The LHCb upgrade Eric van Herwijnen on behalf

The LHCb upgrade Eric van Herwijnen, on behalf of the LHCb collaboration Wednesday, 25 September 2013 International Conference on Advanced Technology and Particle Physics CENTRO DI CULTURA SCIENTIFICA A. VOLTA, Villa del Grumello, Como, Italy

Contents u u u u Aim of LHCb: flavour physics Current LHCb detector Results so far Why the upgrade? How & what Upgraded subdetectors Conclusions 12/21/2021 The LHCb. Upgrade 2

Aim of LHCb: flavour physics u Many open questions of the Standard Model are associated with flavour: n n u Baryon-antibaryon asymmetry Quark mass hierarchy Cabibbo-Kobayashi-Maskawa matrix structure Non zero neutrino mass Search for New Physics: n n Constraints on supersymmetric Higgs bosons: Bs→µ+µDecay products of B 0 → K*0µ+µ- sensitive to helicity structure of NP CP violating asymmetries very sensitive to NP: Bs → J/ᴪ φ, Bs mixing, charm CKM description at sub 10% level 12/21/2021 The LHCb. Upgrade 3

Flavour Physics at LHC u Topology of a flavour physics event: Primary vertex: ~50 tracks B decay vertices: few tracks π- p p π+ µνµ K/π separation 12/21/2021 The LHCb. Upgrade 4

Current LHCb detector u u Forward spectrometer (1. 9 < η < 4. 9) 2% of solid angle, 27% of heavy quark production cross section inside acceptance RICH detectors Vertex Locator (VELO) Muon System Calorimeters Tracking System 12/21/2021 The LHCb. Upgrade 5

Results so far u First evidence of Bs→µ+µ- u New observables in B 0 → K*0µ+µAngular distribution of “P’ 5” as function of µ+µ- invariant mass squared shows 2. 8 σ deviation from SM 12/21/2021 The LHCb. Upgrade 6

Many other results u Constraints on supersymmetry models from B(s)→µ+µ- From D. Straub, http: //arxiv. org/pdf/1205. 6094 v 1. pdf and A. Davis http: //www. quantumdiaries. org/2013/07/23/oh-what-a-beautiful-day/ u u u JPC (1++) measurement of X(3872) Charm mixing in D 0 → Kπ ~160 papers published to date 12/21/2021 The LHCb. Upgrade 7

Why the upgrade? u u LHCb phase 1: 5 fb-1 After 3 fb-1, the Standard Model description of flavour mixing and CP violation seems confirmed n u Higher precision measurements n u Sensitivities comparable to theoretical uncertainties (next slide) After long shutdown 1, higher energy, cross sections, yields n u Strong indirect constraints on NP data doubling in 2015 -2018 After run 2, data doubling would take too long so: n Run at higher luminosity: Linst ≤ 2*1033 cm-2 s-1 n Aim: 50 fb-1 integrated over 10 years 12/21/2021 The LHCb. Upgrade 8

Implications of LHCb measurements and future prospect Eur. Phys. J. C(2013) 73: 2373 12/21/2021 The LHCb. Upgrade 9

Current limitations u L 0 trigger: n n n u Hlt 1: n n n u 1 MHz readout → µ, e, γ and hadron ET thresholds For higher lumi, ET thresholds need to be increased Yields saturate, no gain beyond Linst=2*1032 for hadronic modes Reconstruct Velo tracks, determine primary vertices Forward tracking Select on impact parameter, p, p. T and track quality (Χ 2) Hlt 2: n n Search for secondary vertices Selection based on decay length and mass cuts 12/21/2021 The LHCb. Upgrade 10

How & what u u Increase current readout from 1 MHz → 40 MHz No L 0, full software trigger n n n u Replace all Front End &Back End electronics n u Increase 10 x for muonic, at least 20 x for hadronic yields (lumi*eff(trig), as compared to 2011) Allow fast full reconstruction Initially, run with a hardware Low Level Trigger Replace detectors with embedded electronics Apply new technologies to subdetectors n n withstand higher radiation dose and occupancies enhance performance 12/21/2021 The LHCb. Upgrade 11

