1,721,330 research outputs found
System-size dependence of particle production at mid- and forward rapidity with ALICE
No full textThe pseudorapidity densities of charged particles and inclusive photons produced in high energy nuclear collisions are essential observables to characterise the global properties of the collisions, such as the achieved energy density, and to provide important constraints for Monte Carlo model calculations. In the LHC Run 1 and Run 2 configurations, ALICE had large coverage to measure charged particles over the pseudorapidity range , combining the data from the Silicon Pixel Detector (SPD) and the Forward Multiplicity Detector (FMD). The inclusive photons are measured at forward rapidity using the Photon Multiplicity Detector (PMD), covering the pseudorapidity range . New results on charged-particle pseudorapidity densities measured in pp, pPb, and PbPb collisions at = 5.02 TeV using Run 1 and Run 2 data are presented. Inclusive photon production is reported for pPb collisions at = 5.02 TeV. The charged-particle rapidity densities are derived from the measured charged-particle pseudorapidity densities, and then parameterized by a normal distribution. This allows us to study the evolution of the width of the rapidity distributions as a function of the number of participants in all three collision systems. The performance of the new Inner Tracking System (ITS) designed for ALICE Run 3 configuration is also discussed for pilot beam pp collisions at = 0.9 TeV.The pseudorapidity densities of charged particles and inclusive photons produced in high energy nuclear collisions are essential observables to characterise the global properties of the collisions, such as the achieved energy density, and to provide important constraints for Monte Carlo model calculations. In the LHC Run 1 and Run 2 configurations, ALICE had large coverage to measure charged particles over a pseudorapidity range (), combining the data from the Silicon Pixel Detector (SPD) and the Forward Multiplicity Detector (FMD). The inclusive photons are measured at forward rapidity using the Photon Multiplicity Detector (PMD), covering the pseudorapidity range . New results on charged-particle pseudorapidity densities measured in pp, pPb, and PbPb collisions at = 5.02 TeV using Run 1 and Run 2 data are presented. Inclusive photon production is reported for pPb collisions at = 5.02 TeV. The charged-particle rapidity densities are derived from the measured charged-particle pseudorapidity densities, and then parameterized by a normal distribution. This allows us to study the evolution of the width of the rapidity distributions as a function of the number of participants in all three collision systems. The performance of the new Inner Tracking System (ITS) designed for ALICE Run 3 configuration is also discussed for pilot beam pp collisions at = 0.9 TeV
Pseudorapidity density of charged particles at midrapidity in Pb-Pb collisions at = 5.36 TeV
No full textInitial Stages 2021
No full textParticle production at LHC energies results from the interplay of hard- and soft-QCD processes and is sensitive to non-linear QCD evolution in the initial state. In particular, for p-Pb collisions, one can use the proton to probe the low- dense gluonic fields of the Pb nuclei. The multiplicity and rapidity dependence of charged- and neutral-particle production, therefore, provides important constraints for initial state models and calculations describing the particle production mechanisms.
ALICE has unique coverage at forward rapidity. The Photon Multiplicity Detector can measure neutral-particle production over a kinematic range of . The Forward Multiplicity and the Silicon Pixel Detectors can measure charged particles over a wide range of . For the first time, results at forward rapidity will be presented for both charged and neutral particles in p-Pb collisions at 5.02 TeV and 8.16 TeV. The multiplicity and centrality dependence will be discussed. In this case, the centrality of the collisions is determined using the energy deposited in the Zero-Degree Calorimeters. Finally, the results will be compared to model calculations based on different particle-production mechanisms and initial conditions in the forward soft-QCD regime, in which perturbative-QCD calculations are impossible
Inclusive photon production in p-Pb collisions at forward rapidity using MC event generators
No full textInclusive photon multiplicity at forward pseudorapidities in pp and pPb collisions at = 5.02 TeV with ALICE
Full text linkGlobal observables such as the pseudorapidity distributions of particle
multiplicities in the final state are crucial to shed light into the physics
processes involved in hadronic collisions. In protonlead (pPb) collisions
at Large Hadron Collider (LHC) energies, such measurements provide an important
baseline to understand leadlead (PbPb) results by disentangling hot
nuclear matter effects from the ones due to the cold nuclear matter.
Multiplicity measurements can also put constraints on theoretical models
describing the initial stages of the collision, e.g., to what degree the
nucleon and the nuclei interact as dilute (partons) or dense (CGC-like) fields.
The study of inclusive photon multiplicity aims to provide complementary
measurements to those obtained with charged particles.
In these proceedings, the pseudorapidity distributions of inclusive photons
at forward pseudorapidity () in pp and pPb
collisions at = 5.02 TeV are presented. The data samples
were collected using the Photon Multiplicity Detector (PMD) of ALICE. The
multiplicity dependence of photon production in pPb collisions is presented
and a comparison with charged-particle distributions measured at
mid-pseudorapidity is shown. The results are also compared with predictions
from Monte Carlo event generators.Comment: 5 pages and 3 figures, submitted as conference proceeding to "XXV
DAE-BRNS High Energy Physics Symposium
Inclusive Photon And Charged-Particle Production In Proton-Proton And Proton-Lead Collisions At LHC Energies With ALICE
No full textOne of the primary goals of heavy-ion collision experiments, such as ALICE, is to study and understand the properties of the deconfined state of nuclear matter, commonly known as the quark-gluon plasma (QGP). The first step in characterizing the produced QGP matter is the measurement of global observables, such as the number of produced particles (particle multiplicity) and their distribution in pseudorapidity. These measurements are essential to understand the underlying mechanisms of particle production. Such studies in protonproton (pp) and protonlead (pPb) collisions are also important as they provide baselines for the interpretation of measurements in heavy-ion collisions. In addition, the study of pp and pPb collisions is also interesting on its own right. Recent experimental results in high-multiplicity pp and pPb collisions have shown interesting features usually attributed to QGP formation in heavy-ion collisions. The origin of these phenomena still needs to be fully understood, and therefore, it is of great interest to investigate and understand the global properties of such collision systems, which makes measurements of multiplicity distributions invaluable. This thesis reports: a) the first measurements of multiplicity and pseudorapidity distributions of inclusive photons at forward pseudorapidity () in pp and pPb collisions at the nucleonnucleon centre-of-mass energy = 5.02 TeV using the data obtained with Photon Multiplicity Detector of ALICE, and b) the study of multiplicity distributions of primary charged particles in pPb collisions at = 5.02 TeV over a wide pseudorapidity interval () for the first time at the LHC using the Silicon Pixel Detector and the Forward Multiplicity Detector of ALICE. The multiplicity distributions of both photons and charged particles are parametrized with double negative binomial distributions. The centrality dependence of photon production in pPb collisions is studied and compared to that of charged particles at midrapidity. The measurements are compared to predictions from various theoretical models to draw important physics conclusions. This thesis also briefly discusses the fundamentals of elementary particle physics and presents the ALICE detector sub-systems utilized in this work
Measurements of inclusive photons at forward rapidities in p-Pb collisions at = 5.02 TeV with ALICE
Full text linkWe present multiplicity and pseudorapidity distributions of inclusive photons
at forward rapidity in proton-lead (p-Pb) collisions at =
5.02 TeV using the data obtained from Photon Multiplicity Detector (PMD) of
ALICE. The centrality dependence of pseudorapidity distributions of inclusive
photons is also studied. Results are compared with the previous ALICE
measurements of charged-particle production and with theoretical predictions
from Monte Carlo models, DPMJET and HIJING.Comment: Proceedings of The Ninth Annual Conference on Large Hadron Collider
Physics - LHCP2021 conference, Date: 7-12 June 202
Inclusive Photon Multiplicity at Forward Pseudorapidities in pp and p–Pb Collisions at = 5.02 TeV with ALICE
No full textGlobal observables such as the pseudorapidity distributions of particle multiplicities in the final state are crucial to shed light into the physics processes involved in hadronic collisions. In proton–lead (p–Pb) collisions at Large Hadron Collider (LHC) energies, such measurements provide an important baseline to understand lead–lead (Pb–Pb) results by disentangling hot nuclear matter effects from the ones due to the cold nuclear matter. Multiplicity measurements can also put constraints on theoretical models describing the initial stages of the collision, e.g., to what degree the nucleon and the nuclei interact as dilute (partons) or dense (CGC-like) fields. The study of inclusive photon multiplicity aims to provide complementary measurements to those obtained with charged particles. In these proceedings, the pseudorapidity distributions of inclusive photons at forward pseudorapidity (2.3 3.9) in pp and p–Pb collisions at = 5.02 TeV are presented. The data samples were collected using the Photon Multiplicity Detector (PMD) of ALICE. The multiplicity dependence of photon production in p–Pb collisions is presented and a comparison with charged-particle distributions measured at mid-pseudorapidity is shown. The results are also compared with predictions from Monte Carlo event generators.Global observables such as the pseudorapidity distributions of particle multiplicities in the final state are crucial to shed light into the physics processes involved in hadronic collisions. In protonlead (pPb) collisions at Large Hadron Collider (LHC) energies, such measurements provide an important baseline to understand leadlead (PbPb) results by disentangling hot nuclear matter effects from the ones due to the cold nuclear matter. Multiplicity measurements can also put constraints on theoretical models describing the initial stages of the collision, e.g., to what degree the nucleon and the nuclei interact as dilute (partons) or dense (CGC-like) fields. The study of inclusive photon multiplicity aims to provide complementary measurements to those obtained with charged particles. In these proceedings, the pseudorapidity distributions of inclusive photons at forward pseudorapidity () in pp and pPb collisions at = 5.02 TeV are presented. The data samples were collected using the Photon Multiplicity Detector (PMD) of ALICE. The multiplicity dependence of photon production in pPb collisions is presented and a comparison with charged-particle distributions measured at mid-pseudorapidity is shown. The results are also compared with predictions from Monte Carlo event generators
Charged-particle production in pp collisions at = 13.6 TeV and PbPb collisions at = 5.36 TeV with ALICE
No full textThis article presents the measurement of charged-particle pseudorapidity () density, , in protonproton (pp) collisions at a centre-of-mass energy = 13.6 TeV, and in leadlead (PbPb) collisions at a centre-of-mass energy per nucleon pair = 5.36 TeV. The analysis is performed using the Run 3 data recorded during 2022 and 2023 by the upgraded ALICE detector. The charged-particle multiplicity is measured at midrapidity () using the new monolithic active pixel sensors-based Inner Tracking System and the Time Projection Chamber upgraded with Gas Electron Multiplier-based readout system. The measurements in pp collisions are reported for inelastic events with at least one charged particle having whereas for PbPb collisions, the is obtained for different centrality classes, ranging from 05\% (most central) to 7080\% (most peripheral). The energy dependence of average charged-particle pseudorapidity density () measured in is studied and compared to earlier measurements at lower collision energies. In PbPb collisions, the evolution of as a function of the average number of participating nucleons, , determined with a Glauber model, is also studied and compared with predictions from theoretical models.This article presents the measurement of charged-particle pseudorapidity () density, , in protonproton (pp) collisions at a centre-of-mass energy = 13.6 TeV, and in leadlead (PbPb) collisions at a centre-of-mass energy per nucleon pair = 5.36 TeV. The analysis is performed using the Run 3 data recorded during 2022 and 2023 by the upgraded ALICE detector. The charged-particle multiplicity is measured at midrapidity () using the new monolithic active pixel sensors-based Inner Tracking System and the Time Projection Chamber upgraded with Gas Electron Multiplier-based readout system. The measurements in pp collisions are reported for inelastic events with at least one charged particle having whereas for PbPb collisions, the is obtained for different centrality classes, ranging from 05% (most central) to 7080% (most peripheral). The energy dependence of average charged-particle pseudorapidity density () measured in is studied and compared to earlier measurements at lower collision energies. In PbPb collisions, the evolution of as a function of the average number of participating nucleons, , determined with a Glauber model, is also studied and compared with predictions from theoretical models
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