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2015:groups:tools:hjets

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Study on the validity/performance of different pQCD approximations for non-trivial observables in pp->h+jets (ggF)

The aim is to study various non-trivial observables of experimental interest/relevance with calculations implementing various different perturbative QCD approximations. There is a Rivet routine provided and all participating parties are encouraged in using it.

Setup

Collider: LHC@13TeV

PDF/as: MMHT2014nlo68clas118 (as(mZ)=0.118) (LHAPDF-id: 25200), MMHT2014nnlo68cl (as(mZ)=0.118) (LHAPDF-id: 25300), as applicable

Scales: muR/muF depending on calculation, of course. However, usually there is freedom on pp→h+0j level, thus please choose a scale that reproduces mH/2 in the 0j limit, eg. HT'/2 instead of HT' in pp→h+3j at fixed order. All other scales as needed.

mH: 125 GeV

GammaH: 0.00407 GeV (where applicable)

Uncertainties

* renormalisation and factorisation scale uncertainty

* relevant parton shower / matching uncertainties (starting scale, other choices)

* merging scale uncertainties

Observables

List of Observables

Standard multijets cuts

Higgs boson momentum used below defined through the momentum of either a final state stable Higgs boson or the first pair of photons with an invariant mass of [124,126] GeV

jets (antikt, dR=0.4, pT>30 GeV, |eta|<4.4) in given incl./excl. multiplicity, input are all particles which do not constitute the Higgs boson above)

Higgs observables

pT(h) in incl./excl. 0,1,2,3j bins

y(h) incl.

Jet observables

Jet multiplicities incl./excl. with pT>30,50 GeV

Jet veto (on j1) cross sections on 0j

Jet veto (on j2) cross sections on events with pT(j1)>30,50,100,200,500,1000 GeV

Jet veto (on j2) cross sections on events with pT(h)>50,100,200,500 GeV

pT(j) for nth jet in incl./excl. nj bins (n=1,2,3)

y(j) for nth jet in incl. nj bins

m(j1j2) invariant mass of leading jets in incl. 2j

dphi(j1,j2) rapidity separation of leading jets in incl. 2j

dphi(jfw,jbw) rapidity separation of forward-backward jets in incl. 2j

dy(j1,j2) rapidity separation of leading jets in incl./excl. 2/3j

dy(jfw,jbw) rapiditiy separation of forward-backward jet in inclk.excl. 2/3j

pT(j) for nth jet in incl. 2j (n=1,2,3) for dy(j1,j2)>1,2,3,4,5,6 of leading jets

pT(j) for nth jet in incl. 2j (n=1,2,3) for dy(jfw,jbw)>1,2,3,4,5,6 of forward-backward jet

Higgs-jet correlations

pT(hj1) in incl. 1j

dphi(h,j1) in incl. 1j

dy(h,j1) in incl. 1j

pT(hj1j2) in incl. 2j

dphi(h,j1j2) in incl. 2j

dy(h,j1j2) in incl. 2j

dphi2 azimuthal angle between vector sum of jets forward and backward of the Higgs in incl. 2j

tau(j) transverse mass of the nth (n=1,2,3) jet weighted with the rapidity separation to the Higgs

sum_j tau(j) sum of all tau(j) (j=1,njet) with tau > 8 GeV

max_j tau(j) max of all tau(j) (j=1,njet) with tau > 8 GeV

cross section for dphi(h,j1j2)>2.6

Photon observables

only Higgs-constituting photon pair

cos(theta*) in all events and binned in pT(h) [0,80], [80,200], [200,infty]

dy(y1,y2) rapidity separation of photon pair

pTt

dR(y,j1), dR(y,j2) angular separation of leading and subleading jet and nearest photon

VBF cuts

require the two leading to have m(jj)>400 GeV and dy(j,j)>2.8

Jet observables

Jet multiplicity incl./excl.

dphi(j1,j2) azimuthal separation of leading jets

central jet veto cross section in dependence on rapidity separation of leading jets

Higgs-jet correlations

pT(h,j1j2)

dphi2 azimuthal angle between vector sum of jets forward and backward of the Higgs

cross section for dphi(h,j1j2)>2.6

VBF2 cuts

require any pair of jets to have m(jj)>400 GeV and dy(j,j)>2.8

Jet observables

Jet multiplicity incl./excl.

dphi(j1,j2) azimuthal separation of leading jets

central jet veto cross section in dependence on rapidity separation of leading jets

Higgs-jet correlations

pT(h,j1j2)

dphi2 azimuthal angle between vector sum of jets forward and backward of the Higgs

cross section for dphi(h,j1j2)>2.6

jhj cuts

require the Higgs boson to be in between the leading jets in rapidity

Jet observables

Jet multiplicity incl./excl.

Contributions

The current list is based on the interest expressed in the first meeting, please feel free to complete it with your planned contribution. Also, if you cannot contribute after all, please remove yourself from the list.

Fixed-Order calculations

* Frank Petriello etal. pp→h+j @ NNLO

* Gionata Luisoni etal. pp→h+j, pp→h+jj, pp→h+jjj @ NLO

H+>=1 jet (pdf file)H+>=2 jet (pdf file)H+>=3 jet (pdf file)

* Simon Badger + GoSam Ntuples pp→h+(1,2)j @ nNLO and pp→h+(2,3)j @ nNLO

Analytic resummation

* Massimiliano Grazzini etal. pT(h) incl.

* Frank Tackmann etal. jet veto resummation on top of pp→h and pp→hj

Parton shower matched/Multijet merged calculations

* Marek Schoenherr etal. pp→h+jets (0,1,2@NLO)

* Rikkert Frederix, Eleni Vryonidou pp→h+jets (0,1,2@NLO)

BFKL resummation

* Jeppe Andersen etal. pp→h+jj+jets

Analysis routine

There is a Rivet analysis provided to all interested parties. Please note, the routine is not finalised until marked as such. A few observables that were discussed still have to be added. Nonetheless, it can already be used to test your setup and/or produce preliminary results.

Analysis

To use it, download the file and remove the “.txt” ending. Then add Rivet to your path (conveniently through sourcing rivetenv.sh) and compile using

rivet-buildplugin RivetLHAnalysis.so mc_hjets_lh15.cc

then setting

export RIVET_ANALYSIS_PATH=$PWD

lets Rivet pick up the new library and Rivet is instructed to use it through the option

-a MC_HJETS_LH15

Let us know if you encounter any problems or bugs.

2015/groups/tools/hjets.1433669418.txt.gz · Last modified: 2015/06/07 11:30 by marek.schoenherr