The Ridge and Di-hadron Correlations from the BES at RHIC

Di-hadron correlations are a key observable in heavy-ion collisions, and play a critical role in establishing the equation of state for hot and dense nuclear matter. In this analysis, the first set of results of 2D di-hadron correlations (Δϕ, Δη) for Au+Au collisions with center-of-mass energies sNN=7.7,11.5,14.5,19.6,27, and 39 GeV from the STAR experiment is presented. Anisotropy coefficients of second and third orders (ν2,3{2}) from long range rapidity correlations of di-hadrons are obtained, and when scaled by multiplicity, ν32 shows a non-monotonic behavior as a function of energy.