of Results

• Conclusions

J. Blumlein αs-Workshop Geneva, Oct. 2015

Page 2: 1 fromDeep-InelasticScattering sblumlein/Talks/ALPH1.pdf · 1 αs fromDeep-InelasticScattering J. Bl¨umlein, DESY in collaboration with S. Alekhin and S.O. Moch, U. Hamburg • Introduction

2

αs(M2Z) in 1992

G. Altarelli: QCD - 20 Years Later NLO World-Average [23 years ago.]

αs(M2Z)

Rτ 0.117+0.010

−0.016

DIS 0.112± 0.007

Υ Decays 0.110± 0.010

Re+e−(s < 62GeV) 0.140± 0.020

pp → W + jets 0.121± 0.024

Γ(Z → hadrons)/Γ(Z → ll) 0.132± 0.012

Jets at LEP 0.122± 0.009

Average 0.118± 0.007

@ NLO: still right, but for very different reasons.

NLO error: now down to ∼ 0.0050− 0.0040 (TH: scale uncertainty)

Page 3: 1 fromDeep-InelasticScattering sblumlein/Talks/ALPH1.pdf · 1 αs fromDeep-InelasticScattering J. Bl¨umlein, DESY in collaboration with S. Alekhin and S.O. Moch, U. Hamburg • Introduction

3

ΛQCD and αs(M2Z)

older values: 2000 <∼date <

∼2007

NLO αs(M2

Z) expt theory Ref.

CTEQ6 0.1165 ±0.0065 [1]MRST03 0.1165 ±0.0020 ±0.0030 [2]A02 0.1171 ±0.0015 ±0.0033 [3]ZEUS 0.1166 ±0.0049 [4]H1 0.1150 ±0.0017 ±0.0050 [5]BCDMS 0.110 ±0.006 [6]GRS 0.112 [10]BBG 0.1148 ±0.0019 [9]BB (pol) 0.113 ±0.004 +0.009

−0.006[7]

NLO at least: scale errors of ±0.0050

NNLO αs(M2

Z) expt theory Ref.

MRST03 0.1153 ±0.0020 ±0.0030 [2]A02 0.1143 ±0.0014 ±0.0009 [3]SY01(ep) 0.1166 ±0.0013 [8]SY01(νN) 0.1153 ±0.0063 [8]GRS 0.111 [10]A06 0.1128 ±0.0015 [11]BBG 0.1134 +0.0019/ − 0.0021 [9]

N3LO αs(M2

Z) expt theory Ref.

BBG 0.1141 +0.0020/ − 0.0022 [9]

NNLO systematic shifts down

N3LO slight upward shift

BBG: Nf = 4: non-singlet data-analysis at O(α4s): Λ = 234± 26MeV

Page 4: 1 fromDeep-InelasticScattering sblumlein/Talks/ALPH1.pdf · 1 αs fromDeep-InelasticScattering J. Bl¨umlein, DESY in collaboration with S. Alekhin and S.O. Moch, U. Hamburg • Introduction

4

Deep Inelatsic Scattering

q

k′

k

P Wµν

Lµν

Q2 := −q2, x :=Q2

2pq

ν :=Pq

M,

dQ2 dx∼ WµνL

µν

Wµν(q, P, s) =1

d4ξ exp(iqξ)〈P, s[Jemµ (ξ), Jem

ν (0)]P, s〉

=1

2x

(

gµν −qµqνq2

)

FL(x,Q2)

+2x

Q2

(

PµPν +qµPν + qνPµ

2x−

Q2

4x2gµν

)

F2(x,Q2)

Structure Functions: F2,L contain light and heavy quark contributions=⇒ Further Inclusion of Collider Data: DY (W±, Z), tt, jets.

Page 5: 1 fromDeep-InelasticScattering sblumlein/Talks/ALPH1.pdf · 1 αs fromDeep-InelasticScattering J. Bl¨umlein, DESY in collaboration with S. Alekhin and S.O. Moch, U. Hamburg • Introduction

5

World Data Analysis: Valence Distributions (NS)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

10-3

10-2

10-1 x

xuv(X)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

10-3

10-2

10-1 x

xuv(X)

0

0.1

0.2

0.3

0.4

0.5

10-3

10-2

10-1 x

xdv(X)

0

0.1

0.2

0.3

0.4

0.5

10-3

10-2

10-1 x

xdv(X)

World data:

NS-analysis

W 2 > 12.5 GeV2, Q2 > 4 GeV2

N3LO :

αs(M2Z) = 0.1141+0.0020

−0.0022

J.B., H. Bottcher, A. Guffanti

Nucl.Phys. B774 (2007) 182.

Page 6: 1 fromDeep-InelasticScattering sblumlein/Talks/ALPH1.pdf · 1 αs fromDeep-InelasticScattering J. Bl¨umlein, DESY in collaboration with S. Alekhin and S.O. Moch, U. Hamburg • Introduction

6

Why an O(α4s) analysis can be performed?

assume an ±100% error on the Pade approximant −→ ±2 MeV in ΛQCD

γapprox:3n =

γ(2)n

2

γ(1)n

Baikov & Chetyrkin, April 2006:

γ3;NS2 =

32

9as +

9440

243a2s +

[

3936832

6561−

10240

81ζ3

]

a3s

+

[

1680283336

1777147−

24873952

6561ζ3 +

5120

3ζ4 −

56969

243ζ5

]

a4s

The results agree better than 20%.

This behaviour is even confirmed for the moments N = 3, 4 by Baikov et al. 2013. The

moments for N = 2, 4 were confirmed by Velizhanin 2012, 2014.

Page 7: 1 fromDeep-InelasticScattering sblumlein/Talks/ALPH1.pdf · 1 αs fromDeep-InelasticScattering J. Bl¨umlein, DESY in collaboration with S. Alekhin and S.O. Moch, U. Hamburg • Introduction

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Valence Distributions

10-3

10-2

10-1

1

10

1 10 102

103

104

105

Q2, GeV2

10-3

10-2

10-1

1

10

1 10 102

103

Q2, GeV2

Page 8: 1 fromDeep-InelasticScattering sblumlein/Talks/ALPH1.pdf · 1 αs fromDeep-InelasticScattering J. Bl¨umlein, DESY in collaboration with S. Alekhin and S.O. Moch, U. Hamburg • Introduction

8

Higher Twist Contributions in the Valence Region

J.B. and H. Bottcher, 2012 (BB) [1207.3170 hep-ph]: NS-tails at NNLO :

0.97

0.975

0.98

0.985

0.99

0.995

1

0.3 0.4 0.5 0.6 0.7 0.8 0.9 1x

F2p(valence)/F2

p(x)

Q2 = 4 GeV2

Q2 = 10 GeV2

0.97

0.975

0.98

0.985

0.99

0.995

1

0.3 0.4 0.5 0.6 0.7 0.8 0.9 1x

F2d(valence)/F2

d(x)

Q2 = 100 GeV2

Using ABKM09 we corrected for non NS-tails in F2(x,Q2).

