Refine
Year of publication
Document Type
- Preprint (579)
- Article (371)
- Working Paper (3)
- Conference Proceeding (2)
- Part of a Book (1)
Language
- English (956) (remove)
Has Fulltext
- yes (956)
Is part of the Bibliography
- no (956)
Keywords
- Heavy Ion Experiments (18)
- Hadron-Hadron scattering (experiments) (11)
- Heavy-ion collision (6)
- LHC (6)
- Kollisionen schwerer Ionen (5)
- Hadron-Hadron Scattering (4)
- Quark-Gluon Plasma (4)
- heavy ion collisions (4)
- ALICE experiment (3)
- Heavy Ions (3)
- Jets and Jet Substructure (3)
- Quark Gluon Plasma (3)
- Accelerators & Beams (2)
- Atomic, Molecular & Optical (2)
- Beauty production (2)
- Charm physics (2)
- Experimental nuclear physics (2)
- Experimental particle physics (2)
- Fragmentation (2)
- Jets (2)
- Lepton-Nucleon Scattering (experiments) (2)
- Particle and resonance production (2)
- Particle correlations and fluctuations (2)
- Pb–Pb collisions (2)
- Psychiatric disorders (2)
- QGP (2)
- Quark-Gluon-Plasma (2)
- RNA interference (RNAi) (2)
- Single electrons (2)
- UrQMD Modell (2)
- peptide aptamer (PA) (2)
- pp collisions (2)
- quark-gluon-plasma (2)
- signal transducer and activator of transcription 5 (Stat5) (2)
- 16S rRNA sequencing (1)
- ADAMTS-13 (1)
- ADHD (1)
- ALICE (1)
- ALICE detector (1)
- AO-PCCF (1)
- ATR-FTIR (1)
- Abundance (1)
- Accelerators & storage rings (1)
- Acute coronary syndrome (1)
- Anemia (1)
- Anonymity (1)
- Anterior cruciate ligament (1)
- Anti-kaon–nucleon physics (1)
- Anti-nuclei (1)
- Anticoagulation (1)
- Aortic valve (1)
- Aortic valve replacement (1)
- Atomic & molecular beams (1)
- Atomic and Molecular Physics (1)
- Atrial fibrillation (1)
- Autecology (1)
- Bcr-Abl (1)
- Beam loss (1)
- Biofuel (1)
- Bleeding (1)
- Blood loss (1)
- Blood transfusion (1)
- Breast cancer (1)
- Butanol (1)
- COVID-19 (1)
- Cardiac troponin (1)
- Centrality Class (1)
- Centrality Selection (1)
- Charge-transfer collisions (1)
- Circular accelerators (1)
- Clinical Trials and Observations (1)
- Clinical genetics (1)
- Collective Flow (1)
- Competition (1)
- DTI (1)
- Dark Trading (1)
- Difficult Airway Management (1)
- Ehrlich pathway (1)
- Electron-pion identification (1)
- Electronic transitions (1)
- Electroweak interaction (1)
- Elliptic flow (1)
- Energie (1)
- Epilepsy (1)
- Equation of state (1)
- Exosomes (1)
- Experimental autoimmune encephalomyelitis (1)
- Feeding types (1)
- Fermentation (1)
- Fibre/foam sandwich radiator (1)
- Freshwater (1)
- Genetic engineering (1)
- HER2-positive (1)
- Hadron-Hadron Scattering Heavy (1)
- Hadron-hadron interactions (1)
- Heavy Ion Experiment (1)
- Heavy Quark Production (1)
- Heavy flavor production (1)
- Heavy ion collisions (1)
- Heavy ion storage ring (1)
- Heavy ions (1)
- Heavy-flavour decay muons (1)
- Heavy-flavour production (1)
- Hemostasis (1)
- Human behaviour (1)
- INR (1)
- Immediacy (1)
- In-Hospital Emergencies (1)
- Inflammation (1)
- International normalized ratio (1)
- Invariant Mass Distribution (1)
- Ionisation energy loss (1)
- Isobutanol (1)
- J/ϕ (1)
- Jak2(V617F) (1)
- Kaonic nuclei (1)
- Knee joint (1)
- Laryngeal Tube (1)
- Liquidity (1)
- Local thermodynamical equilibrium (1)
- Low & intermediate-energy accelerators (1)
- Low energy QCD (1)
- Lymphoid Neoplasia (1)
- Magnetic resonance Imaging (1)
- Market Quality (1)
- Market Structure (1)
- Mice (1)
- MicroRNAs (1)
- Microplastic-biota interaction (1)
- Mid-rapidity (1)
- Minimum Bias (1)
- Molecular neuroscience (1)
- Monte Carlo (1)
- Monte-Carlo model for relativistic heavy ion collisions (1)
- Multi-strange baryons (1)
- Multi-wire proportional drift chamber (1)
- Multidetector computed tomography (1)
- Myocardial infarction (1)
- NMR spectroscopy (1)
- Neoadjuvant therapy (1)
- Neonatal brain damage (1)
- Neural circuits (1)
- Neural network (1)
- Nichtgleichgewicht (1)
- Non-equilibrium effects (1)
- Orbital electron capture (1)
- Partial wave analysis (1)
- Particle Correlations and Fluctuations (1)
