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Standard Model measurements with ATLAS
Mateusz Dyndal
(AGH UST / CEA IRFU SPP)

on behalf of the ATLAS Collaboration
QFTHEP'15 Samara, Russia 26 June 2015


Introduction


Standard Model measurements performed to:


validate SM in new energy regime understand processes which are backgrounds for other studies / searches improve precision of known SM parameters constrain new physics contributions (like anomalous couplings)



100 SM ATLAS papers since LHC started; only few analyses presented here, more available at
https://twiki.cern.ch/twiki/bin/view/AtlasPublic/StandardModelPublicResults



Selection of recent results, based on the categories:


Soft QCD, Diffraction and Forward Physics Electroweak Physics: W and Z bosons, Dibosons, .... Jet Physics Direct Photons
M. Dyndal (on behalf of the ATLAS Collaboration) SM measurements with ATLAS (QFTHEP'15) 2

26 June 2015


Run-1 data collection with ATLAS detector




Run-1 data for analysis: 25 fb s = 7 TeV: 4.6 fb-1 s = 8 TeV: 20.3 fb-1

-1

26 June 2015

M. Dyndal (on behalf of the ATLAS Collaboration)

SM measurements with ATLAS (QFTHEP'15)

3


The ATLAS sub-detectors

ZDC
LUCID LUCID

ZDC

ALFA

ALFA: elastic protons measurement

AFP: diffractive protons measurement. A first-phase installation in 2016.
CERN-LHCC-2015-009; ATLAS-TDR-024
SM measurements with ATLAS (QFTHEP'15) 4

26 June 2015

M. Dyndal (on behalf of the ATLAS Collaboration)


Soft QCD, Diffraction and Forward Physics

y (237 m) C-Side [mm]
25 20 15 10 5 0 -5 -10 -15 -20 -25 -25 -20 -15 -10 3000 2000 1000 -5 0 5 10 15 20 25 0 A TLA S
s=7 TeV, 80 b
-1

Total pp cross-section at 7 TeV with ALFA Nuc. Phys B (2014), 486-548
5000 4000



y (237 m) A-side [mm]

ALFA - dedicated tracking detectors in the beam line at z = ±238 & ±241 m Data taking in special runs (high-*) Elastic scattering angle at ATLAS IP maps to a y displacement in ALFA Allows the reconstruction of the 4-momentum transfer: - = ( в )2
M. Dyndal (on behalf of the ATLAS Collaboration) SM measurements with ATLAS (QFTHEP'15) 5

26 June 2015


Soft QCD, Diffraction and Forward Physics



Total pp cross-section at 7 TeV with ALFA Nuc. Phys B (2014), 486-548
The exponential ­t slope is fitted in the region of high ALFA acceptance (> 10%) yielding nuclear slope parameter: B = 19.73 ± 0.14(stat.) ± 0.26(syst.) GeV-2 Total cross-section (obtained via the optical theorem from elastic events): tot (pp X) = 95.35 ±0.38(stat.) ±1.30(syst.) mb
AT LAS T OT EM Lower energy p p Lower energy and cosmic ray pp Cosmic rays COMPET E RRpl2u 13.1 - 1.88ln(s ) + 0.14ln2(s )

/ dt [mb/GeV2]

10

3

ATLAS
s =7 TeV, 80 b
-1

d
10

el

10

2

2011 data Elastic fit



1

140 120 100 80 60

(Fit-data)/data

0.15 0 0.1 0.05 0 -0.05 -0.1 -0.15

0.05

0.1

0.15

0.2

0.25

0.3

0.35

[mb]

Total error Statistical

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35 -t [GeV2]

A TLA S

s = 7 TeV
Luminosity-dependent

A TLA S

s = 7 TeV
Elastic only

TOTEM

Lumi-independent -independent

tot

TOTEM

Luminosity-independent -independent

40 20 0 10
el

ALICE

ATLAS

Luminosity-dependent

MinBias

ATLAS

Elastic

102

103

104 s [GeV]

18

20

22

24

26

28

30 32 34 (pp pp )[mb] el

60

65

70

75

80
inelastic

85 90 (pp X )[mb]

