SpartyJet User`s Manual
Contents
1. DelphesInput DelphesInputMaker is a minor extension of NTupleInputMaker that reads the ROOT files produced by the detector simulator DELPHES Only calorimeter cells are read in 14 6 2 StdTextInput Sample data J1_Clusters dat This form of input reads ASCII files To separate events put one of the following lines between the events Event event N n only the E or e is important in the first two The form of the four vectors should be E px py pz This input is configured simply with input SJ StdTextInput data Ji_Clusters dat If the form is the opposite px py pz E then call the function input invert_input_order True and it will be read in properly An example of this input can be seen in data J1_Clusters dat 6 3 StdHepInput Sample data ttbar_smallrun_pythia_events hep This form of input reads StdHEP format XDR files It will look for particles with the status code of 1 final state It is also able extract the PDG ID code for each particle from the input data to allow further filtering and matching Access to intermediate particles such as the participants in the hard scattering or B hadrons from b quark decays should be possible in the near future This input is configured simply with SJ StdHepInput data ttbar_smallrun_pythia_events hep NOTE To read StdHep files you must enable StdHep compilation as ex plained in Section 2 2 6 4 CalchepPartonTextInput Sample2. Eile Edit View Options Tools j canvas_group X Spartyjet Analysis Tool num cols num rows AntiktT0Pruned 9 1 P GeVie y jetcoll letCollExtended object at 0x67b5510 gt inputcol a tInputCollection object at x67bSade gt retriever lt ROOT SpartyJet JetRetrieverFile object at 0x67a3600 gt input_retriever None 3 3 Filling collection CALOMDF_ 3 Filled collection num 3 num ind 28 input size 28 JetCollection AntiKt10 jetcoll lt R00T SpartyJet JetCol1Extended object at x67b4d3 gt tInputCollection object at x67bSade gt retriever lt ROOT SpartyJet JetRetrieverFile object at x6703600 gt inputcoll lt ROOT Spart input_retriever None 0 Fillling collection AntiKt10_ Filled collection mum 3 num ind 28 input size 28 JetCollection CA1 Filtered jetcoll lt ROOT SpartyJet JetCollExtended object at 0x67b5270 gt inputcoll lt ROOT SpartyJet JetInputCollection object at x67bSade gt retriever lt ROOT SpartyJet JetRetrieverFile object at 0x67a3600 gt input_retriever None 2 Filling collection CAL Filtered_ 2 Filled collection num 3 num ind 28 input size 28 BE 23 Besef leal Reset Line Styled F JetCollections from data output mWjets raot AntiktiOPruned Y CATOMDF W Antiko W CA10Filtered M CA10Wtag j JetCollections from data outpu F JTool root IF AntiktioPruned M CATOMDF M Antiktio Event by Event plots Previous Even 28 lt JNextEvent
3. To meet these goals SPARTYJET is modular it consists of bricks of software put together allowing one to e access a wide variety of input formats e perform any operation on this input including jet finding modification and measurement e save all results and any associated quantities in a ROOT TTree SPARTYJET extends basic jet finding with a large library of built in jet tools to implement input and output cuts jet modifications such as filtering and pile up subtraction and jet measurements moments that can be calculated for every jet and stored in the output file A typical SPARTYJET analysis consists of a script that describes a set of jet algorithms each with a set of jet tools that modify and measure the found jets Section 3 walks through a simple example In addition a graphical interface is in development that allows the user to explore jet analyses interactively 2 Installation 2 1 Requirements OS Most Linux distributions Mac OS X Cygwin presumably possible but not tested Compiler Tested with gcc built with make ROOT Recent version tested with 5 26 but older versions probably OK FastJet included Relies on FASTJET for most jet finding and some internal features Can link against an external copy or build the built in version Python optional Python 2 4 or later not necessary but highly recom mended The Python interface uses PyROOT so you must have built ROOT with this enabled We
4. step that runs the tagger on a given jet WTaggerToo1 This tool wraps the W tagging method of Cui Han and Schwartz which includes a large number of substructure and mass cuts The cuts are taken from data files in external wtag 1 00 data So far there is no way to re train the cuts from within SPARTYJET the idea is to take a pre trained W tagging method and plug it into a SPAR TYJET analysis Since the tagger is taken out of the box there are no input parameters 12 WTaggerToo1 5 4 Miscellaneous Tools ForkToolParent and ForkToo1Child This pair of tools allows the forking of JetTool chains ForkToolParent merely saves a copy of its input A ForkToolChild is associated with a specific parent and it reads in the JetCollection saved by its parent This allows for example one jet algorithm to be run combined with several different jet modifying tool chains for comparison See FJToolExample py for a usage example CalorimeterSimTool This tool applies a very simple calorimeter simulation to its input jets Inputs are sorted into calorimeter cells on a specified 7 grid For each non empty cell a massless output particle is created with the direction of the cell and the total energy of all particles in the cell JetNegEnergyTool This tool is meant to be run twice once before jet finding and once afterward On first run the tool finds and stores all input par ticles with negative energy For each such particle it inverts
