Triggering MinBias at L 1 Richard Hollis Aneta
- Slides: 22
Triggering Min-Bias at L 1 Richard Hollis Aneta Iordanova 4 th December 2006 CMS Week Online Selection Meeting
Outline ¢ ¢ Objective Analysis tools Input particle distributions Number of trigger towers l ¢ ¢ 2 total or transverse energy “Results” Triggering message Heavy-ions Summary Richard Hollis University of Illinois at Chicago 3 rd December 2006 4 th December 2006
Objectives ¢ Study the most effective way to trigger minimum bias events primarily for p+p collisions l for Pb+Pb collisions l • this should be an off-shoot to the p+p work ¢ Need to attain the best efficiency l 3 also consider [rejecting] beam-gas events Richard Hollis University of Illinois at Chicago 3 rd December 2006 4 th December 2006
What is “Min-Bias”? ¢ We consider “Min-Bias” to be all events which undergo an inelastic collision l need not contain a jet! ¢ Mainly soft particle production ¢ Why is it important? l 4 there will be 19 of these mixed in with every CMS event Richard Hollis University of Illinois at Chicago 3 rd December 2006 4 th December 2006
What are “Beam-gas Collision Events”? ¢ Beam-Gas collisions l ¢ inside detector volume interactions with residual gas elements in the beam pipe Not expected to be a large effect l still needs to be considered We (R+A) sometimes refer to these as non-collision events 5 Richard Hollis University of Illinois at Chicago 3 rd December 2006 4 th December 2006
What are “Beam-gas Collision Events”? ¢ Beam-Gas collisions l ¢ interactions with residual gas elements in the beam pipe Not expected to be a large effect l 6 outside detector volume still needs to be considered Richard Hollis University of Illinois at Chicago 3 rd December 2006 4 th December 2006
Analysis Tools ¢ ¢ 7 ORCA 8_13_3 used Min. Bias data set (os 05_Py. MB) ¢ ¢ Details: Tower Cuts (on E) # trigger tower thresholds Hcal. Trig. Prim: Threshold = 0. 0 Hcal. Trig. Prim: Barrel. ECut = 0. 6 Hcal. Trig. Prim: Endcap. ECut = 0. 8 Hcal. Trig. Prim: Forward. ECut = 1. 5 Richard Hollis University of Illinois at Chicago 3 rd December 2006 4 th December 2006
Particle Distributions ¢ Example: the number of particles initially created hadrons l l l ¢ Pythia Simulation All E>1 Ge. V ET>1 Ge. V Average number of particles with large ET is small Define: “N” side and “P” side 8 Richard Hollis University of Illinois at Chicago 3 rd December 2006 4 th December 2006
Particle Distributions ¢ Example: the number of particles initially created (includes γ, e±) l l ORCA Simulation All Sim. Trk: • close to initial vertex • away from vertex ¢ Additional “secondary” particles which will aid triggering l 9 e. g. come from beam pipe Richard Hollis University of Illinois at Chicago 3 rd December 2006 4 th December 2006
Trigger Towers (E) Test: towers vs Sim. Cal. Hits ¢ l ¢ ORCA Simulation proportional But: threshold may be too low? l l try: E>10 Ge. V does not change proportionality • lowers offset 10 Richard Hollis University of Illinois at Chicago 3 rd December 2006 4 th December 2006
Trigger Towers (E) Test: towers vs Sim. Cal. Hits ¢ l ¢ ORCA Simulation proportional But: threshold may be too low? l l try: E>10 Ge. V does not change proportionality • lowers offset 11 Richard Hollis University of Illinois at Chicago 3 rd December 2006 4 th December 2006
Trigger Towers (E) ¢ Optimal Trigger: Towers: N vs P ¢ Strongly correlated ¢ Trigger should cut on n. Towers hit on “N” side and “P” side l 12 ORCA Simulation e. g. N>10 and P>10 Richard Hollis University of Illinois at Chicago 3 rd December 2006 4 th December 2006
Trigger Towers (E) ¢ Optimal Trigger: Towers: N vs P ¢ Strongly correlated ¢ Trigger should cut on n. Towers hit on “N” side and “P” side l 13 ORCA Simulation e. g. N>10 and P>10 Richard Hollis University of Illinois at Chicago 3 rd December 2006 4 th December 2006
