arXiv subjects

J. Magnin

Publications and source records attributed to J. Magnin.

42 records · Page 3Linked to original sources

arXiv1997

Hyperon production asymmetries in 500 GeV/c pion nucleus interactions

We present a preliminary study from Fermilab experiment E791 of Lambda^0 / Lambda^0 bar, Xi^- / Xi^+ and Omega^- /Omega^+ production asymmetries from pi^- nucleus interactions at 500 Gev/c. The production asymmetries for these particles are studied as a function of x_F and pt^2. We observed an asymmetry in the target fragmentation region for Lambda^0's larger than that for Xi's, suggesting diquark effects. The asymmetry for Omega's is significatively smaller than for the other two hyperons consistent with the fact that Omega's do not share valence quarks with either the pion or the target particle. In the beam fragmentation region, the asymmetry tends to 0.1 for both Lambda^0's and Xi's. The asymmetries vs pt^2 are approximately constant for the three strange baryons under study.

hep-ex↗

arXiv1997

Localization-delocalization transition of a reaction-diffusion front near a semipermeable wall

The A+B --> C reaction-diffusion process is studied in a system where the reagents are separated by a semipermeable wall. We use reaction-diffusion equations to describe the process and to derive a scaling description for the long-time behavior of the reaction front. Furthermore, we show that a critical localization-delocalization transition takes place as a control parameter which depends on the initial densities and on the diffusion constants is varied. The transition is between a reaction front of finite width that is localized at the wall and a front which is detached and moves away from the wall. At the critical point, the reaction front remains at the wall but its width diverges with time [as t^(1/6) in mean-field approximation].

cond-mat.stat-mech↗

arXiv1997

Production and polarization of $Λ_c^+$ and the charm of the proton

We propose a two-component model involving the parton fusion mechanism and recombination of a $ud$ valence diquark with a sea $c$-quark of the incident proton to describe $Λ_c^+$ inclusive production in $pp$ collisions. We also study the polarization of the produced $Λ_c^+$ in the framework of the Thomas Precession Model for polarization. We show that a measurement of the $Λ_c$ polarization is a sensitive test of its production mechanism. In particular the intrinsic charm model predicts a positive polarization for the $Λ_c$ within the framework of the Thomas Precession Model, while according to the model presented here the $Λ_c$ polarization should be negative. The measurement of the $Λ_c$ polarization provides a close examination of intrinsic charm Fock states in the proton and give interesting information about the hadroproduction of charm.

hep-ph↗

arXiv1997

The Charm of the Proton and the $Λ_c^{+}$ Production

We propose a two component model for charmed baryon production in $pp$ collisions consisting of the conventional parton fusion mechanism and fragmentation plus quarks recombination in which a $ud$ valence diquark from the proton recombines with a $c$-sea quark to produce a $Λ_c^+$. Our two-component model is compared with the intrinsic charm two-component model and experimental data.

hep-ph↗

arXiv1997

The $Λ_0$ Polarization and the Recombination Mechanism

We use the recombination and the Thomas Precession Model to obtain a prediction for the $Λ_0$ polarization in the $p+p \to Λ_0+X$ reaction. We study the effect of the recombination function on the $Λ_0$ polarization.

hep-ph↗

arXiv1995

Bargmann-Michel-Telegdi equation and one-particle relativistic approach

A reexamination of the semiclassical approach of the relativistic electron indicates a possible variation of its helicity for electric and magnetic static fields applied along its global motion due to zitterbewegung effects, proportional to the anomalous part of the magnetic moment.

hep-th↗