[PPT] - ATLAS/CMS Upgrades Yasuyuki Horii Nagoya University on Behalf of PowerPoint Presentation

SLIDE 1

ATLAS/CMS Upgrades

Yasuyuki Horii Nagoya University

n Behalf of the ATLAS and CMS Collaborations

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Outline

LHC/HL-LHC plan ATLAS/CMS upgrades Physics prospects

2

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LHC/HL-LHC Plan

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Overview

4

SM precision studies and BSM searches with 13-14 TeV and 3000 fb-1. Peak instantaneous luminosity: 5-7x1034 cm-2s-1 — a lot of challenges. Two upgrade phases: Phase 1 (2019-2020) and Phase 2 (2024-2026).

http://hilumilhc.web.cern.ch/about/hl-lhc-project

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Luminosity levelling

5

Lower pileup in the experimental detectors Lower energy deposition by the collisions in the interaction region magnets

The average luminosity is almost the same. HL-LHC is designed to

perate with levelling.

CERN-ACC-2015-0140

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ATLAS/CMS Upgrades

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Challenges

7

Increased luminosity provides a significant challenge for the experiments. Upgrades are essential to exploit the full potential of LHC and HL-LHC.

Higher radiation dose Higher pileup Higher particle rate Higher event rate Replacement of some of the detectors Replacement of the electronics Overall modifications 

n the trigger and readout scheme

→

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Inner tracker

8

Inner trackers will be in an extreme environment at HL-LHC.

1 MeV neutron equivalent fluence up to 2 x 1016 /cm2. Ionisation dose up to 10 MGy. Particle rates up to 2 GHz/cm2 — high occupancy, high bandwidth.

CERN-LHCC-2015-010; LHCC-P-008

Pileup 140 expected at L = 5 x 1034 cm-2s-1 CMS ATLAS CMS

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Inner tracker

9

CERN-LHCC-2012-022; LHCC-I-023. CERN-LHCC-2015-020; LHCC-G-166.

Phase 2 ATLAS

Channel occupancy [%] for 200 pileups Ratio of reconstructed to generated tracks

Entire tracker replacement (all-silicon tracker) at the Phase 2 upgrade. Radiation tolerance, increased granularity, reduced material, extension to forward, …

No pileup dependence with ≧ 11 hits

Pixel thickness possibly 150 µm, pixel size possibly 50 x 50 µm2

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Inner tracker

10

Pixel detector replacement in the end of 2016 (as a Phase 1 project). Entire tracker replacement at the Phase 2 upgrade. Radiation tolerance, increased granularity,  reduced material, extension to forward, …

CERN-LHCC-2015-010; LHCC-P-008

Pixel Pixel +Strip Strip Pixel size considered: 25x100 µm2 and 50x50 µm2

CMS Phase 1/2

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Calorimeter

11

CMS Phase 2

Endcap calorimeter will be replaced — longevity and performance issues.

CERN-LHCC-2015-010; LHCC-P-008

Fraction of the response Hadron fluence 2 x 1014 /cm2 at |η| = 2.6. Defects in lead tungstate scintillating crystal

f the electromagnetic calorimeter.

Response degradation also expected  for the hadron calorimeter.

Light transmission loss

A high-granularity sampling calorimeter with a tungsten/silicon electromagnetic  part (EE) followed by brass/silicon (FH) and brass/scintillator (BH) hadronic parts.

High performance at high pileup

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Muon spectrometer

12

CERN-LHCC-2013-006; ATLAS-TDR-020

Micro-mesh gaseous detector (MM)

ATLAS Phase 1

New Small Wheel will be installed to cope with a relatively high hit rate  (~15 kHz/cm2 at L = 7 x 1034 cm-2s-1) and also to improve muon trigger.

Both MM and sTGC for precision tracking and trigger. Position resolution per layer: ~100 µm. Segment angle resolution at first-level trigger: ~1 mrad. Coverage: 1.3 < |η| < 2.7.

