INFN RoadmapWG Upgrade di luminosit di LHC (SLHC)

Convener: M. de Palma

M de Palma, WG SLHC

Out lineParticipantsPhysics issuesDetectors point of view (limited to those in which INFN is involved)Conclusion and question to WG

NB: WG have still not looked at trigger, DAQ and costs.

M de Palma, WG SLHC

ParticipantsTheorist: Frixione,Colangelo

Atlas: Laurelli, Dardo, Meroni, (ID), Citterio, Costa (ECAL), Del Prete (Hcal), Bagnaia, Nisati, Primavera (MU), DiCiaccio, Veneziano (Trigger) CMS: Messineo, Palla, Bisello (Tracker), Pastrone, Ragazzi (ECAL), Dalla Valle, Paoloucci, Zotto (MU)

LHCb: Bencivenni(Tracker), Lai(Elet.), Marconi(Trigger)

+ all expert and volounteers.

First meetings held the 17 Oct. and 14 Nov.Next meeting 24 Nov.

M de Palma, WG SLHC

Physics issuesThere hasn't been much of theoretical activity recently specially devoted to SLHC. There is of course a lot of work done for LHC, which will be fine for SLHC as well.

Main reference:SLHC physics and detectors: F. Gianotti et al., Eur. J. Phys. C 39 (2005) 293

Two (obvious) caveats:

The physics program of a luminosity upgraded SLHC will be mainlydetermined by the discoveries and the experience collected at LHC in a few years of running

Discussion is based on existing studies (starting point for subsequent work)

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Scenario

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Physics motivationTests of the SM:Multiple gauge boson production Triple gauge couplings

Higgs physics: Higgs pair production and trilinear coupling Couplings to bosons and fermionsRare Higgs decays

Scattering of VB: ( i.e. new strong interaction regime)

Susy:Heavy Higgs bosons of MSSM SUSY particle reach

Exotica:Heavy gauge bosons Quark compositenessExtra-dimensions

Tanks to S. Frixione and P. Colangelo

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Triple gauge boson couplings (I)Three- and (four) -vector-boson couplings are a direct consequence of the non-abelian gauge structure of the SM. In the SM they are uniquely fixed, extensions to SM induce deviations (form factors are introduced -> scale of new physics)LHC favourable channels : W WZ 5 parameters introduced to describe TGCs: g1Z (1 in SM), kz, k, , z (0 in SM) W probes k , and WZ probes g1z, kz, z Expected sensitivity to TGC, 95% CL constraints, ATLAS

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Triple gauge boson couplings (II)Correlations among parametersSLHC improves LHC results by at least 50%14 TeV 100 fb-1 LHC

28 TeV 100 fb-1

14 TeV 1000 fb-1 SLHC 28 TeV 1000 fb-1

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Higgs pair production and self coupling (I)Two Higgs radiated independently (from VB, top) and trilinear self-coupling terms proportional to HHHSM. Higgs self-interactions fully determined in the SM after fixing mH Tests of SM EWSB sector

qq ->VHHqq -> qqVV -> qqHHvery small cross sections, hopeless at LHC (1034), hope at SLHC

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Higgs pair production and self coupling (II)Probably a strongest physics case for SLHC A delicate counting experiment: background control essentialCross sections for Higgs boson pair production in various production mechanisms and sensitivity to HHH. Arrows correspond to variations of HHH from 1/2 to 3/2 of its SM valueATLAS: preliminary study for SLHC (1035 cm-2 s-1) a first measurement of HHH is possible (170 < mH < 200 GeV) better than 25%.

gg HH W+ W W+ W jj jjwith same-sign dileptons

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Scattering of vector bosonsIf no (light) Higgs, anomalies should appear in VB scattering: deviations in WW scattering resonance productionThis should be a possible onset of a new strong interaction regime Vector resonance (r-like) in WLZL scattering from Chiral Lagrangian (BESS) modelScalar resonance in WL WL, ZL ZL -> ZL ZL scattering (BESS model)Preliminary results indicate that these should be observable at SLHC, but not at LHC A discovery" at SLHCA counting experiment; good background knowledge mandatoryDetectors must have good jet-tagging and jet-veto capabilities

