Prospects and Results from the AFP Detector in ATLAS Grzegorz Gach - - PowerPoint PPT Presentation

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Prospects and Results from the AFP Detector in ATLAS Grzegorz Gach on behalf of the ATLAS Collaboration AGH University of Science and Technology 1 December, 2016 Multiple Partonic Interactions at the LHC 2016 Grzegorz Gach (AGH UST) 1 1

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SLIDE 1

Prospects and Results from the AFP Detector in ATLAS

Grzegorz Gach

  • n behalf of the ATLAS Collaboration

AGH University of Science and Technology

1 December, 2016

Multiple Partonic Interactions at the LHC 2016

Grzegorz Gach (AGH UST) 1 1 December, 2016 1 / 22

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SLIDE 2

ATLAS Forward Detectors

ATLAS Forward Proton

detectors dedicated for diffractive processes measurements four stations — two on each side detectors mounted in horizontal roman pots 3D pixels and time-of-flight detectors acceptance in ξ = (E − E′)/E ≈ (0.02, 0.12)

Grzegorz Gach (AGH UST) 2 1 December, 2016 2 / 22

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SLIDE 3

Possible Measurements

1 proton kinematics 2 rapidity gaps 3 gap survival probability 4 energy flow 5 event shapes 6 jets 7 jet–gap–jet 8 jet–photon 9 Pomeron structure 11 heavy quarks 12 Drell-Yan, W 13 exclusive jets 14 exclusive lepton production 15 photon–photon scattering 16 WW production 17 ZZ production 18 resonant production Grzegorz Gach (AGH UST) 3 1 December, 2016 3 / 22

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SLIDE 4

AFP Installation

AFP 0+2 — 2016 AFP 2+2 — 2017

Grzegorz Gach (AGH UST) 4 1 December, 2016 4 / 22

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SLIDE 5

AFP 0+2 Installation

✓ installation of two stations on one side in the tunnel ✓ installation of tracking detectors in the stations ✓ LHC qualification ✓ integration with ATLAS DCS ✓ integration with ATLAS DAQ ✓ integration with ATLAS triggers ✓ data acquisition in special runs

Grzegorz Gach (AGH UST) 5 1 December, 2016 5 / 22

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SLIDE 6

AFP 0+2

3(4) layers of pixel detectors in each station 336 × 80 pixels of 50 × 250 ➭m2 pixel modules are similar to the

  • nes used in ATLAS IBL with

proven radiation hardness detectors are tilted by 14◦ with respect to vertical direction data collected in special low-µ runs with L ≈ 500 nb−1

Grzegorz Gach (AGH UST) 6 1 December, 2016 6 / 22

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SLIDE 7

AFP 0+2 Performance

Pixel hits per event 1 2 3 4 5 6 7 8 9 10 Events [norm.] 0.1 0.2 0.3 0.4 0.5 ATLAS Preliminary

Pixel hits [a.u.]

3 −

10

2 −

10

1 −

10 1 Pixel rows in Plane 0 50 100 150 200 250 300 Pixel rows in Plane 1 50 100 150 200 250 300 ATLAS Preliminary

Pixel hits [a.u.]

3 −

10

2 −

10

1 −

10 1 Pixel rows in Plane 0 50 100 150 200 250 300 Pixel rows in Plane 1 50 100 150 200 250 300 ATLAS Preliminary

in almost 50 % events 2 hits are observed in each plane very good correlation of hits between two planes (first and second)

Grzegorz Gach (AGH UST) 7 1 December, 2016 7 / 22

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SLIDE 8

AFP 0+2 Performance

AFP 212 track position in x [mm]

  • 115
  • 110
  • 105
  • 100
  • 95

AFP 212 track position in y [mm]

  • 5

5 10 15 1 10

2

10 Simulation ATLAS = 14 TeV s * = 0.55 m β beam center

Distance from sensor edge, x [mm] 16 − 14 − 12 − 10 − 8 − 6 − 4 − 2 − Distance from sensor edge, y [mm] 2 4 6 8 10 12 14 16 18 Pixel hits [a.u.]

