611 research outputs found
Plutonium, americium, 90 Sr and 137 Cs in bones of red fox (Vulpes vulpes) from Eastern Poland
No full text90Sr, 238,239+240Pu, 241Am and 137Cs activity concentrations are presented in the jaw bones of red fox (Vulpes vulpes) from eastern Poland. The short description of the applied radiochemical method is presented. Activity concentrations for 90Sr ranged between 2.2±0.7 and 41.4±4.7 Bq/kg (aw = ash weight). Average results for plutonium and americium are on the level of 10 mBq/kg (aw). No clear relationship was observed among the radionuclide concentrations. The samples analyzed do not show elevated contamination levels when compared with results of bones of small animals (rodent or insectivorous mammals) determined previously, so no accumulation of bone seeking isotopes on higher step of food-chain is concluded
Gamma-emitters 90Sr, 238,239+240Pu and 241Am in bones and liver of eagles from Poland
No full textThe present study focused on analyzing samples of bones, livers and kidneys of European white-tailed eagles (Haliaëtus albicilla) and lesser-spotted eagle (Aquila pomarina). Bone samples were collected for both species, from 7 and 2 individuals, respectively, whereas liver and kidney samples for white-tailed eagle species only, 2 and 1 individuals, respectively. The samples were analyzed for the presence of gamma-emitters and then for 90Sr, 238Pu, 239+240Pu and 241Am. The applied radiochemical method is presented. Activity concentration in ashen bones (600 °C) for 90Sr ranged from 4.6±1.2 to 31.0±2.5 Bq/kg, for 239+240Pu from <1.7 to 21±4 mBq/kg, for 238Pu from <2.7 to 6.5±1.3 mBq/kg and for 241Am from <1.2 to 6.5±4.4 mBq/kg. Relatively high 239+240Pu activity concentration of 78±9 mBq/kg (for fresh weight) was recorded in a single kidney sample. The liver samples showed activities of magnitude at least one order lower. No clear correlations were found between the activities of different radionuclides
J/ψ production at midrapidity in p-Pb collisions at √sNN = 8.16 TeV
No full textThe production of inclusive, prompt and non-prompt J/ψ was studied for the first time at midrapidity (−1.37 2 GeV/c. The study of the J/ψ mesons in the dielectron channel used for the first time in ALICE online single-electron triggers from the Transition Radiation Detector, providing a data sample corresponding to an integrated luminosity of 689 ± 13 μb −1. The proton-proton reference cross section for inclusive J/ψ was obtained based on interpolations of measured data at different centre-of-mass energies and a universal function describing the p T-differential J/ψ production cross sections. The p T-differential nuclear modification factors R pPb of inclusive, prompt, and non-prompt J/ψ are consistent with unity and described by theoretical models implementing only nuclear shadowing. [Figure not available: see fulltext.
Inclusive, prompt and non-prompt J/ψ production at midrapidity in p-Pb collisions at √sNN = 5.02 TeV
No full textA measurement of inclusive, prompt, and non-prompt J/ψ production in p-Pb collisions at a nucleon-nucleon centre-of-mass energy sNN = 5.02 TeV is presented. The inclusive J/ψ mesons are reconstructed in the dielectron decay channel at midrapidity down to a transverse momentum pT = 0. The inclusive J/ψ nuclear modification factor RpPb is calculated by comparing the new results in p-Pb collisions to a recently measured proton-proton reference at the same centre-of-mass energy. Non-prompt J/ψ mesons, which originate from the decay of beauty hadrons, are separated from promptly produced J/ψ on a statistical basis for pT larger than 1.0 GeV/c. These results are based on the data sample collected by the ALICE detector during the 2016 LHC p-Pb run, corresponding to an integrated luminosity Lint = 292 ± 11 μb−1, which is six times larger than the previous publications. The total uncertainty on the pT-integrated inclusive J/ψ and non-prompt J/ψ cross section are reduced by a factor 1.7 and 2.2, respectively. The measured cross sections and RpPb are compared with theoretical models that include various combinations of cold nuclear matter effects. From the non-prompt J/ψ production cross section, the b b ̄ production cross section at midrapidity, d σbb ̄/dy, and the total cross section extrapolated over full phase space, σbb ̄, are derived. [Figure not available: see fulltext.