5. F Lego plot F 2D view I Snowmass potential I Parameter space I Event dump Draw On the fly algorithms algo type El bs IS MAA main param param 1 param 2 Create F CA10Filtered M CA10Wtag Run plots Choose a variable to be drawn Cer ptr etai phi mass And or provide the expression s to be draw below use as a wildcard ex _pt to be replaced by checked jets Separate multiple variables with Expression Ex _mass Cuts Ex _pt gt 100 amp amp _pt lt 200 Legend entries for each curve Ex ttharttdijet Draw resef T Normalize M LogX M LogY M No Title M Same Pad Figure 2 A screenshot of the SPARTYJET graphical interface Contact information Any questions comments suggestions email Pierre Antoine Delsart Joey Huston Brian Martin Chris Vermilion delsart in2p3 fr huston pa msu edu marti347 msu edu verm uw edu 18 Pruned Anti k Filtered Number of jets a 2 mass Plgo type _mass gt 0 amp amp _mass lt 100 Pruned Anti k_ T Filtered r Figure 3 An example canvas produced by the run plot option above with the options that produced it below 19
6. and the names of the branches As an example to set up an NtupleInputMaker to read the file data J2_clusters root if you don t know how variables are internally stored in your ntuple do the fol lowing root 1 data J2_clusters root root 0 clusterTree gt MakeClass test Open the file test h and check to see how the variables are stored In this example we see lines like vector lt float gt Cluster_eta indicating that our 4 vectors are stored in vectors of floats Now to configure SPARTYJET to accept this we need to e Create an NtupleInputMaker of the correct type in our case vector lt float gt for eta phi pt E input SJ NtupleInputMaker SJ NtupleInputMaker EtaPhiPtE_vector_float For full list of Input codes see JetCore InputMaker_Ntuple hh e Configure the names of the TBranches input set_prefix Cluster_ input set_n_name N input set_variables eta phi p_T e input setFileTree data J2_clusters root clusterTree e Specify if input is massless only useable in eta phi pt E mode if true pt is ignored input set_masslessMode True e Set the input file and tree names input setFileTree data J2_clusters root clusterTree Python Shortcut To allow SPARTYJET to configure your Ntuple using some assumptions use the following helper function input createNtupleInputMaker data J2_clusters root inputprefix Cluster
7. data gg_ggg_events dat This form of input reads output from CalcHEP It reads in the number of ini tial and final state particles and then for each event saves only the information for the final state particles This input is configured simply with SJ CalchepPartonTextInput data gg_ggg_events dat 15 6 5 HepMCInput Sample data HepMC_sample dat This form of input reads HepMC version 2 format ASCII files HepMC ASCII files contain the following separators E Denotes new event V Information about a vertex P Information about a particle This class reads in the 4 vectors of the particles denoted with a status code of 1 not decayed final state 6 6 Pythialnput This form of input generates and reads events directly from PYTHIA without ever having to write them to a file This requires ROOT s PYTHIA interface versions 6 and 8 will both work See examples_py pythiaExample py for an example of using PYTHIA in this way 6 7 Input Options Multiple input files The MultiInput class can be used to string a set of input files together See examples_py mergedInputExample py for an example Note that the current implementation opens all input files before beginning which may be inefficient Rejecting bad input The InputMaker can be set to remove 4 vectors with negative energy and non physical momenta by using the following function input reject_bad_input bool1 The current default is false no checks