Optimal Trigger ¢ Count number of towers hit on forward N and P side HF ¢ Reasoning l forward calorimeter? • helps with possible beam gas rejection • total energy is large in this region l number of towers, not tower energy? • less likely to be “jet biased” from one large energy deposit (see next slides) ¢ 14 Most of all: it is simple Richard Hollis University of Illinois at Chicago 3 rd December 2006 4 th December 2006
Trigger Towers (ET) ¢ Same analysis, this time used ET ORCA Simulation Test towers vs Sim. Cal. Hits ¢ l 15 proportional Richard Hollis University of Illinois at Chicago 3 rd December 2006 4 th December 2006
Trigger Towers (ET) ¢ Same analysis, this time used ET ORCA Simulation Test Towers: N vs P ¢ l l correlated lost sensitivity • most signal at 0 or 1 towers hit 16 Richard Hollis University of Illinois at Chicago 3 rd December 2006 4 th December 2006
Trigger Towers (ET) ¢ Same analysis, this time used ET ORCA Simulation Test Towers Summed energy: N vs P ¢ l l 17 same as using number of towers distribution very spread Richard Hollis University of Illinois at Chicago 3 rd December 2006 4 th December 2006
“Results” Towers cut on total energy Towers cut on transverse energy ε>90% 18 Richard Hollis University of Illinois at Chicago ε≈60% Cuts on ONE Tower 3 rd December 2006 4 th December 2006
Triggering Message ¢ Count towers l need to cut on E for minimum bias l needs: • 1 bit for yes/no above NTower. Hit (e. g. 5) on both sides l would this vary? or have several bits? • e. g. 1, 5, 10 • this would be useful as we do not know: • physics (much higher multiplicities? ) • detector (hot towers? ) • LHC machine (high beam-gas background? ) ¢ Cutting on ET: l serious reservations as to whether this will work • i. e. would this gain a high enough efficiency 19 Richard Hollis University of Illinois at Chicago 3 rd December 2006 4 th December 2006
Heavy-Ions ¢ We have applied the same logic to Pb+Pb collisions l ¢ 20 b=0 fm Same relative reduction in E and ET l ¢ generator level studies only Hydro Model Calculation compared to total initial particles Number of particles is much larger than minimum bias Pb+Pb collisions Richard Hollis University of Illinois at Chicago 3 rd December 2006 4 th December 2006
Heavy-Ions central ¢ Number of particles in the HF region is large l for all impact parameters except very peripheral ¢ Line shows p+p @ 14 Te. V expectation ¢ Should get reasonable efficiency even for ET 21 peripheral Richard Hollis University of Illinois at Chicago 3 rd December 2006 4 th December 2006
Summary ¢ Optimal minimum bias trigger read-out total energy l count number of towers l • not summed energy l 22 forward calorimeters Richard Hollis University of Illinois at Chicago 3 rd December 2006 4 th December 2006
Recent RHIC Results on Bulk Properties Richard Hollis
Recent RHIC Results on Bulk Properties Richard Hollis
Predicting MinBias and the Underlying Event at the
Northwest Terascale Workshop Modeling MinBias and the Underlying
MinBias and the Underlying Event in Run 2
MinBias Physics Jet Evolution Event Shapes CDF analysis
Predicting MinBias and the Underlying Event at the
Predicting MinBias and the Underlying Event at the
MinBias and the Underlying Event in Run 2
Northwest Terascale Workshop Modeling MinBias and the Underlying
MinBias and the Underlying Event at CDF Outline
Calorimeter Data from MAS GCALOR with phojet minbias
Predicting MinBias and the Underlying Event at the
MinBias and the Underlying Event Extrapolations from the
Stuart Hollis CDI conference 8 11 13 Midlife
School Contact Information 706 883 1580 Hollis Hand
BSM System Health Mike Hollis HP Software Copyright
Stuart Hollis A Simplified Further Education and Skills
Improving Employee Safety at Spartanburg Regional Denise Hollis
Genetic Counseling By Kyle Hollis 4 What is
Senior Project Proposal Micron Contact Tim Hollis thollismicron
Presented By Pawl Hollis Randy Robison All New
