102,109 research outputs found
On rank functions for heaps
Motivated by work of Stembridge, we study rank functions for Viennot's heaps
of pieces. We produce a simple and sufficient criterion for a heap to be a
ranked poset and apply the results to the heaps arising from fully commutative
words in Coxeter groups.Comment: 18 pages AMSTeX, 3 figure
Effects of halo triaxiality, anisotropy and small scale clumping on WIMP direct detection exclusion limits
Weakly Interacting Massive Particle (WIMP) direct detection experiments are
closing in on the region of parameter space where neutralinos may constitute
the Galactic halo dark matter. Numerical simulations and observations of galaxy
halos indicate that the standard Maxwellian halo model is likely to be a poor
approximation to the dark matter distribution. We examine how halo models with
triaxiality and/or velocity anisotropy affect exclusion limits, before
discussing the consequences of the possible survival of small scale clumps.Comment: 6 pages, 5 figures, to appear in proceedings of "IDM 2002, 4th
International Workshop on the Identification of Dark Matter" v2: added 2
footnotes and a referenc
- …