Inclusive, prompt and non-prompt J/psi production at midrapidity in p-Pb collisions at root s(NN)=5.02 TeV
No full textA measurement of inclusive, prompt, and non-prompt J/psi production in p-Pb collisions at a nucleon-nucleon centre-of-mass energy root s(NN) = 5.02 TeV is presented. The inclusive J/psi mesons are reconstructed in the dielectron decay channel at midrapidity down to a transverse momentum p(T) = 0. The inclusive J/psi nuclear modification factor R-pPb is calculated by comparing the new results in p-Pb collisions to a recently measured proton-proton reference at the same centre-of-mass energy. Non-prompt J/psi mesons, which originate from the decay of beauty hadrons, are separated from promptly produced J/psi on a statistical basis for p(T) larger than 1.0 GeV/c. These results are based on the data sample collected by the ALICE detector during the 2016 LHC p-Pb run, corresponding to an integrated luminosity L-int = 292 +/- 11 mu b(-1), which is six times larger than the previous publications. The total uncertainty on the P-T-integrated inclusive J/psi and non-prompt J/psi cross section are reduced by a factor 1.7 and 2.2, respectively. The measured cross sections and R-pPb are compared with theoretical models that include various combinations of cold nuclear matter effects. From the non-prompt J/psi production cross section, the b (b) over bar production cross section at midrapidity, d sigma(b (b) over bar)/dy, and the total cross section extrapolated over full phase space sigma(b (b) over bar) are derived
Centrality dependence of J/ and (2S) production and nuclear modification in p-Pb collisions at TeV
No full textThe inclusive production of the J/ and (2S) charmonium states is studied as a function of centrality in p-Pb collisions at a centre-of-mass energy per nucleon pair TeV at the LHC. The measurement is performed in the dimuon decay channel with the ALICE apparatus in the centre-of-mass rapidity intervals (Pb-going direction) and (p-going direction), down to zero transverse momentum (). The J/ and (2S) production cross sections are evaluated as a function of the collision centrality, estimated through the energy deposited in the zero degree calorimeter located in the Pb-going direction. The -differential J/ production cross section is measured at backward and forward rapidity for several centrality classes, together with the corresponding average and values. The nuclear effects affecting the production of both charmonium states are studied using the nuclear modification factor. In the p-going direction, a suppression of the production of both charmonium states is observed, which seems to increase from peripheral to central collisions. In the Pb-going direction, however, the centrality dependence is different for the two states: the nuclear modification factor of the J/ increases from below unity in peripheral collisions to above unity in central collisions, while for the (2S) it stays below or consistent with unity for all centralities with no significant centrality dependence. The results are compared with measurements in p-Pb collisions at TeV and no significant dependence on the energy of the collision is observed. Finally, the results are compared with theoretical models implementing various nuclear matter effects.The inclusive production of the J/ψ and ψ(2S) charmonium states is studied as a function of centrality in p-Pb collisions at a centre-of-mass energy per nucleon pair = 8.16 TeV at the LHC. The measurement is performed in the dimuon decay channel with the ALICE apparatus in the centre-of-mass rapidity intervals −4.46 < y< −2.96 (Pb-going direction) and 2.03 < y< 3.53 (p-going direction), down to zero transverse momentum (p). The J/ψ and ψ(2S) production cross sections are evaluated as a function of the collision centrality, estimated through the energy deposited in the zero degree calorimeter located in the Pb-going direction. The p-differential J/ψ production cross section is measured at backward and forward rapidity for several centrality classes, together with the corresponding average 〈p〉 and values. The nuclear effects affecting the production of both charmonium states are studied using the nuclear modification factor. In the p-going direction, a suppression of the production of both charmonium states is observed, which seems to increase from peripheral to central collisions. In the Pb-going direction, however, the centrality dependence is different for the two states: the nuclear modification factor of the J/ψ increases from below unity in peripheral collisions to above unity in central collisions, while for the ψ(2S) it stays below or consistent with unity for all centralities with no significant centrality dependence. The results are compared with measurements in p-Pb collisions at = 5.02 TeV and no significant dependence on the energy of the collision is observed. Finally, the results are compared with theoretical models implementing various nuclear matter effects.