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Prospects for tagging at high luminosities at LHC

Marek Taševský (Inst. of Physics Prague)

Forward physics - Prague 30/01 2008

Forward and diffraction physics

FP420 project

RP220 project

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Energy flow and acceptance

Energy flows forwardsand undetected by central calorimeters

Main

CMS/ATLAs

detectors

Lots of interesting physics would remain undiscovered

Equip the forward region by detectors

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Rich program for Forward Physics

Diffraction

F2p at very low x

Two-photon interactions

- Absolute lumi calibration- Calibration, resolution for FPS- Factorization breaking in hard diffr.

Underlying event/Multiple interactions

Long dist. Correl. in rap.(need to cover fwd region)

Huge differences for diff.generators and diff. tunes

Average mult. transv. to leading jet at LHC

Saturation at very low x ?

Evidence for CEP?

[C.Buttar et al., HERA-LHC proc.]

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Central Exclusive Diffraction: Higgs production

b, W

b, WH

- Khoze, Martin, Ryskin hep-ph/0111078- Central system is 0++

- If you see a new particle produced exclusively and with proton tags you know its quantum numbers- Roman Pots give much better mass resolution than central detectorDiscovery difficult in SM but well possible in MSSM

Pile-up is issue for Diffraction at LHC!

But can be kept under control !

5sigma contours:H→bb, mhmax scen., μ=-500GeV [Heinemayer, Khoze, Ryskin, Stirling, M.T., Weiglein]

Log S/Bpu

Offline cuts

Rejectionpower

[CMS-Totem : Prospects for Diffractive and Fwd physics at LHC]

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Forward detectors at LHC

14 m 16 m 14 0 m 1 4 7 m - 2 2 0 m 4 2 0 m

I P 1

I P 5

TOTEM -T2 CASTOR ZDC/FwdCal TOTEM-RP FP420

LUCID ZDC ALFA/RP220 FP420

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Proton taggers for high luminosity

14 m 16 m 14 0 m 1 4 7 m - 2 2 0 m 4 2 0 m

I P 1

I P 5

TOTEM-RP FP420

RP220 FP420

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Proton taggers for high luminosity • At CMS: TOTEM: Roman Pots at 147 and 220m Excellent coverage in and t at low luminosity optics (*=90, 1540m) [talk of M.Deile]Coverage 0.02<<0.2 at high luminosity optics (*=0.5m)

• At ATLAS: RP220 Roman Pots (of Totem design) at 220m Coverage similar to TOTEM at high luminosity optics

• At CMS and ATLAS: FP420: R&D project, aim to instrument region at 420m 0.002<<0.02 (high luminosity optics only)

detectors@420m

FP420

TOTEM-

RP220

xL=P’/Pbeam=

Log

Logt

*=0.5

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Michigan State Univ.

Univ. of Chicago, Argonne (timing det.)

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TOTEM on CMS sideRP220 on ATLAS sideFP420

How to measure the protons

• Cold region of LHC• Too far for L1 trigger FP420

(ATLAS)

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Roman Pot acceptances for Totem and CMS

[CMS-TOTEM: Prospects for Diffractive and Fwd physics at LHC]

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Acceptance for RP220 and FP420 at ATLAS

[W.Plano and P.Bussey, FP420]

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Integration into LHC structure Diffraction protonsdeflected horizontallyand away from the ringOnly horizontal pots from outside needed!

BEAM 2

Diffractionp’s deflectedhorizontallybut insidethe ring

[A.Kupčo, RP220]

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Tracking - ResolutionsRequirements:

Close to the beam => edgeless detectors

High lumi operation => very radiation hard Beam en.smearing σE = 0.77 GeV

Few μm precision, 1μrad precision Beam spot smearing σx,y = 10 μm

Suppress pile-up => add fast timing det. Detector angular resolution = 1, 2 μrad

ATLAS, 1.5 mm (220) and 5 mm (420) from beam

[P.Bussey, FP420]

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First FP420 3D detectors

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Candidates for tracking detectors for RP220

• Baseline: “3D” Pixels detectors (S. Parker)Under development for FP420Stanford, VTT, Sintef

• Backup: Silicon strips:Experienced technologyCanberra, Hamamatsu

Jean-François Genat, RP220 meeting, Oct 17-19th 2007 Krakow, Poland

Readout chip (ATLAS)

50m strips (Canberra) Semi-3D detector (VTT, Finland)

3D (Stanford)

