LHCb Upgrade

1. LHCb Upgrade • LHCb on the eve of the LHC • LHCb upgrade • The physics programme • NP opportunities at LHCb (10 fb-1) and beyond • The data taking opportunity • Increasing statistics by a factor 10-20 • The hardware challenge • Detector modifications needed • Schedule and Conclusions Paula Collins (CERN) On behalf of the LHCb collaboration LHCb Upgrade – P Collins Beauty 09, Heidelberg

2. LHCb: The Day 1 Experiment • bb production correlated and sharply peaked forward-backward • Single-arm forward spectrometer : 15-300 mrad • σbb ~ 500 µb in LHCb acceptance • Production of B+, B0, B, b-baryons.., • LHCb runs at L=2-5 1032 cm-2s-1by not focusing the beam as much as • ATLAS and CMS • maximizes probability of a single interaction per crossing • LHCb will go immediately to design luminosity • Mass resolution: 14 MeV • Time resolution: 40 fs • IP resolution: 14 + 28/pTmm • PID over 2-200 GeV • ~ 1012 bb pairs produced per year • Trigger goes from 40→1 MHz in hardware, then to 2kHz in software LHCb in numbers LHCb Upgrade – P Collins Beauty 09, Heidelberg

3. And in reality LHCb: in design Muon RICH2 TT HCAL ECAL Magnet RICH1 Tracker VELO Outer/Inner Tracker 3 3

4. LHCb 10 fb-1 NP physics highlights • Rare decays: Bs µµ • Direct search for NP • 3s measurement of SM prediction Mixing phase in Bs  J/yf (tree) • Sensitive to NP in mixing • Measure s (fs) ≈ 0.01 Mixing phase in Bs  ff (penguin) • Sensitive to NP in loops • Measure phase≠ 0 (=NP) with s≈ 0.035 CKM angle gfromBd  D/DK, Bs→DsK, Bd->Dp (tree) • Determine standard candle against which NP sensitive measurements can be compared • measurements to ~ 2° degrees • CKM angle g from Bd(s)→pp, KK (penguin), B→hhh • g_NPvs g_SM • Sensitive to ≈ 3° degrees CPV in penguins Bdf Ks: b vs beff • Sensitive to NP in loops • Sensitive to ≈ 0.1 Search for RH currents in radiative decays Bs fg ; Asymmetry FB of Bd  K* µµ • zero of AFB(s) to 7% D meson physics CPV, D-D mixing, rare decays e.g. D0→mm Santos Carson Leroy Leroy Reece, Belyaev Ricciardi Magnin LHCb Upgrade – P Collins Beauty 09, Heidelberg

5. Why upgrade? Or,Why Should We Fully Exploit LHCb b production? • There are hints of NP being just around the corner. If they are confirmed by LHCb e.g. in Bs→J/yf then the path forward is clear and the precision measurements must be pursued • If ATLAS/CMS discover NP, but the effects are more subtle in the flavour sector then we will need precise measurements to test predictions • Pursue channels statistically limited at current experiment e.g. Bs→ff • Keep pace with theoretical predictions which will improve with time e.g. e.g. indirect precision on g 2010: sg ~ 5o >2015: sg ~ factor 5 better thanks to significant improvements from lattice QCD? arXiv:0902.1815v33

6. Pushing the Precision Frontier • fs=-0.0360.002 rad one of the most precisely predicted CPV quantities in the standard model • If NP in the Bs sector turns out to be large, then LHCb upgrade will be needed • If it turns out to be small (as appears to be the case in the Bd sector) then precise measurement is needed to match clean prediction LHCb numbers are with J/y f alone Precision will be even better with other channels e.g. J/y fo(pp) Direct proportionality to ηleads to interesting constraint on UT LHCb precision, 10 fb-1 LHCb Upgrade – P Collins Beauty 09, Heidelberg

7. b→s penguins, a very promising place for NP to lurk Bs0→ff dominated by penguins: NP can enter in mixing box and/or in penguins CP violating asymmetry is zero, due to cancellation of mixing and decay phases At upgrade 0.6M events and error of 0.01 Intriguing pattern emerging, but existing precision poor LHCb and upgrade will clarify this picture Can be complemented by B0→fKs0 and family: At the upgrade we expect 20000 events and a precision of 0.02 LHCb Upgrade – P Collins Beauty 09, Heidelberg