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Valence Distributions: higher twist

0

2

4

6

8

10

0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

PROTON

CHT(x) [GeV2]

4.0 GeV2 < W2 < 12.5 GeV2

NLO

NNLO

N3LO

x-1

0

1

2

3

4

5

0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

DEUTERON

CHT(x) [GeV2]

4.0 GeV2 < W2 < 12.5 GeV2

NLO

NNLO

N3LO

x• agreement between p and d analysis, J.B., H. Bottcher Phys.Lett. B662 (2008) 336

• LGT determination of interest

Page 10: 1 fromDeep-InelasticScattering sblumlein/Talks/ALPH1.pdf · 1 αs fromDeep-InelasticScattering J. Bl¨umlein, DESY in collaboration with S. Alekhin and S.O. Moch, U. Hamburg • Introduction

10

αs(M2Z)

❊①♣❡r✐�❡♥t ☛s✭▼❩✮

◆▲❖✁✂✄ ◆▲❖ ◆◆▲❖ ◆✸▲❖☎

❇❈❉✆❙ ✵✿✶✶✶✶ ✝ ✵✿✵✵✶✽ ✵✿✶✶✞✽ ✝ ✵✿✵✵✵✼ ✵✿✶✶✷✻ ✝ ✵✿✵✵✵✼ ✵✿✶✶✷✽ ✝ ✵✿✵✵✵✻

◆✆❈ ✵✿✶✶✼

✰ ✟✠✟✡✡

☞ ✟✠✟✡✌ ✵✿✶✶✻✻ ✝ ✵✿✵✵✞✾ ✵✿✶✶✺✞ ✝ ✵✿✵✵✞✾ ✵✿✶✶✺✞ ✝ ✵✿✵✵✞✺

❙▲❆❈ ✵✿✶✶✹✼ ✝ ✵✿✵✵✷✾ ✵✿✶✶✺✽ ✝ ✵✿✵✵✞✞ ✵✿✶✶✺✷ ✝ ✵✿✵✵✷✼

❇❇● ✵✿✶✶✹✽ ✝ ✵✿✵✵✶✾ ✵✿✶✶✞✹ ✝ ✵✿✵✵✷✵ ✵✿✶✶✹✶ ✝ ✵✿✵✵✷✶

❇❇ ✵✿✶✶✹✼ ✝ ✵✿✵✵✷✶ ✵✿✶✶✞✷ ✝ ✵✿✵✵✷✷ ✵✿✶✶✞✼ ✝ ✵✿✵✵✷✷

❚❛❜❡❧❧❡ ✻✍ ✎♦♠✏✑✒✓✔♦✕ ♦❢ ✖❤✗ ✈✑✘✉✗✔ ♦❢ ✙s✚✛❩✜ ♦✢✖✑✓✕✗❞ ✢② ✣✎✤✥✦ ✑✕❞ ✧✥✎ ✑✖ ✧★✩ ✇✓✖❤ ✖❤✗

✒✗✔✉✘✖✔ ♦❢ ✖❤✗ ✪✑✈♦✒ ✕♦✕✲✔✓✕❣✘✗✖ ✫✖✔ ✣✣✬ ✑✕❞ ✣✣ ♦❢ ✖❤✗ ✤■✦ ✪✑✈♦✒ ✕♦✕✲✔✓✕❣✘✗✖ ✇♦✒✘❞ ❞✑✖✑✱ ✑✖ ✧★✩✱

✧✧★✩✱ ✑✕❞ ✧✸★✩☎ ✇✓✖❤ ✖❤✗ ✒✗✔✏♦✕✔✗ ♦❢ ✖❤✗ ✓✕❞✓✈✓❞✉✑✘ ❞✑✖✑ ✔✗✖✔✱ ❝♦♠✢✓✕✗❞ ❢♦✒ ✖❤✗ ✗✯✏✗✒✓♠✗✕✖✔ ✣✎✤✥✦

✧✥✎ ✦★✳✎✴

Page 11: 1 fromDeep-InelasticScattering sblumlein/Talks/ALPH1.pdf · 1 αs fromDeep-InelasticScattering J. Bl¨umlein, DESY in collaboration with S. Alekhin and S.O. Moch, U. Hamburg • Introduction

11

S+NS DIS Analysis (NNLO)µ=2 GeV, nf=4

0

2.5

5

7.5

10

10-5

10-4

10-3

10-2

xG

x0

2.5

5

7.5

10

0

1

2

3

0.05 0.1 0.15 0.2 0.25

xG

x0

1

2

3

0

0.25

0.5

0.75

1

10-5

10-4

10-3

10-2

x(u-+d

-)/2

x0

0.25

0.5

0.75

1

0

0.05

0.1

0.15

0.2

0.05 0.1 0.15 0.2 0.25

x(u-+d

-)/2

x0

0.05

0.1

0.15

0.2

0

0.2

0.4

0.6

0.8

0.2 0.4 0.6 x

xu

xd

0

0.2

0.4

0.6

0.8

-0.02

0

0.02

0.04

0.06

10-4

10-3

10-2

10-1

x(d--u

-)

x

-0.02

0

0.02

0.04

0.06

0

0.5

1

1.5

2

10-5

10-4

10-3

10-2 x

x(s+s-)/2

0

0.5

1

1.5

2

0

0.05

0.1

0.05 0.1 0.15 0.2 0.25 x

x(s+s-)/2

0

0.05

0.1

ABM12: shaded region, JR: full line (green), NN23: dashes (blue), MRST: dash-dotted (red), CT10: dots.

Page 12: 1 fromDeep-InelasticScattering sblumlein/Talks/ALPH1.pdf · 1 αs fromDeep-InelasticScattering J. Bl¨umlein, DESY in collaboration with S. Alekhin and S.O. Moch, U. Hamburg • Introduction

12

Higher Twist Contributions

ABM11:

Fi(x,Q2) = FTMC,τ=2

i (x,Q2) +H4

i (x)

Q2+

H6i (x)

Q4+ ...

