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Third chain momentum scale studies

Third chain momentum scale studies. Niels van Eldik ,Peter Kluit, Alan Poppleton MCP meeting 9 January. Introduction. Data sets: Jpsi and Z mc12_8TeV.208001.Pythia8B_AU2_CTEQ6L1_pp_Jpsimu4mu4.merge.AOD.e1331_a159_a173_r3549/

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Third chain momentum scale studies

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  1. Third chain momentum scale studies Niels van Eldik ,Peter Kluit, Alan Poppleton MCP meeting 9 January

  2. Introduction Data sets: Jpsi and Z mc12_8TeV.208001.Pythia8B_AU2_CTEQ6L1_pp_Jpsimu4mu4.merge.AOD.e1331_a159_a173_r3549/ mc12_8TeV.147807.PowhegPythia8_AU2CT10_Zmumu.merge.AOD.e1169_s1469_s1470_r3542_r3549/ data12_8TeV.periodB.physics_Muons.PhysCont.AOD.t0pro13_v01/ Period D ZMUMU reprocessed by Felix: group.det-muon.periodD.physics_Muons.PhysCont.DRAW_ZMUMU.reco.20121112.v1_ESD/ Event selection MCP ID track selection Z selection: Period D For Zs pT > 25 both combined muons mass within 10 GeV Period B pT > 25 and pT > 7 GeV -> measure the 10-45 GeV range The muons should be isolated (track: ptcone40<0.2 pT and calorimeter etcone10<0.2 pT) Jpsi selection: Period B two CB muons pT >7 GeV mass within 150 MeV

  3. Z mass scale plots: EC A Chain 3 SA or ME CB ID

  4. Z mass scale plots: Barrel Chain 3

  5. Z mass scale plots: EC C Chain 3

  6. Z mass scale: Barrel and Endcap Chain 3

  7. Z mass scale plots: EC A Staco

  8. Z mass scale plots: Barrel Staco

  9. Z mass scale plots: EC C Staco

  10. Z mass scale: Barrel and Endcap Staco

  11. Z mass SA scale: chain 3 Period B Selection: pT > 25 and pT > 25 GeV Barrel OK within better than 50 MeV rms 180 MeV over 25x16 eta phi points

  12. pT SA scale: eta dependence Period B VERY similar structure as mass! Barrel moved up 70 MeV (ID scale off)

  13. Z mass CB scale: eta dependence Period B Structure comes from the SA… Main shift of -85 MeV from ID in Barrel and MS in forward

  14. Z mass SA scale: chain 3 Period D Reprocessed Selection: pT > 25 and pT > 25 GeV For very high precision tests Period D should be better… Same conclusion slide 11: Barrel is OK

  15. Z mass SA scale: staco Period D Reprocessed Selection: pT > 25 and pT > 25 GeV Data-MC for Chain3 and Staco is almost point by point identical!

  16. pT SA scale: chain 3 Period D Reprocessed Barrel moved up ~80 MeV (ID scale off)

  17. Z mass CB scale: eta dependence Period D Reprocessed Structure comes from the SA… Main shift of -87 MeV from ID in Barrel and MS in forward

  18. Z mass SA scale: pT 80 GeV Period D Reprocessed Note scale Barrel and Endcap compatible with “0” at high pT Transition |eta| 1-1.7 region shows a dip; Bfield? pT > 25 GeV

  19. Z mass SA scale: pT 80 GeV Period B Note scale Period B and reprocessed D change due to improved alignment in Transition region and Endcap; Barrel rather stable

  20. Jpsi mass scale: ID Jpsi only period B Simple average of mass in 200 MeV region Data-MC test -2.5 MeV rms over eta-phi (16*25) 3 MeV

  21. Jpsi mass scale: SA Simple average of mass in 200 MeV region. Average is off by 40 MeV wrt PDG Data-MC test -5 MeV rms over eta-phi (16*25) 4 MeV

  22. Jpsi mass scale: CB Simple average of mass in 200 MeV region. Average is off by 10-30 MeV wrt PDG Data-MC test -5 MeV rms over eta-phi (16*25) 3 MeV Data and MC agree to -5 MeV level

  23. Jpsi momentum scale: SA-ID Simple average of pT SA – pT ID. Data-MC test -36 MeV rms over eta-phi (16*25) 42 MeV We model Eloss Data-MC at the level of -36 MeV and the spread over the detector is 42 MeV….

  24. Interpretation E loss tuning It is clear that we can profit from a more precise Eloss tuning for the SA momentum. This affects in particular the Jpsi mass. Note however that the data-MC differences are relative stable under this and more importantly the difference is pretty small. In terms of numbers: data-MC for the Jpsi mass is different by 5 MeV. How well do we know the Eloss description in data-MC? From the Jpsis one observes a pT SA – pT ID 36 MeV shift (for pT > 7 GeV) and and r.m.s. of 42 MeV. From the Zs one gets a pT SA – pT ID 80 MeV shift (pT > 25 GeV) with an rms of 130 MeV. An interpretation could be that we know the Eloss in the material to the level of 42 MeV r.m.s. over the full detector. On top of that there is a pT dependent effect that is present in the transition region that amounts to about 100 MeV r.m.s. This could be due to the B field in this region. Locally it would correspond to a correction of at most 0.7%.

  25. Conclusions • The mass scale for the chain 3 for data-MC is good at the level of 0.1% and of the same level as Staco. • It is important to retune the Eloss for chain 3; this will result in smaller biases in the Jpsi mass. • This can be done using the MC12 MC samples for Zs, Jpsis and single muons. • It is seems likely that there is a pT and thus Bfield dependent effect in the transition region that is responsible for the eta dependent structure that is observed with the Z data.

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