8. Bs →mm and Bd →mm – an exciting future SM prediction is precise, and small! Blanke et al, JHEP 0610:003, 2006 This can be reached with 10fb-1 at LHCb. If NP gives significant enhancements then will be seen sooner! However: Certain models, e.g. MCPVMFV, can give enhancements but can also suppress the branching ration < SM depending on phases Need more statistics than available at baseline LHCb 10fb-1 to approach SM 10% precision Rate of (Bd/Bs)→mm tightly constrained and can distinguish SM and MFV (Buras: hep-ph/060405). Might Bd→mm be visible at upgraded LHCb??? LHCb Upgrade – P Collins Beauty 09, Heidelberg

9. Powerful NP laboratory Host of interesting observables. Angular distributions e.g. forward-backward asymmetry of the angle between lepton and B in the dilepton rest frame Position of zero asymmetry crossing point will be measured by LHCb as well as needed, but many other theoretically clean observables will only come into play with > 10 fb-1 0.35 M yield at upgrade 100 fb-1 B → K0* l+l- Egede, JHEP11 (2008) 32 With larger statistics, study of further observables (transverse asymmetries: AT(2) , AT(3) , AT(4) ) sensitive to NP LHCb Upgrade – P Collins Beauty 09, Heidelberg

10. LHCb 10 fb-1 NP physics highlights • Rare decays: Bs µµ • Direct search for NP • 3s measurement of SM prediction Mixing phase in Bs  J/yf (tree) • Sensitive to NP in mixing • Measure s (2bs) ≈ 0.01 Mixing phase in Bs  ff (penguin) • Sensitive to NP in loops • Measure 2bseff ≠ 0 (=NP) with s≈ 0.03 CKM angle gfromBd  D/DK, Bs→DsK, Bd->Dp (tree) • standard candle against which NP sensitive measurements can be compared • measurements to ~ 2° degrees • CKM angle g from Bd(s)→pp, KK (penguin), B→hhh • g_NPvs g_SM • Sensitive to ≈ 3° degrees CPV in penguins Bdf Ks: b vs beff • Sensitive to NP in loops • Sensitive to ≈ 0.1 Search for RH currents in radiative decays Bs fg ; Asymmetry FB of Bd  K* µµ • (zero of AFB(s) to 7%) D meson physics CP, D-D mixing Santos Carson Leroy Leroy Reece, Belyaev Ricciardi Magnin LHCb Upgrade – P Collins Beauty 09, Heidelberg

11. Upgrade LHCb 10 fb-1 NP physics highlights • Rare decays: Bs µµ • Direct search for NP • 3s measurement of SM prediction Mixing phase in Bs  J/yf (tree) • Sensitive to NP in mixing • Measure s (fs) ≈ 0.01 Mixing phase in Bs  ff (penguin) • Sensitive to NP in loops • Measure phase ≠ 0 (=NP) with s≈ 0.03 CKM angle gfromBd  D/DK, Bs→DsK, Bd->Dp (tree) • standard candle against which NP sensitive measurements can be compared • measurements to ~ 2° degrees • CKM angle g from Bd(s)→pp, KK (penguin), B→hhh • g_NPvs g_SM • Sensitive to ≈ 3° degrees CPV in penguins Bdf Ks: b vs beff • Sensitive to NP in loops • Sensitive to ≈ 0.1 Search for RH currents in radiative decays Bs fg ; Asymmetry FB of Bd  K* µµ • (zero of AFB(s) to 7%) D meson physics CP, D-D mixing, rare decays Santos Carson Measure BR to ~5-10%, search for Bd  µµ Improve by factor 4-5 Leroy Improve by factor 3: Level of indirect prediction Comparison at 0.03o level Leroy Reece, Belyaev Measure to s≈0.01, pin down NP New observables to improve NP sensitivty Ricciardi Magnin Measure and characterise CPV sub-degree precision LHCb Upgrade – P Collins Beauty 09, Heidelberg

12. To extend the physics programme, why not just turn up L? • LHC is (will be) capable of delivering to LHCb ~50% of the L delivered to the GPDs – would be more than good enough! • Baseline scenario: increase our luminosity from 2.1032 to 2x1033cm-2s-1 • Crossings with ≥ 1 interaction 10 MHz → 30 MHz • Average number of interactions per crossing 1.2 → 4.8 • Spillover: increases linearly with L • Compatible with SLHC Ihigh x Ilow scenario BUT, it’s all about the trigger! • Level-0: Largest ET hadron, e(g) and m • 1MHz read-out rate is currently the bottle neck in the system • m channels: yield proportional to L • Hadronic channels: If we increase L we have to increase our ET cut and there is no net efficiency gain! • Our current 2.5 us latency is inadequate for a trigger decision of this complexity LHCb Upgrade – P Collins Beauty 09, Heidelberg