8. When the end of the MB file is found it will simply continue from the be ginning There is a third optional Boolean argument to add_minbias_events that tells JetBuilder whether to draw the number of MB events from a Pois son distribution In this case n is the Poisson mean or expected number of MB events 4 3 JetTool Options JetTools are blocks of code that act on a set of Jets implemented as a JetCollection A set of JetTools forms a JetAlgorithm and a JetBuilder holds a set of JetAlgorithms that are each run on its inputs Examples of specific tools can be found in the Jet Tools section JetAlgorithms are added to the via builder add_default_alg too1 where tool is a single JetTool typically a jet finder which forms the basis of the tool chain Default tools are added before and after currently just negative energy correctors if this option is enabled Alternatively to add a JetAlgorithm possibly with multiple JetTools al ready associated with it builder add_custom_alg alg JetTools are added to the execution sequence via builder add_jetTool tool or to the front of the sequence with builder add_jetTool_front tool These add the specified JetTools to all JetAlgorithms A second string argu ment may be passed to these methods specifying which JetAlgorithm the tool should be added to A single sequence of JetTools is run on the input particles before they are passed to each JetAlgorithm This sequence
9. anticipate that the Python interface will migrate to SWIG instead of PyROOT with a future release Fortran compiler optional Needed to compile the libraries allowing Std Hep reading Tested with gfortran 2 2 Compilation To compile Setup ROOT such that root config is in your path for example source root bin thisroot sh cd spartyjet source setup sh make e Options SPARTYJET has several building options to note 1 FastJet SPARTYJET depends on FASTJET for jet finding and some internal features and the latest version is included in the SPARTYJET distribution If you prefer to use your own installation simply add your fastjet bin to the environmental variable PATH such that fastjet config can be found NOTE If you have linking problems between your version of FAST JET and SPARTYJET either recompile your FASTJET with the with pic option enabled before compilation or allow SPARTYJET to compile its own version Note also that to enable all FASTJET plugins you must pass the enable allcxxplugins flag to configure This is done by default for the built in version 2 StdHEP libraries These require a FORTRAN compiler and are auto matically compiled if you have gfortran f77 or g77 in your PATH If you would like to try a different compiler set the environmental variable F77 to the compiler binary 3 Pythia 6 8 interface If you have ROOT compiled with the Pythia 6 andor Pythia 8 interfaces enabled you can us
10. SPARTYJET User s Manual Pierre Antoine Delsart Kurtis Geerlings Joey Huston Brian Martin and Christopher Vermilion February 9 2011 Contents 2 Installation 2 1 Requirements o ee ee ee ee ee 2 2 Compilation oops posa da a K amp B Bok de ee 2 3 RUNN 00 Sar ar a a a a a RA Ew Be eS 3 A Simple Example 4 1 Input Functions aaa 4 2 Minimum Bias Overlay 4 3 JetTool Options s s e sea s tcd tacsa pr ddedryd 44A Constit ents gt gt a wa sw tea 404 528 be ee A 4 5 Text File Output oaa o 5l Selectors s 2h Ad rara atadh dpe DS 5 2 Jet and Event Moment tools a oaoa 5 3 Jet Substructure Tools aoa aoa aa a 5 4 Miscellaneous Tools o o aoa a a a a 6 1 NtuplelnputMaker 6 2 StdTextinputl o a GAR aaa ca oe a a A ee ce cee 6 4 CalchepPartonTextInput 000 6 5 HepMCInput 2 2 2 202 202 0000007 6 6 Pythialtiput 2 acces eae eS Gee BEE See es 6 7 Input Options lt gt o a ac soe aos eos b a a eee ee es 7 Output 16 7 1 Output variable type 17 T2 Constituents lt a AER A 17 8 Analysis 17 1 Overview SPARTYJET is a set of software tools for jet finding and analysis built around the FasTJET library of jet algorithms Besides physics motivations it has been written with three goals in mind e ease of use e flexibility e extensibility
11. as been assigned For example myTree Draw InputJet_e Antikt10_ind 0 will give the energy distribution of constituents in jet number 0 i e highest pr jets for the Antikt10 collection 8 Analysis A graphical user interface is under development for interactive SPARTYJET anal ysis Users can test this out with the guiExample py in the examples_py di rectory A screenshot of the GUI in action is shown in Fig The user can select which algorithms to view by ticking the boxes under JetCollections On the left are several event by event views which will be drawn separately for each algorithm The number of rows and columns are set in the upper left Additional algorithms can be run event by event on the fly using the menu in the lower left On the right full run plots can be selected which are plotted for all algo rithms together an example of this output is shown in Fig B Check boxes are provided for the standard four momentum variables but any stored jet moment can also be plotted by entering the name in the box below e g _subjetM to plot the subjet mass if the HeavierSubjetMass moment has been used Note 17 that is a placeholder for the algorithm name Cuts can be added using TCut syntax e g AntiKt10_mass gt 150 amp amp AntiK10_mass lt 200 Finally legend labels for each algorithm can be given the syntax is ROOT TLatex text e g phi_ 0 produces dp Grab File Edit Capture Window
