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Trigger future strategy. MUON IB - CMS week 26 June 2012. L1 Muon trigger rate problem. The problem of the L1 Muon trigger rate is considered by the L1trigger community, see e.g.:
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Triggerfuturestrategy MUON IB - CMS week 26 June 2012
L1 Muon trigger rate problem The problem of the L1 Muon trigger rate is considered by the L1trigger community, see e.g.: • Trigger Upgrades Meeting - Muon Brainstorming Discussion: https://indico.cern.ch/conferenceDisplay.py?confId=190736 • “Projected L1 Muon Performance to 1-2E34” by Darin: https://indico.cern.ch/getFile.py/access?contribId=15&resId=1&materialId=slides&confId=197142 Karol Buńkowski,UW,
L1 muon trigger upgrade • Cathode Strip Chambers trigger • ME4 chambers to be added in 2013-2014 • New Muon Port Card, new CSC Track Finder, possibility of using the RPC hits in the new CSCTF improve pT resolution and thus reduce rate • Drift Tube trigger • move front-end electronics (“sector collectors”) from UXC to USC (2013) • New DT Track Finder Main motivation are the maintenance issues, performance improvements - to be studied • Resistive Plate Chambers PAC trigger • RE4 chambers to be added in 2013-2014 • Possible to replace the PAC FPGA with bigger chips the trigger algorithms can be optimized, chamber hits de-clustering better pt resolution = smaller rate • HSCP triggering with 25 ns bunch spacing • Global Muon Trigger • New hardware integrated with the GT, more candidates from the subsystem, better measurement of the phi and eta coordinates of the subsystem candidates. See: https://indico.cern.ch/conferenceDisplay.py?confId=171094 The L1 Trigger upgrade TDR is being prepared, see: https://indico.cern.ch/getFile.py/access?contribId=0&sessionId=13&resId=0&materialId=slides&confId=187073 Karol Buńkowski,UW,
L1 muon trigger upgrade schedule Darin Acosta & Alex Tapper https://indico.cern.ch/getFile.py/access?contribId=0&sessionId=13&resId=0&materialId=slides&confId=187073 Karol Buńkowski,UW,
LHC performance projection Will the upgraded L1 Muon trigger be able to cope with the luminosity of ~1.5-2.5 cm-2s-1? New DTTF, CSCTF and G(M)T ready MikeLamont https://indico.cern.ch/getFile.py/access?contribId=37&sessionId=0&resId=1&materialId=slides&confId=187073 Karol Buńkowski,UW,
Muon trigger rate • To keep the SingleMu rate at ~8 kHz at L=2E34, require a threshold of 25GeV • But expect higherrate for √s=14 TeV due to higher xsec • Additionally higher background and pileup DTclean –the problem with the DT candidates |eta| > 1.05 fixed Rate [Hz] normalized to luminosity 1034cm-2s-1 Run 193336 Karol Buńkowski,UW,
GMT rate vs eta. DTclean –the problem with the DT candidates |eta| > 1.05 fixed • The rate distribution vs eta is quite uniform. The lowest is between eta -0.5 and 0.5. • The endcap rate is much lower then predicted in the L1 TDR (2000) • The overlap rete is similar as in the neighboring regions RPC & DT/CSC DT/CSC only RPC only Rate normalized to luminosity 1034cm-2s-1 Run 193336 Karol Buńkowski,UW,
We first must understand the rate of the current L1 muon trigger. • What fraction of the triggered events contain real muon, and what fraction are false triggers? • What fraction are muons good for physic, or muons passing HLT? • Is the main component of rate at given threshold the low pTmuons promoted to the high pTcandidates? If yes – what are the properties of those muons? Can these properties be used to improved the pTestimation? • What can be gained by combining the DT, CSC and RPC data in the common track finder? • What can be gained by using the DT track segment local angel for the pT determination? (CSCTF already does it). • What is the fraction of the events triggered on punch through? • What is the fraction of the events with two close low pT muons promoted to the high pT candidate? • What is the fraction of ghost? • How all above scales with the luminosity? • Can we find a way of reducing the rate of the false triggers and overestimated muon without the significant decrees of the efficiency for the high pT muons? Karol Buńkowski,UW,
Datasets for the trigger analysis Current HLT pass-through’s for L1SingleMu algorithms: • HLT_L1SingleMuOpen_v6 giving rate of order of 0.2 Hz • HLT_L1SingleMu12_v1 giving rate of order of 0.5-1 Hz Request were already presented to decrease the HLT_L1SingleMuOpen prescale. We are discussing other additional pass-through’s (e.g. for L1_SingleMu7 and L1_SingleMu20) just now. Those data set are useful for understanding the rate composition of the current L1 muon trigger (i.e. to answer many question from the previous slide). For the subsystem analysis only the HLT_L1SingleMuOpen can be used (under discussion). For the studies of the modification of the muon trigger, in principle the only useful data set is MinimumBias (the modified trigger can trigger on different events then the current one). Next slide: statistic of the Global Muons in the MiniumBias dataset. Karol Buńkowski,UW,
~280k events ~550k events Karol Buńkowski,UW,
After LS3… • Almost everything depends what the Tracker Trigger will be able to do… will generate stabs? Or reconstruct tracksand measure the pT? • Probably the primary role of the muon system will be to tag a muon, but the pT measurement will be done by tracker (so exactly the same as in the offline reconstruction). • What requirements are for the muon trigger then?: • Purity (no false tracks due to background and punch trough) a few chamber coverage in every place (to require coincidence), • Efficiency of tracks identification redundant chamber coverage in every place (to recover the chamber inefficiencies and damages), • Eta and phi measurement accuracy? Are new detector layers needed? Karol Buńkowski,UW,
