Event Selections

[badeaa3]

ALEPH Big QCD paper: cuts from http://cds.cern.ch/record/690637/files/ep-2003-084.pdf, page2

• LEP2 paper https://arxiv.org/pdf/2312.05084
• LEP1 paper https://arxiv.org/pdf/1906.00489

LEP2 analysis uses many similar cuts as LEP1.

Track selections:

• pt > 0.2 GeV
• |cos(theta)| < 0.94 (for charged tracks only, pwflag == 0)
• |d0| <= 2mm
• |z0| <= 10mm
• ntpc >= 4 hits

Event selections:

• sqrt(s') effective center of mass sqrt(s') > 0.9 sqrt(s) [reduce QED]
• two-jet invariant mass (M_vis) > 0.7 sqrt(s) [reduce QED]
• 7pi/36 < STheta < 29pi/36 -> |cos(STheta)| <= 0.82 [well contained in detector]

• = 5 charged tracks

• = 13 charged tracks + neutral hadrons

• total charged particle energy >= 15 GeV [suppress EM interactions] Unclear if applied for the moment
• missing momentum <= 20 GeV
• passesWW cut (https://github.com/yenjie/StudyMult/blob/f4af2306b5632955ef8a02e6d5c5ff272841e157/DataProcessing/include/eventSelection.h#L231-L264)
• passesISR https://github.com/yenjie/StudyMult/blob/master/DataProcessing/include/eventSelection.h#L230

[jslawless]

What's the best way to find s', effective center of mass?

[badeaa3]

There’s a formula in the Lep 2 paper correlation analysis paper above that has a formula in terms of angles that you can use