[graphic not available: see fulltext]The inclusive production of the J/ and (2S) charmonium states is studied as a function of centrality in p-Pb collisions at a centre-of-mass energy per nucleon pair TeV at the LHC. The measurement is performed in the dimuon decay channel with the ALICE apparatus in the centre-of-mass rapidity intervals (Pb-going direction) and (p-going direction), down to zero transverse momentum (). The J/ and (2S) production cross sections are evaluated as a function of the collision centrality, estimated through the energy deposited in the zero degree calorimeter located in the Pb-going direction. The -differential J/ production cross section is measured at backward and forward rapidity for several centrality classes, together with the corresponding average and values. The nuclear effects affecting the production of both charmonium states are studied using the nuclear modification factor. In the p-going direction, a suppression of the production of both charmonium states is observed, which seems to increase from peripheral to central collisions. In the Pb-going direction, however, the centrality dependence is different for the two states: the nuclear modification factor of the J/ increases from below unity in peripheral collisions to above unity in central collisions, while for the (2S) it stays below or consistent with unity for all centralities with no significant centrality dependence. The results are compared with measurements in p-Pb collisions at TeV and no significant dependence on the energy of the collision is observed. Finally, the results are compared with theoretical models implementing various nuclear matter effects
J/ψ production at midrapidity in p-Pb collisions at s NN = 8.16 TeV
No full textAbstract The production of inclusive, prompt and non-prompt J/ψ was studied for the first time at midrapidity (−1.37 2 GeV/c. The study of the J/ψ mesons in the dielectron channel used for the first time in ALICE online single-electron triggers from the Transition Radiation Detector, providing a data sample corresponding to an integrated luminosity of 689 ± 13 μb −1. The proton-proton reference cross section for inclusive J/ψ was obtained based on interpolations of measured data at different centre-of-mass energies and a universal function describing the p T-differential J/ψ production cross sections. The p T-differential nuclear modification factors R pPb of inclusive, prompt, and non-prompt J/ψ are consistent with unity and described by theoretical models implementing only nuclear shadowing
Exclusive and dissociative J/ψ photoproduction, and exclusive dimuon production, in p-Pb collisions at √sNN=8.16 TeV
No full textThe ALICE Collaboration reports three measurements in ultra-peripheral
protonlead collisions at forward rapidity. The exclusive two-photon process
\ggmm and the exclusive photoproduction of J/ are studied. J/
photoproduction with proton dissociation is measured for the first time at a
hadron collider. The cross section for the two-photon process of dimuons in the
invariant mass range from 1 to 2.5 GeV/ agrees with leading order quantum
electrodynamics calculations. The exclusive and dissociative cross sections for
J/ photoproductions are measured for photonproton centre-of-mass
energies from 27 to 57 GeV. They are in good agreement with HERA results
Measurement of ψ (2S) production as a function of charged-particle pseudorapidity density in pp collisions at √s = 13 TeV and p–Pb collisions at √sNN = 8.16 TeV with ALICE at the LHC
No full textProduction of inclusive charmonia in pp collisions at center-of-mass energy of s = 13 TeV and p–Pb collisions at center-of-mass energy per nucleon pair of sNN = 8.16 TeV is studied as a function of charged-particle pseudorapidity density with ALICE. Ground and excited charmonium states (J/ψ, ψ(2S)) are measured from their dimuon decays in the interval of rapidity in the center-of-mass frame 2.5 < y cms < 4.0 for pp collisions, and 2.03 < y cms < 3.53 and −4.46 < y cms < −2.96 for p–Pb collisions. The charged-particle pseudorapidity density is measured around midrapidity (|η| < 1.0). In pp collisions, the measured charged-particle multiplicity extends to about six times the average value, while in p-Pb collisions at forward (backward) rapidity a multiplicity corresponding to about three (four) times the average is reached. The ψ(2S) yield increases with the charged-particle pseudorapidity density. The ratio of ψ(2S) over J/ψ yield does not show a significant multiplicity dependence in either colliding system, suggesting a similar behavior of J/ψ and ψ(2S) yields with respect to charged-particle pseudorapidity density. Results for the ψ(2S) yield and its ratio with respect to J/ψ agree with available model calculations. [Figure not available: see fulltext.]
Towards the understanding of the genuine three-body interaction for p-p-p and p-p-Lambda
No full textThree-body nuclear forces play an important role in the structure of nuclei and hypernuclei and are also incorporated in models to describe the dynamics of dense baryonic matter, such as in neutron stars. So far, only indirect measurements anchored to the binding energies of nuclei can be used to constrain the three-nucleon force, and if hyperons are considered, the scarce data on hypernuclei impose only weak constraints on the three-body forces. In this work, we present the first direct measurement of the p–p–p and p–p– Λ systems in terms of three-particle correlation functions carried out for pp collisions at s=13 TeV. Three-particle cumulants are extracted from the correlation functions by applying the Kubo formalism, where the three-particle interaction contribution to these correlations can be isolated after subtracting the known two-body interaction terms. A negative cumulant is found for the p–p–p system, hinting to the presence of a residual three-body effect while for p–p– Λ the cumulant is consistent with zero. This measurement demonstrates the accessibility of three-baryon correlations at the LHC
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