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Heavy Higgs bosons of MSSMThe MSSM features a rich Higgs sector (h;H; A;H). The discovery of its heavy part could be beyond reach at LHC for large mAMSSM parameter space regions for > 5 discovery for the various Higgs bosons (both experiments combined)green: region where only one (the h, SM-like) among the 5 MSSM Higgs bosons can be found (assuming SM decay modes)A 95% C.L.exclusion boundary is a further ~ 50 - 100 GeV to the right of the discovery boundarySLHC 3000 fb-1LHC 300 fb-1

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SUSY particle reachSLHC improves LHC reach for up to 0.5 TeV (to ~ 3 TeV in mass) with inclusive searches.

But this is just the reach: the main advantage of increased statistics should be in the sparticle spectrum reconstruction possibilities. Some exclusive searches be come possible at SLHC Higher integrated luminosity obvious increase in mass reach in searchesBut for decay studies good detector performances are needed: lepton, jets, Emiss, b-tagging

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Heavy gauge bosonsAdditional heavy gauge bosons (W,Z-like) are expected in various extensions of the SM symmetry group (LR,E6,SO10..), with couplings to leptons ~ similar to SM W,ZZ production and Z width(assuming same BR as for ZSM)Expected backgrounds from Drell-Yan and tt production at the few % levelFor high mass objects electrons more usefull than muons - thanks to better resolutionWith 10 events to claim discovery, reach improves from 5.3 TeV at LHC to 6.5 TeV at SLHCEx. sequential Z model

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LHC luminosity profile vs physic casescm-2s-1 De Negri

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Physics summary

Significantly increased physics reach in all typical LHC physics channels.

These improvements are, at least, better measurements and better exploitation of the LHC energy domain and make the LHC upgrade very attractive and an obvious next

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SLHC ScenarioThe most relevant SLHC parameter for experimental apparatus are:(from W. Scandale talk) BCO interval: (?)25ns, 15ns, 12.5ns, 10ns Forward area:The closest machine element will be move towards the IP Timescales: Assume 20142 years Environment : Increased radiation levels (and resulting activation)

The luminosity will increase as function of time at LHC, we will need to upgrade the detectors in time to take the maximum advantage of this.We know that some parts of the detector systems might have performance problems or operational problems, and therefore interventions and improvements are require.

Issues: Radiation damage Pileups of MB events Bunch spacing and trigger Timing

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Basic assumption for detector up-grade

To take advantage of a luminosity increase the detector performance of ATLAS and CMS have to be kept at foreseen actual level ( i.e tracking, b-tagging, vertexing, energy resolution and momentum measurements)

The detector changes have to be reasonable. We cannot replace the entire detectors for obvious reasons of cost and time.

One would like to keep as much as possible of the existing large items (calorimeters, muon systems, magnets, cooling, gas, cables, pipes, support structures, movement systems, cryogenic systems, etc).

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work are already started In the experiment;ATLAS: Steering Group established, two workshops in Feb and July 2005.Plan to organise R&D with Steering Group and Project Office as part of technical coordination to ensure coherence.

CMS: Three workshops on SLHC; Feb 2004, July 2004, July 2005. (next Apr 06)To assist in the R&D project definition, already agreed CMS peer-review scheme. Main lines identified:Tracker & TriggerMicroelectronics and PowerOptoelectronics & data architecturesand ouside experiment ( also inside INFN-G5 programs) RD50 in the area of radiation hard sensor R&DActivity on rad-hard electronics Simulation study ....and could be that those attivities faster increase with the end of construction tasks of the LCH experiment

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ATLAS - Muon system from P.Bagnaia, L. NisatiThe detector performance should be Okwith a acceptable degradation of the spatial resolution.

The Front-end electronic should be Okwith some problems with high rate but on DAQ side.

