Azimuthal angle correlation in VBF processes at LHC

1
Azimuthal angle correlation in VBF processes at
LHC

• arXiv0806.XXXX
• Mawatari, Kentarou
• ?? ??????? ???with K.Hagiwara (KEK) and
  Q.Li (Karlsruhe)

2
Higgs properties

• After observation of a Higgs boson at LHC,
  determination of its properties, i.e., all the
  quantum numbers and couplings, is the next goal
  to unravel the underlying theory.
• the gauge, Yukawa, and self-couplings
• the charge, color, spin, CP quantum numbers
• Determination of the CP property
• Higgs decay, e.g. HgtZZgt(ll)(ll)
• Higgs2jet production, ppgtHjj

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Azimuthal angle correlations in WBF
T.Plehn, D.Rainwater, D.ZeppenfeldPRL88(2002)0518
01

• The anomalous HWW couplings
• The azimuthal correlations reflects the tensor
  structure of the Higgs couplings.
• Why is SM flat ? Why is CP-even (odd) suppressed
  at phi90 (0 and 180) ?

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WBF vs. GF with VBF cuts
V. Del Duca et al. NPB616(2001)367

• H2 jet events are produced also via gluon fusion
  (GF)(a) qqgtqqH, (b) qggtqgH, (c) gggtggH.

w/ minimal cuts
w/ minimal and VBF cuts

• minimal cuts
• VBF cuts

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WBF vs. GF in the az dis.
V. Del Duca et al. NPB616(2001)367

• Why is GF suppressed at phi90 ?
• This reflects the effective Hgg coupling
  .
• The VBF cuts may select the t-channel VBF
  diagrams.
• The t-channel vector-boson propagators lead to
  the distinctive far forward jets.
• The kinematical feature is not particular only to
  WBF but the QCD production via the t-channel GF
  processes.

w/ minimal and VBF cuts
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Contents

• Introduction
• Azimuthal correlations in H2jet events
• Formalism and Kinematics
• Helicity amplitudes for the VBF process
• Azimuthal angle correlations
• Higgs bosons
• Massive-gravitons
• Summary

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Formalism and Kinematics

• Helicity amplitude formalism
• Kinematics

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Helicity formalism

• For the VBF process
• the completeness relation for space-like
  vector-boson
• the conserved current

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X decay to a vector-boson pair
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Kinematics
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Helicity amplitudesfor the VBF process

• Fermion current amplituds
• Gluon current amplitudes
• Off-shell VBF amplitudes

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Off-shell vector-boson Current amplitudes

• For the production
• Fermion currents
• Gluon currents

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Fermion current amplitudes
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Gluon current amplitudes
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XVV vertex

• Off-shell VBF amplitudes
• The XVV vertex
• The polarization tensor and the GXX vertices

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Off-shell VBF amplitudes
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Azimuthal angle correlations

• Higgs bosons
• Massive-gravitons

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Quantum interferencebetween the different
helicity states

• The VBF helicity amplitude for Higgs bosons
  (?X0)
• Using the relative phases
• Azimuthal correlations
• H(WBF)
• H(GF)
• A

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Azimuthal correlation of Higgs bosons

• minimal cuts
• VBF cuts

• The VBF contributions can reproduce the
  distributions with the exact matrix elements very
  well not only for VBF but also GF.

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Azimuthal correlation of massive-gravitons

• The full helicity amplitude for massive-gravitons
• The ?X2 caes is dominant.
• There is no interference term.
• No azimuthal dependence.
• "Graviton production with 2 jets at the LHC in
  large extra dimensions" K.Hagiwara, P.Konar,
  Q.Li, K.M., D.Zeppenfeld JHEP0804,019
• "HELAS and MadGraph/MadEvent with spin-2
  particles" K.Hagiwara, J.Kanzaki, Q.Li, K.M.
  appear in EPJ, arXiv0805.2554

P.Konar talk (yesterday)
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Azimuthal correlation of massive-gravitons
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Summary

• We have studied heavy-particle (Higgs boson and
  massive-graviton) productions in association with
  two jets via VBF (WBFGF) and their decays at
  LHC.
• We showed
• the helicity amp explicitly for the VBF
  subprocesses.
• the VBF amp reproduces the exact matrix elements
  by taking into account the dijet large rapidity
  separation.
• quantum interference between different helicity
  states of the intermediate vector-bosons leads to
  a non-trivial azimuthal angle correlation of the
  jets in the production and in the decay.
• These correlations reflect the spin and CP nature
  of the heavy particles produced via VBF
  processes.