Trigger u Hardware Low Level Trigger n n u u 40 MHz → 10 -5 MHz Remove once event filter (CPU) farm has reached its full size First and second level software trigger (HLT 1/2) Studies of HLT 1/2 content ongoing 12/21/2021 The LHCb. Upgrade 12

Low Level Trigger u u Initially, hardware based LLT to reduce rate to 5 -10 MHz LLT efficiency for hadron, µ and γ: 12/21/2021 The LHCb. Upgrade 13

HLT u From simulation: n n n u u → more exclusive trigger lines Upgrade geometry improves speed of forward tracking n n u 25% events contain b or c candidates All events contain at least 2 displaced vertices in the Velo Must use Particle Identification to cut uninteresting b&c candidates Full tracking in HLT 1 PV finding with momentum estimate from tracks Can run HLT 2 as complete trigger, bias-free cuts: n n n Do off-line reconstruction Use off-line lifetime, mass and p. T cuts to select wanted decays Trigger will contain only off-line cuts and thus be 100% efficient w. r. t off-line 12/21/2021 The LHCb. Upgrade 14

Subdetector upgrades New Velo pixel sensors Remove SPD&PS New Upstream Tracker silicon Calo reduce PMT gain & RO New (Central) Tracker Muon MWPCs almost compatible 12/21/2021 Rich 1&2 Modify optics, replace The LHCb. Upgrade HPDs & RO Remove M 1 15

Velo u Pixel modules (55 x 55 µm 2) instead of Silicon strips n n u u u Microchannel cooling Velopix readout chip based on Time. Pix 3 Beampipe radius 5. 5 mm → 3. 5 mm and thinner RF foil (0. 15 mm) n u Enhanced radiation harness Robust and flexible tracking performance Better IP resolution See also M. Gersabeck, ‘The Velo Upgrade’, session XIII 12/21/2021 The LHCb. Upgrade 16

Upstream Tracker No overlapping module boundaries u Finer segmentation close to beampipe Technological challenges: u Reduce material u 12/21/2021 The LHCb. Upgrade 17

Fibre tracker Better resolution in Outer Tracker area, slightly worse close to beam pipe u Simpler tracking Technological challenges: u 2. 5 m long, 250 µm scintillating optical fibres u Radiation hardness of Silicon Photo Multipliers: ~dose u Cooling Si. PMs to -400 C track See also Robert Ekelhof, ‘A Scintillation Fibre Tracker for the LHCb Upgrade’, session VIII u 12/21/2021 The LHCb. Upgrade 18

Backup solution: Silicon IT u 12/21/2021 The LHCb. Upgrade 19

Rich u Reduce occupancies in Rich 1, retain Rich 2 layout n u Increase radius of curvature of Rich 1 mirror (2. 7 → 3. 8 m) Replace Hybrid Photo Detectors by Ma. PMTs (Multi anode photo multipliers). Ongoing studies: n n Ageing Optimization of number of Ma. PMTs in Rich 1&2 12/21/2021 The LHCb. Upgrade 20

Calorimeter and Muon u Remove Scintillating Pad and Preshower detectors n n u Calo electronics upgrade n n u 40 MHz readout Reduced PM gain Remove M 1 n u PID performance will be degraded for low p. T, compensated by improved energy resolution in ECAL due to less material LLT will be loose so role in trigger less important Muon momentum resolution in LLT to be done by tracking system Apart from FE (40 MHz readout), no changes 12/21/2021 The LHCb. Upgrade 21

Upgrade DAQ subdetectors 40 MHz Data PC ~500 units PC Event building network Decodes LLT, refines and passes on to HLT PC Events PC PC 5 -10 MHz PC PC Event Filter Farm HLT processing 20 k. Hz storage 12/21/2021 The LHCb. Upgrade 22

Conclusions u u LHCb upgrade will bring essential contributions to flavour physics Fully approved and part of long-term LHC exploitation Flexible fully software trigger will enhance yields and efficiency for delicate measurements Timeline: 12/21/2021 The LHCb. Upgrade 23