Analysis of Jet Cross-Sections in Neutral Current DIS Events

1. Inclusive Jet Cross-Sections in Neutral Current DIS Events Using the Breit Frame Analysis Status Marcos Jiminez Claudia Glasman Juan Terron Universidad Autonoma de Madrid Jeff Standage York University Thomas Schoerner Hamburg University • Contents • Cross-section & NLO:Data ratio comparisons • Differences between two analyses – so far QCD Meeting, 24th March 2005Jeff Standage, York University

2. Q2 JT/OG (DESY 02-112) 96-97 JS/TSS 98-00 MJ/CG/JT 99p-00 QCD Meeting, 24th March 2005Jeff Standage, York University

3. ET(jet) JT/OG (DESY 02-112) 96-97 JS/TSS 98-00 MJ/CG/JT 99p-00 QCD Meeting, 24th March 2005Jeff Standage, York University

4. η (jet) JT/OG (DESY 02-112) 96-97 JS/TSS 98-00 MJ/CG/JT 99p-00 QCD Meeting, 24th March 2005Jeff Standage, York University

5. Differences Between JS/TS and MJ/CG/JT Analyses JS/TS MJ/CG/JT • Analysis code • Orange/phantom 2004a(.1,.2)Private EAZE job • Orange variables for cutsRelease 2004a.1 (pro) • Zufos/cells for offline jet finding • Noise Suppression (noise02s.fpp) • ecut(1) = 0.08ecut(1) = 0.10 • ecut(2) = 0.14ecut(2) = 0.15 • imbacut = 0.7imbacut = 0.9 • CAL corrections (escale03.fpp) • Individual RCAL cell correctionsNo RCAL cell by cell corrections • Global corrections - Global corrections - • FCAL HAC: 0.941FCAL HAC: 0.95 • FCAL EMC: 1.024FCAL EMC: 1.04 • BCAL HAC: 1.0962BCAL HAC: 1.08 • BCAL EMC: 1.05315BCAL EMC: 1.04 • RCAL HAC: 1.022RCAL HAC: 1.025 • RCAL EMC: 1.022RCAL EMC: 1.025 QCD Meeting, 24th March 2005Jeff Standage, York University

6. Differences Between JS/TS and MJ/CG/JT Analyses JS/TS MJ/CG/JT • Vertex • Cell position corrected forCell position corrected for z-vertex only. • X,Y,Z vertices • Lepton beam energy • Orange: Ee = 27.56 GeVEe = 27.5 GeV • Offline: Ee = 27.52 GeV • Isolation (cone) cut • A cut is put on the electron candidate such that the total energy not associated with the candidate in a radius of R is eta-phi space is less than 10%. This removes photoproduction events and events where a jet remnant is falsely identified as the positron. • R = 0.8R = 0.7 • Sinistra electron • Electron corrected for dead material.Uncorrected Sinistra candidate is used. • Orange variable: Siecorr(3,1)Corresponds to SiCalEne(1) • Event variables • Orange variables being used, All values calculated directly from cells • e.g. SiQ2da(1), SiCeHMom(4,1) information. • Evidence of further orange corrections/differences. QCD Meeting, 24th March 2005Jeff Standage, York University

7. Summary • Analysis differences lead to ~10% difference in events selected • Claudia had 992 events that I have rejected or have no jets. • I have 825 such events that Claudia doesn’t. • Analysis differences lead to complete discrepancy in number of jets in each event. • Have over-ridden orange routines to implement her analysis criteria. • Of those 992 events are still losing 20: • (i) 1 event: Q2 difference (2 cells have different energy). • (ii) 2 events: cosGammaHad. • (iii) 11 events: isolated cone cut (after moving to 0.7). • (iv) 6 events have no jets (still to look into jet finding). • not using orange jets! QCD Meeting, 24th March 2005Jeff Standage, York University

8. Further Progress • Have over-ridden orange routines to implement her analysis criteria. • Of those 992 events are still losing 20: • (i) 1 event: Q2 difference (2 cells have different energy). • (ii) 2 events: cosGammaHad. • (iii) 11 events: isolated cone cut (after moving to 0.7). • (iv) 6 events have no jets (still to look into jet finding). • not using orange jets! • Reasons • Q2 difference due to different cell assignment to some cells used in the event (e.g. cells 1162,1178 CG: FEMC, JS: FHAC): • CG uses phantom routine, ccwhat.fpp, to determine cell type. • JS using orange which uses these lines of code: • fbr = 1 + Caltru_CellNr/16384 • ! Determines forward/barrel/rear (1,2,3) • eh = min(2,max(1, mod(Caltru_CellNr,16)/2 -4)) • ! Determines EMC/HAC (1,2) QCD Meeting, 24th March 2005Jeff Standage, York University

9. Further Progress (cont …) • Have over-ridden orange routines to implement her analysis criteria. • Of those 992 events are still losing 20: • (i) 1 event: Q2 difference (2 cells have different energy). • (ii) 2 events: cosGammaHad. • (iii) 11 events: isolated cone cut (after moving to 0.7). • (iv) 6 events have no jets (still to look into jet finding). • not using orange jets! • Reasons (cont …) • Isolated cone differences due to CG applying this cut only if scattered positron angle is between 20 and 140 degrees, while JS applied it throughout. • Hadronic angle, cos differences are due to “extra cells” in my events. • Events with no jets in have not yet been looked at. Suspect same cells difference as the cause. QCD Meeting, 24th March 2005Jeff Standage, York University

10. In Conclusion • For 99p-00 data: • CG has 9227 DIS events with 1+ jet(s). • Using her methods, cuts, etc., I get 9222 • Differences: • CG has 14 events I don’t (2 cos, 7 no jets, no run 37715). • I have 9 that CG doesn’t. • 9 events have different jet data (ET, L/B). • Rest of the events are identical. • Differences due to slight difference in cells used in the events? QCD Meeting, 24th March 2005Jeff Standage, York University

11. Future steps • Nail down last few events cut differences (worth it?). • Currently comparing detector level MC. • Repeat process for the hadron level in MC • (using JT/CG get_hadsys.fpp). • Compare acceptance corrections. • Jet energy corrections. • Cross-sections. • Decide which methods/corrections are the right ones (why)? QCD Meeting, 24th March 2005Jeff Standage, York University