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HZ Recoil Mass Analysis: Production Requests . LCD WG6 Meeting, 28/02/2012 J.S. Marshall, University of Cambridge. CDR V3 Benchmark Process. Relevant processes for this study are the recoil reaction e + e - HZ Hff , commonly called Higgs- strahlung .
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HZ Recoil Mass Analysis: Production Requests LCD WG6 Meeting, 28/02/2012 J.S. Marshall, University of Cambridge
CDR V3 Benchmark Process • Relevant processes for this study are the recoil reaction e+e-HZHff, commonly called Higgs-strahlung. • By detecting decay products of the Z, can search for Higgs signals without further assumption about Higgs decay modes: “model independent analysis”. • For CDR V3, will search for decays Z and Zee:“X” and “eeX” channels. • Signal is selected by identifying two well-measured leptons in final state, yielding Z mass. Can then compute recoil mass: s = 500GeV Lint = 500fb-1 mH= 120GeV No polarization
Analysis for ILD LoI • Very similar analysis was performed for the ILD Letter of Intent:http://www-flc.desy.de/lcnotes/notes/LC-PHSM-2009-006.pdf • Excellent starting point for considering MC samples required for the analysis: s = 250GeV Lint = 250fb-1 Pe- = -80% Pe+ = +30% *signal samples generated to yield Lint = 10ab-1
Analysis for CLIC CDR V3 • Cross-sections for the signal and background processes relevant to analysis for CLIC CDR V3 obtained from Whizard (thanks to Stephane for providing binary with relevant processes). • Set parameters: sqrts=500, USER_spectrum_mode=13 for correct beam simulation, mH=120GeV for signal samples, mH=12TeV for background. Select desired process and run: Examine stdhep files m mrecoil *signal samples requested to yield Lint = 25ab-1
2-Fermion Backgrounds X Number of events left after each cut. eeX • Looking into ILD LoI study in more detail, see that 2-fermion background were reduced to negligible levels. • If computing resources are stretched, could justify neglecting production of 2-fermion background samples.
4-Fermion Backgrounds • Largest remaining requests are the 4-fermion background samples. Investigate a few simple generator-level cuts to help save computing resources in generation of these samples. • Use stdhepcut package, adding simple lepton pT and invariant mass cuts, in style of existing lepton angle cut class i.e. same function call to find leptons, no cuts made if >2 leptons match criteria. • As initial reaction, suggest application of pT l+l- and |cosl+/l-| pre-cuts to ff and eeff samples.
