arXiv subjects
Publications and source records attributed to Duane A. Dicus.
Higgs boson radiative decays of the form $H\rightarrow f\bar{f}γ$ are calculated in the Standard Model using the complete one-loop expressions for the decay amplitudes. Contributions to the radiative width from leptons and light quarks are given. We also present $e\bar{e}$ invariant mass distributions for $H\rightarrow e\bar{e}γ$, which illustrate the importance of the photon pole contribution and the effects of the box diagrams.
We investigate the production of a pseudoscalar Higgs-boson $A^0$ using the reaction $e\,γ\rightarrow e\,A^0$ at an $e\bar{e}$ collider with center of mass energy of 500 GeV. Supersymmetric contributions are included and provide a substantial enhancement to the cross section for most values of the symmetry breaking parameters. We find that, despite the penalty incurred in converting one of the beams into a source of backscattered photons, the $e\, γ$ process is a promising channel for the detection of the $A^0$.
We present complete analytical expressions for the amplitudes of the process $e\bar{e}\rightarrow Hγ$. The calculation is performed using nonlinear gauges, which significantly simplifies both the actual analytical calculation and the check of its gauge invariance. After comparing our results with a previous numerical calculation, we extend the range of Higgs masses and center of mass energies to those appropriate to LEP 200 and a future linear collider.
We improve, using a larger set of observations including Voyager 2 Neptune flyby data, previous bounds on the amount of dark matter (DM) trapped in a spherically symmetric distribution about the sun. We bound DM by noting that such a distribution would increase the effective mass of the sun as seen by the outer planets and by finding the uncertainty in that effective mass for Uranus and Neptune in fits to the JPL Developmental Ephermeris residuals, including optical data and those two planets' Voyager 2 flybys. We extend our previous procedure by fitting more parameters of the developmental ephemerides. Additionally, we present here the values for Pioneer 10 and 11 and Voyager 1 and 2 Jupiter ranging normal points (and incorporate these data as well). Our principal result is to limit DM in spherically symmetric distributions in orbit about the sun interior to Neptune's orbit to less than an earth mass and interior to Uranus' orbit to about 1/6 of an earth's mass.
We consider the dip-peak structures in the J=0 partial wave amplitudes for processes $γγ\rightarrow W^+W^-~ \mbox{and}~γγ,gg\rightarrow t\overline{t}$ taking into account the corresponding Born term process and the rescattering process where the intermediate state is rescattered through the exchange of Higgs resonance state in the direct channel.
Analytic expressions are given for the $τ$ decays into three charged leptons, $τ\rta \ell\ell\overline \ellν_τ\overline ν_\ell$, where the $\ell$ are combinations of electrons and muons, and for the radiative decays $τ\rta γ\ellν_τ\overline ν_\ell$. The branching ratios are sensitive functions of whether the final state $\ell$ are muons or electrons.
The $ZZ$ pair production rate in high energy $γγ$ collisions is evaluated with photons from laser backscattering. We find that searching for the Standard Model Higgs boson with a mass up to, or slightly larger than, 400 GeV via the $ZZ$ final state is possible via photon fusion with backscattered laser photons at a linear $e^+e^-$ collider with energies in the range 600 GeV $< \sqrt{s_{e^+e^-}} <$ 1000 GeV.
The cross section for photon neutrino scattering is calculated in the standard model assuming that the neutrino is massless and that the center of mass energy is small compared to any charged lepton mass. Although the scattered photons can acquire a (parity violating) circular polarization of order unity, the cross section in this limit is highly suppressed.
We study the effects of a strongly interacting Higgs sector on the amplitudes for $γ\,γ\rightarrow W_L^+\,W_L^-, Z_L^{\,0}\,Z_L^{\,0}$ by unitarizing the $W_L^+\,W_L^-, Z_L^{\,0}\,Z_L^{\,0}, γ\,γ$ system using the $K$--matrix technique. Unitarization produces substantial corrections to the cross sections for gauge boson pair production by photon fusion when $m_H \agt 5-10\;$TeV.