Limiting fragmentation in heavy-ion collisions and percolation of strings

The observed limiting fragmentation of charged particle distributions in heavy ion collisions is difficult to explain as it does not apply to the proton spectrum itself. On the other hand, string percolation provides a mechanism to regenerate fast particles, eventually compensating the rapidity shift (energy loss) of the nucleons. However a delicate energy-momentum compensation is required, and in our framework we see no reason for limiting fragmentation to be exact. A prediction, based on percolation arguments, is given for the charged particle density in the full rapidity interval at LHC energy $(\sqrt s =5500 GeV)$.Comment: 9 pages, 2 figures (2 eps files), late

Responses of six Brachiaria spp. accessions to root zone flooding.

Título em português: Resposta de seis acessos de capim-braquiária ao alagamento do solo

Uso da espectroscopia de refletância no infravermelho próximo visando uma análise discriminatória de diferentes cultivares do gênero Paspalum.

Editado por Ana Rita de Araújo Nogueira, Simone Cristina Méo Niciur

Estabelecimento de leguminosas arbóreas em pastos de capim-marandu e tanzânia.

Parceria: PESAGRO; UFRRJ

Particle production azimuthal asymmetries in a clustering of color sources model

The collective interactions of many partons in the first stage of the collisions is the usual accepted explanation of the sizable elliptical flow. The clustering of color sources provides a framework of partonic interactions. In this scheme, we show a reasonable agreement with RHIC data for pT<1.5 GeV/c in both the dependence of v2 transverse momentum and in the shape of the nuclear modified factor on the azimuthal angle for different centralities. We show the predictions at LHC energies for Pb-Pb. In the case of proton-proton collisions a sizable v2 is obtained at this energy.Comment: To appear in Journal of Physics