28 research outputs found
Lightest-neutralino decays in R_p-violating models with dominant lambda^{prime} and lambda couplings
Decays of the lightest neutralino are studied in R_p-violating models with
operators lambda^{prime} L Q D^c and lambda L L E^c involving third-generation
matter fields and with dominant lambda^{prime} and lambda couplings.
Generalizations to decays of the lightest neutralino induced by subdominant
lambda^{prime} and lambda couplings are straightforward. Decays with the
top-quark among the particles produced are considered, in addition to those
with an almost massless final state. Phenomenological analyses for examples of
both classes of decays are presented. No specific assumption on the composition
of the lightest neutralino is made, and the formulae listed here can be easily
generalized to study decays of heavier neutralinos. It has been recently
pointed out that, for a sizable coupling lambda^{prime}_{333}, tau-sleptons may
be copiously produced at the LHC as single supersymmetric particles, in
association with top- and bottom-quark pairs. This analysis of neutralino
decays is, therefore, a first step towards the reconstruction of the complete
final state produced in this case.Comment: 40 pages, 11 figures, version to appear in JHE
A T-odd asymmetry in neutralino production and decay
We study CP-violating effects in neutralino production and subsequent decay
within the Minimal Supersymmetric Standard Model with complex parameters M_1
and mu. The observable we propose is a T-odd asymmetry based on a triple
product in neutralino production e^+ e^- -> tilde{chi}^0_i tilde{chi}^0_2, i =
1,...,4, with subsequent leptonic three-body decay tilde{chi}^0_2 ->
tilde{chi}^0_1 l^+ l^-, l = e, mu, at an e^+ e^- linear collider with sqrt{s} =
500 GeV and polarised beams. We provide compact analytical formulae for the
cross section and the T-odd asymmetry taking into account the complete spin
correlations between production and decay. We give numerical predictions for
the cross section and the T-odd asymmetry. The asymmetry can go up to 10 %.Comment: 28 pages, LaTeX, 10 figures; v2: typos corrected, published versio
The Higgs Working Group: Summary Report
Report of the Higgs working group for the Workshop "Physics at TeVColliders", Les Houches, France 8-18 June 1999. It contains 6 separatesections: 1. Measuring Higgs boson couplings at the LHC. 2. Higgs boson production at hadron colliders at NLO. 3. Signatures of Heavy Charged Higgs Bosons at the LHC. 4. Light stop effects and Higgs boson searches at the LHC. 5. Double Higgs production at TeV Colliders in the MSSM. 6. Programs and Tools for Higgs Bosons
Associated Production of Higgs Bosons with Scalar Quarks at Future Hadron and Colliders
We analyze the production of neutral Higgs particles in association with the
supersymmetric scalar partners of the third generation quarks at future
high--energy hadron colliders [upgraded Tevatron, LHC] and linear
machines [including the option]. In the Minimal Supersymmetric
extension of the Standard Model, the cross section for the associated
production of the lightest neutral boson with the lightest top squark pairs
can be rather substantial at high energies. This process would open a window
for the measurement of the coupling, the potentially
largest coupling in the supersymmetric theory.Comment: 34 pages, LaTex, 11 PS figures using axodraw.sty. More detailed
discussion on the rho-parameter constraints. Numerical results and
conclusions unchanged. To appear in Nucl. Phys.
Scale Invariant Resummed Thermal Perturbative Expansions
International audienceWe illustrate how our recently developed renormalization group optimized perturbation (RGOPT) efficiently resums perturbative expansions in thermal field theories. The residual renormalization scale dependence of optimized thermodynamical quantities is drastically improved as compared to either standard perturbative expansions, or related methods such as the screened perturbation or (resummed) hard-thermal-loop perturbation. Our approach is illustrated briefly for the nonlinear sigma model, as a toy model for thermal QCD. Finally, preliminary applications of RGOPT to hard thermal loop resummation for the QCD pressure are sketched
Approximations for e+ e- –-> W+ W-
Denner A, Dittmaier S, Fleischer J, Kneur JL, Kolodziej K. Approximations for e+ e- –-> W+ W-. 1991
Measuring Unification
If supersymmetry is observed at the LHC its model parameters can be measured
at the electroweak scale. We discuss the expected precision on the parameter
determination, including a proper treatment of experimental and theoretical
errors. Particular attention is paid to degenerate solutions. Using the SFitter
framework we perform a bottom-up reconstruction of the unified parameters at
the high scale, including a full error propagation.Comment: 16 pages, 12 figures, Journal versio
Triple gauge boson couplings
0Published in In *Geneva 1995, Physics at LEP2, vol. 1* 525-576, and Preprint - Gounaris, G. (rec.Jan.96) 52 pinfo:eu-repo/semantics/publishe