-0.15

-0.125

-0.1

-0.075

-0.05

-0.025

0

0.025

0.05

0.075

0 0.5 x

H2p (1/GeV2)

-0.15

-0.125

-0.1

-0.075

-0.05

-0.025

0

0.025

0.05

0.075

0 0.5 x

HTp (1/GeV2)

-0.15

-0.125

-0.1

-0.075

-0.05

-0.025

0

0.025

0.05

0.075

0 0.5 x

H2 ns (1/GeV2)

❋✐�✉r❡ ✶✵✿ ❚❤✁ ❝✁♥t✂❛❧ ✈❛❧✄✁s ✭s♦❧☎❞ ❧☎♥✁✮ ❛♥❞ t❤✁ ✆✛ ❜❛♥❞s ✭s❤❛❞✁❞ ❛✂✁❛✮ ❢♦✂ t❤✁ ❝♦✁✍❝☎✁♥ts ♦❢ t❤✁

t✇☎st✲✹ t✁✂♠s ♦☞♥ t❤✁ ☎♥❝❧✄s☎✈✁ ❉■❙ st✂✄❝t✄✂✁ ❢✄♥❝t☎♦♥s ♦❜t❛☎♥✁❞ ❢✂♦♠ ♦✄✂ ◆◆▲❖ ☞t ✭❧✁❢t ♣❛♥✁❧✝ ✞✷ ♦❢

t❤✁ ♣✂♦t♦♥✱ ❝✁♥t✂❛❧ ♣❛♥✁❧✝ ✞✟ ♦❢ t❤✁ ♣✂♦t♦♥✱ ✂☎❣❤t ♣❛♥✁❧✝ ♥♦♥✲s☎♥❣❧✁t ✞✷✮✳ ❚❤✁ ❝✁♥t✂❛❧ ✈❛❧✄✁s ♦❢ t❤✁

t✇☎st✲✹ ❝♦✁✍❝☎✁♥ts ♦❜t❛☎♥✁❞ ❢✂♦♠ ♦✄✂ ◆▲❖ ☞t ❛✂✁ s❤♦✇♥ ❢♦✂ ❝♦♠♣❛✂☎s♦♥ ✭❞❛s❤✁s✮✳

Page 13: 1 fromDeep-InelasticScattering sblumlein/Talks/ALPH1.pdf · 1 αs fromDeep-InelasticScattering J. Bl¨umlein, DESY in collaboration with S. Alekhin and S.O. Moch, U. Hamburg • Introduction

13

αs(M2Z)

ABM11

500

1000

1500

2000

0.105 0.11 0.115 0.12 0.125

αs(MZ)

χ2

HERA

600

700

800

900

0.105 0.11 0.115 0.12 0.125

αs(MZ)

χ2

NMC

700

750

800

0.105 0.11 0.115 0.12 0.125

αs(MZ)

χ2

BCDMS

1000

1250

1500

1750

2000

0.105 0.11 0.115 0.12 0.125

αs(MZ)

χ2

SLAC

218

220

222

224

0.105 0.11 0.115 0.12 0.125

αs(MZ)

χ2

DY

NNLO

NLO

❋✐�✉r❡ ✶✾✿ ❚❤✁ ✤✷✲♣✂♦☞❧✁ ✈✁✂s✄s t❤✁ ✈❛❧✄✁ ♦❢ ☛☎✭▼❩✮ ❢♦✂ t❤✁ ❞❛t❛ s✁ts ✄s✁❞✱ ❛❧❧ ❝❛❧❝✄❧❛t✁❞ ✇✆t❤ t❤✁

P❉✝ ❛♥❞ ❍❚ ♣❛✂❛♠✁t✁✂s ☞①✁❞ ❛t t❤✁ ✈❛❧✄✁s ♦❜t❛✆♥✁❞ ❢✂♦♠ t❤✁ ☞ts ✇✆t❤ ☛☎✭▼❩✮ ✂✁❧✁❛s✁❞ ✭s♦❧✆❞ ❧✆♥✁s✞

◆◆▲❖ ☞t✱ ❞❛s❤✁s✞ ◆▲❖ ♦♥✁✮✳

Page 14: 1 fromDeep-InelasticScattering sblumlein/Talks/ALPH1.pdf · 1 αs fromDeep-InelasticScattering J. Bl¨umlein, DESY in collaboration with S. Alekhin and S.O. Moch, U. Hamburg • Introduction

14

αs(M2Z)

❊①♣❡r✐�❡♥t ☛s✭▼❩✮

◆▲❖✁✂✄ ◆▲❖ ◆◆▲❖

❇❈❉☎❙ ✵✿✶✶✶✶ ✝ ✵✿✵✵✶✽ ✵✿✶✶✺✵ ✝ ✵✿✵✵✶✷ ✵✿✶✵✽✹ ✝ ✵✿✵✵✶✸

◆☎❈ ✵✿✶✶✼

✰ ✆✞✆✟✟

✠ ✆✞✆✟✻ ✵✿✶✶✽✷ ✝ ✵✿✵✵✵✼ ✵✿✶✶✺✷ ✝ ✵✿✵✵✵✼

❙▲❆❈ ✵✿✶✶✼✸ ✝ ✵✿✵✵✵✸ ✵✿✶✶✷✽ ✝ ✵✿✵✵✵✸

❍❊❘❆ ❝♦�❜✳ ✵✿✶✶✼✹ ✝ ✵✿✵✵✵✸ ✵✿✶✶✷✡ ✝ ✵✿✵✵✵✷

❉❨ ✵✿✶✵✽ ✝ ✵✿✵✶✵ ✵✿✶✵✶ ✝ ✵✿✵✷✺

❆❇☎✶✶ ✵✿✶✶✽✵ ✝ ✵✿✵✵✶✷ ✵✿✶✶✸✹ ✝ ✵✿✵✵✶✶

❚❛❜❡❧❧❡ ✹☞ ✌✍♠✎✏✑✒✓✍✔ ✍❢ ✕❤✖ ✈✏✗✉✖✓ ✍❢ ✘s✙✚❩✛ ✍✜✕✏✒✔✖❞ ✜② ✢✌✣✤✥ ✏✔❞ ✦✤✌ ✏✕ ✦✧★ ✇✒✕❤ ✕❤✖

✒✔❞✒✈✒❞✉✏✗ ✑✖✓✉✗✕✓ ✍❢ ✕❤✖ ✩✕ ✒✔ ✕❤✖ ✎✑✖✓✖✔✕ ✏✔✏✗②✓✒✓ ✏✕ ✦✧★ ✏✔❞ ✦✦✧★ ❢✍✑ ✕❤✖ ✪✫✬✯ ❞✏✕✏ ✕❤✖ ✦✤✌

❞✏✕✏ ✕❤✖ ✢✌✣✤✥ ❞✏✕✏ ✕❤✖ ✥✧✯✌ ❞✏✕✏ ✏✔❞ ✕❤✖ ✣✱ ❞✏✕✏✲The values of αs(M

2Z) in NLO and NNLO fits are different.

Page 15: 1 fromDeep-InelasticScattering sblumlein/Talks/ALPH1.pdf · 1 αs fromDeep-InelasticScattering J. Bl¨umlein, DESY in collaboration with S. Alekhin and S.O. Moch, U. Hamburg • Introduction

15

ABM fits including Jet Data: D0 run II dijet

ABKM09 (no re-fit)

Y= 0.20data

/NL

O scale unc.

