Long range rapidity correlations and jet production in high energy nuclear collisions

Abstract

The STAR Collaboration at RHIC presents a systematic study of high transverse momentum charged di-hadron correlations at small azimuthal pair separation dphino, in d_s16Au and central Au_s16Au collisions at $rts = 200$ GeV. Significant correlated yield for pairs with large longitudinal separation deta is observed in central Au_s16Au, in contrast to d_s16Au collisions. The associated yield distribution in detano$times$dphi can be decomposed into a narrow jet-like peak at small angular separation which has a similar shape to that found in d_s16Au collisions, and a component which is narrow in dphi and textcolor{black}{depends only weakly on} $deta$, the _s15ridge_s15. Using two systematically independent analyses, textcolor{black}{finite ridge yield} is found to persist for trigger $pt > 6$ GeVc, indicating that it is correlated with jet production. The transverse momentum spectrum of hadrons comprising the ridge is found to be similar to that of bulk particle production in the measured range ($2 < pt < 4 GeVc$).