Very-high-$p_T$ triggered dihadron correlations in PbPb collisions at 2.76~TeV with CMS

Measurements of dihadron correlations triggered by very high-$p_T$ particles in 2.76 TeV PbPb collisions are presented. The analysis explores the full 2011 PbPb data set corresponding to an integrated luminosity of 150$\mu b^{-1}$ collected by CMS. Long-range correlations driven by single-particle azimuthal anisotropies (characterized by the Fourier harmonics, $v_n$) are measured up to $p_T\approx 50$~GeV/c. After subtracting the $v_2-v_4$ harmonic components, the associated particle yields on the near and away side of the residual jet-like dihadron correlations are studied over a wide kinematic range in trigger and associated particle $p_T$, as a function of collision centrality. By comparing to pp data at the same energy, a suppression of about 50\% in the away-side associated yield is observed for $p_T^{\rm assoc} > 3 $~GeV/c. The yield is found to be significantly enhanced up to a factor of $3-4$ on the away side at $p_T^{\rm assoc}\approx 0.5$~GeV/c. A moderate enhancement is suggested on the near side.