4,334 research outputs found
CSM analyses of
We study the modifications of the amplitudes and cross sections of several
processes, especially , generated
by Higgs boson and top quark compositeness, in particular within the CSM
concept. We illustrate the observable differences that may appear between
various, CSM conserving or CSM violating, compositeness possibilities.Comment: 13 pages, 4 figure
Universal and Non Universal New Physics Effects in a General Four-fermion Process: a Z-peak Subtracted Approach
We calculate, using a Z-peak subtracted representation of four-fermion
processes previously illustrated for the case of electron-positron annihilation
into charged lepton-antilepton, the corresponding expressions of the new
physics contributions for the case of final quark-antiquark states, allowing
the possibility of both universal and non universal effects. We show that, in
each case, the main result obtained for the final lepton channel can be
generalized, so that every experimentally measurable quantity can be expressed
in terms of input parameters \underline{measured} on Z resonance, of
and of a small number of subtracted one loop expressions. Some
examples of models are considered for several c.m. energy values, showing that
remarkable simplifications are often introduced by our approach. In particular,
for the case of a dimension-six lagrangian with anomalous gauge couplings, the
same reduced number of parameters that would affect the observables of final
leptonic states are essentially retained when one moves to final hadronic
states. This leads to great simplifications in the elaboration of constraints
and, as a gratifying byproduct, to the possibility of making the signal from
these models clearly distinguishable from those from other (both universal and
non universal) competitors.Comment: 21 pages + 3 figures in ps file, corrected version. (e-mail
[email protected]
Higgs boson form factor effects in production by and fusion
We study the fusion processes and
observable at a future collider and we discuss their sensitivity to an
form factor which may be due to compositeness, in particular when the
and the top quark have common constituents. We make an amplitude analysis and
illustrate which helicity amplitudes and cross sections for specific final
polarizations are especially sensitive to this form factor.Comment: 24 pages, 37 figures, version including changes suggested by the
Physical Review D publication tea
A supersimple analysis of at high energy
According to supersimplicity in MSSM, a renormalization scheme (SRS) may be
defined for any high energy 2-to-2 process, to the 1loop EW order; where the
helicity conserving (HC) amplitudes, are expressed as a linear combination of
just three universal logarithm-involving forms.
All other helicity amplitudes vanish asymptotically. Including to these SRS
amplitudes the corresponding counter terms, the "supersimple" expressions for
the high energy HC amplitudes, renormalized on-shell, are obtained.
Previously, this property was noted for a large number of processes that do
not involve Yukawa interactions or renormalization group corrections. Here we
extend it to , which does involve large Yukawa and
renormalization group contributions. We show that the resulting "supersimple"
expressions may provide an accurate description, even at energies comparable to
the SUSY scale. Such descriptions clearly identify the origin of the important
SUSY effects, and they may be used for quickly constraining physics
contributions, beyond MSSM.Comment: 26 pages, 15 figures. Paper appeared in Phys. Rev. D. The Journal
where Reference 20 has appeared has been adde
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