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  1. In the network of reactions present in the Big Bang nucleosynthesis, the 3 He(n, p) 3 H has an important role which impacts the final 7 Li abundance. The Trojan Horse Method (THM) has been applied to the 3 He(d, pt)H reaction in order to extract the astrophysical S(E)-factor of the 3 He(n, p ) 3 H in the Gamow energy range. The experiment will be described in the present work together with the first preliminary results.
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  5. Abstract The coherent photoproduction of $$\mathrm{J}/\psi $$ J / ψ and $${\uppsi '}$$ ψ ′ mesons was measured in ultra-peripheral Pb–Pb collisions at a center-of-mass energy $$\sqrt{s_{\mathrm {NN}}}~=~5.02$$ s NN = 5.02  TeV  with the ALICE detector. Charmonia are detected in the central rapidity region for events where the hadronic interactions are strongly suppressed. The $$\mathrm{J}/\psi $$ J / ψ is reconstructed using the dilepton ( $$l^{+} l^{-}$$ l + l - ) and proton–antiproton decay channels, while for the $${\uppsi '}$$ ψ ′   the dilepton and the $$l^{+} l^{-} \pi ^{+} \pi ^{-}$$ l + l - πmore »+ π - decay channels are studied. The analysis is based on an event sample corresponding to an integrated luminosity of about 233 $$\mu {\mathrm{b}}^{-1}$$ μ b - 1 . The results are compared with theoretical models for coherent $$\mathrm{J}/\psi $$ J / ψ and $${\uppsi '}$$ ψ ′ photoproduction. The coherent cross section is found to be in a good agreement with models incorporating moderate nuclear gluon shadowing of about 0.64 at a Bjorken- x of around $$6\times 10^{-4}$$ 6 × 10 - 4 , such as the EPS09 parametrization, however none of the models is able to fully describe the rapidity dependence of the coherent $$\mathrm{J}/\psi $$ J / ψ cross section including ALICE measurements at forward rapidity. The ratio of $${\uppsi '}$$ ψ ′ to $$\mathrm{J}/\psi $$ J / ψ coherent photoproduction cross sections was also measured and found to be consistent with the one for photoproduction off protons.« less
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  7. Abstract The production of $$\phi $$ ϕ mesons has been studied in pp collisions at LHC energies with the ALICE detector via the dimuon decay channel in the rapidity region $$2.5< y < 4$$ 2.5 < y < 4 . Measurements of the differential cross section $$\mathrm{d}^2\sigma /\mathrm{d}y \mathrm{d}p_{\mathrm {T}}$$ d 2 σ / d y d p T are presented as a function of the transverse momentum ( $$p_{\mathrm {T}}$$ p T ) at the center-of-mass energies $$\sqrt{s}=5.02$$ s = 5.02 , 8 and 13 TeV and compared with the ALICE results at midrapidity. The differential cross sections at $$\sqrt{s}=5.02$$more »s = 5.02 and 13 TeV are also studied in several rapidity intervals as a function of $$p_{\mathrm {T}}$$ p T , and as a function of rapidity in three $$p_{\mathrm {T}}$$ p T intervals. A hardening of the $$p_{\mathrm {T}}$$ p T -differential cross section with the collision energy is observed, while, for a given energy, $$p_{\mathrm {T}}$$ p T spectra soften with increasing rapidity and, conversely, rapidity distributions get slightly narrower at increasing $$p_{\mathrm {T}}$$ p T . The new results, complementing the published measurements at $$\sqrt{s}=2.76$$ s = 2.76 and 7 TeV, allow one to establish the energy dependence of $$\phi $$ ϕ meson production and to compare the measured cross sections with phenomenological models. None of the considered models manages to describe the evolution of the cross section with $$p_{\mathrm {T}}$$ p T and rapidity at all the energies.« less
    Free, publicly-accessible full text available August 1, 2022