arXiv subjects

J. F. Amundson

Publications and source records attributed to J. F. Amundson.

5 recordsLinked to original sources

arXiv2009

Some alternatives for calculating multipole expansions of the electromagnetic radiation field

We discuss the multipolar expansion of the electromagnetic field with an emphasis on the radiated field. We investigate if the employment of Jefimenko's equations brings a new insight into the calculation of the radiation field. We show that the affirmation is valid if one finds an interesting example in which inverting the order between spatial derivatives and integration is not allowed. Further, we consider the generalization of the multipolar expansion of the power radiated by a confined system of charges and currents to a higher arbitrary order.

physics.class-ph↗

arXiv1996

Quantitative Tests of Color Evaporation: Charmonium Production

The color evaporation model simply states that charmonium production is described by the same dynamics as $D \bar D$ production, {\em i.e.}, by the formation of a colored $c \bar c$ pair. Its color happens to be bleached by soft final-state interactions. We show that the model gives a complete picture of charmonium production including low-energy production by proton, photon and antiproton beams, and high-energy production at the Tevatron and HERA. Our analysis includes the first next-to-leading-order calculation in the color evaporation model.

hep-ph↗

arXiv1995

Colorless States in Perturbative QCD: Charmonium and Rapidity Gaps

We point out that an unorthodox way to describe the production of rapidity gaps in deep inelastic scattering, recently proposed by Buchmüller and Hebecker, suggests a description of the production of heavy quark bound states which is in agreement with data. The approach questions the conventional treatment of the color quantum number in perturbative QCD.

hep-ph↗

arXiv1992

Radiative $D^*$ Decay Using Heavy Quark and Chiral Symmetry

The implications of chiral $SU(3)_L \times SU(3)_R$ symmetry and heavy quark symmetry for the radiative decays $D^{*0}\to D^0γ$, $D^{*+}\to D^+γ$, and $D_s^*\to D_sγ$ are discussed. Particular attention is paid to $SU(3)$ violating contributions of order $m_q^{1/2}$. Experimental data on these radiative decays provide constraints on the $D^* Dπ$ coupling.

hep-ph↗

arXiv1992

Meson Decay Constants from Isospin Mass Splittings in the Quark Model

Decay constants of $D$ and $B$ mesons are estimated within the framework of a heavy-quark approach using measured isospin mass splittings in the $D$, $D^*$, and $B$ states to isolate the electromagnetic hyperfine interaction between quarks. The values $f_D = (262 \pm 29)$ MeV and $f_B = (160 \pm 17)$ MeV are obtained. Only experimental errors are given; possible theoretical ambiguities, and suggestions for reducing them, are noted.

hep-ph↗