26 June 2015

M. Dyndal (on behalf of the ATLAS Collaboration)

SM measurements with ATLAS (QFTHEP'15)

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Soft QCD, Diffraction and Forward Physics



Exclusive pp() ppl+l- production at 7 TeV CERN-PH-EP-2015-134
Photon-induced (PI) processes: cross-section dominated by so-called single- and double-proton dissociative reactions. Non-negligible background for many analyses (low, high-mass DY, */pT(Z) measurement, ...) Preselection:




pT>10 GeV, ||<2.4, M+->20 GeV pTe>12 GeV, |e|<2.4, Me+e->24 GeV
Events
Events / 1.5 GeV

108 10
7



Exclusive selection:


ATLAS s = 7 TeV, 4.6 fb-1 Baseline selection

Data 2011 +Z/ * Multi-jet Diboson + Z/ *
-

tt Double-diss. Single-diss. Exclusive
+-

++-

104

ATLAS s = 7 TeV, 4.6 fb-1 Baseline selection + exclusivity veto + Z region removed

Data 2011 Z/ *
++++-

106 105 104 103 102 10 1

103

Double-diss. Single-diss. Exclusive

Data / MC

Data / MC

3 mm dilepton-vertex longitudinal isolation pT of the dilepton system < 1.5 GeV

102

10

1.2 1.1 1 0.9 0.8

10 Tracks associated with di-muon vertex

1 0 1.5

5

10

15

20

25

30

35

40

1 0.5 0 5 10 15 20 25 30 35 40

pT

+-

45 [GeV]

2

3

4 5 6 7 8 910 20 30 40 50 Tracks associated with di-muon vertex

pT

+-

45 [GeV]

26 June 2015

M. Dyndal (on behalf of the ATLAS Collaboration)

SM measurements with ATLAS (QFTHEP'15)

7


Soft QCD, Diffraction and Forward Physics



Exclusive pp() ppl+l- production at 7 TeV CERN-PH-EP-2015-134
Signal extraction: binned maximum-likelihood fit to the measured dilepton acoplanarity distribution Corresponding fiducial cross-sections:
. +- = . +- =
Events / 0.002

350 ATLAS 300 250
Data 2011

s = 7 TeV, 4.6 fb-1

200 150 100 50

Exclusive Single-diss. Double-diss. Z/ * e e
+-

e+ee+ee+e-



0.428 ± 0.035(stat.) ± 0.018(syst.) pb

0.628 ± 0.032(stat.) ± 0.021(syst.) pb

0 0

0.01

0.02

0.03

0.04



Theory predictions (QED-EPA), with absorptive corrections from Phys. Lett. B741 (2015) 66-70 (20% effect)
, . +- , . +-

0.05 1-|

e+e

-

0.06 |/

meas. EPA / nominal stat. uncertainty stat. syst. uncertainty

EPA corr. EPA

/ /

EPA nominal EPA nominal

theo. uncertainty
EPA = nominal 4.07 pb

CMS (m
+-

+-

, 40 pb-1
T

> 11.5 GeV, p > 4 GeV, | | < 2.1)

= 0.398 ± 0.007(theo.) pb
= 0.638 ± 0.011(theo.) pb

ATLAS (m
ee
+-

e+e , 4.6 fb-1
e T

-

> 24 GeV, p > 12 GeV, | e| < 2.4)

EPA = nominal 0.496 pb



Agreement also with similar CMS measurement
M. Dyndal (on behalf of the ATLAS Collaboration)

ATLAS (m
+-

+-

, 4.6 fb-1
T

> 20 GeV, p > 10 GeV, | | < 2.4)

EPA = nominal 0.794 pb

ATLAS 0 .3 0 .4 0 .5

s = 7 TeV 0 .6 0 .7 0 .8 0 .9 1 /
EPA nominal

1 .1

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SM measurements with ATLAS (QFTHEP'15)