3 −

10

2 −

10

1 −

10 1 ATLAS Preliminary

hits in AFP near (205 m) station at 5σ + 400 ➭m from the beam centre visible pattern of diffractive protons

Grzegorz Gach (AGH UST) 8 1 December, 2016 8 / 22

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SLIDE 9

AFP 0+2 Physics Single Diffractive Dissociation

(P) (P')

relatively high cross section special runs with pile-up free environment provide clean events single proton detectable in AFP AFP provides access to so far non-measurable quantities like ξ = (E − E′)/E or t = (P − P′)2

Grzegorz Gach (AGH UST) 9 1 December, 2016 9 / 22

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SLIDE 10

AFP 0+2 Physics — Inclusive Single Diffraction

D

f 0.1 0.15 0.2 0.25 0.3 0.35 0.4

SS

R 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18

Data 2015 Pythia8 SS =0.085 ε Pythia8 DL, =0.060 ε Pythia8 DL, =0.10 ε Pythia8 DL, Pythia8 MBR EPOS LHC QGSJET-II

ATLAS

  • 1

b µ =13 TeV, L=60.1 s

Phys.Rev.Lett. 117 (2016) 182002

60 65 70 75 80 85 90 ATLAS = 7 TeV s )[mb] X → pp (

inelastic

σ

Elastic only Lumi-independent

  • independent

ρ MinBias Elastic

TOTEM ALICE ATLAS

Nuclear Physics B (2014), 486-548 σSD + DD measured together with inelastic cross-section at 7 TeV and 13 TeV using MBTS signal on one side combination of ALFA and ATLAS σinelastic at 7 TeV gives σSD for ξ < 5.1 × 10−6

Grzegorz Gach (AGH UST) 10 1 December, 2016 10 / 22

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SLIDE 11

AFP 0+2 Physics — Inclusive Single Diffraction

1 2 3 4 5 6 7 8

[mb]

F

η ∆ /d σ d 1 10

2

10

  • 1

b µ Data L = 7.1 PYTHIA 6 ATLAS AMBT2B PYTHIA 8 4C PHOJET ATLAS = 7 TeV s > 200 MeV

T

p

F

η ∆ 1 2 3 4 5 6 7 8 MC/Data 1 1.5

  • Eur. Phys. J. C72 (2012) 1926

1 2 3 4 5 6 7 8

[mb]

F

η ∆ /d σ d 1 10

2

10

  • 1

b µ Data L = 7.1 PYTHIA 8 4C Non-Diffractive Single Diffractive Double Diffractive ATLAS = 7 TeV s > 200 MeV

T

p

F

η ∆ 1 2 3 4 5 6 7 8 MC/Data 1 1.5

  • Eur. Phys. J. C72 (2012) 1926

ATLAS dedicated measurement done only at √s = 7 TeV possible large contribution of double diffraction background no measurement of differential cross sections dσ/dξ or dσ/dt improvement and extension of current measurements by tagging protons in 13 TeV

Grzegorz Gach (AGH UST) 11 1 December, 2016 11 / 22

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SLIDE 12

AFP 0+2 Physics — Single Diffractive Jets

0.2 0.4 0.6 0.8 1 0.01 0.1 1 purity, S / (S + B) mean pile-up, <µ> SD Jet production, pT

jet1 > 20 GeV

AFP 204 m, √s = 13 TeV, β* = 055 m, dAFP = 2.85 + 0.3 mm AFP tag + one vtx

ATLAS-TDR-024-2015

10-1 100 101 102 103 104 0.01 0.1 1 significance, S / √(S + B) mean pile-up, <µ> SD Jet production, pT

jet1 > 50 GeV

AFP 204 m, √s = 13 TeV, β* = 055 m, dAFP = 2.85 + 0.3 mm, nb = 10, τ = 100 h AFP tag + one vtx

ATLAS-TDR-024-2015 probing Pomeron universality between ep and pp colliders measurement of gap survival probability Monte Carlo tuning

Grzegorz Gach (AGH UST) 12 1 December, 2016 12 / 22

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SLIDE 13

AFP 0+2 Summary

✓ despite challenging schedule the installation was successful ✓ very good detector performance ✓ collected more data than initially planned ✓ good data for soft diffraction analysis ✓ very good data for detector performance and background studies

Grzegorz Gach (AGH UST) 13 1 December, 2016 13 / 22

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SLIDE 14

AFP 2+2 Installation

installation of two missing stations

  • n the other side in the tunnel

installation of tracking detectors installation of timing detectors on both sides LHC qualification integration of timing detectors triggers with ATLAS data acquisition in special runs data acquisition in standard runs

Grzegorz Gach (AGH UST) 14 1 December, 2016 14 / 22

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SLIDE 15

AFP 2+2 Time-of-Flight Detectors

time resolution 10 ps or better efficiency not smaller than 90 % fast enough to provide trigger signal pile-up background reduction useful but not critical in special low-µ run necessary in standard runs with high pile-up

Grzegorz Gach (AGH UST) 15 1 December, 2016 15 / 22

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SLIDE 16

AFP 2+2 Physics — Single Diffractive Dissociation

(P) (P')

  • nly in special low-µ runs

clean pile-up free environment doubled number of events with respect to AFP 0+2

Grzegorz Gach (AGH UST) 16 1 December, 2016 16 / 22

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SLIDE 17

AFP 2+2 Physics — Central Diffraction

special as well as standard runs give access to processes with medium and relatively small cross-sections double proton tag with time measurements allows direct