Y= 0.60

Y= 1.00 Y= 1.40

Y= 1.80 Y= 2.20

MJJ (GeV)

Dat

a/T

heo

ry

0.20.40.60.8

11.21.41.61.8

22.2 < 0.4

max|y|

-1DØ, L = 0.7 fb

0.2 0.4 0.6 0.8 1 1.2 1.40.20.40.60.8

11.21.41.61.8

22.2

Data/NLOSystematic Uncertainty

< 1.6max

1.2 < |y|

= 1.96 TeVs

= 0.7coneR

< 0.8max

0.4 < |y|

0.2 0.4 0.6 0.8 1 1.2 1.4

variationF

µ, R

µMSTW2008 Uncertainty

< 2.0max

1.6 < |y|

< 1.2max

0.8 < |y|

)/2T2

+ pT1

= (pF

µ = R

µ

[TeV]JJM0.2 0.4 0.6 0.8 1 1.2 1.4

CTEQ6.6 w/ Uncertainty

< 2.4max

2.0 < |y|

ABM (2011). Note that the cross section is known to NLO only !

Page 16: 1 fromDeep-InelasticScattering sblumlein/Talks/ALPH1.pdf · 1 αs fromDeep-InelasticScattering J. Bl¨umlein, DESY in collaboration with S. Alekhin and S.O. Moch, U. Hamburg • Introduction

16

D0 run II djet data

Y= 0.20data

/NL

O

Y= 0.60

µR/µF=1 µR/µF=0.5

Y= 1.00 Y= 1.40

Y= 1.80 Y= 2.20

ET (GeV)

Y= 0.20data

/NL

O

Y= 0.60

Y= 1.00 Y= 1.40

Y= 1.80 Y= 2.20

ET (GeV)

before the fit after the fit

ABM (2011) χ2 = 104/110

Page 17: 1 fromDeep-InelasticScattering sblumlein/Talks/ALPH1.pdf · 1 αs fromDeep-InelasticScattering J. Bl¨umlein, DESY in collaboration with S. Alekhin and S.O. Moch, U. Hamburg • Introduction

17

αs(M2Z)

µ=3 GeV

0

1

2

3

4

5

6

0.02 0.04 0.06 0.08 0.1

x

xG(x

,µ)

ABM11

ABM11+ATLAS(1jet,PT>150 GEV)

ABM11+ATLAS(1jet,PT>100 GEV)

ABKM09+D0(1jet)

MSTW08

10-4

10-3

10-2

10-1

1

0.2 0.4 0.6

xxG

(x,µ

)

❋✐�✉r❡ ✷✽✿ ●❧✁♦♥ ❞✂st✄✂❜✁t✂♦♥ ♦❜t❛✂♥☎❞ ❜② ✂♥❝❧✁❞✂♥❣ t❤☎ ❆❚▲❆❙ ❥☎t ❞❛t❛ ✂♥t♦ t❤☎ ❆❇▼✶✶ ❛♥❛❧②s✂s✳

Page 18: 1 fromDeep-InelasticScattering sblumlein/Talks/ALPH1.pdf · 1 αs fromDeep-InelasticScattering J. Bl¨umlein, DESY in collaboration with S. Alekhin and S.O. Moch, U. Hamburg • Introduction

18

αs(M2Z): Inclusion of Tevatron Jets (NLO)

❊①♣❡r✐�❡♥t ☛s✭▼❩✮

◆▲❖✁✂✄ ◆▲❖ ◆◆▲❖☎

❉✵ ✶ ❥❡t ✵✿✶✶✻✶✰ ✆✝✆✆✹✞

✟ ✆✝✆✆✹✽ ✵✿✶✶✾✵ ✠ ✵✿✵✵✶✶ ✵✿✶✶✡✾ ✠ ✵✿✵✵✶✷

❉✵ ✷ ❥❡t ✵✿✶✶✼✡ ✠ ✵✿✵✵✵✾ ✵✿✶✶✡✺ ✠ ✵✿✵✵✵✾

❈❉❋ ✶ ❥❡t ✭❝♦♥❡✮ ✵✿✶✶☞✶ ✠ ✵✿✵✵✵✾ ✵✿✶✶✸✡ ✠ ✵✿✵✵✵✾

❈❉❋ ✶ ❥❡t ✭❦❄✮ ✵✿✶✶☞✶ ✠ ✵✿✵✵✶✵ ✵✿✶✶✡✸ ✠ ✵✿✵✵✵✾

❆❇✌✶✶ ✵✿✶✶☞✵ ✠ ✵✿✵✵✶✷ ✵✿✶✶✸✡ ✠ ✵✿✵✵✶✶

❚❛❜❡❧❧❡ ✺✍ ✎✏♠✑✒✓✔✕✏✖ ✏❢ ✗❤✘ ✈✒✙✉✘✕ ✏❢ ✚s✛✜❩✢ ✏✣✗✒✔✖✘❞ ✣② ✤✥ ✇✔✗❤ ✗❤✘ ✏✖✘✕ ✣✒✕✘❞ ✏✖ ✔✖✦✙✉❞✔✖❣

✔✖❞✔✈✔❞✉✒✙ ❞✒✗✒ ✕✘✗✕ ✏❢ ✧✘✈✒✗✓✏✖ ★✘✗ ❞✒✗✒ ✔✖✗✏ ✗❤✘ ✒✖✒✙②✕✔✕ ✒✗ ✩✪✫✳ ✧❤✘ ✩✩✪✫☎ ✬✗ ✓✘❢✘✓✕ ✗✏ ✗❤✘ ✩✩✪✫

✒✖✒✙②✕✔✕ ✏❢ ✗❤✘ ✤■❙ ✒✖❞ ✤❨ ❞✒✗✒ ✗✏❣✘✗❤✘✓ ✇✔✗❤ ✗❤✘ ✩✪✫ ✒✖❞ ✕✏❢✗ ❣✙✉✏✖ ✓✘✕✉♠♠✒✗✔✏✖ ✦✏✓✓✘✦✗✔✏✖✕ ✛✖✘✯✗✲

✗✏✲✙✘✒❞✔✖❣ ✙✏❣✒✓✔✗❤♠✔✦ ✒✦✦✉✓✒✦②✢ ❢✏✓ ✗❤✘ ✱ ★✘✗ ✔✖✦✙✉✕✔✈✘ ❞✒✗✒✳

S. Alekhin, J.B., S. Moch, Phys.Rev. D86 (2012) 054009

=⇒ value depends on data set

=⇒ value depends on the jet algorithm

=⇒ no large values

Page 19: 1 fromDeep-InelasticScattering sblumlein/Talks/ALPH1.pdf · 1 αs fromDeep-InelasticScattering J. Bl¨umlein, DESY in collaboration with S. Alekhin and S.O. Moch, U. Hamburg • Introduction

