J. Kim — Page 14 | Searcharxiv

arXiv1996

Carbon superatom thin films

Assembling clusters on surfaces has emerged as a novel way to grow thin films with targeted properties. In particular, it has been proposed from experimental findings that fullerenes deposited on surfaces could give rise to thin films retaining the bonding properties of the incident clusters. However the microscopic structure of such films is still unclear. By performing quantum molecular dynamics simulations, we show that C_28 fullerenes can be deposited on a surface to form a thin film of nearly defect free molecules, which act as carbon superatoms. Our findings help clarify the structure of disordered small fullerene films and also support the recently proposed hyperdiamond model for solid C_28.

cond-mat.mtrl-sci↗

arXiv1996

Enhanced Supersymmetric Corrections to Top-Quark Production at the Tevatron

We calculate the one-loop supersymmetric electroweak-like and QCD-like corrections to the top-quark pair-production cross section at the Tevatron, including the important effects of non-degenerate top-squarks and left-right top-squark mixing. The largest electroweak effects yield a negative shift in the cross section and are enhanced right below the threshold for top-quark decay into top-squark and higgsino-like neutralino, and can be as large as $-35\%$. The largest QCD effects are positive and are enhanced for light top-squark masses, and can be as large as $20\%$. Such shifts greatly exceed the present theoretical uncertainty in the Standard Model prediction, and therefore may be experimentally observable. We also explore the one-loop shifts in scenarios containing light top-squarks and higgsino-like neutralinos that have been recently proposed to explain various apparent experimental anomalies.

hep-ph↗