Muon+hadron alley

1. Muon+hadron alley Outline: HLT overview Objectives of muon+hadron Algorithm flow Selection parameters Monitoring Summary required Determination of parameters Antonio Pérez-Calero Hugo Ruiz

2. HLT overview L0 m L0 dim o(100 KHz) Alleys Confirm Confirm Extra ms Goodhadrs Extra ms Recovr’ddim m + hadr Single m Dim o(10 KHz) Global HLT reconstruction Generic B Exclusive sels. Single m m + hadr D* J/y ~ 1 KHz Hugo Ruiz – Winter Meeting Santiago 2007

3. Objectives of the alley • Source of TOS for semileptonics: give ~ all semileptonics to excl/incl selection • Efficiency on BdD*mn: (Pessimistic) Hugo Ruiz – Winter Meeting Santiago 2007

4. Objectives of the incl. selection • Source of tagging-enriched TIS for any other channel: 4109 unbiased B per year • Better: count only events with other B in acceptance • Even better: TIS efficiency on offl-selected evts • And  etageff Hugo Ruiz – Winter Meeting Santiago 2007

5. Objectives of the incl. selection • Exemple with the released version (mpT>1GeV, hadrpT>0.5GeV, both |IP| in [0.1,3]mm, DOCA<0.2mm, Pointing<0.4, Dz>2mm) • 4.36 KHz, somewhere between alley and incl. selection • For muonless samples of Hans’ preselection(Bs2Dspi, Bs2DsDs, Bd2Kpi, Bd2D0Kst, Bd2KstD2KSPiPi, Bs2PhiPhi, Bu2KD->KSPiPi, Bd2PiPiPi, Bu2Kee) • Events: 10,808 • L0: 55% • HltMuHad: 4.8% of those passing L0 • TOS: 2.25% of those passing L0 • TIS: 1.7 % of those passing L0 • With extra tagging power • Additional: nice muon id calibration sample? Hugo Ruiz – Winter Meeting Santiago 2007

6. Alley algorithm flow Legend: Muon Hadron TrackFilter Sequencer L0+T+VELO m VertexMaker 1 mpT, mIP VertexFilter VELO 3D VertexUpgrader 2 hadron IP Reconstruction VertexMaker: DOCA VELO forward 3 hadronpT VertexUpgrader Pointing, Dz 3 selection steps Hugo Ruiz – Antonio Perez-Calero, HLT workshop at Amsterdam

7. Selection parameters • Selection: 7 parameters (2: alley & selection) • m: pT, Ipmin (Ipmax) • Hadron:pT, Ipmin (IPmax) • Vertices: DOCA, Pointing, Dz Needstilltostudy: • IP vs IPS • Can removeIpmax? (yes fromeff vs rate) • Reconstruction: Allparametersfor: • Confirmed muon • VELO3D • VELO-forward Hugo Ruiz – Winter Meeting Santiago 2007

8. Monitoring • What we need is what the standard algorithms will provide at the 3 selection steps: EVERYTHING • This includes: • Input and output rate at each filtering level • # of input and output candidates at each filtering level • Note that #filtering levels > #algorithms • Distributions of the variables in which we cut • And of the ‘best’ of the candidates, to be able to extract the dependence of the rate on the variable • Need: HLT-PVSS GUI that allows navigation in HLT alleys and algorithms to display rates, variable distributions… • For shift team: rates + access to variable reference histos (with reference histos) Hugo Ruiz – Winter Meeting Santiago 2007

9. Summary required • For TISTOSing: • Needed only summary from last HltVertexFilter • Vertices that triggered • Their two tracks • For TIS/TOSING based on summary to be a better approximation, we need the recoalgos to give a chance to ALL good combinations • Not the best nth, for instance Hugo Ruiz – Winter Meeting Santiago 2007

10. Summary required • To study alley performance (on offl-selected events) we need at each step: • Output candidates (LHCb id’s) • Cut values • Extinguish “pretrigger and trigger” • The info is made available from the standard algorithm summaries • # objects in summaries: Hugo Ruiz – Winter Meeting Santiago 2007

11. Determination of parameters • Aim: highest possible: • Semileptonic efficiency on alley • B purity on incl. selection for the allowed rate (muon alley will optimize muon confirmation efficiency) • Rate at any set of parameters: from running HLT emulation on sample of random L0 triggered events • Assume: • 1st ~ 2fb-1 of data on disk • Then try to think about first months… Hugo Ruiz – Winter Meeting Santiago 2007

12. Determination of parameters • Alley: efficiency on TOS for semileptonics • Need to optimize it on TIS, running the HLT simulation • How many TIS semileptonics will have? • B/S>0, but shouldn’t expect HLT to do better than offline! • How many triggered on the other side? 15 M * 0.5 * 0.015 = 110 K events / year • Can use this events to optimize alley parameters • Plot in slide 3 done with ~ 1 K events Hugo Ruiz – Winter Meeting Santiago 2007

13. Determination of parameters • Incl. sel: efficiency on TIS for generic B • Take as starting point decays with highest rates: • B+ J/yK+: 1.74 M events/year, B/S = 0.37 • Bd J/yK*: 0.67 M events/year, B/S = 0.17 • >2M with kite good B/S • Require TOS: ~ 100% • Pass a typical muon+hadron: 2 M * 0.5 * 0.015 ~ 15 K events / year in the interesting region of an optimization plot (TIS efficiency vs rate). Hugo Ruiz – Winter Meeting Santiago 2007

14. First months • Assume 21032, 107 sec/year: • Alley: 1.5 Hz of semileptonics (plot like in slide 2 in 1000 seconds, ~ 20’) • Incl. sel: • J/yK+/K*: 0.2 Hz • Need more. Can add more selections, in particular add semileptonics of point 1 to get a sample of ~ 2Hz • Use them to evaluate trigger on the other side • Here penalisation of factor ~ 0.5 * 0.015  need 30 hours to get same statistics Hugo Ruiz – Winter Meeting Santiago 2007

15. First months • If for these events we: • save the output of the HLT global reconstruction • send them to the monitoring farm • We can obtain online Antonio’s plots: • Muon from muon alley summaries • Hadron from global reconstruction summaries • Rate from monitoring of cut variables Hugo Ruiz – Winter Meeting Santiago 2007

16. And the first weeks… • At start-up lumi << 21032 • Any combination of cuts will give << allowed rate • Just apply a set of minimum cuts to debug the alley! • Under the carpet: • GEC/no GEC • Different luminosity setups Hugo Ruiz – Winter Meeting Santiago 2007