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Example Tutorial 2 : ZH -->Z + H (-->Diphotons) analysis

version 0.91, John Yoh, 12/22/06, updated 1/18/07

This example is from work-in-progress of the IMSA SIR project of Stephaine Bian, Je-ok Choi, and Angela Suh, in collaboration with John Yoh and Tim Barklow (who provided the datasets used).

These simple example programs looks at a ILC 350 GeV ZH (with 120 GeV Higgs --> diphotons) datasets (both signal ZH and background ZAA, where A is photon), extract events with 2 photons (A) within cuts, and compare the signal and background with various cuts
Recoil mass is also calculated and plotted--in the case of AA1 program, recoil masses are plotted for all 11 ff types (v(e), v(m), v(t), u, c, ee, mm, tautau, d, s, b --NOTE : there is a bug in the program so that it bombs after the first mm (MuMu) event and ONLY for the Signal sample--so only the first 6 types will be available until the bug is fixed.

Note that in addition to the high tail in the recoil mass--due to beamstrahlung (initial and final state radiation, which effectively reduce the Root(S) of the interaction to below 500 GeV, thus leading to a spuriously high recoil mass) ---there are also additional processes which only affect the v(e)v(e)AA (WW fusion) and eeAA (ZZ fusion), giving additional High recoil mass events.

for the AA1 program, if you compare ther recoil mass plot of the v(e)v(e) type with the v(m)v(m) type, you will see a big difference --v(m)v(m) see only the Z with a small beamstrahlung tail, while the v(e)v(e) will see a big high mass tail due to WW fusion, which populates the higher recoil mass region

  1. Make sure that you have Java and JAS3 loaded into your PC/laptop properly--and tested
  2. In general, it would be easier if you store both the datafile and .java file in the disk area where your JAS3 "open file" points to
  3. Download the .java program files and the 2 datafiles (S signal and B background)
    ILC-doc-378 --> ZH example tutorial programs (for the 2 program files--note--NOT the HiggsRecoilMass.java, which is the program file for tutorial 1 above)
    ILC-doc-376,-- for >ffAA (background datafile--where A = Photon, f = fermion--mostly from Z)
    and ILC-doc-377 and -- ---> ZH--> ffHAA.. (Signal file--ff from Z, etc. decays, and AA from Higgs)
  4. The 2 program files differs by
    HiggsAA1_wBeamsS.java analyze all 11 ff types--and plot recoil mass for all 11 types--the AA analysis is more primitive
    HiggsAA23.java only analyze vvAA (for all 3 v types) concentrates on diphoton mass distribution-- with more sophisticated cuts on the photon and diphoton resulting in improved S/B results. --and ignore all other f typos.
  5. Now run JAS3, "Open file" data file above, "open file" xxxx.java, compile (right click inside .java window), load, and click on > on upper bar.
  6. Your analysis should be running--you can double click on some histograms to sse them incrementing.
  7. The datasets, curtesy of Tim Basklow, are generated by Whizard, with the signal datasets including all real Higgs (ZH as well as WW and ZZ fusion), and background datasets including most known ffAA sources (with ff mostly coming from real Z or virtual photon). note that many other backgrounds, especially those with fake photons, have not been included.
  8. These are particle level studies, and we will try to have a FASTMC example version ready--hopefully in the next 4-6 weeks.
  9. play with the code--adding new histograms or cuts, do other kinematic calculations, etc.--enjoy
  10. Note that final state particles are coded --1-6 is the 6 quark types duscbt, 11/12, 13/14, 15/16 are the lepton types e/v(e), Mu/v(mu), tau/v(tau), photon is id 22.
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