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Trigger

13

More luminosity — more interesting events but also more background. Without changes, trigger rates exceed the limits of trigger/readout system.

Simply increasing the threshold would kill the signal.

CERN-LHCC-2012-022; LHCC-I-023. CERN-LHCC-2015-019; LHCC-G-165. CERN-LHCC-2015-020; LHCC-G-166.

Choice of ATLAS and CMS at Phase 2 upgrades

Increase trigger rates. First level: ~100 kHz → 750-1000 kHz Storage level: ~1 kHz → 5-10 kHz Increase latency — improve algorithm. First level: ~3 µs → 6-12.5 µs Electronics replacements for all sub-systems.

CMS ATLAS

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Trigger

14

Track trigger implementation in the first-level trigger. Benefits: improved pT determination, better identification of charged leptons, … Technologies: studies ongoing for Associative Memories, FPGA, …

Electron trigger

CERN-LHCC-2015-010; LHCC-P-008.

Muon trigger CMS Phase 2

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Trigger

15

Calorimeter trigger upgrade Muon trigger upgrade

Higher granularity information provided at first-level trigger. Less sensitive to pileup. Extend muon trigger acceptance  in the barrel by additional chambers.

CERN-LHCC-2013-017; ATLAS-TDR-022-2013. O. Kortner, VCI 2016.

Current Phase 1

Additional RPCs

Phase 2

Muon A x ε in barrel could be improved  from ~70% to ~95%. Trigger rate reduction for e, γ, …

ATLAS

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Physics Prospects — Examples

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ttH

17

ATL-PHYS-PUB-2014-012

Direct probe of Higgs-top coupling.

Observation expected for ttH, H→γγ. ATLAS expected: 8.2σ (3000 fb-1).

gg→H and H→γγ indirect (loops).

[GeV]

γ γ

m 100 120 140 160 200

Background subtracted events Signal Fit

100 120 140 160

Events / ( 2 GeV ) 100 200 300

=14 TeV s ,

1

L dt = 3000 fb

∫

Simulation Background Fit

ATLAS Simulation Preliminary

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H→bb

18

ATL-PHYS-PUB-2014-011

[GeV]

bb

m

50 100 150 200 250

Events / 20 GeV

10000 20000 30000 40000 50000 60000 70000 80000 90000

ATLAS Simulation Preliminary

> = 140 µ <

1

L dt = 3000 fb

∫

= 14 TeV s

> 200 GeV

V T

1 lep., 2 jets, p

VH(bb)x10 VZ WW Multijet t t t, s+t-chan Wt W+bb W+bl W+cc W+cl W+l Z+bb Unc.

Observation expected for VH, H→bb (V = Z or W). ATLAS expected significance at 3000 (300) fb-1: 8.8σ (3.9σ).

[GeV]

bb

m 50 100 150 200 250 Events / 20 GeV 500 1000 1500 2000 2500

ATLAS Simulation Preliminary

> = 140 µ , <

1

= 14 TeV, 3000 fb s 2 lep, 2 jets, 2 tags, > 200 GeV

T Z

p

ZH x 10 Diboson t t Z+bb Z+bl Z+cc Z+cl Z+l Unc.

Access to Higgs-bottom coupling.

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H→µµ

19

CERN-LHCC-2015-010; LHCC-P-008. ATL-PHYS-PUB-2013-014.

Reduction of the material and better  spacial resolution for tracking at Phase 2. Mass resolution expected:  40% better with respect to ‘Phase 1 aged’  (radiation damage for 1000 fb-1 assumed).

Observation expected for H→µµ. ATLAS expected: 7.0σ (3000 fb-1).

Access to Higgs-muon coupling.