12. e this from within SPARTYJET to generate events in Pythia and feed the output directly to SPARTYJET To enable this set the variable PYTHIA6DIR andor PYTHIASDIR If you do not have PYTHIA support in ROOT you can add it by doing cd ROOTSYS configure enable pythia6 enable pythia8 with pythia6 libdir my pythia6 with pythia8 incdir my pythia8145 include with pythia8 libdir my pythia8145 lib make e Libraries This will build a set of libraries in spartyjet libs that you can load from a ROOT session or Python script or you can link to to build an executable libs libFast JetCore so FASTJET code and some wrappers libs libJetCore so Core infrastructure libs libIO so Facilities for reading and writing a variety of file formats libs libFastJet so Tools that rely on FASTJET including jet fnding libs libJet Tools so Other JetTools libs libEventShape so Thrust and other eventshapes libs libSpartyDisplay so SPARTYJET GUI libs libExternalTools so A set of external jet tools with wrappers 2 3 Running Working examples of how to use SPARTYJET can be found in the following directories spartyjet examples_py Python scripts recommended spartyjet examples_C ROOT scripts and compiled programs in C The Python interface to SPARTYJET is strongly preferred and C access may be deprecated in a future release We are also planning to switch from PyROOT to SWIG for Python access to SPARTYJET librari
13. ent tools in action The following are other moment storing tools available in SPARTYJET HullMomentTool This tool finds the convex hull enclosing each jet and saves the hull length and area as Hull and HullA respectively EtaPhiMomentTool This tool calculates angular second moments in 7 and of each jet stores them as M2eta and M2phi PtDensityTool This tool calculates each event s pr density using FASTJET It does this by finding all the jets in the event with no minimum pr requirement It then extracts the pr density from these jets by selecting the mean pr density for each bin in 7 These pr densities are stored as ptDensity and the 7 bin limits are stored as ptDensityBins JetAreaCorrectionTool This tool uses the area of each jet and the pTDen sity found by the PtDensityTool to calculate a correction stored as jet moment JetAreaCorr to the jet s pr YSplitterTool This tool uses FASTJET to calculate the y values associated with a set of recombinations In this implementation SPARTYJET will run a FASTJET algorithm of the user s choice on the constituents of a given jet It can be called with either of the following constructors YSplitterTool float R fastjet JetAlgorithm alg int ny int njet YSplitterTool fastjet JetDefinition jet_def int ny int njet where njet is the number of jets for which the y values will be calculated and ny is the number of y values to calculate for each jet 5 3 Jet Substructure Tools Se
14. es with ROOT only used for output To use the Python scripts some environment variables needs to be set which can be accomplished via source setup sh in the spartyjet directory This exports the relevant paths to your LD_LIBRARY_PATH and sets the environment variable SPARTYJETDIR which allows the SPARTYJET Python modules and libraries to be accessible from any directory The relevant lines of setup sh could also be copied into your shell s rc file e g bashre 3 A Simple Example The simplest way to get a feel for how SPARTYJET works is to consider an exam ple in this section we walk through the script spartyjet examples_py simpleExample py This script runs the anti ky algorithm on the first 10 events listed in data J1_Clusters dat makes a simple measurement on the found jets and stores the results e Load the libraries that are needed for the algorithms that you are run ning you need to source setup sh in the main directory first to set up environment variables from SpartyJetConfig import e Create a JetBuilder object to manage SPARTYJET jobs The argument sets the output message level options are DEBUG INFO WARNING ERROR Log messages throughout the code are tagged with a message level messages with level lower than the current output level are sup pressed Note that the SpartyJet namespace is loaded as SJ builder SJ JetBuilder SJ INFO e Create an input object of type StdText Input with the file