13. LHCb upgrade strategy = Move to a full software trigger The idea • Trigger uses ALL event information, reconstructs all primary vertices, and can cut on pT for high i.p. • Preliminary studies show that the hadron efficiency will improve by ~2, and yield will be proportional to L • Increase in statistics x20 for hadronic channels and x10 for leptonic channels • This gives the additional flexibility to adapt to the physics landscape in the next decade The consequence The consequence: Read out all sub-systems at 40 MHz • Aim to operate at L=2.1033 • Perform entire trigger on • CPU farm with input rate 30 MHz • Goal is to double trigger efficiency for hadronic channels and make the yield scale with luminosity • All subsystems must be fully read out at 40 MHz • Replace most FE electronics, silicon modules, RICH HPDs, FE boards of calorimeter and outer tracker • Replace all FE-electronics; all silicon modules, RICH-HPDs, FE boards of Calorimeter, Outer Tracker FE • Case study: Bs  ff (after HTL1) • L= 2x1032 cm-2s-1 • ET> 3.5 GeV e≈ 22% • Min.Bias retention 10 kHz • L= 1033 cm-2s-1 • ET> 2 GeV e≈ 45% • Min.Bias retention 28 kHz LHCb Upgrade – P Collins Beauty 09, Heidelberg

14. LHCb Upgrade TimeLine • First upgrade workshop Jan ‘07 Edinburgh • EOI submitted April ‘08 • Upgrade task force formed • TDR planned for 2010 Plan to: • Accumulate 10fb-1 @ LHCb in 5 years • Install substantial upgrade in 2015-16 (in synch with machine shut downs and long GPD interventions) Extract from EOI LHCb-2008-007 LHCb Upgrade – P Collins Beauty 09, Heidelberg

15. Detector Environment @ Upgrade B yield from tracking efficiency (no spillover) • Radiation: • Current detector designed to withstand 20 fb-1 • Affects mainly large h (trackers, inner part of calorimeter) • Running experience needed • Note that VELO in any case will be replaced • Tracking and Occupancy: • Si can be operated without spillover: giving occupancy increase of ~2 • Outer tracker straws: occupancy too high: • Increase area coverage of IT and use faster gas • Move to scintillating fibres • Material Budget an important issue (occupancy, momentum resolution) Luminosity (1032 cm-2s-1) LHCb Upgrade – P Collins Beauty 09, Heidelberg

16. Vertexing @LHCb Upgrade Dose after 100 fb-1 • Upgrading the VELO to 40 MHz implies complete replacement of all modules and FE electronics. • Two major challenges • Data rate of ~1300 GBit/s • Radiation levels and hence thermal management of modules • Important to maintain current performance by keeping material low • Small modules with low power • Thinning of sensor and electronics • Use of CVD diamond planes for cooling and/or sensor • Removal/rework of RF foil 500 neqcm-2 x 1016 TID (MRad) 50 5 Radius (cm) tip of current VELO LHCb Upgrade – P Collins Beauty 09, Heidelberg

17. Vertexing @ LHCb upgrade Candidate module designs strip pixel • Strip solution • Small inner radius • Thin sensors • Diamond cooling plane • New electronics needed • Occupancy 1-2% • Pixel Solution • Low occupancy helps for PR and timing • TIMEPIX (55x55 mm) is a promising candidate for FE electronics • square pixel and buttable design allows single layer construction • Modification needed to architecture • Testbeams this summer show excellent performances Timepix: 55 mm pitch PRELIMINARY Residual (micron) Estimated track contribution to residual 2.5 mm Track angle (degrees) LHCb Upgrade – P Collins Beauty 09, Heidelberg

