Explanation of systematics of CMS p plus Pb high multiplicity dihadron data at √sNN=5.02 TeV

In a recent article [K. Dusling and R. Venugopalan, arXiv:1210.3890 [Phys. Rev. D (to be published)]], we showed that high multiplicity dihadron proton-proton (p + p) data from the CMS experiment are in excellent agreement with computations in the color glass condensate effective field theory. This agreement of the theory with several hundred data points provides a nontrivial description of both nearside ("ridge'') and awayside azimuthal collimations of long range rapidity correlations in p + p collisions. Our prediction in Dusling and Venugopalan [arXiv: 1210.3890 [Phys. Rev. D (to be published)]] for proton-lead (p + Pb) collisions is consistent with results from the recent CMS p + Pb run at root s(NN) = 5.02 TeV for the largest track multiplicity N-track similar to 40 we considered. The CMS p + Pb data shows the following striking features: (i) a strong dependence of the ridge yield on N-track, with a significantly larger signal than in p + p for the same Ntrack, (ii) a stronger p(T) dependence than in p + p for large N-track, and (iii) a nearside collimation for large N-track comparable to the awayside for the lower p(T) = p(T)(trig) = p(T)(assoc) dihadron windows. We show here that these systematic features of the CMS p + Pb di-hadron data are all described by the color glass condensate (with parameters fixed by the p + p data) when we extend our prediction in Dusling and Venugopalan [arXiv: 1210.3890 [Phys. Rev. D (to be published)]] to rarer high multiplicity events. We also predict the azimuthally collimated yield for yet unpublished windows in the p(T)(trig) and p(T)(assoc) matrix. DOI: 10.1103/PhysRevD.87.054014