Changes between Version 2 and Version 3 of LowMassSMHiggs


Ignore:
Timestamp:
04/12/12 11:22:49 (7 years ago)
Author:
md987
Comment:

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  • LowMassSMHiggs

    v2 v3  
    99WH -> ell+- + 2b[[br]]ZH -> ell+ ell- + 2b[[br]]tth -> ell+ ell- 4b
    1010
    11 <br /> We are now focusing on ttH
     11[[br]] We are now focusing on ttH
    1212=== II. Goal ===
    1313
     
    1818|| events with no ISR || S_3 || S_4 ||
    1919
    20 <br />By estimating S_1,S_2 ... we will provide a reasonable estimate[[br]]of the maximum significance that can be reached at the LHC, and will[[br]]also show what are the most important factors controlling this maximum significance.
     20[[br]]By estimating S_1,S_2 ... we will provide a reasonable estimate[[br]]of the maximum significance that can be reached at the LHC, and will[[br]]also show what are the most important factors controlling this maximum significance.
    2121
    2222The strategy is to organize the work into a validation procedure (first step) and a pheno study (second step).
     
    6363=== IV. Pheno study ===
    6464
    65 <br /> - Redo the analysis, but with samples of events that are as realistic as possible.[[br]][[br]] - Evaluate all the systematic uncertainties.
     65[[br]] - Redo the analysis, but with samples of events that are as realistic as possible.[[br]][[br]] - Evaluate all the systematic uncertainties.
    6666=== V. Inputs of the analysis ===
    6767
    68 <br />[[br]]We will do the analysis for the LHC at '''14 TeV'''.[[br]]There are several input parameters that need to be fixed right now.[[br]][[br]]Even during the validation procedure, it will be very useful if we [[br]]consider realistic values the parameters associated with the [[br]]final-state cuts, the reconstruction efficiencies, [[br]]the b-taggings and the energy resolution.[[br]]In such a way, the significance that we will obtain[[br]]at the end of the validation procedure will not be completely unrealistic,[[br]]and this will give us some insights to jump into the second part[[br]](e.g. if we find that the significance is extremely low for a given [[br]]signature even under ideal conditions, it may not be worth to push [[br]]the analysis further for this signature.)
     68[[br]][[br]]We will do the analysis for the LHC at '''14 TeV'''.[[br]]There are several input parameters that need to be fixed right now.[[br]][[br]]Even during the validation procedure, it will be very useful if we [[br]]consider realistic values the parameters associated with the [[br]]final-state cuts, the reconstruction efficiencies, [[br]]the b-taggings and the energy resolution.[[br]]In such a way, the significance that we will obtain[[br]]at the end of the validation procedure will not be completely unrealistic,[[br]]and this will give us some insights to jump into the second part[[br]](e.g. if we find that the significance is extremely low for a given [[br]]signature even under ideal conditions, it may not be worth to push [[br]]the analysis further for this signature.)
    6969
    7070For the theoretical parameters, we can stick to the default param_card.dat file on the web.
    7171===== A. Cuts =====
    7272
    73 <br />We need to agree on a set of cuts to be applied on the jets and on the leptons.[[br]]I think a resonable set of cuts are (see http://arxiv.org/pdf/1106.0902.pdf)
     73[[br]]We need to agree on a set of cuts to be applied on the jets and on the leptons.[[br]]I think a resonable set of cuts are (see http://arxiv.org/pdf/1106.0902.pdf)
    7474
    7575pT(jets) > 30 GeV, ||eta(jet)||<2.4 delta R (p_i,p_j) > 0.3 with p_i, p_j =jet or lepton
     
    7777pT(e) > 20 GeV, ||eta(e)||<2.5, pT(mu)> 30 GeV, ||eta(mu)||< 2.5
    7878
    79 <br />[[br]]<em>Parton-level cuts vs reconstructed-level cuts</em>:[[br]][[br]]In the validation procedure, parton-level cuts are different from reconstructed-level cuts[[br]]because:[[br]] - parton-level events are boosted in the transverse plan (if ISR is taken into account) [[br]] - final-state parton energies are smeared according to the shape of the transfer function[[br]][[br]]So one need to apply looser cuts at the parton-level, and then apply the correct set of cuts [[br]]at the "reconstructed level".
     79[[br]][[br]]<em>Parton-level cuts vs reconstructed-level cuts</em>:[[br]][[br]]In the validation procedure, parton-level cuts are different from reconstructed-level cuts[[br]]because:[[br]] - parton-level events are boosted in the transverse plan (if ISR is taken into account) [[br]] - final-state parton energies are smeared according to the shape of the transfer function[[br]][[br]]So one need to apply looser cuts at the parton-level, and then apply the correct set of cuts [[br]]at the "reconstructed level".
    8080===== B. Transfer function =====
    8181
    82 <br />For the parametrization of the transfer functions,[[br]]we can stick to the usual asumptions: a superposition[[br]]of two Gaussian distributions for the energy of the jets, [[br]]a delta function for all other visible quantities.
     82[[br]]For the parametrization of the transfer functions,[[br]]we can stick to the usual asumptions: a superposition[[br]]of two Gaussian distributions for the energy of the jets, [[br]]a delta function for all other visible quantities.
    8383
    8484The parametrization of the TF for jet energies is given by