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Effective Lagrangian analysis of observed Higgs-like boson

V. Bunichev
Mosow State University

In collaboration with E. Boos, M. Dubinin, Y. Kurihara

V. Bunichev, SINP MSU

QFTHEP 2013

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Higgs-like Boson
M = 125 G eV

Production of Higgs-boson:

Gluon fusion

Vector boson fusion

Assotiated production

Top quark fusion

V. Bunichev, SINP MSU

QFTHEP 2013

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Higgs Signals:
(vbf) WW



bb

ZZ

V. Bunichev, SINP MSU

QFTHEP 2013

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Signal strength
Available experimental data provides the signal strength:

where i is a number of Higgs boson decay channel and j is the number of Higgs production process for a given final state.

Best fit value of a signal strength can be expressed using the observed number of signal events Nobs, the number of background events Nbackgr and the number of signal events calculated in the SM Nsignal,i

V. Bunichev, SINP MSU

QFTHEP 2013

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Global 2 defined as:

for the number of production channels Nch . Theoretical predictions for jhand related errors can be found on the LHC Higgs Cross Sections WG webpage Minimization of 2 2 gives us the 1, 2 and 3 regions 2 = 2min +2 where 2 is defined by cumulative distribution function.

V. Bunichev, SINP MSU

QFTHEP 2013

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Table calculations in CompHEP

V. Bunichev, SINP MSU

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2 analysis and contour plots in CompHEP

V. Bunichev, SINP MSU

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2 analysis and contour plots in CompHEP

V. Bunichev, SINP MSU

QFTHEP 2013

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Comparison of CompHEP calculations with well known results
Partial 2 fit in the (a, c) plane

CompHEP

J.R. Espinosa, C. Grojean, M. Muhlleitner, M. Trott, Fingerprinting Higgs Suspects at the LHC, JHEP 1205, 097 (2012)
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Global 2 fit in the (a, c) plane (based of 2012 data)

CompHEP
JHEP 1205, 097 (2012)

V. Bunichev, SINP MSU

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Global 2 fit in the (a, c) plane (based of 2013 data)

CompHEP Global 2 diagrams diagrams based on
V. Bunichev, SINP MSU

fits in the (a, c) plane. (left) - calculated without VBF in the , WW and ZZ channels, (right) - calculated with VBF in the , W W and ZZ channels preliminary 2013 data
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Complete set of gauge invariant dim 6 operators:
W. Buchmuller, D. Wyler, Effective lagrangian analysis of new interactins and flavour conservation, Nucl.Phys. B268 (1986) 621

We avoid mixing in the gauge field kinetic terms by subtraction of v2/2 For the same reason the a operator
V. Bunichev, SINP MSU QFTHEP 2013

is excluded.
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Dim 6 operators and corresponding vertices

V. Bunichev, SINP MSU

QFTHEP 2013

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Combining contributions from different operators we get a complete set of Feynman rules

The Feynman rules inserted into the CompHEP and are used for calculation the cross sections for Higgs production processes

V. Bunichev, SINP MSU

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Conclusion and results:


We choose the basis in space of dim 6 operators. We significantly expanded functions of the CompHEP package for table calculations, statistical analysis and graphical representations of results. For validation of our machinary we compare our calculations with well known results. We start calculation in frame of our basis (in progress .....)







V. Bunichev, SINP MSU

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