SLHC Upgrades CMS Perspectives Physics cases Global overview

SLHC Upgrades CMS Perspectives Physics cases Global overview of CMS upgrades Roadmap/Strategy 16 October 2006 J. Nash - CMS Upgrade Perspective 1

SLHC Physics: Extra gauge bosons • SLHC extends reach for Z’ – Cross sections fall with E – SLHC gives access to higher E • Good electron resolution required (including understanding saturation) 16 October 2006 J. Nash - CMS Upgrade Perspective 2

SUSY searches - measurements • SLHC statistics will be vital in reaching understanding of complicated SUSY channels Reach vs luminosity, jets + Etmiss channel – Sparticles seen, but statistics for reconstruction limited at LHC • Performance of the detector here is vital – B-tagging – Lepton id 16 October 2006 J. Nash - CMS Upgrade Perspective 3

What if no Higgs is found? • Will need to look at WW scattering – Some mechanism required to avoid unitarity violation • Forward Jet Tagging Essential Fake fwd jet tag (| | > 2) probability from pile-up (preliminary. . . ) ATLAS full simulation 3000 fb-1 (SLHC) 16 October 2006 J. Nash - CMS Upgrade Perspective 4

LHC performance and parameters CARE-HHH n = 3. 75 mm in all the options 16 October 200627 June 2006 - J. Nash - CMS Upgrade Perspective. W. Scandale, LHC luminosity and energy 5

CMS from LHC to SLHC 1032 cm-2 s-1 1034 1033 1035 I. Osborne With 88 evts/xing 16 October 2006 J. Nash - CMS Upgrade Perspective 6

CMS Upgrade Issues • • These upgrade scenarios put different constraints on the detector – 12. 5 ns or 75 ns beam crossings • 12. 5 ns reduces the pile-up in the detector, although out of time pileup is an issue for detectors (cross-talk from previous bunch) • 75 ns puts a very large pile-up, but is “easier” for some of the electronics to cope with (no out of time pile-up - use 25 nsec electronics) Detector issues – Effects on Calorimetry • Noise from pile-up: Bkgd noise increases by 2 -5 times • Jet and e, gamma resolution worse • Forward jet tagging - may be compromised by IR changes – Tracking • Pattern recognition, vertex resolution • B-tagging - how much worse with extreme pile-up? – Trigger • 12. 5 ns pushes some of the front end capabilities 16 October 2006 J. Nash - CMS Upgrade Perspective 7

Radiation environment for trackers Innermost layers will require new sensor technology (1016 N/cm 2) R. Horisberger 16 October 2006 J. Nash - CMS Upgrade Perspective 8

Tracker occupancy 1034 (18 Min Bias) Do we want/need an analog or digital readout tracker? 16 October 2006 1035 (88 Min Bias - 12. 5 nsec BX) R (cm) <Nch>/cm 2/12. 5 ns <Nch>/ (1. 28 cm)2/12. 5 ns 8 2. 41 3. 94 11 1. 47 2. 41 14 0. 97 1. 59 J. Nash - CMS Upgrade Perspective A. Rose 9

Tracking with 500 min Bias events • • • Study of current CMS tracker for Heavy Ion events Track density very similar to 75 ns running – dnch/d /crossing ≈ 3000 – – Tracker occupancy very high Need more pixel layers Inner layers of strips reach 30% occupancy on every xing! Tracking possible – – When tracks are found they are well measured Efficiency and fake rate suffer Momentum Resolution Pixel layers Transverse Impact Parameter Resolution • Efficiency nhit > 12 o Fake Rate 16 October 2006 J. Nash - CMS Upgrade Perspective C. Roland 10

B-Tagging • Pile-up overlaps with High Pt event faking a displaced vertex – – • B-tag performance depends on – – – • 12. 5 ns dnch/d /crossing ≈ 600 and ≈ 3000 tracks in tracker acceptance 75 ns dnch/d /crossing ≈ 3000 and ≈ 15000 tracks in tracker acceptance Vertex resolution Luminosity/bunch crossing Size of luminous region (how far apart are the min-bias events) For 75 ns option expect 2 -3 min-bias events within 200 mm of any interesting event. – – Need simulation to understand how much this reduces b-tagging efficiency All this pushes for larger area of Pixel coverage, need to look at pixel size as well 16 October 2006 J. Nash - CMS Upgrade Perspective 11

Level 1 Trigger has no discrimination for PT > ~ 20 Ge. V/c • The trigger/daq system of CMS will require an upgrade to cope with the higher occupancies and data rates at SLHC • One of the key issues for CMS is the requirement to include some element of tracking in the Level 1 Trigger – There may not be enough rejection power using the muon and calorimeter triggers to handle the higher luminosity conditions at SLHC – Adding tracking information at Level 1 gives the ability to adjust PT thresholds 16 October 2006 J. Nash - CMS Upgrade Perspective 12

Tracking Trigger? 1 mm (y-z) 1 cm (y-z) Geometrical p. T-cut - J. Jones, A. Rose, C. Foudas LECC 2005 High momentum tracks are straighter so pixels line up γ Search Window • Why not use the inner tracking devices in the trigger? – Number of hits in tracking devices on each trigger is enormous – Impossible to get all the data out in order to form a trigger inside – How to correlate information internally in order to form segments? • Possible topic requiring substantial R&D – “Stacked” pixels which can measure p. T of track segments locally • Two layers about 1 mm apart that could communicate 16 October 2006 J. Nash - CMS Upgrade Perspective 13

