Charmless and Penguin Decays at CDF

Penguin transitions play a key role in the search of New Physics hints in the heavy flavor sector. During the last decade CDF has been exploring this opportunity with a rich study of two--body charmless decays of neutral B mesons into charged final--state particles. After briefly introducing the aspects of this physics peculiar to the hadron collision environment, I report on two interesting results: the first polarization measurement of the B^0_s --> phi phi decay and the update of the B^0(_s) --> h^+h'^- decays analysis.Comment: 7 pages, 3 figures. Proceedings of CKM2010, the 6th International Workshop on the CKM Unitarity Triangle, University of Warwick, UK, 6-10 September 201

Exact theory of freeze out

We show that the standard theory of thermal production and chemical decoupling of WIMPs is incomplete. The hypothesis that WIMPs are produced and decouple from a thermal bath implies that the rate equation the bath particles interacting with the WIMPs is an algebraic equation that constraints the actual WIMPs abundance to have a precise analytical form down to the temperature $x_\ast=m_\chi /T_\ast$. The point $x_\ast$, which coincides with the stationary point of the equation for the quantity $\Delta= Y-Y_0$, is where the maximum departure of the WIMPs abundance $Y$ from the thermal value $Y_0$ is reached. For each mass $m_\chi$ and total annihilation cross section $\langle \sigma_\text{ann}v_\text{r}\rangle$, the temperature $x_\ast$ and the actual WIMPs abundance $Y(x_\ast)$ are exactly known. This value provides the true initial condition for the usual differential equation that have to be integrated in the interval $x\ge x_\ast$. The matching of the two abundances at $x_\ast$ is continuous and differentiable. The dependence of the present relic abundance on the abundance at an intermediate temperature is an exact result. The exact theory suggests a new analytical approximation that furnishes the relic abundance accurate at the level of $1\%-2\%$ in the case of $S$-wave and $P$-wave scattering cross sections. We conclude the paper studying the evolution of the WIMPs chemical potential and the entropy production using methods of non equilibrium thermodynamics.Comment: 10 pages, 2 figure: V3 similar to the published version in EPJ

Measurements of the masses, lifetimes and decay modes of hadrons at Tevatron

The Tevatron provides 1.96 TeV ppbar collisions and allows for collection of rich b-hadron samples to the two experiments CDF and D0. The study of heavy flavor properties represents a fruitful opportunity to investigate the flavor sector of the Standard Model (SM) and to look for hints of New Physics (NP). Here we report the first measurement of polarization amplitudes in B^0_s charmless decays, world leading results on b-hadron lifetimes, and measurements of several other properties of b-hadrons.Comment: 4 pages, 2 figures, contribution submitted to 45th Rencontres de Moriond, QCD and High Energy Interactions, La Thuile, March 13-20, 201