15. hipped with SPARTYJET The relevant definitions can be found in JetTools 5 1 Selectors These tools allow the user to remove some Jets from an input output JetCol lection and are defined in JetTools JetSelectorTool hh JetPtSelectorTool double ptmin Removes jets with pr below cut JetPtORESelectorTool doule ptmin double emin Removes jets with pr or energy below cuts JetEtaCentralSelectorTool double abs_eta Removes jets outside of cen tral y region JetEtaForwardSelectorTool double abs_eta Removes jets inside of cen tral 1 region JetMassSelectorTool double mass Removes jets with m below cut JetInputPdgldSelectorTool std vector lt int gt pdglds Removes input jets with given PDG IDs Useful when the input jets are just single particles from a Monte Carlo where leptons neutrinos etc are included JetMomentSelectorTool lt T gt std string momentName T min T max Finds the given jet moment calculated by another tool and requires it be within min max T can be any type supporting less than comparison 5 2 Jet and Event Moment tools These tools calculate moments for each jet or event which can be any type that ROOT knows how to store most commonly floats or ints The generic JetMomentTool and EventMomentTool calculate and store any user implemented JetMoment lt T gt or EventMoment lt T gt object See JetTools JetMomentTool hh for some specific examples and FJToolExample py for mom
16. n the Johns Hopkins top tagging method arXiv 0806 0848 the latter re produces the mass drop step in the the Higgs analysis of See JetTools TopDownPruneTool hh The constructors are JHPruneTool double delta_p 0 1 double delta_r 0 19 int max_split 2 string name JHPrune MassDropTool double mu_cut 0 67 double ycut 0 09 int max_split 1 string name MassDrop max_split is the number of recursions to allow looking for symmetric split tings max_split 1 continues until all branchings are unresolved Note that this implementation of the Johns Hopkins pruning step is slightly dif ferent than the original in that asymmetric branchings below the main splitting are discarded even if no subsequent symmetric splitting is found SubjetCutTool The various implementations of TopDownPruneToo1 all store a jet moment for the number of subjets found This simple selector tool cuts on the number of subjets found by a given tool and optionally unclusters the jet such that the last merging is N 1 if N subjets are required Construct with SubjetCutTool TopDownPruneTool subjet_tool int Nsubjets 2 bool uncluster false string name SubjetCut SubjetMergeTool If something like SubjetCutTool has been used to identify more than two subjets of the final jet this tool merges the two whose combined mass is closest to a given value mw say for a top jet If the final merging is N 1 this inserts a 2 1 me
17. nal simple text output for quick visual check of results builder add_text_output data output text_simple dat 1JetAlgorithm is an awkward name for this object something like JetToolChain would be more accurate The name will likely change in a future release e Configure the Ntuple output by specifying the name of the tree and the ROOT file you want the data to be stored in This output can be manip ulated via your own ROOT scripts or be viewed with the SPARTYJET GUI see guiExample py builder configure_output SpartyJet_Tree data output simple root e Give the command to run the algorithms on the first 10 events builder process_events 10 Running the script will process the first 10 events on the file specified in the input object and produce the root file specified in configure_output To view the output with the GUI run examples_py guiExample py data output simple root from the main directory This is meant as a basic introduction and there are many more functions than listed here See the other examples for more 4 JetBuilder JetBuilder is the job manager for SPARTYJET JetBuilder takes the in put from an InputMaker see Section 6 and passes it through a sequence of JetTools A sequence of JetTools makes up a JetAlgorithm The final list of jets and associated moments is passed to an NtupleMaker which prepares the output This is shown schematically in Fig 4 1 Input Functions Exam
18. name containing the events Many types of input are available see Section 5 input SJ StdTextInput data J1_Clusters dat builder configure_input input e Define the jet algorithm s that you want to run Most algorithms are implemented in FASTJET via the FastJetFinder tool The three argu ments are a name for the tool the algorithm FASTJET enumeration in fastjet JetAlgorithm and the R parameter You can also pass your own fastjet JetDefinition including a plugin algorithm see FJExample py for examples Note that the fastjet namespace is loaded as fj name Antikt4 alg fj antikt_algorithm R 0 4 antikt4 SJ FastJet FastJetFinder name alg R e Pass algorithm to your JetBuilder This sets up a JetAlgorithm object which holds a chain of JetTools to be executed A jet finder is one example of a JetTool see Section 5 for many more add_default_alg adds some default tools before and after the jet finder passed currently negative energy correctors if enabled add_custom_alg inserts a user provided JetAlgorithn builder add_default_alg antikt4 e Insert another tool in the chain in this case making a measurement of jets angular moments in 7 and These will also be stored in the output ROOT file add_jetTool can take a second argument the name of an algorithm to add the tool to otherwise the tool is added to all algorithms builder add_jetTool SJ EtaPhiMomentTool e Configure optio
