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LCTs as a function of trigger , E nergy, and Luminosity. Paul Padley, Diane Choi With help from Antony Adair, Gian Piero Di Giovanni, Jinzhong Zhang, and others. LCTs in non muon events.
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LCTs as a function of trigger, Energy, and Luminosity Paul Padley, Diane Choi With help from Antony Adair, GianPiero Di Giovanni, Jinzhong Zhang, and others
LCTs in non muon events • Previously we showed that there are significant number of events with LCTs even when they are not triggered by muons. • For example, here are events triggered with L1_SingleJet128 Number of LCTs
Mixture of real muons and something else Station Number
Compare to muon triggers Station Number
Jet Trigger Only a tiny fraction of these events have muon triggers as well Presumably these are muons Station Number
Jet Trigger What is this stuff? Something other than muons Is giving rate in ME11 Station Number
Hypothesis 1, Jet punch through • Punch through from jets • By this I mean a jet hits the calorimeter and some of the energy leaks out the back into the muon system. • Test this hypothesis by looking for energy dependence • For a quick simple study, only want to look at trigger data, not reconstruction • Try comparing 2011 (7TeV), 2012 (8TeV) data • Try looking as a function of trigger threshold
2011-2012 comparison • Look at Zero Bias triggers • We have checked and other triggers, such as jet triggers, show the same behavior No significant difference
Trigger Threshold Comparison • Data from a couple of 2012 runs combined • Runs 194115 and 195115 Probably no trend
Luminosity dependence • Looking at numerous plots and numbers we could not find clear evidence of an energy dependence • However, we did notice there is a strong instantaneous luminosity dependence (Ivan et al. have previously reported seeing a pile up dependence so this is not surprising.)
LHC Fill 2622 • This is a very interesting fill • It went on for 22 hours and luminosity varied by about a factor of 5 from beginning to end. • It is split into 4 runs, with decreasing instantaneous luminosity.
LCT Fractions Fill 2622 Zero bias triggers Clear correlation with luminosity.
Event Displays In CSC digis are being shown
Same event, 3D view There is no jet, or significant energy pointing at these ME11 hits.
Same Event 3D view These clusters are less than 1 GeV each
Same event 3D view Again no significant energy pointing at CSC digi
Summary: LCTs as a function of Trigger • We have the tools to study LCTs as a function of L1Trigger • Using these tools we observe that triggers that don’t require muons have a significant rate of LCTs in station 1 that don’t appear to be associated with real muons. • They also are not associated with significant calorimeter energy in the region or event
Summary: LCTs with changing Luminosity • The rate of “non-muon” LCTs depends upon instantaneous luminosity • Previous studies (Ivan et al., CSC group) have shown LCT rate dependences on Pile-up/luminosity so this is no surprise.
Future work • LHC fill 2622 provides a great set of data to study these effects in detail • We will try to study this fill Lumi-section by Lumi-section in order to make a finer grained correlation with instantaneous luminosity.