18. Tracking @ LHCb upgrade OT Occupancy 75 ns gate 50 ns gate • High Luminosity will produce high occupancy and ghosts in the tracking system • particularly in the Outer Tracker where a gas technique is used (drift time in straw tubes) and signal is collected in 50-75 ns • The area coverage of the Inner Tracker has to be increased, along with new sensors, new FE chip • Full silicon tracker in front of magnet must be rebuilt • Finer pitch? More layers? • Material budget is an important issue • Critical for momentum resolution and PR • Also: Radiation/cooling 2x1032 cm-2s-1 OT+IT LHCb Upgrade – P Collins Beauty 09, Heidelberg

19. 19 AlternativeSolutions OT IT • A fiber tracker with mixed fiber dimensions (250 mm for inner part, 700-1000 mm for outer) to be readout with SiPM and/or conventional MaPMT • Simplified services configuration: no cables, no cooling, frames thinning, FEE outside  gives less X/X0 • Good timing performances • Increased granularity in x – spatial resolution enough • Problems to be addressed: • SiPM readout and its optimisation • radiation hardness • mechanics 32 channels Si PM: 0.25 x 1 mm2 Lausanne Preliminary: 80 mm residuals

20. Particle ID in the RICH system • Need to replace front end electronics AND photon detectors to cope with 40 MHz readout • Baseline approach; keep current geometrical layout RICH1 (aerogel+C4F10) + RICH2 (CF4) • OR, replace aerogel with new TOF system (TORCH) located after RICH2 • Photon sensors together with their new (independent) chip are the critical item: • could be MaPMT • 0.3M channels • R&D needed (x talk, spillover, B field, lens...) • or upgraded HPDs • study ion feedback rate • many new components: production time an issue • or MCPs • B tolerance, timing, new idea... Next generation MaPMTs Example PID over full momentum range with TORCH

21. New concept for RICH: the TORCH Time of flight detector based on a quartz plate, for the identification of p<10 GeV hadrons (replacing aerogel) reconstruct photon flight time and direction in specially designed standoff box Clock arrival time to ~20 ps Deduce photon emission time → track ToF R&D on hardware needed: Microchannel plate PM with multianode readout MCP-PM achieved in testbeam 10-20 ps time resolution with 30-20 p.e. mechanics, electronics (Timepix?), aging etc. possible synergy with PANDA and VELO E.Ramberg /TIPP09

22. Calorimeters 22 September 2009: calorimeter modules placed in LHC tunnel to accumulate dose • HLT seeds already provided at 40 MHz • Modifications to electronics needed: • Upgraded FE boards • Lower PM gain (÷5) and increase preamp sensitivity and lower noise accordingly • No showstopper foreseen • Radiation tolerance currently an open issue • Affects inner part of ECAL (would need replacement) • Tested up to 2.5 Mrad (1 upgrade year) • R&D underway to collect more comprehensive data • Pile-up (~4 at upgrade) will affect resolution: watch carefully for low pT, g physics Resolution 2x1032 cm-2s-1 Q varying 2x1033 cm-2s-1 Energy

23. 23 Muon System Maximum rates per channel at 2.1033 • FEE readout already at 40 MHz • Two main concerns: • dead time due to high rate in inner regions • aging due to radiation in inner regions • An evaluation of these effects will come • from first data R z Accumulated chage (C/cm) on wires for 100 fb-1 R z Possibility of replacement of the inner parts with large area GEM (70x30 cm2) or with MWPC, in any case with new, smaller pad readout M1, due to background and to upgraded L0, will be removed A transition to a fully 3D muon projective readout (and not based on strips crossing) could reduce the fake associations (detailed studies to be performed)

24. Outlook • LHCb commissioning is well underway • On course to accumulate 10 fb-1 in ~ 5 years • Upgrade strategy SLHC independent: • Goal: 100 fb-1 in 5 years at L=2x1033 • X20 statistics in hadron channels • X10 statistics in leptonic channels • Maintain tracking and PID performance • Upgrade TDR out in 2010 LHCb Upgrade – P Collins Beauty 09, Heidelberg

25. B+ B- Amplitude fit, model error 7o Binned fit, CLEO-c error 2o Binned fit, CLEO-c error 5o Homing in on g • Interferencesbetween the bc and bu tree transition for B-(D°/D°)K- • Example : Dalitzanalysis of D°/D°Ksππ to extract (rB,δB,γ) Here D final state is common to D and Dbar, many possibilities. Want to exploit As many modes as possible but each decay brings its own strong phase Difference which needs to be known Precision of 3-3 deg with 10 fb-1? LHCb Upgrade – P Collins Beauty 09, Heidelberg