19. ol uses a provided top tagging class to select jets and identify their subjets In the current implementation TopTaggerTool is templated with a top tagger class and will work with either JHTopTagger or CMTopTagger both external tools JHTopTagger implements the Johns Hopkins top tagging method of arXiv 0806 0848 CMTopTagger is an alter native unpublished method by Gavin Salam TopTaggerTool uses the common functions maybe_top determines whether the jet is tagged W subjet and subjets The stored jet is taken to be the sum of subjets with the two subjets the jet returned by W_subjet and the full jet minus the W No further substructure is stored this is not yet available in CMTopTagger The value of the function cos_theta h is stored as the jet moment cosThetaH The constructor is TopTaggerTool Tagger tagger string name TopTagger Note that in Python you must supply the template argument JHtool SJ FastJet TopTaggerTool fj JHTopTagger JHtagger The constructors for the top taggers are JHTopTagger double delta_p 0 10 double delta_r 0 19 double mW 81 0 CMTopTagger double zmin 0 0 double mass_max 0 0 Note that the implementation of these taggers has been changed slightly for inclusion in SPARTYJET they are set up to be constructed once and run multiple times so the original constructors have been split into new constructors taking parameters and a run ClusterSequence PseudoJet amp
20. ple examples_py inputExample py Input is passed to JetBuilder via builder configure_input input where input can be any class deriving from InputMaker See Section 6 for examples 4 2 Minimum Bias Overlay Example examples_py overlayExample py JetBuilder allows the user to add minimum bias MB events to the signal events to study the effects of pileup To enable MB events one must 1 Create another input object MBinput SJ StdTextInput data MB_Clusters dat 2 Tell JetBuilder to add n MB events to each signal event builder add_minbias_events n MBinput JetBuilder job manager input tools common to all JetAlgorithms JetTool b gt JetToo gt JetTool JetAlgorithm Jet Tool JetTool y ER JetTool JetTool y JetTool E etToo as ae JetTool JetTool Figure 1 The structure of a SpartyJet analysis A JetBuilder gets input from a file using an InputMaker passes the input through a sequence of input JetTools and passes the output to several JetAlgorithms JetAlgorithms consist of a sequence of JetTools that are run sequentially The output of each JetAlgorithm is passed to an NTupleMaker which stores the final jets and accompanying moments in a file JetBuilder will start at the beginning of the MB data file and read the first n events for the first data event then the second n events for the second data event so on
21. rging followed by N 1 gt 1 A variant of this tool is MinMassTool which merges the two subjets with minimum combined mass and therefore does not shape the background distribution as strongly The constructors are SubjetMergeTool double m string name SubjetMergeTool MinMassTool string name MinMassTool FilterTool and BDRSFilterTool These wrap the Filter and FilteredJet classes written by Gavin Salam to implement jet filtering as in the final step of the Higgs analysis in arXiv 0802 2470 Both assume that their input JetCollection holds jets found with Cambridge Aachen Filtering unclusters these jets down to some angular scale Rfilt and keeps the 11 hardest nfilt as well as any above a pr cut ptkeep Each jet in the input is filtered and copied into the output JetCollection For FilterTool the Filter is created once and used for all jets for BDRSFilterTool the filter is recreated for each jet using Rg min Ran AR12 2 The constructors are FilterTool fastjet Filter filt double R 1 0 string name FilterTool BDRSFilterTool double R 1 0 double Rfilt 0 3 int nfilt 3 double ptkeep numeric_limits lt double gt max double rho 0 string name BDRSFilter If rho is non zero area based subtraction is also performed The R pa rameter in the constructors should be the R parameter the jets were found with the algorithm is not re run See external Filter hh TopTaggerTool This to
22. starts empty to add to it use builder add_jetTool_input tool This is useful for initial tools like py and 7 cuts that are common to all algo rithms 4 4 Constituents SPARTYJET retains information about each jet s full recombination history The method by which this information is stored is explained in Section 7 By default this is enabled to disable history saving you must add false as a second argument builder add_default_alg alg False The full recombination history is stored in memory but storage to disk has not yet been implemented We hope to have this available in the near future 4 5 Text File Output The text file output option tells JetBuilder to produce an easily readable text file that contains a list of all jets found from all algorithms for all events To turn on the text file output you must call builder add_text_output and pass it the filename you want to create For example builder add_text_output data output text_output dat 5 JetTools JetTools are blocks of code that act on a JetCollection for every event They generally perform one or more of the following functions e Add or remove jets from the list e Modify the jets themselves e Add information about each jet as a JetMoment e Add information about each event as an EventMoment Jet tools can be added either before or after the primary jet finder e g kr algorithm in the JetAlgorithm The following is a list of JetTools s
