Third chain momentum scale studies
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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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Third chain momentum scale studies

Third chain momentum scale studies

Niels van Eldik ,Peter Kluit, Alan Poppleton

MCP meeting 9 January


Introduction

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


Z mass scale plots ec a

Z mass scale plots: EC A

Chain 3

SA or ME

CB

ID


Z mass scale plots barrel

Z mass scale plots: Barrel

Chain 3


Z mass scale plots ec c

Z mass scale plots: EC C

Chain 3


Z mass scale barrel and endcap

Z mass scale: Barrel and Endcap

Chain 3


Z mass scale plots ec a1

Z mass scale plots: EC A

Staco


Z mass scale plots barrel1

Z mass scale plots: Barrel

Staco


Z mass scale plots ec c1

Z mass scale plots: EC C

Staco


Z mass scale barrel and endcap1

Z mass scale: Barrel and Endcap

Staco


Z mass sa scale chain 3

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


Pt sa scale eta dependence

pT SA scale: eta dependence

Period B

VERY similar structure as mass!

Barrel moved up 70 MeV

(ID scale off)


Z mass cb scale eta dependence

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


Z mass sa scale chain 31

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


Z mass sa scale staco

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!


Pt sa scale chain 3

pT SA scale: chain 3

Period D

Reprocessed

Barrel

moved up

~80 MeV

(ID scale off)


Z mass cb scale eta dependence1

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


Z mass sa scale pt 80 gev

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


Z mass sa scale pt 80 gev1

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


Jpsi mass scale id

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


Jpsi mass scale sa

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


Jpsi mass scale cb

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


Jpsi momentum scale sa id

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….


Interpretation

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%.


Conclusions

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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