Long-range correlations in high-multiplicity proton-proton collisions at the LHC

Gunther Roland (MIT)
DESY Auditorium, 17:00h

The CMS collaboration recently announced the observation of long-range near-side angular correlations in proton-proton collisions at LHC. In this measurement, we have found a novel correlation where particles produced in the collision are aligned in their azimuthal angle over a large pseudorapidity region. This "ridge"-like structure is absent in minimum bias events but emerges as the produced particle multiplicity reaches very high values. This phenomenon has not been observed before in proton-proton collisions but resembles similar effects seen in collisions of nuclei such as copper and gold ions at RHIC. In this talk, I will report on the experimental aspects of this measurement and discuss some of the recent proposals regarding the physical origin of the effect."