  • bservation of central diffraction with suppressed

backgrounds (including pile-up) direct access to proton kinematics

Grzegorz Gach (AGH UST) 17 1 December, 2016 17 / 22

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SLIDE 18

AFP 2+2 Physics — Central Diffractive Jets

mass fraction 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 (pb) s)

2

ξ

1

ξ /

dijet

/d(W

dijet

σ d

2

10

3

10

4

10

5

10 =-1 ν =-0.5 ν standard (HERA Fit PDF) 20% uncertainty bar =0.5 ν =1 ν

gluons < 0.15 ξ 0.015 <

Phys.Rev. D88 (2013) no.7, 074029

(GeV)

T

p 40 50 60 70 80 90 100 (pb/GeV)

T

/dp

dijet

σ d 10

2

10

=-1 ν =-0.5 ν standard (HERA Fit PDF) 20% uncertainty bar =0.5 ν =1 ν

gluons < 0.15 ξ 0.015 <

Phys.Rev. D88 (2013) no.7, 074029 probing gluon structure of Pomeron sensitive to gap survival probability testing Pomeron universality between ep–pp colliders

Grzegorz Gach (AGH UST) 18 1 December, 2016 18 / 22

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SLIDE 19

AFP 2+2 Physics — Central Diffractive γ–jet

(GeV)

T

p

20 22 24 26 28 30 32 34 36 38 40 42 T

/dp

dijet

σ /d

T

/dp

jet γ

σ d

  • 3

10 d/u = 0.25 d/u = 0.5 d/u = 1 d/u = 2 d/u = 4

d = s, u + d + s = const. < 0.02 ξ 0.0015 <

SCI model

Phys.Rev. D88 (2013) no.7, 074029

M(GeV) 60 80 100 120 140 160 180 200 220 240 /dM

dijet

σ /dM/d

jet γ

σ d

  • 3

10 d/u = 0.25 d/u = 0.5 d/u = 1 d/u = 2 d/u = 4

d = s, u + d + s = const. < 0.02 ξ 0.0015 <

SCI model

Phys.Rev. D88 (2013) no.7, 074029 probing quark structure of Pomeron testing Pomeron universality between ep–pp colliders interesting variables pT and M = √sξ1ξ2

Grzegorz Gach (AGH UST) 19 1 December, 2016 19 / 22

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SLIDE 20

AFP 2+2 Physics — Exclusive Dijets

102 103 104 105 106 107 108 109 1010 1011 pT AFP ∆z ∆φ yjj-yX mjj/mX mX Rj tracks number of events L = 40 fb-1 √s = 14 TeV µ = 23 ATLAS Simulation Preliminary exclusive jets non-diff. jets single-diff. jets DPE jets

ATL-PHYS-PUB-2015-003

[GeV/c]

min T

leading jet transverse momentum, p 150 200 250 300

min T

number of events above p 200 400 600 800 1000 1200 1400 1600 1800

exclusive jets non-diffractive jets single diffractive jets central diffractive jets ATLAS Simulation Preliminary = 23 µ ,

  • 1

= 14 TeV, L = 40 fb s (t)=10 ps σ = 60%), ε AFP (

2

< 660 GeV/c

jj

200 < M

ATL-PHYS-PUB-2015- 003 calculations can be done using QCD without Pomeron no Pomeron remnants sensitive to unintegrated gluon PDF sensitive to rescattering corrections analysis inspired by Khoze, Martin, Ryskin publications

Grzegorz Gach (AGH UST) 20 1 December, 2016 20 / 22

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SLIDE 21

AFP 2+2 Physics — γ–γ Processes

π |/

  • e

+

e

φ ∆ 1-| 0.01 0.02 0.03 0.04 0.05 0.06 Events / 0.002 50 100 150 200 250 300 350 ATLAS

  • 1

= 7 TeV, 4.6 fb s

Data 2011

  • e

+

e → γ γ Exclusive

  • e

+

e → γ γ Single-diss.

  • e

+

e → γ γ Double-diss.

  • e

+

e → * γ Z/

Physics Letters B 749 (2015) 242-261 improvement and extension of existing measurements exclusive lepton production with tagged protons possible new physics with anomalous quartic couplings (W and Z production) very good background rejection for γγ production

Grzegorz Gach (AGH UST) 21 1 December, 2016 21 / 22

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SLIDE 22

Summary

very successful first stage of AFP installation AFP 0+2 data collected in 2016 are interesting not only from detector performance point of view but also physics next year final installation stage AFP 2+2 will be completed reach physics program for special low-µ focused mainly on soft diffraction timing detectors open access to measuring protons in high pile-up conditions and allow measuring processes with small cross sections

Grzegorz Gach (AGH UST) 22 1 December, 2016 22 / 22