8


Soft QCD, Diffraction and Forward Physics



Underlying event in Z boson events Eur. Phys. J. C 74, 3195 (2014)
UE probe everything but the hard scatter: multi-parton interactions, colour reconnection etc. Measured charged-particle track observables: pT and Nch per · unit, average mean pT Three regions considered, depending on to the direction of the Z boson: toward, away, transverse





26 June 2015

M. Dyndal (on behalf of the ATLAS Collaboration)

SM measurements with ATLAS (QFTHEP'15)

9


Soft QCD, Diffraction and Forward Physics



Underlying event in Z boson events Eur. Phys. J. C 74, 3195 (2014)
At high-pT the < Nch > UE looks to be a universal quantity Disagreement at low-pT due to the hard scale (mZ) in Z events MC model predictions qualitatively describe the data well
1.6 1.4
> [GeV]

ATLAS

s = 7 TeV

Transverse region
-1,

Data 2011: Z events (4.6 fb-1) Data 2010: Minimum bias and jet events (168

37 pb-1)

1.2 1
1 .2

0.8 0.6 0.4 0.2 0
Minimum bias events Jet events Z events

MC/Data

1

2 1.8 1.6 1.4 1.2 1 0.8 0.6 0.4
1.1 1.05
0

ATLAS

s = 7 TeV, 4.6 fb-1 Toward region


>

< pT /

Da t a P y th i a 8 A U 2 P o w h e g + P y th i a 8 A U 2 20 40 60 80 100

Alpgen+Herwig+Jimmy AUET2 Sher pa Pythia6 Perugia2011C Her wig++ UE- EE- 3 120 140 160 180 200


>

0 .8 0 .6 0 .4 0 .2 0 5 10 15 20 25 30 35 40 45 50

1 0.95 0.9 0.85 0.8 0 20 40 60 80 100 120 140 160 180
T

p [GeV]
T

50 100 150 200 250 300 350 400 450 500

pZ or p
T

leadtrack T

or p

leadjet T

[GeV]

200

pZ [GeV]

26 June 2015

M. Dyndal (on behalf of the ATLAS Collaboration)

SM measurements with ATLAS (QFTHEP'15)

10


Electroweak Physics (W, Z bosons)



W+jets cross-sections at 7 TeV Eur. Phys. J. C (2015) 75:82
Tests of perturbative QCD over 5 orders of magnitude Electroweak effects become important at large W boson pT (> 1 TeV) - not included in predictions used here Many exclusive + inclusive differential distributions compared to a variety of theoretical predictions
(W +N ) [pb]
Pred. / Data

106

ATLAS
j

W(

ant i-kt jet s, R=0. 4,
j T

105

p > 30 GeV, |y | < 4. 4

Pred. / Data

10

4

l ) + jet s Dat a, -1 s = 7 TeV, 4. 6 f b BLACKHAT+SHERPA HEJ ALPGEN SHERPA M EPS@NLO

1.4

BLACKHAT+SH ER PA

jet s

1.2

1

0.8

0.6

ATLAS
0 1 2 3 4 5 6 7

1.4

H EJ

1.2

Nj

ets

103

1

0.8

102

0.6

0

1

2

3

4

5

6

7

Pred. / Data



1.4

AL PGEN

1.2

Nj

ets

10

1

0.8

1

0.6

0

1

2

3

4

5

6

7

Pred. / Data

1.4

S HE RP A

10-1

1.2

Nj

ets

1

10-2

0.8

0.6

M E P S @ NLO

0

1

2

3

4

5

6

7

0
s

1

2

3

4

5

6

7

Njet

Njet

s

26 June 2015

M. Dyndal (on behalf of the ATLAS Collaboration)

SM measurements with ATLAS (QFTHEP'15)

11


Electroweak Physics (W, Z bosons)



W+jets cross-sections at 7 TeV Eur. Phys. J. C (2015) 75:82
Overall good agreement with predictions is found (but in some regions of phase-space significant disagreement observed)
/dp [1/GeV]
W+ 2j/d

