Abstract
Results on two-particle angular correlations are presented in proton–proton collisions at center of mass energies of 7 TeV, over a broad range of pseudorapidity and azimuthal angle. In very high-multiplicity events at 7 TeV, a pronounced structure emerges in the two-dimensional correlation function for particle pairs with intermediate pT of 1–3 GeV/c, in the kinematic region 2.0 < |Δη| < 4.8 and small Δϕ. This structure, which has not been observed in pp collisions before, is similar to what is known as the ‘ridge’ in heavy-ion collisions. It is not predicted by commonly used proton–proton Monte Carlo models and is not seen in lower multiplicity pp collisions. Updated studies of this new effect as a function of particle transverse momentum, rapidity and event characteristics are shown.
Highlights
Results on two-particle angular correlations are presented in proton-proton collisions at center of mass energies of 7 TeV, over a broad range of pseudorapidity and azimuthal angle
In very high multiplicity events at 7 TeV, a pronounced structure emerges in the two-dimensional correlation function for particle pairs with intermediate pT of 1–3 GeV/c, in the kinematic region 2.0 < |∆η| < 4.8 and small ∆φ
The novel structure resembles similar features observed in relativistic heavyion experiments. This striking feature is most evident in the intermediate transverse momentum range of both 1
Summary
The high multiplicity data exhibit a jet-like correlation peak in the yield for small |∆η| and show significant and roughly constant yield out to the highest |∆η| regions. This is qualitatively similar to what has been observed in central PbPb collisions at √s = 2.76 TeV [3] but is NN completely absent in minimum bias pp collisions as well as pp MC models
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