[GeV]

µ µ

m 80 100 120 140 160 180 200 Events / 0.5 GeV

2

10

3

10

4

10

5

10

6

10

7

10

8

10

9

10

ATLAS Simulation Preliminary

1

dt = 3000 fb L

∫

= 14 TeV s =125 GeV

H

, m µ µ → H µ µ → Z t t ν µ ν µ → WW

[GeV]

µ µ

m 100 110 120 130 140 150 160 (Data - Background) / 0.5 GeV

5000
4000
3000
2000
1000

1000 2000 3000 4000 5000

ATLAS Simulation Preliminary = 14 TeV s

1

dt = 3000 fb L

∫

S+B toy Monte Carlo S+B model B-only model

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Higgs couplings

20

)

Y

κ

X

κ ( ∆ =

XY

λ ∆ 0.05 0.1 0.15 0.2 0.25

)Z γ (Z

λ

Z γ

λ

gZ

λ

Z µ

λ

Z τ

λ

bZ

λ

tg

λ

WZ

λ

gZ

κ

ATLAS Simulation Preliminary

= 14 TeV: s

1

Ldt=300 fb

∫

;

1

Ldt=3000 fb

∫

ATL-PHYS-PUB-2014-016. arXiv:1307.1347 [hep-ph].

For various coupling scale factor ratios,  the precision of % level expected at 3000 fb-1.

Similar precision expected for ATLAS and CMS.

Fit with a fully generic parametrisation No assumption on the total width κgZ (= κgκZ/κH) overall scale parameter  common to all signal channels No assumption on new particle contribution  through loops

Hashed areas: current theory systematic uncertainties

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Higgs couplings

21

CERN-LHCC-2015-019; LHCC-G-165

Significant improvement expected with 14 TeV, 3000 fb-1. Precision test of Yukawa terms for various ‘flavors’: t, b, τ, and µ.

mass (GeV)

0.1 1 10 100

1/2

r (g/2v)

λ

4

10

3

10

2

10

1

10 1 WZ t b τ µ

68% CL

CMS

Projection

(14 TeV)

1

3000 fb

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Bs,d→µµ

22

Some of new physics scenarios  may boost the Bs,d→µµ decay rates. Bs/Bd ratio provides a stringent test 

f various models beyond SM.

B (Bs→µµ) = (3.65 ± 0.23) x 10-9 B (Bd→µµ) = (1.06 ± 0.09) x 10-10

C. Bobeth, et al., PRL 112, 101801 (2014)

Bs,d→µµ decays are only proceed  through FCNC processes  and are highly suppressed in SM.

B (Bs→µµ) = (2.8+0.7-0.6) x 10-9 B (Bd→µµ) = (3.9+1.6-1.4) x 10-10

D. M. Straub, arXiv:1012.3893

B (Bs→µµ) = (0.9+1.1-0.8) x 10-9 B (Bd→µµ) < 4.2 x 10-10 (95% CL)

CMS and LHCb, Nature 522, 68 (2015) ATLAS, arXiv:1604.04263 [hep-ex]

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Bs,d→µµ

23

(GeV)

µ µ

m

4.9 5 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9

S/(S+B) Weighted Events / ( 0.02 GeV)

20 40 60 80 100 120

CMS Simulation )|<1.4 µ ( η |

data full PDF

µ

+

µ →

s

B

µ

+

µ →

d

B combinatorial bkg semileptonic bkg peaking bkg

1

Scaled to L = 300 fb

(GeV)

µ µ

m

4.9 5 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9

S/(S+B) Weighted Events / ( 0.01 GeV)

100 200 300 400 500

CMS Simulation )|<1.4 µ ( η |

data full PDF

µ

+

µ →

s

B

µ

+

µ →

d

B combinatorial bkg semileptonic bkg peaking bkg

1

Scaled to L = 3000 fb

300 fb-1 3000 fb-1

σ x B predicted by SM assumed.

B (Bs→µµ) precision: 13% B (Bd→µµ) precision: 48% (2.2σ) B (Bs→µµ) precision: 11% B (Bd→µµ) precision: 18% (6.8σ)

CERN-LHCC-2015-010; LHCC-P-008. K. F. Chen, EPS-HEP 2015.