102 10 1

T

j

y

103

W+ 2j

ATLAS W( anti-kt jets, R=0.4, j j p > 30 GeV, |y | < 4.4 T Scaled Predictions

j1,j2

d

l ) + 2 jet Data, s=7 TeV, 4.6 f b-1 BLACKHAT +SHERPA ALPGEN+HERWIG S HE RP A

104 103 102 10 1

ATLAS W( anti-kt jets, R=0.4, j j p > 30 GeV, |y | < 4.4 T Scaled Predictions

e ) + 2 jet Data, s=7 TeV, 4.6 f b-1 BLACKHAT +SHERPA ALPGEN+HERWIG S HE RP A

d

10-1 10-2 10-3 10-4

10-1

MC / Data MC / Data NLO / Data

p (leading jet) [GeV]
T

j

MC / Data MC / Data NLO / Data

1.4 1.2 1 0.8 0.6 1.4 1.2 1 0.8 0.6

100 BLACK HAT +SHE300 200 RPA

400

500

600

700

100

200 ALPGEN

300

400

500 600 700 j p (leading jet) [GeV]
T

1 .4 1 .2 1 0 .8 0 .6

100

SHERPA

200

300

400

500 600 700 j p (leading jet) [GeV]
T

100

200

300

400 500 600 700 pj (leading jet) [GeV]
T

1.4 0 1.2 1 0.8 0.6 0 1.4 1.2 1 0.8 0.6 0 1 .4 1 .2 1 0 .8 0 .6

1 LACK HAT +2 HERPA 3 B S

4

5

6 y

j1,j2

1 ALPGEN

2

3

4

5

6 y
j 1 ,j 2

1

SHERPA

2

3

4

5

6 y
j 1 ,j 2

0

1

2

3

4

5

6 y

j1 ,j2

26 June 2015

M. Dyndal (on behalf of the ATLAS Collaboration)

SM measurements with ATLAS (QFTHEP'15)

12


Electroweak Physics (W, Z bosons)



Low-mass DY differential cross-section at 7 TeV JHEP 06 (2014) 112
Access to dilepton invariant mass down to 12 GeV (low-x region) Fixed-order NNLO QCD + NLO EW + PI (photon-induced dilepton pair production) calculations describe the data well
d [pb/GeV] dmll

3.5 3

ATLAS
L dt = 1.6 fb s=7 TeV MSTW2008 68% C.L | l|<2.4, pl > 12 & 15 GeV
T -1

d [pb/GeV] dmll

25 20
Data

ATLAS
L d t = 3 5 pb s=7 TeV
-1

2.5 2 1.5
Data

15 10

F E WZ N L O +

HO EW

+

PI HO EW

POWHEG NLO+LLPS+ F E WZ N N L O +
HO EW

+

PI

+

PI

1 0.5

F E WZ N L O +

HO EW

+

PI HO EW

POWHEG NLO+LLPS+ F E WZ N N L O +
HO EW

+

PI

5

MSTW2008 68% C.L | l|<2.4, pl > 6 & 9 GeV
T

+

PI

Theory / Data

1.1 1 0.9 0.8 30 35 40 45 50 55 60 65
mll [GeV]

Theory / Data

1.2 1 0.8 0.6 20 30 40 50 60
mll [GeV]

mll [GeV]

mll [GeV]

26 June 2015

M. Dyndal (on behalf of the ATLAS Collaboration)

SM measurements with ATLAS (QFTHEP'15)

13


Electroweak Physics (W, Z bosons)



FB asymmetry in lepton pair production (7 TeV) CERN-PH-EP-2014-259
Measurement of asymmetry defined as
=
cos 0 cos 0

- +

cos <0 cos <0

as a function of the dilepton invariant mass

26 June 2015

M. Dyndal (on behalf of the ATLAS Collaboration)

SM measurements with ATLAS (QFTHEP'15)

14


Electroweak Physics (W, Z bosons)



FB asymmetry in lepton pair production (7 TeV) CERN-PH-EP-2014-259
Effective weak mixing angle (sin2 ) is also extracted - from the detector-level AFB values



sin2 = 0.2308± 0.0005(stat.) ± 0.0006(syst.) ± 0.0009(PDF)