Implementing stacked layers • Single stacked layer gives a PT cut • Two stacked layers give a PT measurement Cooling System Optical Transceiver Correlator ASIC Optical fibre to Opto. TX card 16 October 2006 Flip bonded sensors Kevlar-Carbon Fibre Laminate Support Structure Thermal Epoxy J. Nash - CMS Upgrade Perspective 14

Key issues for tracker upgrades • • Power – How to get current needed to the electronics – More complicated front ends will want more power • DC-DC converters, Serial powering Material Budget – Can we build a better/lighter tracker? Tracker R&D focus – – – 16 October 2006 Performance and detector layout Sensor material and operation Outer tracker readout system definition Pixel system and triggering Manufacture and material budget J. Nash - CMS Upgrade Perspective 15

Calorimeters/Muons • ECAL – Crystal calorimeter electronics designed to operate in SLHC conditions – Electronics for barrel is not accessible without disassembly of the barrel HCAL – Scintillator may suffer damage for >2 • R & D required • Finer granularity – HF some very high towers lost • HF and shielding system issues with new insertion • • MUON – • system front end electronics look fairly robust at SLHC Trigger electronics for the muon systems would most likely need to be replaced/updated – Some Electronics is “less” radiation hard (FPGA) – Coping with higher rate/different bunch crossing frequency – May have to limit coverage in ( > 2) due to radiation splash • This effect will be known better after first data taking, potential additional cost of chamber replacement 16 October 2006 J. Nash - CMS Upgrade Perspective 16

Issues with Bunch crossing timing • • Assume new tracker and trigger electronics can cope with the choice of bunch timing Electronics for other detectors – – – • Situation for 12. 5 ns or 25 ns very different from 10 ns or 15 ns – – – • ECAL - not easily accessible HCAL - can be changed MUONS - can be changed Electronics clocked at 40 Mhz QPLL which synchronizes links to this clock has a very narrow frequncy lock Can clock system at 40 Mhz and cope with 12. 5 ns 75 ns should not be a problem 16 October 2006 J. Nash - CMS Upgrade Perspective 17

Ideas on a new tracker concept? • Strawman - A much larger pixel tracker, some triggering layers, more segmented strips TOB – 10 cm layer with current pixels (500 Ch. F/cm 2) • Around 1 m 2 TIB – 20/40/60 cm layers with bigger pixels (100 Chf/cm 2) PD • around 25 m 2 • 25 MChf – Outer layers long pixels/short strips (30 Chf/cm 2) • Around 170 m 2 • 50 MChf – Some triggering layers. • 1 layer for Pt cut only or 2 layers to measure Pt • Or perhaps full scale hardware pattern recognition? • This is the at the limit of affordability - How much can we re-use? – Can we use the TOB mechanical structures (a copy at least) – Can we re-use services – Re-use of some of the TOB - at least the concept if not the actual modules 16 October 2006 TOB TIB TEC TID PD J. Nash - CMS Upgrade Perspective 18

Roadmap for tracker/trigger upgrades • Within 5 years of LHC start – New layers within the volume of the current Pixel tracker which incorporate some tracking information for Level 1 Trigger • Room within the current envelope for additional layers • Possibly replace existing layers – “Pathfinder” for full tracking trigger • Proof of principle, prototype for larger system – Elements of new Level 1 trigger • Utilize the new tracking information • Correlation between systems • Upgrade to full new tracker system by SLHC (8 -10 years from LHC Startup) – Includes full upgrade to trigger system 16 October 2006 J. Nash - CMS Upgrade Perspective 19

CMS Detector Replacements Inner Tracker Outer Tracker Level 1 Trigger DAQ Other Front Ends Infrastructure 30 MChf 90 MChf 20 MChf 10 MChf 15 MChf Total 175 MChf Across collaboration Materials Cost for Collaboration (CORE) ~ 900 FTE 16 October 2006 J. Nash - CMS Upgrade Perspective 20

SLHC R&D: Next steps • Expression of Interest – Reasonably brief document (40 pages) • – – Brief case for upgrade Outlines scope of upgrade work • – • What detectors/Timescale To be submitted by End 2006 • – Section authors identified Circulated to collaboration September CMS Week Prepare funding agencies Letter of Intent – – – A larger document More complete physics case Includes organization and rough costings of detector work • – Submitted to LHCC • – 16 October 2006 Including how CMS will organize the effort Allow funding agencies to “release” funding Target Summer 2007 J. Nash - CMS Upgrade Perspective 21

Alternative IP Schemes dipole magnets dipole triplet magnets dipole first & small crossing angle triplet magnets dipole first & large crossing angle & long bunches or crab cavities • New options for IR optics consider bringing magnetic elements literally into CMS • Important to understand background induced in trackers • May have very severe consequences forward calorimetry 16 October 2006 J. Nash - CMS Upgrade Perspective 22

CMS IP Upgrade Triplet moves closer to IP Dipole inside end disks 16 October 2006 J. Nash - CMS Upgrade Perspective 23

Conclusions • SLHC will be a challenging machine for the detector as well as the machine • CMS at SLHC will require a substantially larger pixel detector – We may also need to understand how to form tracks with these detectors at 40 MHz as input to the Level 1 • R&D required is substantial – Needs to start now – Needs to be focused • Important to converge on tracker design requirements • Crucial input on machine designs affect the detector design • Physics will also have a role in defining the upgraded detector 16 October 2006 J. Nash - CMS Upgrade Perspective 24