Head-Tail Modes for Strong Space Charge

The head-tail modes are described for the space charge tune shift significantly exceeding the synchrotron tune. A general equation for the modes is derived. The spatial shapes of the modes, their frequencies, and coherent growth rates are explored. The Landau damping rates are also found. The suppression of the transverse mode coupling instability by the space charge is explained.Comment: 11 pages, 7 figures, submitted to Phys. Rev. ST-Accel. Beam

Hadronic production of the PP-wave excited BcB_c-states (BcJ,L=1∗B_{cJ,L=1}^*)

Adopting the complete $\alpha_s^4$ approach of the perturbative QCD (pQCD) and updated parton distribution functions, we have estimated the hadronic production of $P$-wave excited $B_c$-states ($B_{cJ,L=1}^*$). In the estimate, special care on the relation of the production amplitude to the derivative of wave function at origin of the potential model is payed. For experimental references, main uncertainties are discussed, and the total cross sections and the distributions of the production with reasonable cuts at the energies of Tevatron and LHC are computed and presented. The results show that $P$-wave production may contribute to the $B_c$-meson production indirectly by a factor about 0.5 of the direct production, and with such a big cross section, it is worth further to study the possibility to observe the $P$-wave production itself experimentally.Comment: 23 pages, 9 figures, to replace for revising the misprints ec

Empirical tests of status consumption : evidence from women's cosmetics

Nearly all applied work in consumer demand assumes the absence of status consumption. The validity of this assumption has not been supported through empirical inquiry which confirms the unimportance of status motivations in consumer behavior. However, it is feasible to conduct tests which differentiate between status-motivated behavior and consumer purchasing in which no status motivations are present. This paper provides such a test, which is based on the fact that social visibility is ordinarily necessary for a good to serve as a status symbol. We investigate brand buying among four cosmetics products, and find, as hypothesized, that more "status" is purchased with the more socially visible products. Specifically, we find that visible goods have a lower price-quality correlation and a pattern of brand buying favoring higher-priced brands. We also investigate differing degrees of status-consumption by income, education, race, and urban/suburban dwelling. Our results provide strong support for the existence of status-consumption and are not consistent with theories in which no status-consumption is occurring.gender differences;status;consumption

Quantum oscillations of spin current through a III-V semiconductor loop

We have investigated the transport of spin polarization through a classically chaotic semiconductor loop with a strong Rashba spin-orbit interaction. We found that if the escape time of a particle is long enough, the configuration averaged spin conductance oscillates strongly with the geometric spin phase. We predict a sizable rotation of spin polarization along its flowing path across the loop from the injector to the collector. We have also discovered a quantized universal spin relaxation in a 2D reservoir connected to such a semiconductor loop.Comment: 4 pages, 1 figur