Agreement with the current world average

26 June 2015

M. Dyndal (on behalf of the ATLAS Collaboration)

SM measurements with ATLAS (QFTHEP'15)

15


Electroweak Physics (Multi-bosons)



WW/WZ ljj cross-section at 7 TeV JHEP 01 (2015) 049
Events / 5 GeV

Measurement of combined WW/WZ cross-section in semi-leptonic final state Background composition:


22000 20000 18000 16000 14000 12000 10000 8000

ATLAS L dt = 4.6 fb s = 7 TeV
-1

Data W W /W Z top quarks multijet W /Z + jets

W/Z+jets (89%), multi-jet (5%) - data driven Top (4%) - MC estimate
( D a t a - F it t e d B k g ) / 5 G e V
1000

W

l + 2 jets





. = 68 ± 7(stat.) ± 18(syst.) pb,

400

W

l + 2 jets

Data/Fit

Signal yield extracted from a fit to mjj distribution (3.4 significance)

ATLAS
800

6000 4000 2000 0
1.1 1.05 1 0.95 0.9

L dt = 4.6 fb-1 s = 7 TeV
Data

600

W W /W Z (Best Fit) Systematic Uncertainty

50

100

150

200

250

200

compared with

50

100

150

. = 61.1 ± 2.2 pb .

0

Dijet Mass [GeV]

200

250

-200

50

100

150

200

250

Dij et Mass [GeV]

26 June 2015

M. Dyndal (on behalf of the ATLAS Collaboration)

SM measurements with ATLAS (QFTHEP'15)

16


Electroweak Physics (Multi-bosons)



WW/WZ ljj cross-section at 7 TeV JHEP 01 (2015) 049
Limits on aTGC: binned maximumlikelihood fit of a chosen observable (pT jj)
Events / 25 GeV
10 10
5 4

ATLAS
95% CL intervals LEP Scenario

ATLAS l jj, s = 7TeV 4.6 fb-1,
FF

=

CMS l jj, s = 7TeV 5.0 fb-1,
FF

ATLAS -1 L d t = 4 .6 f b s = 7 TeV

=

Data =0.05 SM WW/WZ W/Z+jets top quarks multijet

ATLAS WW, s = 7TeV

gZ
1

4.6 fb-1,

FF

=

CMS WW, s = 7TeV 4.9 fb-1,
FF

=

103 102 10 1

ATLAS WZ, s = 7TeV 4.6 fb-1,
FF

=

ATLAS W , s = 7TeV 4.6 fb-1,
FF

W

+ 2 jets

=

CMS W , s = 7TeV 5.0 fb-1,
FF

=

D0 com b., s = 1.96TeV 8.6 fb-1,
FF

= 2TeV

LEP comb. 0.7 fb-1,
FF

=

10

-1

0
3.5 3 2.5 2 1.5 1 0.5 0

100
=0.05

200

300

400

500

Data/SM

0

100

200

300

400

500

-0.4

-0.2

0

0.2

p [GeV]
T jj

0.4 0.6 0.8 95% CL Limits
17

26 June 2015

M. Dyndal (on behalf of the ATLAS Collaboration)

SM measurements with ATLAS (QFTHEP'15)


Electroweak Physics (Multi-bosons)



Evidence of W production at 8 TeV CERN-PH-EP-2015-009
Events / 50 GeV



First evidence of W production with > 3 significance ( 20.3 fb-1, inclusive selection: Njets 0) Largest background: jets faking photon or lepton (data-driven estimate) Fiducial cross-section obtained using a maximum-likelihood fit:

70 60 50 40 30 20 10 0 0

ATLAS

D at a W Z W j + W jj + jets O t h e r b a c k g ro u n d s s = 8 TeV, 20.3 fb-1 muon channel (N 0)
je t s

100

200

300

400 500 m [GeV]

Events

70 60 50 40 30 20 10 0 0

ATLAS

D a ta W Z W j + Wj + Wjj + j e ts O th e r b a c k g r o u n d s s = 8 TeV, 20.3 fb-1 muon channel