- Pathological complete response (1)
- Patient blood management (1)
- Personalized medicine (1)
- Photon counting (1)
- Plastic polymers (1)
- Point-of-care testing (1)
- Polarization (1)
- Polymers (1)
- Posterior cruciate ligament (1)
- Predictive markers (1)
- Preference for early resolution of uncertainty (1)
- Production Cross Section (1)
- Properties of Hadrons (1)
- Proton–proton (1)
- Pyrolysis GC–MS (1)
- QCD (1)
- QGP signals (1)
- QMD Modell (1)
- QMD model (1)
- Quark Production (1)
- Quark gluon plasma (1)
- Radiation detectors (1)
- Rapidity Range (1)
- Relativistic heavy ion physics (1)
- Relativistic heavy-ion collisions (1)
- Resolution Parameter (1)
- SARS-CoV-2 (1)
- SPS (1)
- Saccharomyces (1)
- Single particle decay spectroscopy (1)
- Statistical model (1)
- Supraglottic Airway Devices (1)
- Suspended solids (1)
- Systematic Uncertainty (1)
- TBSS (1)
- TR (1)
- Time Projection Chamber (1)
- Tracking (1)
- Transcatheter based aortic valve implantation (1)
- Transition radiation detector (1)
- Trigger (1)
- Triple negative (1)
- Two body weak decay (1)
- URQMD (1)
- Ultra-relativistic Quantum Molecular Dynamics model (1)
- Ultrarelativistic Quantum Molecular Dynamics (1)
- Ultrarelativistic Quantum Molecular Model (1)
- Ultrarelativistisches Quant Molekulares Modell (1)
- UrQMD model (1)
- Valine biosynthesis (1)
- Vector (1)
- Vector Boson Production (1)
- Visual analysis (1)
- Xenon-based gas mixture (1)
- Yeast (1)
- Zustandsgleichung (1)
- accessory proteins (1)
- antibodies (1)
- asparaginyl endopepdidase (AEP) (1)
- asset pricing (1)
- attention (1)
- b-cell lymphomas (1)
- bendamustine (1)
- canonical/non-canonical (1)
- cardiac surgery (1)
- cardiovascular pharmacology (1)
- cell-free protein synthesis (1)
- chemokines (1)
- chemotherapy regimen (1)
- chimeric antigen receptor t-cell therapy (1)
- chimeric antigen receptors (1)
- chronic hypoxia (1)
- chronic myeloid leukemia (CML) (1)
- cross-section of expected stock returns (1)
- dE/dx (1)
- development (1)
- dileptons (1)
- ectosomes (1)
- energy (1)
- equation of state (1)
- exosomes (1)
- extracellular vesicles (1)
- flow (1)
- functional magnetic resonance imaging (fMRI) (1)
- glycolysis (1)
- guidelines (1)
- hadron hadron Kollision (1)
- hadron hadron collision (1)
- heart failure (1)
- heavy ion experiments (1)
- heavy ions (1)
- hematopoietic stem cell transplantation (1)
- hemispherotomy (1)
- human erythroid leukemia (HEL) (1)
- humoral factors (1)
- hyperactivity (1)
- hypoparathyroidism (1)
- implied volatility (1)
- impulsivity (1)
- indication (1)
- inhibition of DNA-binding (1)
- interleukin-6 (1)
- intrinsically disordered region (1)
- juvenile brain lesion (1)
- legumain (1)
- leukapheresis (1)
- lokales thermodynamisches Gleichgewicht (1)
- lower leg fracture (1)
- lymphoma (1)
- microbiome (1)
- microparticles (1)
- microvesicles (1)
- minimal information requirements (1)
- molecular mechanisms (1)
- multiple myeloma (1)
- multiple sclerosis (1)
- nonstructural proteins (1)
- object tracking (1)
- pancreatic cancer (1)
- pancreatic surgery (1)
- particle ratios (1)
- plasticity (1)
- polygenic risk score (1)
- postoperative complications (1)
- ppK − (1)
- propofol anesthesia (1)
- prostate and breast cancer cell lines (1)
- protein transduction (1)
- protein/lentiviral transduction (1)
- quark gluon plasma (1)
- recurrent laryngeal nerve palsy (1)
- registry (1)
- relativistic (1)
- relativistische (1)
- remodelling (1)
- remote ischemic preconditioning (1)
- reproducibility (1)
- rigor (1)
- rituximab (1)
- schwere Ione (1)
- selective attention (1)
- spectra (1)
- standardization (1)
- strangeness (1)
- structural proteins (1)
- substance abuse disorder (1)
- therapy (1)
- thermalization (1)
- thrombotic microangiopathy (1)
- thrombotic thrombocytopenic purpura (1)
- thyroid resection (1)
- tibial fracture (1)
- toddler’s fracture (1)
- vascular surgery (1)
- venturesomeness (1)
- visuo-spatial attention (1)
- von Willebrand factor (1)
