Omega and Eta Analysis
Because the
ω\omega
and the
η\eta
can both decay into
π+ππ0\pi^+\pi^-\pi^0
, the analysis in this decay channel is organized in a single analysis task: AliAnalysisTaskNeutralMesonToPiPlPiMiPiZero.cxx.
Analogue to the neutral pion analysis, there is a single macro that starts the first afterburners needed to process the output files of the task. The start_FullOmegaMesonAnalysis.sh macro -- even though the name might be misleading -- takes care of the signal extraction (using ExtactSignalPiPlPiMiPiZero.cxx) and its correction (using CorrectSignalPiPlPiMiPiZero.cxx) for
ωπ+ππ0\omega\rightarrow\pi^+\pi^-\pi^0
and
ηπ+ππ0\eta\rightarrow\pi^+\pi^-\pi^0
.
start_FullOmegaAnalysis.sh [-$OPTION] $Data-file.root [$MC-file.root] eps
In case either the data- or MC-file is missing, you can just pass the macro a dummy string. E.g the command
bash start_FullOmegaAnalysis.sh /Path/To/datafile.root bla eps
will run the signal extraction macro two times -- once for the
ω\omega
and once for the
η\eta
-- but won't run the correction macro afterwards, because it detected that you didn't provide it with a valid MC file.
There are several options available for this macro (which are still work in progress) that let you e.g. only analyse the
ω\omega
(--omegaOnly) or the
η\eta
(--etaOnly). For a full list of available options please use the -h flag.
If you start the start_FullOmegaAnalysis.sh macro by hand, you will be asked about several things needed for the signal extraction and correction. The questions are similar to the ones asked e.g. by start_FullMesonAnalysis_TaskV3.sh, however there are some differences, so we will go through the questions one-by-one in the following chapter.