1

2

3

4

5

6 Nje

7
ts

26 June 2015

M. Dyndal (on behalf of the ATLAS Collaboration)

SM measurements with ATLAS (QFTHEP'15)

18


Electroweak Physics (Multi-bosons)



Evidence of W production at 8 TeV CERN-PH-EP-2015-009
aQGC limits set for Njets = 0 (exclusive selection) and m > 300 GeV Limits better or similar to LEP and D0 CMS is more sensitive in and 0 ( WW measurement)
f
E T0 4

LEP D0 WW CMS W V

ATLAS
CMS WW ATLAS W

AQGC Limits 95% CL

[TeV -4]

a

W C 2

[TeV -2]

a

W 0 2

[TeV -2]
-105 -104 -103 -102 -10
3 5 10 102 10 104 10

- scale at which new physics appears, a, f - coupling of the respective operator.

26 June 2015

M. Dyndal (on behalf of the ATLAS Collaboration)

SM measurements with ATLAS (QFTHEP'15)

19


Electroweak Physics (Multi-bosons)



EW WWjj production at 8 TeV Phys. Rev. Lett. 113, 141803
Same-sign W±W± scattering: a key process to study the SM nature of EWSB at the LHC



Events/50 GeV

2

-1

10

Syst. Uncertainty W W jj Electroweak W W jj Strong Prompt Conversions Other non-prompt

Events

Measurement of EW WWjj: selection at high mjj and cutting on|yjj| (VBS region) 10 A0T.LAfbS , s = 8 TeV Data 2012 30 ATLAS 23
25 20 15 10 5
Data/Background

20.3 fb -1, s = 8 TeV mjj > 500 GeV

1

Data 2012 Syst. Uncertainty W W jj Electroweak W W jj Strong Prompt Conversions Other non-prompt

10-1

5

Data/Bkg Bkg Uncertainty (Sig+Bkg)/Bkg

mjj [GeV]

0

1

2

3

4

5

6

7

8

9 | yjj|

0 200 400 600 800 1000 1200 1400 1600 1800 2000 mjj [GeV]

Prompt - prompt leptons from multilepton processes Conversions - photon conversions and charge mis-ID

26 June 2015

M. Dyndal (on behalf of the ATLAS Collaboration)

SM measurements with ATLAS (QFTHEP'15)

20


Electroweak Physics (Multi-bosons)



EW WWjj production at 8 TeV Phys. Rev. Lett. 113, 141803
A total of 34 candidate events in VBS region Measured cross-sections in agreement with theory prediction First aQGC limits on 4, 5 parameters are also set (for notation see
Phys.Rev. D22 (1980) 200)
1

ATLAS 20.3 fb -1, s=8 TeV ee
0.4 1.0 4.0 [fb]

SM

VBS WW

=0.95

0.06 [fb]

NLO, POWHEG-BOX, CT10

0.8

0.6

e
1.3 0.6 0.25 [fb]

0.4

1.7

0.8

0.15 [fb]

0.2

Combination
1.3 0.4 0.2 [fb]

0

-1

-0.5

0

0.5

1

1.5

2

VBS. WW

2.5 [fb]

1

ATLAS 20.3 fb -1, s=8 TeV ee
2.0 1.5 0.5 [fb]

SM

in c l WW

=1.52

0.11 [fb]

NLO, POWHEG-BOX, CT10

0.8

0.6

e
2.1 0.7 0.3 [fb]

0.4

2.2
0.2

0.9

0.2 [fb] 0.3 [fb]

Combination
2.1 0.5

0

0.5

1

1.5

2

2.5

3

in c l. WW

3.5 [fb]

26 June 2015

M. Dyndal (on behalf of the ATLAS Collaboration)

SM measurements with ATLAS (QFTHEP'15)

21


Jet Physics



Inclusive jet cross-section at 7 TeV JHEP 02 (2015) 153
Double-differential cross-section measurement as a function of jet p and rapidity Two jet radii are used: R = 0.4 and R = 0.6. Jets with pT > 100 GeV and |y| < 3 considered. 10 10 Comparison with NLO predictions 10 corrected for EW and NP effects. 10 Several PDF investigated.
d2 /dp dy [pb/GeV]
10 anti-kt jets, R =0.4 L dt=4.5 fb-1, 7