- x-ray techniques (1)
- yeast-two-hybrid (Y2H) (1)
Institute
- Physik (909)
- Frankfurt Institute for Advanced Studies (FIAS) (811)
- Informatik (775)
- Medizin (34)
- Center for Financial Studies (CFS) (3)
- ELEMENTS (3)
- Hochschulrechenzentrum (3)
- Informatik und Mathematik (3)
- Wirtschaftswissenschaften (3)
- Biowissenschaften (2)
Understanding the production mechanism of light (anti)nuclei is one of the key challenges of nuclear physics and has important consequences for astrophysics, since it provides an input for indirect dark-matter searches in space. In this paper, the latest results about the production of light (anti)nuclei in pp collisions at s√=13 TeV are presented, focusing on the comparison with the predictions of coalescence and thermal models. For the first time, the coalescence parameters B2 for deuterons and B3 for helions are compared with parameter-free theoretical predictions that are directly constrained by the femtoscopic measurement of the source radius in the same event class. A fair description of the data with a Gaussian wave function is observed for both deuteron and helion, supporting the coalescence mechanism for the production of light (anti)nuclei in pp collisions. This method paves the way for future investigations of the internal structure of more complex nuclear clusters, including the hypertriton.
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¯¯¯¯¯¯ 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¯¯¯¯¯¯ 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¯¯¯¯¯¯ momentum from 25% to 90% for cosmic-ray sources. The results indicate that 3He¯¯¯¯¯¯ nuclei can travel long distances in the Galaxy, and can be used to study cosmic-ray interactions and dark-matter annihilation.
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 1.17≤p<10 GeV/c. 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¯¯¯¯¯¯ 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¯¯¯¯¯¯ momentum from 25% to 90%. The absolute uncertainties associated to the 3He¯¯¯¯¯¯ inelastic cross section measurements are of the order of 10%−15%. The reported results indicate that 3He¯¯¯¯¯¯ nuclei can travel long distances in the galaxy, and can be used to study cosmic-ray interactions and dark-matter decays.
The ALICE Collaboration reports the first fully-corrected measurements of the N-subjettiness observable for track-based jets in heavy-ion collisions. This study is performed using data recorded in pp and Pb−Pb collisions at centre-of-mass energies of √s=7 TeV and √sNN=2.76\,TeV, respectively. In particular the ratio of 2-subjettiness to 1-subjettiness, τ2/τ1, which is sensitive to the rate of two-pronged jet substructure, is presented. Energy loss of jets traversing the strongly interacting medium in heavy-ion collisions is expected to change the rate of two-pronged substructure relative to vacuum. The results are presented for jets with a resolution parameter of R=0.4 and charged jet transverse momentum of 40≤pT,jet≤60 GeV/c, which constitute a larger jet resolution and lower jet transverse momentum interval than previous measurements in heavy-ion collisions. This has been achieved by utilising a semi-inclusive hadron-jet coincidence technique to suppress the larger jet combinatorial background in this kinematic region. No significant modification of the τ2/τ1 observable for track-based jets in Pb--Pb collisions is observed relative to vacuum PYTHIA6 and PYTHIA8 references at the same collision energy. The measurements of τ2/τ1, together with the splitting aperture angle ΔR, are also performed in pp collisions at √s=7 TeV for inclusive jets. These results are compared with PYTHIA calculations at √s=7 TeV, in order to validate the model as a vacuum reference for the Pb−Pb centre-of-mass energy. The PYTHIA references for τ2/τ1 are shifted to larger values compared to the measurement in pp collisions. This hints at a reduction in the rate of two-pronged jets in Pb--Pb collisions compared to pp collisions.