23. the energy to be positive On second run the JetNegEnergyTool loops over jets and for each constituent that initially had a negative energy it corrects the jet energy by subtracting twice the constituent s positive energy The JetBuilder method do_correct_neg_energy true inserts this pair of tools before and after all jet finders added with add_default_algorithm tool by default this is not done EConversionTool This tool simply converts the units of all the jets between MeV and GeV The user can convert to arbitrary units as well 6 Input All SPARTYJET jobs need an InputMaker object to read input from some data file and prepare a list of 4 vectors for JetTools to process There are several types of InputMakers available An example of the implementation for each type of input can be seen in examples_py inputExample py For Python scripts the utility module python SpartyJetConfig py defines the helper function getInputMaker fileName which will create the appropriate InputMaker by looking at the filename extension 6 1 NtupleInputMaker Sample data J2_clusters root This form of input reads ROOT files This InputMaker requires the com ponents of the input 4 vectors to be stored in separate branches of a ROOT TTree The following definitions are supported e px Py pz E 13 e psuedo rapidity phi pt E e psuedo rapidity phi pt m You need only specify how the information is stored array or vector float or double
24. veral tools to modify jet substructure have recently been proposed and many have now been incorporated into SPARTYJET Some are implemented natively some are essentially wrappers for existing FASTJET tools External tools that are not part of FASTJET are included in the external directory Currently all of these external tools are available on the The file external README notes which files are external and where they came from These tools are in active development should be considered beta and are subject to change in syntax and behavior User feedback on which features are most useful which tools are missing etc is strongly encouraged Examples of how to use these tools can be found in examples_py FJTool py 10 TopDownPruneTool This is a generic tool implementing the pruning away of asymmetric branchings that is the first step in several recent substructure methods Derived classes implement the branch_test method to test if a branching represents a symmetric branching found two subjets an unresolved branching e g the two subjets are too close together found one subjet or an asymmetric branching where one subjet is discarded and the procedure recurses on the other subjet The user can specify how many splittings to look for one splitting will yield up to two subjets two splittings yields up to four etc Two specific examples are implemented JHPruneTool and MassDropTool The former reproduces the first step i
25. will be done An alternative to this method of dealing with bad input is to use the JetNegEnergyTool described in the JetTools section Reading of PDG ID codes The InputMaker can be set to read PDG ID codes from the input data with the following function This is done by default input readPdgld boo1 This makes the PDG IDs available for input selection and saves the IDs of the input particles for offline analysis 16 7 Output When using the JetBuilder class the result is a ROOT Ntuple containing jet variables for each algorithm added plus variables for input particles to the jet algorithms Jet and event moments are also stored in a similar way 7 1 Output variable type It is possible to choose the type of the variable saved in the Ntuple built by JetBuilder Choice are between pure C array or STL vector of floats or doubles builder output_var_style array_type vector default other option is array builder output_var_style base_type float default other option is double 7 2 Constituents For all algorithms constituent information can be saved as follows Assuming an algorithm named MyJet has been added two additional variables are stored in the ROOT TTree MyJet_numC MyJet_ind MyJet_numC is an array of size MyJet_N MyJet_numC i is the number of constituents of i th jet MyJet_ind is an array of size InputJet_N MyJet_ind i is the index of the jet to which the i th input constituent h
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