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Flow-like signals including the ridge structure observed in small collision systems that are similar to those in large collision systems have led to questions about the onset of collectivity in nuclear collisions. In this study, we use the string melting version of a multi-phase transport model with or without the sub-nucleon geometry for the proton to study multiparticle cumulants in p + p collisions at 13 TeV. Both versions of the model can produce negative c 2 { 4 } values at high multiplicities. In addition, the dependences of c 2 { 4 } and c 2 { 2 } on the parton cross section σ are found to be strong and non-monotonous, where only an intermediate range of σ values leads to negative c 2 { 4 }. Furthermore, the model with sub-nucleon geometry better describes the multiplicity dependence of c 2 { 4 } , demonstrating the importance of the sub-nucleon geometry for studies of small systems. [ABSTRACT FROM AUTHOR]

Predictions made in Albacete et al. [ Int. J. Mod. Phys. E 22 (2013) 1330007] prior to the LHC Pb run at TeV are compared to currently available data. Some predictions shown here have been updated by including the same experimental cuts as the data. Some additional predictions are also presented, especially for quarkonia, that were provided to the experiments before the data were made public but were too late for the original publication. [ABSTRACT FROM AUTHOR]

We trace the development of azimuthal anisotropy ( v n , n = 2 , 3 ) via parton–parton collision history in two transport models. The parton v n is studied as a function of the number of collisions of each parton in Au + Au and d + Au collisions at s NN = 200 GeV . It is found that the majority of v n comes from the anisotropic escape probability of partons, with no fundamental difference at low and high transverse momenta. The contribution to v n from hydrodynamic-type collective flow is found to be small. Only when the parton–parton cross-section is set unrealistically large does this contribution start to take over. Our findings challenge the current paradigm emerged from hydrodynamic comparisons to anisotropy data. [ABSTRACT FROM AUTHOR]

Predictions for cold nuclear matter effects on charged hadrons, identified light hadrons, quarkonium and heavy flavor hadrons, Drell–Yan dileptons, jets, photons, gauge bosons and top quark pairs produced in p +Pb collisions at s N N = 8.16 TeV are compiled and, where possible, compared to each other. Predictions of the normalized ratios of p +Pb to p + p cross sections are also presented for most of the observables, providing new insights into the expected role of cold nuclear matter effects. In particular, the role of nuclear parton distribution functions on particle production can now be probed over a wider range of phase space than ever before. [ABSTRACT FROM AUTHOR]