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Bs→J/ψφ

24

ATL-PHYS-PUB-2013-010. PRD 91, 073007 (2015).

Luminosity 250 fb-1 3000 fb-1 σ(φs) (Stat.) 0.064 rad 0.022 rad

) [GeV]

s

(B

T

p 10 20 30 40 50 60 70 80 ) [ps]

s

(B

τ

σ 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2

> = 20 µ ATLAS 2012 < > = 60 µ IBL Layout, < > = 200 µ ITK Layout, <

ATLAS simulation Preliminary

Run 1 Run 2, … CP violation due to interference between  direct decay and decay with Bs-Bs mixing. New physics can show up in the mixing. Phase difference between interfering amplitudes φs extracted from decay time defined on the transverse plane: . Improve decay time resolution στ by 30%  with respect to Run 1 at ATLAS.

_

φs = -0.0365 rad

+0.0013

0.0012

SM global fit by CKMfitter

Bs Bs J/ψφ

_

Method improvement in arXiv:1601.03297 [hep-ex].

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t→qγ, qZ, and qH

25

ATL-PHYS-PUB-2013-007. ATLAS-PHYS-PUB-2013-012. CMS PAS FTR-13-016.

FCNC top quark decays are highly suppressed in SM: B < 10-13. New physics scenarios may enhance the rate up to B ~ 10-4. HL-LHC expected limits at 95% CL are B = 10-4–10-5.

) γ q → BR(t

5

10

4

10

3

10

2

10

1

10 1 qZ) → BR(t

5

10

4

10

3

10

2

10

1

10 1

LEP

(q=u only)

ZEUS

(q=u only)

H1 D0 CDF )

1

ATLAS (2 fb )

1

CMS (4.6 fb ATLAS preliminary (simulation) extrapolated to 14 TeV:

1

300 fb (sequential)

1

3 ab (sequential)

1

3 ab (discriminant)

95% C.L. EXCLUDED REGIONS

)

4

cH) (x10 → Br(t 1 1.5 2 2.5 3

S

CL

3

10

2

10

1

10 1

ATLAS Preliminary

s = 14 TeV √ ,

1

L dt = 3 ab

∫

cuts

T

Expected, tight jet p cuts, conservative bkg

T

Expected, tight jet p cuts

T

Expected, loose jet p cuts, conservative bkg

T

Expected, loose jet p

95%

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Conclusion

26

Aim for SM precision studies and BSM searches  with 300 fb-1 (LHC) and 3000 fb-1 (HL-LHC) at ATLAS and CMS. Potential observation of the processes related with ‘flavors’:  ttH, H→bb, H→µµ, Bd→µµ, … Potential CP-violation measurement of Bs→J/ψφ, … Increased luminosity (5-7 x 1034 cm-2s-1) provides a significant  challenge for the experiments. High radiation dose, pileup, particle rate, and event rate. Overcome the difficulties by the upgrades in various aspects.

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Backup Slides

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Calorimeter

28

ATLAS Phase 2

Maintain required performance under HL-LHC conditions  and therefore do not need replacement with possible exception for FCal. FCal replacement with high-granularity one (100 µm gap) under discussion. Addition of timing detector (intrinsic resolution O(10) ps) under discussion.

LAr: radiation hardness

CERN-LHCC-2015-020; LHCC-G-166

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Calorimeter

29

CMS Phase 2

Radiation dose at 3000 fb-1 for the scintillating tiles

f the endcap hadron calorimeter

will reach up to 300 kGy  — response degradation expected.

CERN-LHCC-2015-010; LHCC-P-008

For the new endcap calorimeter, exploit advances in silicon detectors in terms of cost per unit area  and radiation tolerance. The silicon sensors to be used  will be simple, large area, and  single-sided.