Also the LV1 electronic should be Ok If BC < 25 ns If the trigger decision can be taken on 2 and BCID done al LVL2

Single tube resolution(bck x 5, x 2 worseningfor charge fluctuation) MDTMuon system designed with a 5 safety margin on bck rate

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ATLAS - Muon system from A. Di Ciaccio

All along the test (8 ATLAS year, safety factor 5 = 100 Hz/cm2), chamber performance (efficiency, cluster size, rate capability) have remained largely above the actual ATLAS requirements and cover the SLHC request. (provided that Temperature, RH of the environment and gas mixture are kept at a proper value)

The detector performance should be OK

Since all tests have been done with final Front-end electronic that should be also OK (without safety factor on bkg level)At SLHC additional shielding and beryllium beam pipe should be inserted to further decrease (x 2 reduction) the background rate The expected rate in the Barrel muon system could be estimated ~50-100 Hz/cm2SLHCRPC RPC efficiency after 7 ATLAS yearFew Hz/cm2500 Hz/cm2

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CMS - Muon system from M. Dallavalle

MDT The detector performance should be Ok but study on general ageing are still needed.

Since chamber will demand higher currents than now available,HV PS system would require some upgrading

SLHC would require a full redesign of the trigger and readout electronics, in new technologies to cope with radiation environment, (and to be able to operate at 80 MHz)

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CMS - Muon system from P. Paolucci

BARREL: muon rate ~10 Hz/cm2, n and < 40-50 Hz/cm2ENDCAP: muon rate ~10 KHz/cm2, n and < 10 KHz/cm2RPC GIF Test on production chamber (equivalent to ~ 15 CMS years) have shown good efficiency and stable current

The detector performance should be Ok but without safety margin, more studies needed

Front-end work up to 5 MHz Ok

Trigger electronic should be Ok but it is at limit.

Situation is very different for End-Cap where even the detector technology is no more adequate

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Atlas LAr Calorimeter from M. Citterio The liquid argon calorimeter was optimized for the nominal LHC luminosity, a x 10 increase of this luminosity would rise concerns on:

Space charge effects signal reductionArgon contamination signal reductionCharge density increase pile-up Activation noise increasephase instability operation problemsVoltage drop in the HT distribution rate dependent responseGeneral radiation damage of electronics single element (now built in 13 different ICs) could not be changed (next slide)The high occupancy of SLHC require a new read-out chain designA BC rate > 40 MHz require new pipeline

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32 SCA16 ADC8 GainSel1 GLink1 Config.2 SCAC1 SPAC1 MUX32 Shaper1 TTCRx7 CLKFO14 pos. Vregs+6 neg. Vregs2 LSB32 0T128inputsignals1 fiber to RODAnalogsumsto TBBDMILLDSMAMSCOTS2 DCUTTC,SPACsignalsOverview of main components on a FEB

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Atlas LAr Calorimeter(II)15Those affects as expected to be non critical and, since it is impossible to change the detector, we have to survive. More study to drive an optimization strategy are needed. Detector is assumed to be Ok

The HV system will be revisited and HV filter must be redesigned to reduce the rate fluctuation response and noise.

79 A complete new architecture of the read-out system is needed.

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Atlas -Tile hadron calorimeter from T. Del PreteDetector should be OKA decrease of the light budget produces a degradation of the energy measurement (3-5%) which effects Jet Energy Reconstruction. /E 10% @1034 30% @ 1035 for Ejet = 100 GeV

All Electronic components have been tested above the rad doses for 10Y @ 1034 . They should survive 5Y @ L = 1035 but no NO safety margin.Some part: (Mother Boards, Digitisers, Interface..) are more rad-fragile

If SLHC needs to increase BC rate, all the F/E logic has probably to be redesigned.

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CMS EM Calorimeter from N. PastroneCrystalThe dose in the Barrel ( = 2.4) goes from 0.15 Gy/h @ 1034 to 1.5 Gy/h, in the EndCap it reaches 30 Gy/h at = 2,6 and 75 Gy/h at = 3. Those produce at SLHC a significant change in LY: drops by ~25% in barrel, 30% Endcap.In EndCap we are close to the saturation condition.

Still more study are needed ( irradiation test, calibration study)

LY for different densities of colour centres( Radiation damage increase colour centres)

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CMS EM Calorimeter (II)PhotosensorsIn Barrel, sensible increase of leakage current (130 A at SLHC) of APD is expected. It translates in large increase in electronic noise ( ~190 MeV per channel with respect to ~ 40 MeV al LHC) (study performance with higher n fluxes)In Endcap, VTP glass window has to be tested at the expected dose.

