Quarkonium production and polarization in pp collisions with the CMS detector

The studies of heavy quarkonium inclusive production and polarization at LHC are becoming crucial to solve the puzzle of hadron formation. The results by CMS and the other LHC experiments are compactly presented for the five S-wave states J/Psi, Psi(2S) and Y(nS) (n=1,2,3) and briefly discussed especially in comparison to the theoretical predictions provided by Non Relativistic QCD.Comment: 6 pages, 4 figures; Proceedinsg of the Second Annual LHCP, New York, U.S.A., June 2-7, 201

Persistence of some additive functionals of Sinai's walk

We are interested in Sinai's walk $(S\_n)\_{n\in\mathbb{N}}$. We prove that the annealed probability that $\sum\_{k=0}^n f(S\_k)$ is strictly positive for all $n\in[1,N]$ is equal to $1/(\log N)^{\frac{3-\sqrt{5}}{2}+o(1)}$, for a large class of functions $f$, and in particular for $f(x)=x$. The persistence exponent $\frac{3-\sqrt{5}}{2}$ first appears in a non-rigorous paper of Le Doussal, Monthus and Fischer, with motivations coming from physics. The proof relies on techniques of localization for Sinai's walk and uses results of Cheliotis about the sign changes of the bottom of valleys of a two-sided Brownian motion.Comment: 30 pages, 2 figure