T

A TLA S
0.5

s=7 T eV

|y | < 0.5 ( 10 ) |y | < 1.0 ( 10 ) |y | < 1.5 ( 10 ) |y | < 2.0 ( 10 ) |y | < 2.5 ( 10 |y | < 3.0 ( 10
-12 -15 -9 -6 -3

0

4

1.0

1.5

2.0

) )

T

2.5

Theory / data

Theory / data

1.2 1

|y | < 0.5

2 1.5 1 0.5

1.5

|y | < 2.0

ATLAS
L dt = 4.5 f b s = 7 TeV anti-k t jets , R =0.4
-1

10

-2

10-5 10-8 10-11 10-14 10
-17 -20
Syste ma tic unce rta intie s NLOJET++ (CT10) Non-pe rt. corr. EW corr.

0.8 0.6 1.2 1 0.8 0.6
0.5 |y | < 1.0

2 1.5 1 0.5

2.0

|y | < 2.5

Data

NLOJET++ = =p
F R

m ax T

Non-pert and EW c orr.

1.4 1.2 1 0.8 10
2

1.0

|y | < 1.5

2 1.5 1 0.5 10
3

2.5

|y | < 3.0

CT10

MSTW 2008 NNPDF 2.1

10

102

103

p [GeV]
T

p [GeV]
T

102

103

p [GeV]
T

26 June 2015

M. Dyndal (on behalf of the ATLAS Collaboration)

SM measurements with ATLAS (QFTHEP'15)

22


Jet Physics



Three-jet production cross-section at 7 TeV Eur. Phys. J. C (2015) 75
Double-differential cross-section measurement as a function of mjjj and Y* = |yj1- yj2|+ |yj2- yj3|+ |yj1- yj3| Asymmetric kinematic cuts: pT j1 > 150 GeV, pT j2 > 100 GeV and pT j3 > 50 GeV Comparison with NLO predictions corrected for NP effects. Several PDF investigated.
Prediction/Data

Dijet: JHEP 05 (2014) 059
104 102 1 10-2 10-4 10-6 10
4
anti-k t R = 0.4

d2 /dmjjj/d|Y*| [pb/GeV]

ATLAS
L dt = 4.5 fb
-1

s = 7 Te V



|Y*|<2 (x100 ) 2<|Y*|<4 (x101 ) 4<|Y*|<6 (x102 ) 3 6<|Y*|<8 (x10 ) 8<|Y*|<10 (x104 )

NLO QCD CT 10 non-pert. corr

L dt = 4.5 fb

-1

CT 10 MSTW 2008 GJR 08

d2 /dmjjj/d|Y*| [pb/GeV]

1.4 1.2 1 0.8 0.6

|Y*|<2

AT L AS
s = 7 T eV anti-k t R = 0.4
10
3

NLO QCD PDF non-pert. corr.

400
anti-k t R = 0.6

1000

2000 3000 mjjj [GeV] ATLAS
L dt = 4.5 fb
-1

DATA Uncert. Total Statistical

1.4 4 102|Y*|<4 2< 1.2 1 0.8 0.6 1.6 4 10 |Y*|<8 6< 1.4 1.2 1 0.8 0.6 0.4
2

2 10

3

102 1 10
-2

s = 7 Te V

1.4 m jjj [GeV] 1.2 1 0.8 0.6

4<|Y*|<6

10

3

2 10

3

m jjj [G1.6] 4 10 eV

1.4 1.2 1 0.8 0.6 0.4

8<|Y*|<10 10

2

3

2 10

3

m jjj [GeV]

10-4 10-6
103 2 103 m jjj[GeV]

|Y*|<2 (x100 ) 2<|Y*|<4 (x101 ) 4<|Y*|<6 (x102 ) 3 6<|Y*|<8 (x10 ) 8<|Y*|<10 (x104 )

