425 research outputs found

    A translator for automated code generation for service-based systems

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    Service based systems are playing a major role in industry today, everything from the verification of credit cards to booking airplane reservations are using some form of a service based approach. This unfortunately brings up a really big problem, how do we know that these services are actually doing what they are supposed to? Or, how do we know the service based system doesn\u27t get somehow compromised when handling sensitive information.;A collaborative project involving Arizona State University and West Virginia University began in 2004 to first create a language, called alpha-calculus. We can prove that the code written in alpha-calculus adheres to the requirements. The next step was to create a translator that could convert code written in alpha-calculus to Secure Operations Language (SOL), which could then be used to develop service-based systems.;While research has been done in this area, the alpha-calculus to SOL translator provides a real world solution to creating provable/verifiable service based systems

    Pseudorapidity densities of charged particles with transverse momentum thresholds in pp collisions at √ s = 5.02 and 13 TeV

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    The pseudorapidity density of charged particles with minimum transverse momentum (pT) thresholds of 0.15, 0.5, 1, and 2 GeV/c is measured in pp collisions at the center of mass energies of √s=5.02 and 13 TeV with the ALICE detector. The study is carried out for inelastic collisions with at least one primary charged particle having a pseudorapidity (η) within 0.8pT larger than the corresponding threshold. In addition, measurements without pT-thresholds are performed for inelastic and nonsingle-diffractive events as well as for inelastic events with at least one charged particle having |η|2GeV/c), highlighting the importance of such measurements for tuning event generators. The new measurements agree within uncertainties with results from the ATLAS and CMS experiments obtained at √s=13TeV.

    Multiplicity dependence of inclusive J/ψ production at midrapidity in pp collisions at √s=13 TeV

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    Measurements of the inclusive J/ψ yield as a function of charged-particle pseudorapidity density dNch/dη in pp collisions at √s = 13 TeV with ALICE at the LHC are reported. The J/ψ meson yield is measured at midrapidity (|y| < 0.9) in the dielectron channel, for events selected based on the charged-particle multiplicity at midrapidity (|η| < 1) and at forward rapidity (−3.7 < η < −1.7 and 2.8 < η < 5.1); both observables are normalized to their corresponding averages in minimum bias events. The increase of the normalized J/ψ yield with normalized dNch/dη is significantly stronger than linear and dependent on the transverse momentum. The data are compared to theoretical predictions, which describe the observed trends well, albeit not always quantitatively

    First measurement of the absorption of 3He^{3}\overline{\rm He} nuclei in matter and impact on their propagation in the galaxy

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    Antimatter particles such as positrons and antiprotons abound in the cosmos. Much less common are light antinuclei, composed of antiprotons and antineutrons, which can be produced in our galaxy via high-energy cosmic-ray collisions with the interstellar medium or could also originate from the annihilation of the still undiscovered dark-matter particles. On Earth, the only way to produce and study antinuclei with high precision is to create them at high-energy particle accelerators like the Large Hadron Collider (LHC). Though the properties of elementary antiparticles have been studied in detail, knowledge of the interaction of light antinuclei with matter is rather limited. This work focuses on the determination of the disappearance probability of \ahe when it encounters matter particles and annihilates or disintegrates. The material of the ALICE detector at the LHC serves as a target to extract the inelastic cross section for \ahe in the momentum range of 1.17p<101.17 \leq p < 10 GeV/cc. This inelastic cross section is measured for the first time and is used as an essential input to calculations of the transparency of our galaxy to the propagation of 3He^{3}\overline{\rm He} stemming from dark-matter decays and cosmic-ray interactions within the interstellar medium. A transparency of about 50% is estimated using the GALPROP program for a specific dark-matter profile and a standard set of propagation parameters. For cosmic-ray sources, the obtained transparency with the same propagation scheme varies with increasing 3He^{3}\overline{\rm He} momentum from 25% to 90%. The absolute uncertainties associated to the 3He^{3}\overline{\rm He} inelastic cross section measurements are of the order of 10%-15%. The reported results indicate that 3He^{3}\overline{\rm He} nuclei can travel long distances in the galaxy, and can be used to study cosmic-ray interactions and dark-matter decays

    Measurement of beauty production via non-prompt D0{\rm D}^{0} mesons in Pb-Pb collisions at sNN\sqrt{s_{\rm NN}} = 5.02 TeV

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    The production of non-prompt D0{\rm D}^{0} mesons from beauty-hadron decays was measured at midrapidity (y5 GeV/c\left| y \right| 5~\mathrm{GeV}/c in the 0100-10% central Pb-Pb collisions. The data are described by models that include both collisional and radiative processes in the calculation of beauty-quark energy loss in the quark-gluon plasma, and quark recombination in addition to fragmentation as a hadronization mechanism. The ratio of the non-prompt to prompt D0{\rm D}^{0}-meson RAAR_{\rm AA} is larger than unity for pT>4 GeV/cp_{\rm T} > 4~\mathrm{GeV}/c in the 0100-10% central Pb-Pb collisions, as predicted by models in which beauty quarks lose less energy than charm quarks in the quark-gluon plasma because of their larger mass

    Measurements of inclusive J/ψ\psi production at midrapidity and forward rapidity in Pb-Pb collisions at sNN\sqrt{s_{\mathrm{NN}}} = 5.02 TeV

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    International audienceThe measurements of the inclusive J/ψ\psi yield at midrapidity (y<0.9\left | y \right | < 0.9) and forward rapidity (2.5 <y<< y < 4) in Pb-Pb collisions at sNN=5.02\sqrt{s_{\mathrm{NN}}}=5.02 TeV with the ALICE detector at the LHC are reported. The inclusive J/ψ\psi production yields and nuclear modification factors, RAAR_{\rm AA}, are measured as a function of the collision centrality, J/ψ\psi transverse momentum (pTp_{\rm T}), and rapidity. The J/ψ\psi average transverse momentum and squared transverse momentum (pT\langle p_{\mathrm{T}}\rangle and pT2\langle p_{\mathrm{T}}^{\mathrm{2}}\rangle) are evaluated as a function of the centrality at midrapidity. Compared to the previous ALICE publications, here the entire Pb-Pb collisions dataset collected during the LHC Run 2 is used, which improves the precision of the measurements and extends the pTp_{\rm T} coverage. The pTp_{\rm T}-integrated RAAR_{\rm AA} shows a hint of an increasing trend towards unity from semicentral to central collisions at midrapidity, while it is flat at forward rapidity. The pTp_{\rm T}-differential RAAR_{\rm AA} shows a strong suppression at high pTp_{\rm T} with less suppression at low pTp_{\rm T} where it reaches a larger value at midrapidity compared to forward rapidity. The ratio of the pTp_{\rm T}-integrated yields of J/ψ\psi to those of D0^{0} mesons is reported for the first time for the central and semicentral event classes at midrapidity. Model calculations implementing charmonium production via the coalescence of charm quarks and antiquarks during the fireball evolution (transport models) or in a statistical approach with thermal weights are in good agreement with the data at low pTp_{\rm T}. At higher pTp_{\rm T}, the data are well described by transport models and a model based on energy loss in the strongly-interacting medium produced in nuclear collisions at the LHC

    Measurement of anti-3^3He nuclei absorption in matter and impact on their propagation in the Galaxy.

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    In our Galaxy, light antinuclei composed of antiprotons and antineutrons can be produced through high-energy cosmic-ray collisions with the interstellar medium or could also originate from the annihilation of dark-matter particles that have not yet been discovered. On Earth, the only way to produce and study antinuclei with high precision is to create them at high-energy particle accelerators. Although the properties of elementary antiparticles have been studied in detail, the knowledge of the interaction of light antinuclei with matter is limited. We determine the disappearance probability of 3He^{3}\overline{\rm He} when it encounters matter particles and annihilates or disintegrates within the ALICE detector at the Large Hadron Collider. We extract the inelastic interaction cross section, which is then used as input to calculations of the transparency of our Galaxy to the propagation of 3He^{3}\overline{\rm He} stemming from dark-matter annihilation and cosmic-ray interactions within the interstellar medium. For a specific dark-matter profile, we estimate a transparency of about 50%, whereas it varies with increasing 3He^{3}\overline{\rm He} momentum from 25% to 90% for cosmic-ray sources. The results indicate that 3He^{3}\overline{\rm He} nuclei can travel long distances in the Galaxy, and can be used to study cosmic-ray interactions and dark-matter annihilation

    First measurement of the t|t|-dependence of incoherent J/ψ\psi photonuclear production

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    International audienceThe first measurement of the cross section for incoherent photonuclear production of J/ψ\psi vector meson as a function of the Mandelstam t|t| variable is presented. The measurement was carried out with the ALICE detector at midrapidity, y<0.8|y|<0.8, using ultra-peripheral collisions of Pb nuclei at a centre-of-mass energy per nucleon pair sNN=5.02\sqrt{s_{\mathrm{NN}}} = 5.02 TeV. This rapidity interval corresponds to a Bjorken-xx range (0.3(0.3-1.4)×1031.4)\times 10^{-3}. Cross sections are reported in five t|t| intervals in the range 0.04<t<10.04<|t|<1~GeV2^2 and compared to the predictions of different models. Models that ignore quantum fluctuations of the gluon density in the colliding hadron predict a t|t|-dependence of the cross section much steeper than in data. The inclusion of such fluctuations in the same models provides a better description of the data

    Measurement of nuclear effects on ψ(2S)\psi\rm{(2S)} production in p-Pb collisions at sNN=8.16\sqrt{\textit{s}_{\rm NN}} = 8.16 TeV

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    Inclusive ψ(2S) production is measured in p-Pb collisions at the centre-of-mass energy per nucleon-nucleon pair sNN \sqrt{s_{\mathrm{NN}}} = 8.16 TeV, using the ALICE detector at the CERN LHC. The production of ψ(2S) is studied at forward (2.03 < ycms_{cms}< 3.53) and backward (−4.46 < ycms_{cms}< −2.96) centre-of-mass rapidity and for transverse momentum pT_{T}< 12 GeV/c via the decay to muon pairs. In this paper, we report the integrated as well as the ycms_{cms}- and pT_{T}-differential inclusive production cross sections. Nuclear effects on ψ(2S) production are studied via the determination of the nuclear modification factor that shows a strong suppression at both forward and backward centre-of-mass rapidities. Comparisons with corresponding results for inclusive J/ψ show a similar suppression for the two states at forward rapidity (p-going direction), but a stronger suppression for ψ(2S) at backward rapidity (Pb-going direction). As a function of pT_{T}, no clear dependence of the nuclear modification factor is found. The relative size of nuclear effects on ψ(2S) production compared to J/ψ is also studied via the double ratio of production cross sections [σψ(2S)_{ψ(2S)}J/ψ_{J/ψ}]pPb/[σψ(2S)_{ψ(2S)}J/ψ_{J/ψ}]pp_{pp} between p-Pb and pp collisions. The results are compared with theoretical models that include various effects related to the initial and final state of the collision system and also with previous measurements at sNN \sqrt{s_{\mathrm{NN}}} = 5.02 TeV.[graphic not available: see fulltext]Inclusive ψ\psi(2S) production is measured in p-Pb collisions at the centre-of-mass energy per nucleon-nucleon pair sNN=8.16\sqrt{s_{\rm{NN}}}=8.16 TeV, using the ALICE detector at the CERN LHC. The production of ψ\psi(2S) is studied at forward (2.03<ycms<3.532.03 < y_{\rm cms} < 3.53) and backward (4.46<ycms<2.96-4.46 < y_{\rm cms} < -2.96) centre-of-mass rapidity and for transverse momentum pTp_{\rm{T}} << 12 GeV/cc via the decay to muon pairs. In this paper, we report the integrated as well as the ycmsy_{\rm cms}- and pTp_{\rm T}-differential inclusive production cross sections. Nuclear effects on ψ\psi(2S) production are studied via the determination of the nuclear modification factor that shows a strong suppression at both forward and backward centre-of-mass rapidities. Comparisons with corresponding results for inclusive J/ψ\psi show a similar suppression for the two states at forward rapidity (p-going direction), but a stronger suppression for ψ\psi(2S) at backward rapidity (Pb-going direction). As a function of pTp_{\rm T}, no clear dependence of the nuclear modification factor is found. The relative size of nuclear effects on ψ\psi(2S) production compared to J/ψ\psi is also studied via the double ratio of production cross sections [σψ(2S)/σJ/ψ]pPb/[σψ(2S)/σJ/ψ]pp[\sigma_{\psi(2S)}/\sigma_{\rm{J/}\psi}]_{\rm pPb}/[\sigma_{\psi(2S)}/\sigma_{\rm{J/}\psi}]_{\rm pp} between p-Pb and pp collisions. The results are compared with theoretical models that include various effects related to the initial and final state of the collision system and also with previous measurements at sNN\sqrt{s_{\rm{NN}}} = 5.02 TeV

    J/ψ\psi elliptic and triangular flow in Pb-Pb collisions at sNN\sqrt{s_{\rm NN}} = 5.02 TeV

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    The inclusive J/ψ elliptic (v2_{2}) and triangular (v3_{3}) flow coefficients measured at forward rapidity (2.5 < y < 4) and the v2_{2} measured at midrapidity (|y| < 0.9) in Pb-Pb collisions at sNN \sqrt{s_{\mathrm{NN}}} = 5.02 TeV using the ALICE detector at the LHC are reported. The entire Pb-Pb data sample collected during Run 2 is employed, amounting to an integrated luminosity of 750 μb1^{−1} at forward rapidity and 93 μb1^{−1} at midrapidity. The results are obtained using the scalar product method and are reported as a function of transverse momentum pT_{T} and collision centrality. At midrapidity, the J/ψ v2_{2} is in agreement with the forward rapidity measurement. The centrality averaged results indicate a positive J/ψ v3_{3} with a significance of more than 5σ at forward rapidity in the pT_{T} range 2 < pT_{T}< 5 GeV/c. The forward rapidity v2_{2}, v3_{3}, and v3_{3}/v2_{2} results at low and intermediate pT_{T} (pT_{T} ≲ 8 GeV/c) exhibit a mass hierarchy when compared to pions and D mesons, while converging into a species-independent curve at higher pT_{T}. At low and intermediate pT_{T}, the results could be interpreted in terms of a later thermalization of charm quarks compared to light quarks, while at high pT_{T}, path-length dependent effects seem to dominate. The J/ψ v2_{2} measurements are further compared to a microscopic transport model calculation. Using a simplified extension of the quark scaling approach involving both light and charm quark flow components, it is shown that the D-meson vn_{n} measurements can be described based on those for charged pions and J/ψ flow
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