19

αs(M2Z): NNPDF vs Data Sets

❊①♣❡r✐�❡♥t ☛s✭▼❩✮

◆▲❖✁✂✄ ◆▲❖ ◆◆▲❖

❇❈❉☎❙ ✵✿✶✶✶✶ ✝ ✵✿✵✵✶✽ ✵✿✶✷✵✹ ✝ ✵✿✵✵✶✺ ✵✿✶✶✺✽ ✝ ✵✿✵✵✶✺

◆☎❈✄ ✵✿✶✶✾✷ ✝ ✵✿✵✵✶✽ ✵✿✶✶✺✵ ✝ ✵✿✵✵✷✵

◆☎❈✄❞ ✵✿✶✶✼

✰ ✆✞✆✟✟

✠ ✆✞✆✟✻ ✵✿✶✶✹✡ ✝ ✵✿✵✶✵✼

❙▲❆❈ ❃ ✵✿✶✷✹ ❃ ✵✿✶✷✹

❍❊❘❆ ■ ✵✿✶✷✷✸ ✝ ✵✿✵✵✶✽ ✵✿✶✶✾✾ ✝ ✵✿✵✵✶✾

☞❊❯❙ ❍✷ ✵✿✶✶✼✵ ✝ ✵✿✵✵✷✼ ✵✿✶✷✸✶ ✝ ✵✿✵✵✸✵

☞❊❯❙ ❋✷❈ ✵✿✶✶✹✹ ✝ ✵✿✵✵✡✵

◆✉❚❡❱ ✵✿✶✷✺✷ ✝ ✵✿✵✵✡✽ ✵✿✶✶✼✼ ✝ ✵✿✵✵✸✾

❊✡✵✺ ✵✿✶✶✡✽ ✝ ✵✿✵✶✵✵

❊✽✡✡ ✵✿✶✶✸✺ ✝ ✵✿✵✵✷✾

❈❉❋ ❲❛✌② ✵✿✶✶✽✶ ✝ ✵✿✵✵✡✵

❈❉❋ ☞r❛♣ ✵✿✶✶✺✵ ✝ ✵✿✵✵✸✹ ✵✿✶✷✵✺ ✝ ✵✿✵✵✽✶

❉✵ ☞r❛♣ ✵✿✶✷✷✼ ✝ ✵✿✵✵✡✼

❈❉❋ ❘✷❑❚ ✵✿✶✷✷✽ ✝ ✵✿✵✵✷✶ ✵✿✶✷✷✺ ✝ ✵✿✵✵✷✶

❉✵ ❘✷❈❖◆ ✵✿✶✶✡✶✰ ✆✞✆✆✍✟

✠ ✆✞✆✆✍✎ ✵✿✶✶✹✶ ✝ ✵✿✵✵✸✶ ✵✿✶✶✶✶ ✝ ✵✿✵✵✷✾

◆◆✷✶ ✵✿✶✶✾✶ ✝ ✵✿✵✵✵✡ ✵✿✶✶✼✸ ✝ ✵✿✵✵✵✼

❚❛❜❡❧❧❡ ✼✏ ✑♦♠✒✓✔✕✖♦✗ ♦❢ ✘❤✙ ✈✓✚✛✙✖ ♦❢ ✜s✢✣❩✤ ♦✥✘✓✕✗✙✦ ✥✧ ★✑✩✪✫✱ ✬✪✑✱ ✓✗✦ ✩✯ ✓✘ ✬✲✳ ✇✕✘❤

✘❤✙ ✔✙✖✛✚✘✖ ♦❢ ✬✬✴❀ ❢♦✔ ✘❤✙ ❁✘✖ ✘♦ ✩❂✫ ✓✗✦ ♦✘❤✙✔ ❤✓✔✦ ✖❝✓✘✘✙✔✕✗❣ ✦✓✘✓ ✓✘ ✬✲✳ ✓✗✦ ✬✬✲✳ ✓✗✦ ✘❤✙

❝♦✔✔✙✖✒♦✗✦✕✗❣ ✔✙✖✒♦✗✖✙ ♦❢ ✘❤✙ ✦✕❄✙✔✙✗✘ ✦✓✘✓ ✖✙✘✖ ✓✗✓✚✧✖✙✦❅

Page 20: 1 fromDeep-InelasticScattering sblumlein/Talks/ALPH1.pdf · 1 αs fromDeep-InelasticScattering J. Bl¨umlein, DESY in collaboration with S. Alekhin and S.O. Moch, U. Hamburg • Introduction