In conclusion:Considering work for disassembly and refurbishing (at least 2 years) and the costs involved, ECAL barrel could be used even with a degradeted performances (to be studied !) due to decrease of LY, increase of noise and pileup.

For the Endcap, the situation is more difficult.

Read out chain should be OK for BC 2 X 40 MHz

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Inner tracking detector The limiting factor for the detector lifetime will be radiation damage, which is mainly a function of the integrated luminosity. Assuming 3000 fb-1 at SLHC ( x 6 the integrated luminosity for which currently planned silicon system has been designed) the hadrons fluence and radiation dose at different radius are:Cumulative effects (NIEL, TID) increase by a factor 5 Instantaneous effects (occupancy, SEU) increase by a factor 10General consideration:LHCSLHC

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Inner tracking detector The silicon sensor, both strip and pixel, would suffer substantial radiation damage strongly degrading the performance.For the electronic, the situation is somewhat more favourable but similar.Most of material (frames, glues, insulators etc.. are not tested to the dose above. The inner detector system must be completely rebuilt, both for ATLAS and CMSThe bunch timing should have a strong impact on tracker project, both on sensor and electronic. Shorter Bunch give less occupancy but requires better time resolutionGeneral considerations:Information for Atlas came from a 3 days dedicated Workshop (18-20/07/2005) in Genova: http://atu-2005.ge.infn.it/ while the CMS comments presented here are only representative of our present thinking.

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Trackers Sensor Material issues

SubstrateOuter layers, silicon looks promisingn+-in-n (as for today pixel), p-type floating zone FZ (50% cheaper, need single side processing) for strips Oxygen doped, Magnetic, High resistivityInner region - no proven alternative to silicon yet - but are other materials possible?PerformanceSeries noise (Cdet) can decrease but parallel (Ileak) may not (Ileak ~ strip length, thickness, particle fluence)Charge collection, high bias voltage (>1000 V), S/NStructurePixel and pixel 3D, short strips, 2D detectors (stripxel), SS, DSPower dissipationManufacturability

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Trackers Electronic issuesVery rad-hard electronics Single Event Upset (SEU) will be a serious problems.

Technology and design 0.13 m or smaller CMOS for Pixel, BiCMOS e CMOS per strips:

Data rate / opto-links:

Power scheme

Trigger (with muon system, very appealing but difficult, some ideas from CMS)

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Trackers design issuesDimensions sensor size, finer pitch, number of different nodule type,.

Ease of handling and assemblyWe must minimize handling - could this be done by industry?Should be base units still the Module or Stave or Sector (could high integration give yield problems)?

Module construction

Integration (still to proof al LHC!)

CostPresent design originates in bottom-up approach, underestimates many costs and difficultiesNeed we approach !

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ATLAS Tracker, from G. Darbo Number of layers 811 (most probably 10):

Inner layer: Pixel, 34 layers, 300400 m x 50 m, 2.93.7 m2. Middle layer: short strips or stripxel, 34 layers, 3.5 cm x 80 m, 2127 m2.

Outer layer: strips, 24 layers, 9 cm x 80 m, 116 327 m2.

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CMS Tracker from F. PallaInner part (R< 60cm) Pixel layersPixel system 1 - 1 layer at radius about 7 cmChange detector more often (annually)Improve fluence limit of sensor. Need to study sensors more RD50 activity fundamental research rather than development)

Pixel System 2 - 2 layers at 18 and 22 cm ( need cheaper pixel technology) Single sided pixel detectors, n+ on p Silicon (Czochralski) Large Module size, e.g. 32 x 80 mm sensitive areaPixel area ~ 160 mm x 650 mm

Pixel System 3 - 3 Layers 30, 40 and 50 cmMacro pixel detectors of 1 mm x 1 mm/ Micro strips of 200 mm x 5 mm Simple DC coupled p+ on n Silicon detector

External part ( R> 60cm) strip layerStrip System 3-4 Layers fro 60 to 110 cm About similar to present one

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Schedule The WG idea about time:

2006-2008 General R&D program ( maybe shared with other programs (ILC, -factory, etc)

2009-2010 Definition of detector upgrading design within clear SLHC machine project.