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Muon spectrometer

30

CERN-LHCC-2013-006; ATLAS-TDR-020

Current drift tube chambers: inefficiency and resolution degradation

with hit rate above 300 kHz/tube.

Impact on the endcap inner layer with L > 1034 cm-2s-1.

ATLAS

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Muon spectrometer

31

CMS Phase 2

(i) new irradiation tests must be performed to confirm that all types of existing muon detectors will survive the harsher conditions.  (ii) additional muon detectors in the forward region 1.6 < |η| < 2.4 to increase redundancy and enhance the trigger and reconstruction capabilities.  (iii) extension of muon coverage up to |η| = 3 or more behind the new endcap calorimeter to take advantage of the pixel tracking coverage extension. Possible additional chambers GEM — micro-pattern gas amplification detector RPC — time resolution of ~100 ps for pileup mitigation

CERN-LHCC-2015-010; LHCC-P-008

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Higgs couplings

32

Scenario 1: all systematic uncertainties unchanged. Scenario 2: improved theoretical/systematic uncertainties.

CERN-LHCC-2015-010; LHCC-P-008. ATL-PHYS-PUB-2014-016.

i

y

3

10

2

10

1

10 1 Z W t b τ µ ATLAS Simulation Preliminary

= 14 TeV s

ν l ν l → WW* → 4l, h → ZZ* → , h γ γ → h γ Z → , h µ µ → bb, h → , h τ τ → h ]

µ

κ ,

τ

κ ,

b

κ ,

t

κ ,

W

κ ,

Z

κ [ =0

i,u

BR

1

dt = 300 fb L

∫

1

dt = 3000 fb L

∫

[GeV]

i

m

1

10 1 10

2

10 Ratio to SM

0.8 0.9 1 1.1 1.2

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Bs,d→µµ

33

Without trigger upgrade,

unsustainable event rate at HL-LHC.

Track trigger with upgraded CMS

detector plays an essential role.

Invariant mass mµµ resolution at

Level-1 trigger expected: ~70 MeV.

Level-1 trigger rate expected:

a few hundred Hz (<< 1 MHz).

(GeV)

µ µ

m

4 5 6

Events / (0.02 GeV)

1 10

2

10

3

10

4

10

5

10

6

10

7

10

8

10

CMS Simulation

µ

+

µ →

s

B

µ

+

µ →

d

B Background Total signal

1

Scaled to L = 3000 fb L1TrkMu (PhaseII) Trigger ) > 3 GeV µ (

T

p )| < 2 µ ( η | ) > 4 GeV µ µ (

T

p )| < 2 µ µ ( η | )| < 1 cm µ µ (

z

d ∆ | ) < 6.9 GeV µ µ 3.9 < m(

at Level-1 trigger

CERN-LHCC-2015-010; LHCC-P-008. K. F. Chen, EPS-HEP 2015.

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Bs→J/ψφ

34 Opposite-side tagging studied and calibrated  by B±→J/ψK± (flavor provided by kaon charge). Di-muon trigger with pT > 11 GeV (both muons)  assumed at ATLAS at HL-LHC. Systematic error of Run 1 analysis: uncertainties in flavor charge tagging, likelihood fit modelling, trigger efficiency determination, contribution of B→J/ψK* decays, inner tracker alignment — will benefit from the larger data samples.

ATL-PHYS-PUB-2013-010

Number of reconstructed PV 10 20 30 40 50 60 70 80 90 100 ) [ps]

s

(B

τ

σ 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2

> = 20 µ ATLAS 2012 < > = 60 µ IBL Layout 11,11 < > = 200 µ ITK Layout 11,11 <

ATLAS simulation Preliminary

Run 1 Run 2, …

Slight στ increase (14%) in Run 2 with number of primary vertices — but stable at > 40.

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t→qH

35

arXiv:1509.06047v2 [hep-ex]

Current 95% CL upper limit on the branching ratio at the order of 10-3.