The production of π and πβ² mesons is studied in proton-proton and proton-lead collisions collected with the LHCb detector. Proton-proton collisions are studied at center-of-mass energies of 5.02 and 13TeV and proton-lead collisions are studied at a center-of-mass energy per nucleon of 8.16TeV. The studies are performed in center-of-mass (c.m.) rapidity regions 2.5<π¦c.m.<3.5 (forward rapidity) and β4.0<π¦c.m.<β3.0 (backward rapidity) defined relative to the proton beam direction. The π and πβ² production cross sections are measured differentially as a function of transverse momentum for 1.5<πT<10GeV and 3<πT<10GeV, respectively. The differential cross sections are used to calculate nuclear modification factors. The nuclear modification factors for π and πβ² mesons agree at both forward and backward rapidity, showing no significant evidence of mass dependence. The differential cross sections of π mesons are also used to calculate π/π0 cross-section ratios, which show evidence of a deviation from the world average. These studies offer new constraints on mass-dependent nuclear effects in heavy-ion collisions, as well as π and πβ² meson fragmentation.
more »
« less
Morphology-dependent optical anisotropies in the n -type polymer P(NDI2OD-T2)
