INKA USER'S GUIDE Contents 1. Introduction 2 2
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1. transverse momentum Then you would use Histogrammer like this Create a Histogrammer object each histogram will have 250 bins in the region 0 1000 MeV Histogrammer hist new Histogrammer 250 0 1000 Set input and output files hist gt set_input_output Users klapidus development pNb35_NT_a1l1_201011 root Users klapidus development hist_output root Specify the name of the tree ntuple in the input file hist gt init KOSNT add variables names of branches which you d like to study specify numbers of bins and ranges hist gt add_variable PtK0S 14 0 1050 YKOS 11 0 36788 1 46788 hist gt execute 0 0 all events in the input file hist gt finalize Note that you should provide Histogrammer with the names of the variables in the tree branches in the considered example they are PtKOS and YKOS Assume you d like to make additionally an m y analysis in the same time Then you add the following command to the script above hist gt add_variable MtK0S 15 500 1500 YKOS 11 0 36788 1 46788 Histogrammer also supports the one dimensional case This way you make a py analysis hist gt add_variable PtK0S 14 0 1050 Now all the necessary histograms are in the output file What you usually need to do next is to fit them in order to find background contributions and extract signals This is a job of Fitter see section 3 2 2 Multiple file input In order to us2. x NDF of the fit there is a method Float_t Fitter get_chi2_norm_integral_spectrum Example of usage chi2 fit gt get_chi2_norm_integral_spectrum INKA USER S GUIDE A method Fitter get_fit_param_integral_spectrum Int_t n fit param Float t value allows to access the value of a parameter after the fit of the integral spectrum 8 KIRILL LAPIDUS 4 Corrector 4 1 Basic usage Corrector reguires three files 1 a file with raw distributions delivered by Fitter 2 a file with simulated usually in 47 particles all necessary variables like PtKOS YKOS should be in a tree and 3 a file after final analysis symmetric to the experimental data create a Corrector object Corrector corr new Corrector give a name of the tree corr gt init KOSNT set the input file with raw histograms corr gt set raw file Users klapidus development hist output root set an output file corr gt set_output Users klapidus development corr_output root add a geant cleaner file and a file after analysis geant cleaner is a file with initial simulated particles corr gt add_file Users klapidus development K0S_simDst_clean_shift 1 2 root Users klapidus development pNb_KOS_simMicroDst_list_shift root set vertex cuts corr gt set_svertex_cuts vdx mtd vda vdb add distributions you want to correct corr gt add_variable PtK0S nptbins 0 1050 YKOS nybins yleft yright corr g
3. 1 2 291 22 2 3 2 4 2 5 2 6 3 3 1 3 2 3 3 3 4 3 5 4 1 4 2 4 3 4 4 INKA USER S GUIDE KIRILL LAPIDUS CONTENTS Introduction Histogrammer Basic usage Multiple file input Arbitrary cuts Secondary vertex cuts Integral spectrum Additional methods Fitter Basic usage Changing the initial fit parameters Reading writing fit parameters from into a file Changing fit parameters for particular bins Integral spectrum Corrector Basic usage Multiple simulation files Cuts Employing the Geant info number Date January 26 2012 00 000000 0aDd oo okk a a A bd 2 KIRILL LAPIDUS 1 INTRODUCTION INKA is a class library that allows to make a differential analysis via invariant mass for example K gt HT or A gt p 7 It includes three main classes Histogrammer Fitter and Corrector The main feature of INKA is that a user doesn t have to create fill save any single histogram Even in the case INKA is not suited for a particular analysis you might try the nifty Histogrammer class 1There is a way to use INKA for a single particle analysis please contact the author if you need more information INKA USER S GUIDE 3 2 Histogrammer The task of this class is to produce histograms As an input it takes a file or files after the final analysis 2 1 Basic usage Let s assume that you need to produce invariant mass distribu tions in 11 bins in y rapidity variable and 14 bins in p
4. ackDist Float_t aVerDistA Float_t aVerDistB These cuts will be also applied to all histograms including the integral spectrum see below 2 5 Integral spectrum It is useful to have an opportunity to produce an integral spectrum without any restrictions except for the vertex or other added cuts A special method exists for this case Histogrammer set inv mass all nbins min max nbins number of bins you d like to have min max minimum maximum value of the variable If you use this method then a folder named integral spectrum will be created in the output root file 2 6 Additional methods To set the title of the X axis Histogrammer set invmass title TString ainvmass title INKA USER S GUIDE 5 3 Fitter 3 1 Basic usage In case you don t need any special features work with Fitter is simple you only need to specify the input file and which histograms you d like to fit create a Fitter object 250 is a minimum number of counts in the histogram 380 and 600 define a range in which the fits will be performed Fitter fit new Fitter 250 380 600 input file output of the Histogrammer fit gt set input Users klapidus development hist output root fit gt init fit gt add_variable PtKOS 14 0 1050 YKOS 11 0 36788 1 46788 fit gt execute fit gt finalize After Fitter is done in the input file a folder named fit_PtKOS_YKOS for the considered example with raw spect