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Silicon strips tests in Prague (July 2007)

-5

0

5

10

15

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30 Current (nA)

1 31 61 91 121 151 181 211 Voltage (V)

One strip

Canberra detectors: Reverse current measurement depending on the strip position typically 25 nA OK.Further tests need a full detector wire-bonded and biased.Breakdown voltage 110-130 V OK

Jean-François Genat, RP220 meeting, Oct 17-19th 2007 Krakow, Poland

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3D Silicon detector layout for RP220

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3D Detectors Layout for Horiz. Pots

14 mm

240 mm

2 mmBeam

< 40 mm

Existing FP 420 modulesNo dead zone with 100m Y , and 3mm X overlaps

J-F Genat, RP220 Prague Meeting, Jan 24-25th 2008

Integration:Expertise at ManchesterFP420: Scott Kolya Ray Thompson

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Fast timing detectorsFast development on several fronts for several applications !FP420 and RP220 need to reduce PILE-UP background heavily

At least for H->bb: overlay of 3 events (2 SD + non-diffr. dijets) fakes signal perfectly and

with prob. 1010 x higher than signal. Can be reduced by applying strict central-matching-RP

conditions + fast timing det.

10ps (2-3mm) resol.

may separate different

vertices

Rejection of up to 40

FP420: UTA/ Alberta/ FNAL/ Louvain: first tests with Quartic det. RP220: collaboration with Univ. Chicago, Stony Brook, Argonne and Photonis see also workshop on timing det.: Saclay, 8-9.3.2007, http://www-d0.fnal.gov/royon/timing

200 GHz electronicsMultiChannel Plates Simul. tools

[A.Kupčo and M.T]

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Level 1 TriggerFP420: cannot be put directly into L1 – only in special runs with larger L1 latency

available triggers: 2j, μ (L1 threshold for 2μ is 3 GeV), e, j+lepton

- μ-triggers can save up to 20%

of bb signal

- WW signal saved by lepton triggers

RP220: Can be put into L1: A BIG added value to FP420! Very similar trigger rates

as for foreseen CMS-TOTEM L1 trigger:

CMS-TOTEM L1 trigger STUDY

RP220 L1 trigger study

Total reduction: 10 (RP) x 2 (jet isol) x 2 (2 jets same hemisph as p) = 40

ETjet > 40 && RP220-1side

[A.Pilkington,FP420]

[A.Kupčo,RP220]

[M.Grothe et al., CMS Note 2006-054]

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Machine induced background

Horizontal beam profiles for nominalbeam optics and momentum spread

σbeam1 = 250 μmσbeam2 = 180 μm

RP220: SIGNAL/Background ~ 10

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Design for RP220

Design for RP220 not yet fixed. Still need to consider:

1) Alignment and calibration: BPMs themselves should be quite precise (about 10 μm?). But we need physics processes to cross-check and also for the detector calibration. The price for that is high: 2 additional vertical RPs.

2) Fast timing detector: not enough space in the current RP (Totem) design because fast timing det. need large radiators to collect a good number of

photons → put movable beam pipe behind RP

3) Size of 3D-Si sensors: what is the best size of sensors in the (x,y) -region of interest wrt yield?

4) L1 trigger: 3D-Si: standard pixel trigger is just YES/NO for the full detector,while we need to know which strip is hit at L1 to measure ξ or mass at L1 →needs to develop a new trigger card. Si-strips: needs to include trigger in ABCNext chip, unfortunately not first

priority for CERN

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FP420 and RP220 Timetable

• FP420 is currently an R&D collaboration between ATLAS, CMS and

non-affiliated groups

• In addition, there is a strong complementary program to upgrade the

220 region with horizontal pots at ATLAS, which adds significant value

to FP420

• Proposal to ATLAS for a sub-detector upgrade in Spring 2008

for 420m and 220m upgrades

• If accepted by ATLAS (and/or CMS) this would lead to TDR from experiment to LHCC in Spring 2008

• FP420 cryostat and baseline detectors designed to be ready in Autumn 2009

• RP220 Roman Pots and baseline detectors designed to be ready in Autumn 2010

• Or RP220 on one side and FP420 on the other.

220m and 420m tagging detectors have the potential to add significantly

to the discovery reach of ATLAS and CMS for modest cost, particularly

in certain regions of MSSM. Besides the discovery physics, there is a rich

QCD and EW physics program

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B A C K U P S L I D E S

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RP220 in L1

[P. Le Du, RP220]