Measurement of the ${\mathbf{B}}^0$-meson production cross section in proton--proton collisions at $\sqrt{\text{s}}=13.6$ TeV

Abstract

This article reports the measurement of the transverse-momentum ($p_{\mathrm{T}}$) differential production cross section of B${}^0$ mesons in proton-proton collisions at a centre-of-mass energy of $\sqrt{s}=13.6$ 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 $p_{\mathrm{T}}=1\mathrm{GeV}/c$ at LHC energies. The B${}^0$ mesons and their charge conjugates were reconstructed via the B${}^0\to$D${}^{-}{\pi }^{+}$ decay channel, followed by the D${}^{-}\to$K${}^{+}{\pi }^{-}{\pi }^{-}$ decay. The measured $p_{\mathrm{T}}$-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 $p_{\mathrm{T}}$-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 $\mathrm{d}\sigma ({\mathrm{B}}^0)/\mathrm{d}y{|}_{|y|<0.5}=24.2\pm 1.4(\text{stat.})\pm 2.6(\text{syst.}{)}_{-0.3}^{+0.2}(\text{extrap.})\mu \mathrm{b}$.

29 pages, 9 captioned figures, 1 table, authors from page 24 submitted to JHEP, figures at http://alice-publications.web.cern.ch/node/13173