1405.4123baidu.com

ISTEP2016TutorialZprimeSearchesat13TeVppColliderQiangLi2016/07https://pan.
baidu.
com/s/1mi72vDQ1.
IntroductionVariousextensionsoftheStandardModelspredicttheexistenceofnewkindsofheavygaugebosons[1],eitherneutral(Z')orcharged(W').
Duetotheirsimplicityandcleansignatureinleptonicdecay,searchesforZ'andW'serveasthebenchmarktoexaminethepotentialoffuturehighenergycolliders.
Inthisstudy,weareparticularinterestedintheSequentialStandardModel(SSM)[2].
TheSSMZ'isacarboncopyofSMZbosonwiththesamecouplings,butonlywithaheaviermass.
InSSM,Z'iscreatedthroughqqbarannihilationandthendecayswithdecaywidthGamma(Z')~0.
03MZ'.
Asearchfornewhigh-massnarrowresonancesindimuonanddielectroninvariantmassspectrahasbeenobtainedatthe7and8TeVLHC.
Withabout20fb-1of8TeVdata,the95%CLlowerlimitsonSSMZ'massare2.
90TeVfromATLAS[3]and2.
90TeVfromCMS[4].
TheUSSnowmassreport[5]presentedtheabilitytoexcludeaZ'atcollisionenergyof14/33TeVwith300/3000fb-1ofcollecteddata.
The95%CLlowermasslimitsforSSMZ'massis6.
44TeVgiven300fb-1atsqrt(s)=14TeV.
[1]seee.
g.
arXiv:0801.
1345;sites.
google.
com/site/zprimeguide[2]G.
Altarelliet.
al.
,Z.
Phys.
C45(1989)109;V.
Barger,W.
Y.
Keung,Phys.
Lett.
B94(1980)377-380.
[3]arXiv:1405.
4123[4]arXiv:1412.
6302[5]arXiv:1308.
5874https://pan.
baidu.
com/s/1b54D2m2.
ExampleFeynmanDiagramsareshowninthefollowingpage:DY,TTbar,Diboson,Singletop,andourZprimesignal3.
CMSplotsandlimits(8TeV2012)MlldistributionsCumulativeMlldistributionsCMS8TeVmu-channelLimitplot(BrazilianPlot)4.
MG5_aMC@NLO,ZprimeandBackgroundSamplesDownloadMG5_aMC@NLO,".
/bin/mg5","tutorial",getfamiliarwithit;"installpythia-pgs","installExRootAnalysis","installDelphes"WeprovidetheZ'modeldirectory"sm-ZP",pleaseputitunder"models"inMGpackage;generatepp>Zp>mu+mu-withCTEQ6L1,SwitchonPythia,cutsas:PTl>10GeV,|etal|900GeVForyourrefs:MZ'(GeV)Width(GeV)Xsec(pb)200059.
80.
01558+-2.
035e-05pb250074.
80.
004547+-6.
202e-06pb300089.
90.
001466+-2.
782e-06pb3500104.
90.
0005123+-1.
173e-06pb4000119.
90.
0001894+-3.
144e-07pb4500134.
97.
523e-05+-1.
546e-07pbBKGandSignalsamplesprovidedbyus:DY80K,0.
007476+-6.
427e-06pbTTbar40K,0.
0007598+-1.
198e-06pbTW10K,8.
888e-05+-2.
135e-07pbWW40K,0.
000338+-3.
497e-07pbNoteallthesesamplesareappliedwithMll>900GeV,assumingthisisaspecialtriggerof2muonswithinvariantmasslargerthan900GeV.
WealsoprovidesignalsamplesforZ'massfrom2TeVto4.
5TeV,eachwith10K.
Thesedefinethe"lumiweight"or"lumiScalefactor"foreachsample:Lumi/(Nevent/xsec)5.
ISTEP2016ZprimeTutorialhttps://pan.
baidu.
com/s/1mi72vDQdefaultlumiis1fb-1;Nevent/xsecstoredas"SF"1.
".
xproducehiso.
C"togetMllhistograms.
(outputiscalledout.
root)2.
Wealsoprovide"data"namedas"outdata.
root".
Useplot.
CtomakeDATA/MCcomparisonplot.
(SwitchtoPoissonErrorbars)3.
fit2.
CtofitSignal:root-b-qfit2.
C\(\"ZP3000\"\)4.
cutcounting.
Ctoperformsimplestatisticstudies,basedonhistograms.
5.
runsmalltuple.
shtogetNtupleinsteadofHistograms.
Use"hadd"tohaveonesinglerootfilenamedaszprimetraining.
root.
6.
cutcounting2.
Ctoperformsimplestatisticstudies,basedonntuples.
7.
PlotcumulativeMlldistributionsandotherplotse.
g.
PTll…8.
Runmva/mva-ana/MVA_ana.
Cwithinputfromstep5.
GetfamiliarwithMVA:training+application.
PutTMVA.
rootundermva/testanduseplotall.
Ctomakeplots.
TrymethodsincludingBDTG,Fisheretc.
,andchangetheirsettings.
(Notetrainingandapplicationareusingthesameinputsjustforthistoystudy)9.
Comparesignificancefrom4,6and8.
https://pan.
baidu.
com/s/1b54D2m6.
ExamplePlots:7.
AdvancedProjects7.
1HowtocorrectMCpredictionsforvariousbackgrounds7.
2CanwesuppressTTbarbkg7.
3WeonlyconsiderWWbutnotWZorZZforthedibosoncontributions,canyougiveanestimatehowmuchWZorZZcontribute7.
4Whatotherbackgroundsarewestillmissing7.
5Bkgfitting7.
6ShapeAnalysisinsteadofCut/countingYoucanthinkandtestmore