Measurement of the B0-meson production cross section in proton-proton collisions at √s=13.6 TeV

A bstract This article reports the measurement of the transverse-momentum ( p T ) differential production cross section of B 0 mesons in proton-proton collisions at a centre-of-mass energy of √s=13.6 TeV with the ALICE detector at the CERN LHC. For the first time, the B 0 production cross section is measured at midrapidity (| y | < 0 . 5) down to p T = 1 GeV /c at LHC energies. The B 0 mesons and their charge conjugates were reconstructed via the B 0 → D − π + decay channel, followed by the D − → K + π − π − decay. The measured p T -differential production cross section is described within uncertainties by state-of-the-art models based on perturbative quantum-chromodynamics calculations. Its rapidity dependence is also studied by computing the p T -differential ratios between the ALICE measurement and the one of B + mesons performed by the LHCb Collaboration at forward rapidity. The B 0 production cross section per unit of rapidity at midrapidity is $$d{σ }^{B⁰}/{.dy|}|y|<0.5=24.2± 1.4(stat.)± 2.6{(syst.)}-0.3+0.2(extrap.) b$$ .