2010-2012 (?) Prototypes, modules 0, start of construction

2012- 2015 (?) Construction

2015(?)- 2017(?) Assembling, integration, commissioning.

Running

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Conclusion The Inner Detectors will need to be replaced (the actual have been designed for a lifetime of 10 years at 1034).

Ageing and space-charge effects of calorimeters and muon chambers, due to the radiation and activation levels increase, need to be studied in more detail to point out the optimization and/or modifications needed with the goal to change as little as possible. The read-out electronic chain in some case, need to be replaced

Depending on the chosen BCO frequency - the impact on the existing electronics can change significantly.

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Questions to WG (I)

Physics case

Competition and competitivity

Interest of INFN teams involved in LCH exp. to participate ad SLHC: On same item On new item

Needed upgrade to the different detectors in both exp. considering the different LHC upgrade scenarios

There is!

No competitors are foreseen in the SLHC time scale

At moment, all team show interest toward SLHC on the same LHC item

Subject of firsts WG meetings, we have reported here

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Questions to WG (II) Within the different LHC upgrade scenarios and after the first LHC results when (and how) decide to start: the dedicate R&Dthe experiment upgrade(a later start of dedicate R&D could compromise the detector upgrade)

Within the different LHC upgrade scenarios versus SLC:The detector up-grade costTheir share(?)The dedicated R&D cost

Two experiment remain general purpose experiments. Still two experiment are needed.

More detail should be point out in next meetings..

next meetings ..

at moment, seem yes

seem yes

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Other physics case

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Higgs couplings to fermions and bosonsCombining different production mechanisms and decay modes get ratios of Higgs couplings to bosons and fermions. Ratios of rates are theory-independent measurements; i.e. are independent form tot Higgs, H, and Lint.It is mostly statistics limited at LHC therefore should benefit from SLHC luminosity increase provided detector performances are not significantly reduced.

At the SLHC the ratios of Higgs couplings should be measurable with a ~ 10% precisionfull symbols: LHC (300 fb-1 per exp)open symbols: SLHC (3000 fb-1 per exp)

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Multiple gauge boson production Test of high energy behaviour of weak interactionsW and Z -> leptons cleanest channel, but the rates are limited at LHC -> SLHCexpected numbers of events in purely leptonic final states, 3 and 4 Vector Boson production, SLHC 6000 fb-1 (lepton cuts: pt > 20 GeV, || < 2.5, assumed reconstruction efficiency 90%)WZZ -> 5 leptons, ZZZ -> 6 leptons accessible at SLHC WWWW -> 4 leptons could allow to put limits on 5-ple coupling (zero in SM)

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Higgs rare decaysIncreased statistics would allow to look for rare decay modes (difficult to observe at LHC). A couple of cases with BR=O(10-4) have been considered.

HSM Z +-

At the LHC (300 fb-1/experiment) signicance is about 3.5 At the SLHC (3000 fb-1/experiment) signicance is about 11

HSM + -

Impossible to discover at the LHC (significance

CompositenessQuarks (and leptons) may be composite structures, bound states of preons", whose interactions are characterized by a mass scale Symmetry considerations imply that > O(1 TeV)Effect of compositenessA counting experiment: deviation in high-pT SM jet productionangular distribution of the jet pairs from QCDMay not be observed at LHC, but evidence at SLHC

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Extra-dimensionsTheories with extra dimensions lead to expect characteristic new signatures /signals at LHC/SLH. Various models exist and their scales are completely unknown.

As a result, an immense spectrum of possibilities opens up in a high-energy regime.

Strategies are typically based on (direct or indirect) graviton and/or on Kaluza-Klein excitation searches, and generally involve dileptons orjets plus missing ET signals.

The signatures are expected to be spectacular, and detectorperformances are probably less crucial than elsewhere.

All this is very, very, very speculative. But it's probably the most ground-breaking discovery LHC/SLHC can possibly make.

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