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Physics Motivation: measure Higgs Yukawa coupling to muons, which provides a useful test for ratio of Yukawa coupling between 2nd/3rd generation leptons (with
); between 2nd generation lepton/quark (with
).
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Two different works are ongoing or finish in soon.
 Work using DBDworld samples: explored at of 250/500 GeV, left/righthanded beam polarization, two processes of
LaTeX Math Inline 

body  e^+e^ \to q\overline{q}H 


and LaTeX Math Inline 

body  e^+ e^ \to \nu \overline{\nu} H 


 Work using IDRworld samples: written in above
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Two muons are selected using IsolatedLeptonTagging (without
and impact parameters) as the
candidate. Various precuts are applied to select signal and reject background. Further background rejection is done using TMVA(BDTG). Estimating the precision on
LaTeX Math Inline 

body  \sigma \times \mathrm{BR}(H \to \mu ^+ \mu ^) 


is done using
the toy MC technique. In the signal process, two processes are mixed up:
LaTeX Math Inline 

body  e^+ e^ \to ZH \to \nu \overline{\nu} \mu ^+ \mu ^ 


and
LaTeX Math Inline 

body  e^+ e^ \to \nu \overline{\nu}H \to \nu \overline{\nu} \mu ^+ \mu ^ 


via
fusion. These two should be separated in the end, but such separation is not considered in the analysis; it is beyond the scope of this analysis.
Candidate Plots for IDR.
Some comparison comparisons between IDRL and IDRS in reconstructed particle level has done. More details can be found in my talk on 2019Apr03. All plots are lefthanded beam polarization. All histograms are normalized to 1.
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Similar plot for "barrel category"; require requires both muons are in barrel region
LaTeX Math Inline 

body  \cos \theta _{\mu ^{\pm}} < 0.7 


.
is significantly better in IDRL,
LaTeX Math Inline 

body  \sigma (M_{\mu ^+ \mu ^}) 


as well.
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Only ~5% events are the case with both muons flying in endcap/forward region. We will not discuss it here.
Remaining Events After All Cuts.
A toy MC technique is applied by using overall
distribution after BDTG score cut to estimate the precision on
LaTeX Math Inline 

body  \sigma \times \mathrm{BR}(H \to \mu ^+ \mu ^) 


. Two detector models and two beam polarization cases are considered.
Next The next table shows the total remaining events in the full range (120  130 GeV) after BDTG score cut for each detector model and each beam polarization.
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 In the righthanded case, is pretty small, hard to perform the precise measurement. We only have ~8 signal events with 1600 fb1 statistics from the beginning. We will not consider the righthanded case for further discussion.
 We see some differences in in between IDRL and IDRS, but this is due to statistical fluctuation caused by the lack of MC statistics for SM background.
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From the table above,
and
in the full range are pretty much
the same between IDRL and IDRS. The level of total background fluctuates due to
the limited number of MC statistics, thus, we can conclude that the background distribution and
the total number of backgrounds in full range are the same. For further analysis, we treat the background condition is common in IDRL and IDRS. We take the average number of
and average slope in background modeling of IDRL and IDRS, for generating
pesudopseudobackground data. We perform toy MC using common parametrization for background
, and evaluate the precision.
Next The next table shows the final result of the precision on
LaTeX Math Inline 

body  \sigma \times \mathrm{BR}(H \to \mu ^+ \mu ^) 


after 50000 times pseudoexperiments. The theoretical number is provided in addition which assumes 100% signal efficiency, no backgrounds, and no detector effects.
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 My real analysis is about a factor of 3 worse than the theoretical number. There are several reasons mixed up: imperfection of cuts, existence of irreducible backgrounds mainly come from
LaTeX Math Inline 

body  e^+ e^ \to W^+ W^ \to 2\mu 2\nu 


, detector effect, and so on.  IDRL gives relatively 2.8% better precision than IDRS.
 Because overall distribution is better in IDRL. In detail, IDRL gives significantly better performance in "barrel category", and similar performance in "mixed category". Almost all events are categorized in these two groups, resulting in better result results with IDRL.
 The number of signal events in peak region is basically the same between IDRL and IDRS, but ~10% more backgrounds lyng lying in the peak region with IDRS due to ~10% wider width caused by worse momentum resolution. This ~10% more backgrounds background can translate into ~3~2.3% 6% difference in the statistical significance. This 2.8% difference is consistent to with the estimation from statistics.
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 IDRL gives better result than IDRS, because of better momentum resolution in barrel region.
 Worse momentum resolution makes wider width of distribution of signal, resulting in more backgrounds lying in peak region, and resulting in worse precision on
LaTeX Math Inline 

body  \sigma \times \mathrm{BR}(H \to \mu ^+ \mu ^) 


.Specifically for this analysis,
IDR
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IDR note.
You can see my private overleaf project from here. The contents are only IDRworld.
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