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 ($\mathrm{p}+\mathrm{p}$) 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 $\mathrm{p}+\mathrm{p}$ collisions. Our prediction in Dusling and Venugopalan [arXiv:1210.3890 [Phys. Rev. D (to be published)]] for proton-lead ($\mathrm{p}+\mathrm{Pb}$) collisions is consistent with results from the recent CMS $\mathrm{p}+\mathrm{Pb}$ run at ${\sqrt{s}}_{\mathrm{NN}}=5.02\mathrm{TeV}$ for the largest track multiplicity $N_{\mathrm{track}}\sim 40$ we considered. The CMS $\mathrm{p}+\mathrm{Pb}$ data shows the following striking features: (i) a strong dependence of the ridge yield on $N_{\mathrm{track}}$, with a significantly larger signal than in $\mathrm{p}+\mathrm{p}$ for the same $N_{\mathrm{track}}$, (ii) a stronger $p_T$ dependence than in $\mathrm{p}+\mathrm{p}$ for large $N_{\mathrm{track}}$, and (iii) a nearside collimation for large $N_{\mathrm{track}}$ comparable to the awayside for the lower $p_T=p_T^{\mathrm{trig}}=p_T^{\mathrm{assoc}}$ dihadron windows. We show here that these systematic features of the CMS $\mathrm{p}+\mathrm{Pb}$ di-hadron data are all described by the color glass condensate (with parameters fixed by the $\mathrm{p}+\mathrm{p}$ 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 We also predict the azimuthally collimated yield for yet unpublished windows in the $p_T^{\mathrm{trig}}$ and $p_T^{\mathrm{assoc}}$ matrix.

• Received 20 November 2012

DOI:https://doi.org/10.1103/PhysRevD.87.054014