5. e several files as an input one should use the method Histogrammer add file Note that in this case one has also to use the method Histogrammer set output An example of usage 4 KIRILL LAPIDUS Histogrammer hist new Histogrammer 250 0 1000 Set the input and output files hist gt set_output Users klapidus development hist_output root hist gt add file Users klapidus development input1 root hist gt add_file Users klapidus development input2 root hist gt add_file Users klapidus development input2 root 2 3 Arbitrary cuts To apply cuts to the data sample use this method Histogrammer add_cut TString name TString operator Float_t value Let s consider an example you d like to apply a cut on the ThetaKOS variable ThetaK0S lt 30 In the same time you d like to fulfill the conditions N_Tracks gt 3 and N_Tracks lt 7 The following code will do the job Histogrammer hist new Histogrammer 250 0 1000 hist gt add_cut ThetaK0S lt 30 add the first cut hist gt add_cut N_Tracks gt 3 add the second cut hist gt add_cut N_Tracks lt 7 add the third cut hist gt execute 0 0 all events in the input file All cuts you add in this way will be applied to all histograms including the integral spectrum see below 2 4 Secondary vertex cuts To apply secondary vertex cuts there is a special method Histogrammer set svertex cuts Float t aVerDistX Float t aMinTr
6. ra will appear 3 2 Changing the initial fit parameters For the fitting of histograms the fol lowing 12 parameter function is used y par0 TMath Gaus x par1 par2 gauss1 par3 TMath Gaus x par1 par4 gauss2 par5 par6 x par7 x x par8 x x x polynomial par9 TMath Landau x par10 par11 Landau function Two gaussians correspond to a signal a background is fitted by a polynomial Landau function Initial values of parameters and their limits are set inside the code fitter cc There is a possibility to change them globally for all fits in a user program with the following methods Fitter set fit param Int t n_fit_param Float t value Fitter set_fit_param_limits Int_t n fit param Float t value min Float t value max An example of usage Fitter fit new Fitter 250 fit gt set fit param 10 525 fit gt set fit param 11 30 fit gt set fit param limits 10 521 529 fit gt execute fit gt finalize 2At the moment only this function can be used Eventually more flexibility will be offered 6 KIRILL LAPIDUS 3 3 Reading writing fit parameters from into a file Use this method to write all obtained fit parameters into a file Fitter write fit param TString avarnamel TString avarname2 TString aoutput and this one to read fit parameters from a file this way you set them as initial values for the fit Fitter read fit param TString avarnamel Int_t anbins1 TSt
7. ring avarname2 Int t anbins2 TString ainput An example of usage Fitter fit new Fitter fit gt read fit param PtKOS nptbins YKOS nybins param output1 txt fit gt write fit param PtKOS YKOS param output1 txt Note that a file with fit parameters also contains fit ranges parameters xleft and xright for every single fit so you can modify it as well 3 4 Changing fit parameters for particular bins This method is not avail able anymore since the needed functionality is completely covered by parameter in put output see 3 3 Since the fit doesn t always work perfectly sometimes it is needed to change the fit parameters for a particular bin This is possible with the method Fitter change fit Int t j Int_t i Float_t axleft Float_t axright where j and i define a bin At the moment only the range of the fit can be changed but it is straightforward to extend the method In future a more general and flexible approach will be developed 3 5 Integral spectrum In 2 5 the way to produce an integral spectrum was ex plained With the method Fitter fit_integral_spectrum Float_t afit_range_left Float_t afit_range_right you can fit the integral spectrum two parameters define the fitting range and with Fitter get_sig_bg_integral_spectrum Float_t amp signal Float_t amp bg extract the values of the signal and the background in the integral spectrum In case you need to access normalized x
8. t execute 0 corr gt correct 4 2 Multiple simulation files Corrector supports a possibility to use many in put files with weights corr gt add_file simDst_clean_1 root channel1_final_analysis root 1 5 corr gt add_file simDst_clean_2 root channel2_final_analysis root 7 6 Note that in case you don t provide a weight a default value of 1 0 will be assigned 4 3 Cuts In full analogy with Histogrammer Corrector has methods to apply secondary vertex and arbitrary cuts Corrector set_svertex_cuts Float_t aVerDistX Float_t aMinTrackDist Float_t aVerDistA Float_t aVerDistB Corrector add_cut TString name TString oper Float_t value 4 4 Employing the Geant info number To weight entries which have a Geant info number assigned the following method should be used Corrector add_channel_weight Int_t geant_info_num Float_t weight An example of usage Corrector corr new Corrector corr gt add_channel_weight 3227810 0 3325 corr gt add_channel_weight 1835783 0 00147 INKA USER S GUIDE corr gt correct
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