20

❊①♣❡r✐�❡♥t ☛s✭▼❩✮

◆▲❖✁✂✄ ◆▲❖ ◆◆▲❖

❇❈❉☎❙ ✖✆❀ ❋✷ ✵✿✶✶✶✶ ✝ ✵✿✵✵✶✽ ✞ ✵✿✶✵✽✺ ✝ ✵✿✵✵✾✺

❇❈❉☎❙ ✖❞❀ ❋✷ ✵✿✶✶✸✺ ✝ ✵✿✵✶✺✺ ✵✿✶✶✶✼ ✝ ✵✿✵✵✾✸

◆☎❈ ✖✆❀ ❋✷ ✵✿✶✶✼

✰ ✟✠✟✡✡

☞ ✟✠✟✡✻ ✵✿✶✌✼✺ ✝ ✵✿✵✶✵✺ ✵✿✶✌✶✼ ✝ ✵✿✵✵✼✼

◆☎❈ ✖❞❀ ❋✷ ✵✿✶✌✍✺ ✝ ✵✿✵✶✶✺ ✵✿✶✌✶✺ ✝ ✵✿✵✵✼✵

◆☎❈ ✖✎❂✖✆ ✵✿✶✌✽✵ ✵✿✶✶✍✵

❊✍✍✺ ✖✆❀ ❋✷ ✵✿✶✌✵✸ ✞

❊✍✍✺ ✖❞❀ ❋✷ ✞ ✞

❙▲❆❈ ✏✆❀ ❋✷ ✵✿✶✶✽✵ ✝ ✵✿✵✵✍✵ ✵✿✶✶✹✵ ✝ ✵✿✵✵✍✵

❙▲❆❈ ✏❞❀ ❋✷ ✵✿✶✌✼✵ ✝ ✵✿✵✵✾✵ ✵✿✶✌✌✵ ✝ ✵✿✵✵✍✵

◆☎❈✱❇❈❉☎❙✱❙▲❆❈✱ ❋✑ ✵✿✶✌✽✺ ✝ ✵✿✵✶✶✺ ✵✿✶✌✵✵ ✝ ✵✿✵✵✍✵

❊✽✽✍✴◆✉❙❡❛ ✆✆✱ ❉❨ ✪❝✐t❡❲❡❜❜✒✌✵✵✸❜❥ ✞ ✵✿✶✶✸✌ ✝ ✵✿✵✵✽✽

❊✽✽✍✴◆✉❙❡❛ ✆❞❂✆✆✱ ❉❨ ✵✿✶✶✼✸ ✝ ✵✿✶✵✼ ✵✿✶✶✹✵ ✝ ✵✿✵✶✶✵

◆✉❚❡❱ ✗✓❀ ❋✷ ✵✿✶✌✵✼ ✝ ✵✿✵✵✍✼ ✵✿✶✶✼✵ ✝ ✵✿✵✵✍✵

❈❍❖❘❯❙ ✗✓❀ ❋✷ ✵✿✶✌✸✵ ✝ ✵✿✵✶✶✵ ✵✿✶✶✺✵ ✝ ✵✿✵✵✾✵

◆✉❚❡❱ ✗✓❀ ✔❋✕ ✵✿✶✌✼✵ ✝ ✵✿✵✵✾✵ ✵✿✶✌✌✺ ✝ ✵✿✵✵✼✺

❈❍❖❘❯❙ ✗✓❀ ✔❋✕ ✵✿✶✌✶✺ ✝ ✵✿✵✶✵✺ ✵✿✶✶✽✺ ✝ ✵✿✵✵✼✺

❈❈✘❘ ✵✿✶✶✾✵ ✞

◆✉❚❡❱ ✗✓ ✦ ✖✖❳ ✵✿✶✶✺✵ ✝ ✵✿✵✶✼✵ ✞

❍✶ ✏✆ ✾✼✲✵✵✱ ✛✙✚✜ ✵✿✶✌✺✵ ✝ ✵✿✵✵✼✵ ✵✿✶✌✵✺ ✝ ✵✿✵✵✺✺

✢❊❯❙ ✏✆ ✾✺✲✵✵✱ ✛✙✚✜ ✵✿✶✌✸✺ ✝ ✵✿✵✵✍✺ ✵✿✶✌✶✵ ✝ ✵✿✵✵✍✵

❍✶ ✏✆ ✾✾✲✵✵✱ ✛✚✚✜ ✵✿✶✌✽✺ ✝ ✵✿✵✌✌✺ ✵✿✶✌✼✵ ✝ ✵✿✵✌✵✵

✢❊❯❙ ✏✆ ✾✾✲✵✵✱ ✛✚✚✜ ✵✿✶✶✌✺ ✝ ✵✿✵✶✾✺ ✵✿✶✶✍✺ ✝ ✵✿✵✵✾✺

❍✶✴✢❊❯❙ ✏✆❀ ❋ ✣❤✤✥♠

✷ ✞ ✵✿✶✶✍✺ ✝ ✵✿✵✵✾✺

❍✶ ✏✆ ✾✾✲✵✵ ✐♥❝❧✧ ❥❡t★ ✵✿✶✶✍✽✰ ✟✠✟✟✩✫

☞ ✟✠✟✟✕✩ ✵✿✶✶✌✼ ✝ ✵✿✵✵✾✸

✢❊❯❙ ✏✆ ✾✍✲✵✵ ✐♥❝❧✧ ❥❡t★ ✵✿✶✌✵✽✰ ✟✠✟✟✩✬

☞ ✟✠✟✟✩✟ ✵✿✶✶✼✺ ✝ ✵✿✵✵✺✺

❉✵ ■■ ✆✯✆ ✐♥❝❧✧ ❥❡t★ ✵✿✶✶✍✶✰ ✟✠✟✟✩✡

☞ ✟✠✟✟✩✬ ✵✿✶✶✽✺ ✝ ✵✿✵✵✺✺ ✵✿✶✶✸✸ ✝ ✵✿✵✵✍✸

❈❉✘ ■■ ✆✯✆ ✐♥❝❧✧ ❥❡t★ ✵✿✶✌✵✺ ✝ ✵✿✵✵✹✺ ✵✿✶✶✍✺ ✝ ✵✿✵✵✌✺

❉✵ ■■ ✳ ✦ ❁✗ ❛★②�✧ ✞ ✞

❈❉✘ ■■ ✳ ✦ ❁✗ ❛★②�✧ ✞ ✞

❉✵ ■■ ❃ r❛♣✧ ✵✿✶✶✌✺ ✝ ✵✿✵✶✵✵ ✵✿✶✶✸✍ ✝ ✵✿✵✵✽✹

❈❉✘ ■■ ❃ r❛♣✧ ✵✿✶✶✍✵ ✝ ✵✿✵✵✼✵ ✵✿✶✶✺✼ ✝ ✵✿✵✵✍✼

☎❙❚❲ ✵✿✶✌✵✌✰ ✟✠✟✟✡✷

☞ ✟✠✟✟✡❄ ✵✿✶✶✼✶ ✝ ✵✿✵✵✶✹

❚❛❜❧❡ ✽✒ ❅♦●❏❑P◗❬♦❭ ♦❢ ❪❫❴ ✈❑❵❣❴❬ ♦❢ ❦sq✇❩③ ♦④❪❑◗❭❴⑤ ④⑥ ⑦❅⑧⑨⑩❶ ❷⑨❅❶ ❸❹❺❻❼❽❴❪ ❑❭⑤ ⑧❾ ❑❪ ❷❿➀

➁◗❪❫ ❪❫❴ P❴❬❣❵❪❬ ♦❢ ❪❫❴ ⑨⑩➂➃ ➄❪❬ ❪♦ ⑧➅⑩ ❑❭⑤ ♦❪❫❴P ❫❑P⑤ ❬➆❑❪❪❴P◗❭➇ ⑤❑❪❑ ❑❪ ❷❿➀ ❑❭⑤ ❷❷❿➀ ❑❭⑤ ❪❫❴

➆♦PP❴❬❏♦❭⑤◗❭➇ P❴❬❏♦❭❬❴ ♦❢ ❪❫❴ ⑤◗➈❴P❴❭❪ ⑤❑❪❑ ❬❴❪❬ ❑❭❑❵⑥❬❴⑤❶ ➆❢➉ ➊◗➇❬➉ ➋❑ ❑❭⑤ ➋④ ◗❭ ⑨⑩➂➃❾➌➉ ❹❭❪P◗❴❬ ❭♦❪

➇◗✈❴❭ ➆♦PP❴❬❏♦❭⑤ ❪♦ ❦sq✇❩③ ➆❴❭❪P❑❵ ✈❑❵❣❴❬ ④❴❵♦➁ ❾➍➎➎❾ ♦P ❑④♦✈❴ ❾➍➎➏❾➐ ◗❭ ➆❑❬❴ ❭♦ ❴PP♦P❬ ❑P❴ ❑❬❬◗➇❭❴⑤

❪❫❴❬❴ ❑P❴ ❵❑P➇❴P ❪❫❑❭ ❪❫❴ ④♦❣❭⑤❬ ❏P♦✈◗⑤❴⑤ ◗❭ ❢♦P● ♦❢ ❪❫❴ ❏❵♦❪❬ ◗❭ ⑨⑩➂➃❾➌➉

MSTW08 vs Data Sets

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21

Nuclear Targets

ABM: none

CTEQ: CCFR, CDHSW

JR: none

MMHT: NUTEV, CHORUS

NNPDF: NUTEV, CHORUS

Jet Fits: NLO only!

ABM: singly selected: D0,CDF,ATLAS

CTEQ: CDF, D0, ATLAS, CMS

JR: CDF,D0

MMHT: H1,ZEUS incl., CDF, D0, ATLAS, CMS

NNPDF: CDF, D0, ATLAS, CMS

• Different nuclear targets!

It is likely that the QCD evolution differs off nuclear targets due to the internal composition

(π’s, confinement size varies, etc.; various sources leading to the EMC effect.)

Impact on FL ? Differing EMC effects for different structure functions (NS, S).

• Mixing NLO and NNLO fits necessarily does not lead to an extraction of αNNLOs .

• As the NLO values are higher than those at NNLO αs increases.

• In the strict sense MSTW, MMHT, CT14, and NNPDF are not pure NNLO analyses, but

contain quite a part of data currently being fitted at NLO only.

Page 22: 1 fromDeep-InelasticScattering sblumlein/Talks/ALPH1.pdf · 1 αs fromDeep-InelasticScattering J. Bl¨umlein, DESY in collaboration with S. Alekhin and S.O. Moch, U. Hamburg • Introduction

22

αs(M2Z) - Higher Twist Correlation

ABM11 NNLO

-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

x

coef

fici

ent

of c

orre

lati

on w

ith

α s

H2(x)HT(x)

❋✐�✉r❡ ✷✵✿ ❚❤✁ ❝♦✂✂✁❧❛t✄♦♥ ❝♦✁✍❝✄✁♥t ♦❢ ☛s✭▼❩✮ ✇✄t❤ t❤✁ ♥☎❝❧✁♦♥ t✇✄✆t✲✹ ❝♦✁✍❝✄✁♥t✆ ❍✝ ✭✆♦❧✄❞ ❧✄♥✁✮

❛♥❞ ❍✞ ✭❞❛✆❤✁✆✮ ✈✁✂✆☎✆ ① ❛✆ ♦❜t❛✄♥✁❞ ✄♥ ♦☎✂ ◆◆▲❖ ☞t✳

=⇒ Including scales as Q2 < 10GeV2 requires fit of higher twist terms (Singlet Analysis).

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23

αs(M2Z): NNLO Comparison ABM, BBG, NNPDF, MSTW

❉❛t❛ ❙❡t ❆❇▼✶✶ ❇❇● ◆◆✷✶ ▼❙❚❲

❇❈❉▼❙ ✵✿✶✵✹✽ ✝ ✵✿✵✵✶✸ ✵✿✶✶✷✻ ✝ ✵✿✵✵✵✼ ✵✿✶✶✺✽ ✝ ✵✿✵✵✶✺ ✵✿✶✶✵✶ ✝ ✵✿✵✵✾✹

◆▼❈ ✵✿✶✶✺✷ ✝ ✵✿✵✵✵✼ ✵✿✶✶✺✸ ✝ ✵✿✵✵✸✾ ✵✿✶✶✺✵ ✝ ✵✿✵✵✷✵ ✵✿✶✷✶✻ ✝ ✵✿✵✵✼✹

❙▲❆❈ ✵✿✶✶✷✽ ✝ ✵✿✵✵✵✸ ✵✿✶✶✺✽ ✝ ✵✿✵✵✸✹ ❃ ✵✿✶✷✹

�✁✂✂✄� ☎ �✁��✆� ✞♣

�✁✂✟✟� ☎ �✁��✆� ✞❞

❍❊❘❆ ✵✿✶✶✷✻ ✝ ✵✿✵✵✵✷

�✁✂✂✠✠ ☎ �✁��✂✠

�✁✂✟✡✂ ☎ �✁��✡�

✵✿✶✷✵✽ ✝ ✵✿✵✵✺✽

❉❨ ✵✿✶✵✶ ✝ ✵✿✵✷✺ ☛ ☛ ✵✿✶✶✸✻ ✝ ✵✿✵✶✵✵

✵✿✶✶✸✹ ✝ ✵✿✵✵✶✶ ✵✿✶✶✸✹ ✝ ✵✿✵✵✷✵ ✵✿✶✶✼✸ ✝ ✵✿✵✵✵✼ ✵✿✶✶✼✶ ✝ ✵✿✵✵✶✹

❚❛❜❧❡ ✾☞ ✌♦♠♣✍r✐s♦♥ ♦❢ ✎❤✞ ♣✉✏✏s ✐♥ ✑✒✓✔❩✮ ♣✞r ❞✍✎✍ s✞✎ ✕✞✎✇✞✞♥ ✎❤✞ ✖✗✘✂✂✱ ✗✗✙✱ ✚✚✟✂✱ ✘✛✜✢

✍♥✍✏②s✞s ✍✎ ✚✚✣❖✳

=⇒ Despite the NNLO values for αs(M2Z) of NNPDF and MSTW are close to each other, the

contribution of the different data sets differ considerably.

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24

O(α2

s)

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

10 102

Q2 (GeV2)

x=0.00018

ZEUS(RunI)H1(RunII)

Fc,exact

2 (Nf=3)

Fc,BMSN

2

Fc,asymp

2 (Nf=4)

0

0.1

0.2

0.3

0.4

0.5

10 102

Q2 (GeV2)

x=0.003

0

0.025

0.05

0.075

0.1

0.125

0.15

0.175

0.2

10 102

Q2 (GeV2)

x=0.03

❋✐❣✉r❡ ✶✿ ❈♦♠♣❛�✁s♦♥ ♦❢ ✂❝✷ ✁♥ ❞✁☛✄�✄♥t s☎❤✄♠✄s t♦ ❍✆✲ ❛♥❞ ❩❊❯❙✲❞❛t❛✳ ❙♦❧✁❞ ❧✁♥✄s✝ ●▼❱✞◆ s☎❤✄♠✄

✁♥ t❤✄ ❇▼❙◆ ♣�✄s☎�✁♣t✁♦♥✱ ❞❛s❤✲❞♦tt✄❞ ❧✁♥✄s✝ ✸✲✟❛✈♦� s☎❤✄♠✄✱ ❞❛s❤✄❞ ❧✁♥✄s✝ ✹✲✟❛✈♦� s☎❤✄♠✄✳ ❚❤✄ ✈✄�t✁☎❛❧

❞♦tt✄❞ ❧✁♥✄ ❞✄♥♦t✄s t❤✄ ♣♦s✁t✁♦♥ ♦❢ t❤✄ ☎❤❛�♠✲q✠❛�❦ ♠❛ss ✡❝ ❂ ✆☞✹✸ ●✄❱✳

Heavy Flavor Treatment

Interpolating scheme: BSMN (1996) to be used; many private models in use (RT, etc.)

