519 research outputs found
Signatures of gravitational fixed points at the LHC
We study quantum-gravitational signatures at the CERN Large Hadron Collider (LHC) in the context of theories with extra spatial dimensions and a low fundamental Planck scale in the TeV range. Implications of a gravitational fixed point at high energies are worked out using WilsonÂżs renormalization group. We find that relevant cross sections involving virtual gravitons become finite. Based on gravitational lepton pair production we conclude that the LHC is sensitive to a fundamental Planck scale of up to 6 TeV
Ueber die praktischen Ergebnisse der neueren Malariaforschung und einige weitere Aufgaben derselben 1 )
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Prospects for Higgs properties determination at the LHC
The strategies recently developed to study Higgs boson properties at the LHC
are reviewed. It is shown how to obtain model-independent determinations of
couplings to fermions and gauge bosons by exploiting different production and
decay channels. We consider in some detail the case of Weak Boson Fusion Higgs
production with H --> b \bar b as well as the prospects for the determination
of the Higgs self-coupling at the SLHC.Comment: LaTeX (using npb style), 5 pages, 1 .eps figure. Talk presented at
RADCOR and Loops and Legs 2002, 8-13 September 2002, Kloster Banz, Germany.
Added one referenc
Ueber die Pathologie Kameruns mit RĂŒcksicht auf die unter den KĂŒstennegern vorkommenden Krankheiten
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Determining the Higgs Boson Self Coupling at Hadron Colliders
Inclusive Standard Model Higgs boson pair production at hadron colliders has
the capability to determine the Higgs boson self-coupling, lambda. We present a
detailed analysis of the gg\to HH\to (W^+W^-)(W^+W^-)\to
(jjl^\pm\nu)(jj{l'}^\pm\nu) and gg\to HH\to (W^+W^-)(W^+W^-)\to
(jjl^\pm\nu)({l'}^\pm\nu {l''}^\mp\nu) (l, {l'}, {l''}=e, \mu) signal channels,
and the relevant background processes, for the CERN Large Hadron Collider, and
a future Very Large Hadron Collider operating at a center-of-mass energy of 200
TeV. We also derive quantitative sensitivity limits for lambda. We find that it
should be possible at the LHC with design luminosity to establish that the
Standard Model Higgs boson has a non-zero self-coupling and that lambda /
lambda_{SM} can be restricted to a range of 0-3.8 at 95% confidence level (CL)
if its mass is between 150 and 200 GeV. At a 200 TeV collider with an
integrated luminosity of 300 fb^{-1}, lambda can be determined with an accuracy
of 8 - 25% at 95% CL in the same mass range.Comment: 28 pages, Revtex3, 9 figures, 3 table
Implications of gauge-mediated supersymmetry breaking with vector-like quarks and a ~125 GeV Higgs boson
We investigate the implications of models that achieve a Standard Model-like
Higgs boson of mass near 125 GeV by introducing additional TeV-scale
supermultiplets in the vector-like 10+\bar{10} representation of SU(5), within
the context of gauge-mediated supersymmetry breaking. We study the resulting
mass spectrum of superpartners, comparing and contrasting to the usual
gauge-mediated and CMSSM scenarios, and discuss implications for LHC
supersymmetry searches. This approach implies that exotic vector-like fermions
t'_{1,2}, b',and \tau' should be within the reach of the LHC. We discuss the
masses, the couplings to electroweak bosons, and the decay branching ratios of
the exotic fermions, with and without various unification assumptions for the
mass and mixing parameters. We comment on LHC prospects for discovery of the
exotic fermion states, both for decays that are prompt and non-prompt on
detector-crossing time scales.Comment: 32 pages. v2: references added, figure caption 5.3 correcte
Asymptotic safety and Kaluza-Klein gravitons at the LHC
We study Drell-Yan production at the LHC in low-scale quantum gravity models
with extra dimensions. Asymptotic safety implies that the ultra-violet behavior
of gravity is dictated by a fixed point. We show how the energy dependence of
Newton's coupling regularizes the gravitational amplitude using a
renormalization group improvement. We study LHC predictions and find that
Kaluza-Klein graviton signals are well above Standard Model backgrounds. This
leaves a significant sensitivity to the energy scale Lambda_T where the
gravitational couplings cross over from classical to fixed point scaling.Comment: 25 pages, 14 figure
Examining the Higgs boson potential at lepton and hadron colliders: a comparative analysis
We investigate inclusive Standard Model Higgs boson pair production at lepton
and hadron colliders for Higgs boson masses in the range 120 GeV < m_H < 200
GeV. For m_H < 140 GeV we find that hadron colliders have a very limited
capability to determine the Higgs boson self-coupling, \lambda, due to an
overwhelming background. We also find that, in this mass range, supersymmetric
Higgs boson pairs may be observable at the LHC, but a measurement of the self
coupling will not be possible. For m_H > 140 GeV we examine ZHH and HH nu
bar-nu production at a future e+e- linear collider with center of mass energy
in the range of sqrt{s}=0.5 - 1 TeV, and find that this is likely to be equally
difficult. Combining our results with those of previous literature, which has
demonstrated the capability of hadron and lepton machines to determine \lambda
in either the high or the low mass regions, we establish a very strong
complementarity of these machines.Comment: Revtex, 25 pages, 2 tables, 10 figure
Robust LHC Higgs Search in Weak Boson Fusion
We demonstrate that an LHC Higgs search in weak boson fusion production with
subsequent decay to weak boson pairs is robust against extensions of the
Standard Model or MSSM involving a large number of Higgs doublets. We also show
that the transverse mass distribution provides unambiguous discrimination of a
continuum Higgs signal from the Standard Model.Comment: 12p, 2 figs., additional comments on backgrounds, version to appear
in PR
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