NLO QCD CT 10 non-pert. corr

4 102

103

2 103

m jjj[GeV] 4 102

400

1000

2000 3000 mjjj [GeV]

26 June 2015

M. Dyndal (on behalf of the ATLAS Collaboration)

SM measurements with ATLAS (QFTHEP'15)

23


Direct Photons



Inclusive photon cross-section at 7 TeV Phys. Rev. D 89, 052004 (2014)
Cross-section for isolated, high-pT photons (with ET,>100 GeV, ET,iso<7 GeV) Isolation requirement reduces jet background E >100 GeV | |<1.37 EM shower shape variables provide Data 2011 s=7 TeV t i ght tight / loose photon identification non- t i ght
Entries / GeV
200 10
3

180

T

160

140

120

Signal purity

1 .0 4 1 .0 2 1 0 .9 8 0 .9 6 0 .9 4 0 .9 2 0 .9 0 .8 8

ATLAS

100 80 60 40 20 0 -10 -5 0 5 10 15

L dt = 4.6 fb

-1

ATLAS

L dt = 4.6 fb

-1

20

25

30
iso

35

40

Data 2011 s=7 T eV | |<1.37 1.52<| |<2.37

ET [GeV]

0 .8 6 100 200 300 400 500 600 700 800 900 1000 ET [GeV]

26 June 2015

M. Dyndal (on behalf of the ATLAS Collaboration)

SM measurements with ATLAS (QFTHEP'15)

24


Direct Photons



Inclusive photon cross-section at 7 TeV Phys. Rev. D 89, 052004 (2014)
Production is sensitive to the gluon content of the proton (qgq) Comparison with LO and NLO predictions corrected for NP effects
10 L dt = 4.6 fb 1 10-1 10
-2 -1

/ d E T [pb/GeV]

[pb]

400 350 300 250 200 150 ET >100 GeV
Data 2011 s=7 T eV PYT HIA (M RST 2007 LO*) HERWIG (M RST 2007 LO*)
-1

D a ta 2 0 1 1 s = 7 T e V PY THIA (MRST 2007 LO*) HERWIG (MRST 2007 LO*) N L O ( J e tp h o x ) C T 1 0 Total unce rtainty Scale unce rtainty NLO (Je tphox ) MSTW2008nlo

/d

L dt = 4.6 fb

NLO (Jetphox) CT 10 T otal uncertainty Scale uncertainty NLO (Jetphox) M ST W2008nlo

d

10-3

ATLAS
10
-4

d

100 50

| |<1.37

ATLAS

Theory/Data

0.8

0.6

1 .2 1 .1 1 0 .9 0 .8 0 .7 0 .6 0 .5 100

Theory/Data

10-5 .4 1.14 100 1 .3
1

100 200 300 400 500 600 700 800 900 1000 200 300 400 500 600 700 800 9001000 1.2
100
200 200 300 300 400 400 500 500 600 600 700 700 800 800 900 900 1000 1000

.2 1.120 1 .1 1 1 0 .9 .8 0.08 0 .7 0 0

0

0. 0.55

1 1

1. 1.55

2 2

2. 2.55

0. 0.5 5

1 1

1. 1.5 5

2 2

2. 2.5 5

ET [GeV]

||

26 June 2015

M. Dyndal (on behalf of the ATLAS Collaboration)

SM measurements with ATLAS (QFTHEP'15)

25


Summary


SM measurements are important to explore new kinematic regimes, to test theoretical predictions and to improve precision of the SM parameters

26 June 2015

M. Dyndal (on behalf of the ATLAS Collaboration)

SM measurements with ATLAS (QFTHEP'15)

26


Summary


New measurements for soft QCD / Diffraction / Forward Physics, Electroweak studies, Jet Physics and Direct Photons are presented

26 June 2015

M. Dyndal (on behalf of the ATLAS Collaboration)

SM measurements with ATLAS (QFTHEP'15)

27


Summary



New data at s = 13 TeV being collected!

26 June 2015

M. Dyndal (on behalf of the ATLAS Collaboration)

SM measurements with ATLAS (QFTHEP'15)

28