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25

Heavy Flavor Treatment: consistent determination of mc

Alekhin, JB, Daum, Lipka, Moch:Phys.Lett. B720 (2013) 172.

mMSc 1.24± 0.03

+0.03

−0.03ABDLM, DIS, FFNS, χ2 = 61/52

mMSc 1.279± 0.013 Chetyrkin et al., e+e−

mMSc 1.275± 0.025 PDG

mPolec 1.67± 0.07 PDG

mPolec 1.25 MMHT [1510.02332] GMVFNS; αs = 0.1167;χ2 = 72/52

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26

Heavy Flavor Treatment

50 100 150 200Ξ

-1.0

-0.5

0.5

1.0C m assive ,H2L

asym ptotic

g1 casy

g1 b

g1 c

JB, G. Falcioni, A. De Freitas, DESY 15-171

• Exact O(α2s) calculations show the gradual interpolation for charm and bottom effects in DIS as a

function of ξ = Q2/m2H bridging form NF → NF + 1. [Note the negative corrections at low scales!]

• The matching at Q2 = m2c for NF → NF + 1 is definitely sub-optimal and may lead to wrong

results.

• Adding as complete as possible HQ effects in the fixed flavor scheme in the lower Q2 range is the

better option. Van Neerven 1993; Gluck, Reya, Stratmann, 1994; ABM2009–

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27

Effect on the Gluon density∆[xG(x)]

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

10-2

10-1

x

ABKM09

ABKM09 with FNMC

2

µ=2 GeV

-0.2

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

0.2

10-2

10-1

x

µ=165 GeV

wrong treatment (FNMC2 ): larger gluon at x ≃ 0.1

=⇒ It is important to fit the reduced cross sections, including the correct FL-behavior to NNLO.

=⇒ ABM,JR, NNPDF.

Page 28: 1 fromDeep-InelasticScattering sblumlein/Talks/ALPH1.pdf · 1 αs fromDeep-InelasticScattering J. Bl¨umlein, DESY in collaboration with S. Alekhin and S.O. Moch, U. Hamburg • Introduction

28

Why is MSTW’s αs(M2Z) so high ?

αs(M2Z) with σNMC with FNMC

2 difference

NLO 0.1179(16) 0.1195(17) +0.0026 ≃ 1σ

NNLO 0.1135(14) 0.1170(15) +0.0035 ≃ 2.3σ

NNLO + FLO(α3s) 0.1122(14) 0.1171(14) +0.0050 ≃ 3.6σ

S. Alekhin, J.B., S. Moch, Eur.Phys.J. C71 (2011) 1723 [arXiv:1101.5261].

=⇒ also fixed target data shall be analyzed using σ.

=⇒ This applies to NMC in particular.

• Wrong treatment of FL(x,Q2) in NMC F2 extraction.

=⇒ also necessary for BCDMS, see BBG (2006).

• MMHT still fits structure functions but includes FL @ NLO.

• There is still a significant difference from FL @ NLO and NNLO at low x.

Use: W 2 > 12.5 GeV2, Q2 > 2.5 GeV2 and no HT: αs(M2Z) = 0.1191± 0.0016

Use: W 2 > 12.5 GeV2, Q2 > 10 GeV2 and no HT: αs(M2Z) = 0.1134± 0.0008

NNPDF Q2 > 5GeV2.

Page 29: 1 fromDeep-InelasticScattering sblumlein/Talks/ALPH1.pdf · 1 αs fromDeep-InelasticScattering J. Bl¨umlein, DESY in collaboration with S. Alekhin and S.O. Moch, U. Hamburg • Introduction

29

NNLO Analysesαs(M2

Z)

SY 2001 0.1166± 0.0013 Fep2

SY 2001 0.1153± 0.0063 xF νN3

h. Nucl.

A02 2002 0.1143± 0.0020

MRST03 2003 0.1153± 0.0020

BBG 2004(06,12) 0.1134+0.0019

−0.0021valence analysis, NNLO

GRS 2006 0.112 valence analysis, NNLO

A06 2006 0.1128± 0.0015

JR 2008 0.1128± 0.0010 dynamical approach

JR 2008 0.1162± 0.0006 including NLO-jets

ABKM 2009 0.1135± 0.0014 HQ: FFNS Nf = 3

ABKM 2009 0.1129± 0.0014 HQ: BSMN

MSTW 2009 0.1171± 0.0014

Thorne 2013 0.1136 [DIS+DY+HT∗]

ABM11J 2010 0.1134− 0.1149± 0.0012 Tevatron jets (NLO) incl.

NN21 2011 0.1174± 0.0006± 0.0001 +h. Nucl.

ABM12 2013 0.1133± 0.0011

ABM12 2013 0.1132± 0.0011 (without jets)

CTEQ 2013 0.1140 (without jets)

CTEQ 2015 0.1150+0.0060

−0.0040∆χ2 > 1 +h. Nucl.

MMHT 2015 0.1172± 0.0013 +h. Nucl.

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30

Other Lower αs Values

NNLO αs(M2Z)

Gehrmann et al. 2009 0.1131 + 0.0028− 0.0022 e+e− thrust

Abbate et al. 2010 0.1140± 0.0015 e+e− thrust

Hoang et al. 2010 0.1123± 0.0015 C-param. dist.

Bazavov et al. 2014 0.1166+0.0012

−0.0008lattice 2+1 fl.

CMS 2013 0.1151+0.0028

−0.0027tt

NLO αs(M2Z)

Frederix et al. 2010 0.1156+0.0041

−0.0034e+e− → 5 jets

H1 2009 0.1160+0.0095

−0.0080ep jets

D0 2010 0.1156+0.0041

−0.0034pp → jets

ATLAS 2012 0.1151+0.0093

−0.0087jets

CMS 2013 0.1148± 0.0052 3/2 jet ratio

NNLO ep and pp jet analyses are utterly needed.

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31

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32

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Page 33: 1 fromDeep-InelasticScattering sblumlein/Talks/ALPH1.pdf · 1 αs fromDeep-InelasticScattering J. Bl¨umlein, DESY in collaboration with S. Alekhin and S.O. Moch, U. Hamburg • Introduction

33

5. Conclusions

• The N3LO DIS analysis yields : αs(M2Z) = 0.1141± 0.0021

• Correct NNLO anlyses require the fit of d2σ/dxdQ2 and the correct description of FL, Fcc2 .

• NNLO αs(M2Z) values in the range 0.1122− 0.1147± 0.0014 are obtained.

• The various systematic shifts are understood; presently not possible to resolve δαs < 0.0008.

• The difference to the MSTW08 value can be explained.

• Consistent αs and mc fits are mandatory.

• PDF fits, assuming the value of αs may lead to biases, as they are not reaching χ2min in general.

• NLO analyses yield systematic higher αs(M2Z) values than NNLO analyses;

averaging of these values is not possible

• Direct relevance for the Higgs search at Tevatron and LHC and

likewise for the other standard candle processes (W/Z, tt).

• Many more αs(M2Z) values at NNLO, and even at NLO, come out lower than the present

World average.

• Next important analysis: inclusion of the LHC jet data in complete NNLO fits.