start_FullOmegaAnalysis.sh

First we start the macro using (e.g.):
bash start_FullOmegaMesonAnalysis.sh /referenceDirectory/Legotrain-vAN-20171122-7TeV-omegaAnalysis/LHC10_GammaConvNeutralMesonPiPlPiMiPiZero_0_29.root /referenceDirectory/Legotrain-vAN-20171122-7TeV-omegaAnalysis/LHC14j4_GammaConvNeutralMesonPiPlPiMiPiZero_0_29.root eps
First, the macro will print the full path of the input files you specified. This comes in handy to track down if you got something wrong while using e.g. relative paths. The first thing you will be asked is to specify the method (mode) used to reconstruct the decay-photons of the
π0\pi^0
:
The data file specified is /data/alice/pp7TeV/Legotrain-vAN-20171122-7TeV-omegaAnalysis/LHC10_GammaConvNeutralMesonPiPlPiMiPiZero_0_29.root
The MC file specified is /data/alice/pp7TeV/Legotrain-vAN-20171122-7TeV-omegaAnalysis/LHC14j4_GammaConvNeutralMesonPiPlPiMiPiZero_0_29.root
Which mode are you running? 40 (PCM-PCM *), 41 (PCM-EMCAL *), 42 (PCM-PHOS *), 43 (PCM-DCAL), 44 (EMCAL-EMCAL *), 45 (PHOS-PHOS*), 46 (DCAL-DCAL), 47 (PCM-DALITZ), 48 (EMCAL-DALITZ), 49 (PHOS-DALITZ), 50 (DCAL-DALITZ)
As you may have noticed, the mode numbers used for this analyisis differ from the ones used for the
γγ\gamma\gamma
-analysis. This was implimented to avoid any conflicts between the two analysis (e.g. between
ηγγ\eta\rightarrow\gamma\gamma
and
ηπ+ππ0\eta\rightarrow\pi^+\pi^-\pi^0
). The modes currently implemented are marked with a '*'. For the sake of completeness, you can find a nicely formated table of the numbering scheme used in this analysis below:
mode
reconstruction technique
40
PCM-PCM
41
PCM-EMCal
42
PCM-PHOS
43
PCM-DCal
44
EMCal-EMCal
45
PHOS-PHOS
46
DCal-DCal
47
PCM-Dalitz
48
EMcal-Dalitz
49
PHOS-Dalitz
50
DCal-Dalitz
This information will later be used by the signal extraction macro to check if your choice is actually consistent with the input files you provided. After you entered the desired mode, you will be asked
Do you want to take an already exitsting CutSelection.log-file. Yes/No
If you select no, the macro will write all the cut strings found in the input file in a file called CutSelection.log sperated by [ENTER] (using the MakeCutLog.C macro) and then run the signal extraction (and correction) for each cut string in that file. If you select yes, the macro will search for an existing CutSelection.log file in the current working directory and run the afterburners for all cut strings contained in that file. This option is therefore useful if you just want to run the afterburners on a particular set of cut strings.
Let's assume we want to run the afterburners on all the cuts contained in the input file, so we answer with "no". The output should look something like this:
-> found TopDir: GammaConvNeutralMesonPiPlPiMiPiZero
0_00000113_00200009327000008250400000_0103503800000000_302010708_0153503000000000
0_00000113_00200009327000008250400000_0103503800000000_302010708_0b53503000000000
0_00000113_00200009327000008250400000_0103503800000000_302010708_0c53503000000000
0_00000113_00200009327000008250400000_0103503800000000_302010708_0d53503000000000
Which collision system do you want to process? 8TeV ([email protected]), 7TeV ([email protected]), 13TeV ([email protected], 900GeV ([email protected]), 2.76TeV ([email protected]), PbPb_2.76TeV ([email protected]), pPb_5.023TeV ([email protected])
Make sure that the macro detected all the cuts correctly and proceed by entering the collision system you are analysing. In this example, we will choose [email protected]
The collision system has been selected to be 7TeV.
How many p_T bins do you want to use for Omega? 36(7gev), 37(8gev), 38(10gev), 39(12gev), 40 (16gev), 41 (20gev), 42 (25gev)
After the collision system was selected, you have to specify how many
pTp_T
-bins should be analysed. This question is a bit misleading, because you are actually specifying up to what index in your
pTp_T
-bin array stored in ExtractSignalBinning.h you want to do the analysis. The total number of analysed bins would then be
NStartBinNEndBinN_{\text{StartBin}}-N_{\text{EndBin}}
. Important: Make sure that the
pTp_T
-bin choosen here is not actually greater than the length of the array containing your binning for this analysis (see ExtractSignalBinning.h) ! Also: At the moment only the use of same number of
pTp_T
bins for
ω\omega
and
η\eta
are supported.
You have chosen 14 pt bins for Omega
mode has been chosen: 40
I went into standard modes
Which fit do you want to do? CrystalBall or gaussian convoluted with an exponential function? CrystalBall/Gaussian?
Gaussian
Gaussian chosen ...
Please check that you really want to process all cuts, otherwise change the CutSelection.log. Remember at first all gamma cutstudies will be carried out. Make sure that the standard cut is the first in the file. Continue? Yes/No?
Yes
After choosing the desired fitting function for the
ω\omega
/
η\eta
-peak (using gaussian is recommended, no testing was done for crystal ball so far), you will be asked if you are sure to process all cuts. After confirming this final question, the afterburners should go to work!

ExtractSignalPiPlPiMiPiZero.C

This macro is used to extract the invariant mass distribution of the meson signal for each analyzed
pTp_T
-bin and its usage and tasks are almost identical to ExtractSignalV2.C. You can start the macro using:
root -b -x- q -l 'TaskV1/ExtractSignalPiPlPiMiPiZero.C+("$MESONAME","/path/to/input.root","$CUTNUMBER","$SUFFIX","$MCOPTION","$ENERGY","Gaussian","","","",$NPTBINS,$OPTIONADDSIG,$MODE)'
Example usage (Data):
root -b -x- q -l 'TaskV1/ExtractSignalPiPlPiMiPiZero.C+("Omega","/data/alice/pp7TeV/Legotrain-vAN-20171122-7TeV-omegaAnalysis/LHC10_GammaConvNeutralMesonPiPlPiMiPiZero_0_29.root","0_00000113_00200009327000008250400000_0103503800000000_302010708_0d53503000000000","pdf","kFALSE","7TeV","Gaussian","","","",14,kFALSE,40)'
Example usage (MC):
root -b -x- q -l 'TaskV1/ExtractSignalPiPlPiMiPiZero.C+("Omega","/data/alice/pp7TeV/Legotrain-vAN-20171122-7TeV-omegaAnalysis/LHC14j4_GammaConvNeutralMesonPiPlPiMiPiZero_0_29.root","0_00000113_00200009327000008250400000_0103503800000000_302010708_0d53503000000000","pdf","kTRUE","7TeV","Gaussian","","","",14,kFALSE,40)'

Further Processing

The following macros that allow further processing of the extracted signals have been implemented for
ω\omega
/
η\eta
analysis so far: