ϒ production in p–Pb collisions at √sNN=8.16 TeV

ϒ production in p–Pb interactions is studied at the centre-of-mass energy per nucleon–nucleon collision √sNN = 8.16 TeV with the ALICE detector at the CERN LHC. The measurement is performed reconstructing bottomonium resonances via their dimuon decay channel, in the centre-of-mass rapidity intervals 2.03 < ycms < 3.53 and −4.46 < ycms < −2.96, down to zero transverse momentum. In this work, results on the ϒ(1S) production cross section as a function of rapidity and transverse momentum are presented. The corresponding nuclear modification factor shows a suppression of the ϒ(1S) yields with respect to pp collisions, both at forward and backward rapidity. This suppression is stronger in the low transverse momentum region and shows no significant dependence on the centrality of the interactions. Furthermore, the ϒ(2S) nuclear modification factor is evaluated, suggesting a suppression similar to that of the ϒ(1S). A first measurement of the ϒ(3S) has also been performed. Finally, results are compared with previous ALICE measurements in p–Pb collisions at √sNN = 5.02 TeV and with theoretical calculations.publishedVersio

Study of b-jet production and properties at the LHC

Jet production is a fundamental probe of perturbative quantum chromodynamics (pQCD). They play a vital role also in other areas of high energy physics. Jet quenching is arguably one of the most spectacular proofs of the creation of quark-gluon plasma in ultrarelativistic collisions of heavy ions. Nowadays, the rise of novel experimental techniques, including jet substructure observables and the application of machine learning algorithms, are revolutionizing this field of study. New jet tagging capabilities allow for comparative studies between jet flavours. Substructure measurements open doors for direct observation of the effects, entangled into more generic observables. A perfect example is the dead-cone measurement by ALICE. Results shown in this thesis benefit from both of these advances. The first part describes the analysis of the beauty-jet production cross section, measured in pp collisions at $\sqrt{s}$ = 5.02 TeVby the ALICE experiment at the LHC. It is the first application of machine learning for heavy-flavour jet measurements in ALICE. The new method significantly improves tagging efficiency and purity, and shows a good stability over a wide range of these parameters. Results are consistent with the NLO pQCD predictions and the ALICE results obtained with other methods. The second part shows simulation studies for the dead-cone effect measurement for beauty jets in heavy-ion collisions. The study focuses on the removal of distortions introduced by uncorrelated heavy-ion background. The combination of jet reclustering and jet grooming allows for the restoration of the quantitative properties related to the dead-cone effect of jets. Additionally, this thesis highlights some potential issues that may arise during future measurements of this effect, which are not immediately apparent

The Fast Interaction Trigger Upgrade for ALICE

In preparation for the LHC Run 3 ALICE will upgrade its subsystems to cope with the increased interaction rate of 50 kHz in Pb–Pb and up to 1 MHz in other collision systems, resulting in a data throughput from the detector up to 3 TB/s. Storing and analyzing such amount of data is a significant challenge and therefore, online event selection will be required.The Fast Interaction Trigger (FIT) will generate minimum-bias and multiplicity triggers with maximum latency of 425 ns. It will measure the time of collision with a resolution better than 40 ps. Moreover, FIT will be used to reconstruct the vertex position, forward particle multiplicity, centrality and event plane as well as study diffractive physics.In this contribution, we present the FIT components, discuss their role in the upgraded ALICE setup and show the results of performance and trigger simulations

Interferometry correlations in central p+Pb collisions

Abstract We present results on interferometry correlations for pions emitted in central p+Pb collisions at $$\sqrt{s_{NN}}=5.02~\hbox {TeV}$$ sNN=5.02TeV in a $$3+1$$ 3+1 -dimensional viscous hydrodynamic model with initial conditions from the Glauber Monte Carlo model. The correlation function is calculated as a function of the pion pair rapidity. The extracted interferometry radii show a weak rapidity dependence, reflecting the lack of boost invariance of the pion distribution. A cross term between the out and long directions is found to be nonzero. The results obtained in the hydrodynamic model are in fair agreement with recent data of the ATLAS Collaboration

Exploring the strong interaction of three-body systems at the LHC

International audienceDeuterons are atomic nuclei composed of a neutron and a proton held together by the strong interaction. Unbound ensembles composed of a deuteron and a third nucleon have been investigated in the past using scattering experiments and they constitute a fundamental reference in nuclear physics to constrain nuclear interactions and the properties of nuclei. In this work K$^{+}-$d and p$-$d femtoscopic correlations measured by the ALICE Collaboration in proton$-$proton (pp) collisions at $\sqrt{s}=13$ TeV at the Large Hadron Collider (LHC) are presented. It is demonstrated that correlations in momentum space between deuterons and kaons or protons allow us to study three-hadron systems at distances comparable with the proton radius. The analysis of the K$^{+}-$d correlation shows that the relative distances at which deuterons and proton/kaons are produced are around 2 fm. The analysis of the p$-$d correlation shows that only a full three-body calculation that accounts for the internal structure of the deuteron can explain the data. In particular, the sensitivity of the observable to the short-range part of the interaction is demonstrated. These results indicate that correlations involving light nuclei in pp collisions at the LHC will also provide access to any three-body systems in the strange and charm sectors

Exploring the strong interaction of three-body systems at the LHC

International audienceDeuterons are atomic nuclei composed of a neutron and a proton held together by the strong interaction. Unbound ensembles composed of a deuteron and a third nucleon have been investigated in the past using scattering experiments and they constitute a fundamental reference in nuclear physics to constrain nuclear interactions and the properties of nuclei. In this work K$^{+}-$d and p$-$d femtoscopic correlations measured by the ALICE Collaboration in proton$-$proton (pp) collisions at $\sqrt{s}=13$ TeV at the Large Hadron Collider (LHC) are presented. It is demonstrated that correlations in momentum space between deuterons and kaons or protons allow us to study three-hadron systems at distances comparable with the proton radius. The analysis of the K$^{+}-$d correlation shows that the relative distances at which deuterons and proton/kaons are produced are around 2 fm. The analysis of the p$-$d correlation shows that only a full three-body calculation that accounts for the internal structure of the deuteron can explain the data. In particular, the sensitivity of the observable to the short-range part of the interaction is demonstrated. These results indicate that correlations involving light nuclei in pp collisions at the LHC will also provide access to any three-body systems in the strange and charm sectors

Exploring the strong interaction of three-body systems at the LHC

Deuterons are atomic nuclei composed of a neutron and a proton held together by the strong interaction. Unbound ensembles composed of a deuteron and a third nucleon have been investigated in the past using scattering experiments and they constitute a fundamental reference in nuclear physics to constrain nuclear interactions and the properties of nuclei. In this work K$^{+}$--d and p--d femtoscopic correlations measured by the ALICE Collaboration in proton--proton (pp) collisions at $\sqrt{s}=13$~TeV at the Large Hadron Collider (LHC) are presented. It is demonstrated that correlations in momentum space between deuterons and kaons or protons allow us to study three-hadron systems at distances comparable with the proton radius. The analysis of the K$^{+}$--d correlation shows that the relative distances at which deuterons and proton/kaons are produced are around 2 fm. The analysis of the p--d correlation shows that only a full three-body calculation that accounts for the internal structure of the deuteron can explain the data. In particular, the sensitivity of the observable to the short-range part of the interaction is demonstrated. These results indicate that correlations involving light nuclei in pp collisions at the LHC will also provide access to any three-body systems in the strange and charm sectors.Deuterons are atomic nuclei composed of a neutron and a proton held together by the strong interaction. Unbound ensembles composed of a deuteron and a third nucleon have been investigated in the past using scattering experiments and they constitute a fundamental reference in nuclear physics to constrain nuclear interactions and the properties of nuclei. In this work K$^{+}-$d and p$-$d femtoscopic correlations measured by the ALICE Collaboration in proton$-$proton (pp) collisions at $\sqrt{s}=13$ TeV at the Large Hadron Collider (LHC) are presented. It is demonstrated that correlations in momentum space between deuterons and kaons or protons allow us to study three-hadron systems at distances comparable with the proton radius. The analysis of the K$^{+}-$d correlation shows that the relative distances at which deuterons and proton/kaons are produced are around 2 fm. The analysis of the p$-$d correlation shows that only a full three-body calculation that accounts for the internal structure of the deuteron can explain the data. In particular, the sensitivity of the observable to the short-range part of the interaction is demonstrated. These results indicate that correlations involving light nuclei in pp collisions at the LHC will also provide access to any three-body systems in the strange and charm sectors

Exploring the strong interaction of three-body systems at the LHC

International audienceDeuterons are atomic nuclei composed of a neutron and a proton held together by the strong interaction. Unbound ensembles composed of a deuteron and a third nucleon have been investigated in the past using scattering experiments and they constitute a fundamental reference in nuclear physics to constrain nuclear interactions and the properties of nuclei. In this work K$^{+}-$d and p$-$d femtoscopic correlations measured by the ALICE Collaboration in proton$-$proton (pp) collisions at $\sqrt{s}=13$ TeV at the Large Hadron Collider (LHC) are presented. It is demonstrated that correlations in momentum space between deuterons and kaons or protons allow us to study three-hadron systems at distances comparable with the proton radius. The analysis of the K$^{+}-$d correlation shows that the relative distances at which deuterons and proton/kaons are produced are around 2 fm. The analysis of the p$-$d correlation shows that only a full three-body calculation that accounts for the internal structure of the deuteron can explain the data. In particular, the sensitivity of the observable to the short-range part of the interaction is demonstrated. These results indicate that correlations involving light nuclei in pp collisions at the LHC will also provide access to any three-body systems in the strange and charm sectors