arXiv subjects

James F. Amundson

Publications and source records attributed to James F. Amundson.

4 recordsLinked to original sources

arXiv1995

Comparison of potential models through HQET

I calculate heavy-light decay constants in a nonrelativistic potential model. The resulting estimate of heavy quark symmetry breaking conflicts with similar estimates from lattice QCD. I show that a semirelativistic potential model eliminates the conflict. Using the results of heavy quark effective theory allows me to identify and compensate for shortcomings in the model calculations in addition to isolating the source of the differences in the two models. The results lead to a rule as to where the nonrelativistic quark model gives misleading predictions.

hep-ph↗

arXiv1993

Subleading Heavy Quark Effects in a Nonrelativistic Quark Model

I present a very simple model, based on the model of Isgur, Scora, Grinstein and Wise \cite{ISGW}, which can be used to calculate the effects which appear at subleading order in heavy quark effective theory. I include both general formalism and specific results. The formalism transparently reproduces the results of heavy quark effective theory, while giving insight into such things as the vanishing of certain form factors at zero recoil. I discuss the implications of these results for both heavy quark effective theory and the Isgur-Scora-Grinstein-Wise model.

hep-ph↗

arXiv1992

Test for Right-Handed $b$ Quark Decays

Gronau and Wakaizumi have proposed a model in which the dominant $b$ decays are due to exchange of a new right-handed gauge boson. A test of this model via the study of polarized $Λ_b$ baryons produced in $e^+ e^- \to Z \to Λ_b + X$ is suggested.

hep-ph↗

arXiv1992

Heavy Quark Symmetry Violation in Semileptonic Decays of D Mesons

The decays of $D$ mesons to $K l ν$ and $K^* l ν$ final states exhibit significant deviations from the predictions of heavy-quark symmetry, as one might expect since the strange quark's mass is of the same order as the QCD scale. Nonetheless, in order to understand where the most significant effects might lie for heavier systems (such as $B \to D lν$ and $B \to D^* lν$), the pattern of these deviations is analyzed from the standpoint of perturbative QCD and ${\cal O}(1/m_s)$ corrections. Two main effects are noted. First, the perturbative QCD corrections lead to an overall decrease of predicted rates, which can be understood in terms of production of excited kaonic states. Second, ${\cal O}(1/m_s)$ effects tend to cancel the perturbative QCD corrections in the case of $Klν$ decay, while they have minimal effect in $K^*lν$ decay.

hep-ph↗