Transcript Using CalcHEP package to study Higgs decay

Using CalcHEP package to
study Higgs boson decay
By
Hosam M.Abd Elazeem
B.Sc, Beni-Sueif University
Some features of CalcHEP package
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Any process within any model: decay and scattering.
Tree-level processes.
Squared matrix element calculation but with no spin
information for outgoing particles – spin averaged
amplitude
Very quick for 2-2 production or width calculations
Straightforward to enter new models, CalcHEP and
related CompHEP used as core for several other
programs.
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Limitations of CalcHEP package
Limit on number of external legs
(involved particles) and number of
diagrams
official limit – 6 ,, unofficial – none
 limit set from the practical point: 2 -> 6
(1->7) : is the essential time limit
 number of diagrams ~ 100-200: time and
disk-space limit
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The Decay Modes of the Higgs Boson
The possible decay modes of the Higgs boson
are essentially determined by the value of its
mass.
 When the Higgs boson mass lies in the
range
95 Gev< Mh<130Gev , the Higgs is quite narrow
Γh<10 MeV and the main branching ratios come
from the heaviest fermions that are accessible
kinematically (b,B), followed by (l,L), then (c,C )
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The Decay Modes of the Higgs Boson
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For a heavier Higgs, i.e. Mh>130 GeV, the
vector boson channels h
VV* with V=W,Z
are dominant.
Finally, for the total decay width, the Higgs
boson is very narrow in the low mass range,
Γh< 10 MeV, but the width becomes rapidly
wider for masses larger than 130 GeV,
reaching ∼ 1 GeV slightly above the ZZ
threshold.
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THANK YOU
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