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The process of Higgs production through vector boson fusion shown in
fig. 2.1b will only be important for high Higgs
masses where the coupling to longitudinal polarised vector bosons is
strong (see section 2.3.1).
At the high energies where a heavy Higgs particle is created the
vector bosons act essentially as massless particles and can be treated
as particles present inside the colliding protons. With this
simplification the full process in fig. 2.1b can be
separated into a calculation of the vector boson structure function in
the proton and a calculation of Higgs production in colliding vector
boson beams. The method is called the effective W approximation.
Following the derivation in [10] the cross section for
production of a particle X in the fusion of two vector bosons can be
written as

(q_{1}q_{2} q_{1}'q_{2}'X ) = F_{}(x)F_{}()(X VV ),
 (24)

where F_{} is the structure function for the vector boson V
with partial width
in the state with polarisation
,
= x_{1}x_{2}s the centre of mass energy squared of
the two colliding quarks and q_{1}' , q_{2}' denoting the two outgoing
quarks.
For the production of a Higgs, the decay width described in
section 2.3.1 is dominated by the longitudinal
polarised state. Ignoring the small contribution from the
transverse polarised states the cross section for a heavy Higgs can
be written as

(q_{1}q_{2} q_{1}'q_{2}'H ) = F_{L}(x)F_{L}()(H VV ).
 (25)

To get the full cross section for the Higgs from vector boson fusion
the cross section above has to be convoluted with the structure
functions of the incoming quarks. For all possible values of the Higgs
mass the cross section is below the gluon fusion process, but with the
additional signature of the two outgoing quarks participating in the
process the identification will be easier in this production channel
for a large Higgs mass. Chapter 8 details
how a heavy Higgs can be identified with the use of the forward
jets.
Next: Associate production
Up: Higgs Production
Previous: Gluon fusion
Ulrik Egede
1/8/1998