Name: CMS_2016_I1454211
Year: 2016
Summary: Boosted $t\bar{t}$ in $pp$ collisions at $\sqrt{s} = 8~\TeV$
Experiment: CMS
Collider: LHC
InspireID: 1454211
Status: VALIDATED
Reentrant: true
Authors:
 - Salvatore Rappoccio <rappoccio@gmail.com>
 - Maral Alyari <maralaly@buffalo.edu>
 - Julia Thom <thom.julia@gmail.com>
 - Louise Skinnari <louise.skinnari@cern.ch>
 - Susan Dittmer <Susan.Dittmer@cern.ch>
 - Matthew Bellis <mbellis@sienna.edu>
References:
 - CMS-PAS-TOP-14-012 (PAS)
 - CERN-EP-2016-078   (paper)
RunInfo:
  '$pp$ QCD interactions at $\sqrt{s} = 8~\TeV with $t\bar{t}$ process. Data collected by CMS
  during the year 2012. Boosted topology restricts phase space, requiring high statistics in
  a single run or custom merging of the YODA files.'
Luminosity_fb: 19.7
Beams: [p+, p+]
Energies: [8000]
Options:
 - TMODE=PARTICLE,BOTH
Description:
  'The cross section for pair production of top quarks with high transverse momenta
  ($p_\mathrm{T} > 400$~\GeV) is measured in 19.7~fb$^{-1}$ of $\mathrm{pp}$
  collisions, collected with the CMS detector at $\sqrt{s} = 8~\TeV$. The
  measurement is performed for lepton+jets events, where one top quark decays
  according to $t \rightarrow Wb \rightarrow \ell \nu b$, with $\ell$ denoting an
  electron or muon, and the second top quark decays to an hadronic final state and
  is reconstructed as a single large-radius jet and identified as a top quark
  candidate using jet substructure techniques. Integrated cross sections, as well
  as differential cross sections as a function of the top quark $p_\mathrm{T}$ and
  rapidity, are measured both at particle level within a fiducial region
  resembling the detector-level selections and at parton level.

  RIVET:
  This analysis is to be run on $t\bar{t}$ Monte Carlo.  It utilizes the
  PartonicTops projection, which assumes top quarks in the event record. The
  analysis has been validated with Powheg+Pythia6.

  The parton-level phase space is defined by requiring two PartonicTops.
  Exactly one PartonicTop must decay directly to a muon or electron (no
  intermediate tau), and exactly one PartonicTop decays hadronically.  For
  $t\bar{t}$ Monte Carlo, this is equivalent to requiring the event to be
  semileptonic at parton level.  The parton-level top quark is defined as the
  hadronically decaying top. The parton-level top quark is required to have
  $p_\mathrm{T} > 400~\GeV$.

  The particle-level phase space is defined using the following object definitions:
  - Lepton: A dressed electron or muon, meaning the lepton has been clustered with all photons within a cone of $R=0.1$. The DressedLepton projection is used to construct the dressed lepton.  The lepton is required to have $p_\mathrm{T} > 45$~GeV and $|\eta| < 2.1$.
  - B Jet Candidate: Gen AK5 jets are formed by clustering the final state particles in the event using the anti-$k_{T}$ algorithm with distance parameter $R=0.5$.  Neutrinos are excluded from the clustering, as are any particles included in the dressed lepton.  The gen AK5 jet is required to have $p_{T} > 30$~GeV and $|\eta| < 2.4$. Gen AK5 jets in the same hemisphere as the lepton ($\Delta R(e/\mu,~\mathrm{jet}) < \pi/2$) are defined as $b$-jet candidates.
  - Top Jet Candidate: Gen CA8 jets are formed by clustering the final state particles in the event using the Cambridge-Aachen algorithm with distance parameter $R=0.8$. Neutrinos are excluded from the clustering, as are any particles included in the dressed lepton. The gen CA8 jet is required to have $p_{T} > 30$~GeV and $|\eta| < 2.4$. Gen CA8 jets which have $p_{T} > 400$~GeV, 140 GeV $<$ mass $<$ 250 GeV, and are in the opposite hemisphere from the lepton ($\Delta{R(e/\mu,\mathrm{jet})} > \pi/2$) are defined as top jet candidates.

  The particle-level phase space is defined by requiring $\geq 1$ b jet
  candidate, $\geq 1$ top jet candidate, and exactly one lepton. This is in
  addition to the parton-level semileptonic requirement. The highest-$p_\mathrm{T}$ top
  jet candidate is defined as the particle-level $t$ jet.'
BibKey: Khachatryan:2016gxp
BibTeX: '@article{Khachatryan:2016gxp,
      author         = "Khachatryan, Vardan and others",
      title          = "{Measurement of the integrated and differential t-tbar
                        production cross sections for high-pt top quarks in pp
                        collisions at sqrt(s) = 8 TeV}",
      collaboration  = "CMS",
      year           = "2016",
      eprint         = "1605.00116",
      archivePrefix  = "arXiv",
      primaryClass   = "hep-ex",
      reportNumber   = "CMS-TOP-14-012, CERN-EP-2016-078",
      SLACcitation   = "%%CITATION = ARXIV:1605.00116;%%"
}'
ReleaseTests:
 - $A pp-8000-ttbar-sl-boosted