In particle collider experiments, elementary particle interactions with large momentum transfer produce quarks and gluons (known as partons) whose evolution is governed by the strong force, as described by the theory of quantum chromodynamics (QCD). These partons subsequently emit further partons in a process that can be described as a parton shower which culminates in the formation of detectable hadrons. Studying the pattern of the parton shower is one of the key experimental tools for testing QCD. This pattern is expected to depend on the mass of the initiating parton, through a phenomenon known as the dead-cone effect, which predicts a suppression of the gluon spectrum emitted by a heavy quark of mass mQ and energy E, within a cone of angular size mQ/E around the emitter. Previously, a direct observation of the dead-cone effect in QCD had not been possible, owing to the challenge of reconstructing the cascading quarks and gluons from the experimentally accessible hadrons. We report the direct observation of the QCD dead cone by using new iterative declustering techniques to reconstruct the parton shower of charm quarks. This result confirms a fundamental feature of QCD. Furthermore, the measurement of a dead-cone angle constitutes a direct experimental observation of the non-zero mass of the charm quark, which is a fundamental constant in the standard model of particle physics.
Background and Objectives: Proteins of the coagulation system contribute to autoimmune inflammation in patients with multiple sclerosis (MS). On blood-brain barrier (BBB) disruption, fibrinogen enters the CNS and is rapidly converted to fibrin, unfolding pleiotropic autoimmune mechanisms. Fibrin accumulation leads to subsequent proteolytic degradation that results in D-dimer generation. The primary objective of this study was to determine intrathecal levels of D-dimer in CSF as a measure of intrathecal coagulation cascade activation and to evaluate its diagnostic utility in patients with MS in contrast to healthy subjects. Key secondary objectives included analysis of CSF D-dimer in differential diagnoses of MS and its relation to routine clinical markers of disease activity.
Methods: Patients admitted for the assessment of suspected MS were prospectively recruited from October 2017 to December 2020. Blood plasma and citrated CSF samples were analyzed using a highly sensitive luminescent oxygen channeling immunoassay. Intrathecal generation of D-dimer was analyzed by adjusting for CSF/serum albumin (Qalb) and CSF/plasma D-dimer quotients (QD-dimer), and corresponding CSF fibrinogen levels were determined. Final diagnoses after full evaluation and clinical data were recorded.
Results: Of 187 patients, 113 patients received a diagnosis of MS or clinically/radiologically isolated syndrome. We found increased intrathecal CSF D-dimer generation levels (QD-dimer/Qalb-index) for patients with relapsing-remitting MS (RRMS; n = 71, median 4.7, interquartile range [IQR] 2.5–8.0) when compared with those for disease controls (n = 22, median 2.6, IQR 2.1–4.8, p = 0.031). Absolute CSF D-dimer values correlated with CSF fibrinogen levels (r = 0.463; p < 0 .001) and CSF leukocytes (r = 0.273; p = 0.003) and were elevated in MS patients with contrast enhancement (CE) compared with MS patients without CE on MRI (n = 48, median 6 ng/mL, and IQR 3–15.25 vs n = 41, median 4 ng/mL, and IQR 2–7; p = 0.026). Exploratory subgroup analyses indicated a correlation of intrathecal inflammatory activity and CSF D-dimer levels.
Discussion: D-dimer in CSF can be reliably determined and correlates with markers of CNS inflammation and CSF fibrinogen levels. Adjusted for BBB dysfunction, CSF D-dimer may allow the identification of intrathecal coagulation cascade activation in patients with MS.
Classification of Evidence: This study provides Class I evidence that CSF D-dimer levels are elevated in patients with RRMS.
The production of prompt D0, Ds+, and Λc+ hadrons, and their ratios, Ds+/D0 and Λc+/D0, are measured in proton–proton collisions at √s=13 TeV at midrapidity (|y|<0.5) with the ALICE detector at the LHC. The measurements are performed as a function of the charm-hadron transverse momentum (pT) in intervals of charged-particle multiplicity, measured with two multiplicity estimators covering different pseudorapidity regions. While the strange to non-strange Ds+/D0 ratio indicates no significant multiplicity dependence, the baryon-to-meson pT-differential Λc+/D0 ratio shows a multiplicity-dependent enhancement, with a significance of 5.3σ for 1<pT<12 GeV/c, comparing the highest multiplicity interval with respect to the lowest one. The measurements are compared with a theoretical model that explains the multiplicity dependence by a canonical treatment of quantum charges in the statistical hadronisation approach, and with predictions from event generators that implement colour reconnection mechanisms beyond the leading colour approximation to model the hadronisation process. The Λc+/D0 ratios as a function of pT present a similar shape and magnitude as the Λ/KS0 ratios in comparable multiplicity intervals, suggesting a potential common mechanism for light- and charm-hadron formation, with analogous multiplicity dependence. The pT-integrated ratios, extrapolated down to pT=0, do not show a significant dependence on multiplicity within the uncertainties.
Fluctuation measurements are important sources of information on the mechanism of particle production at LHC energies. This article reports the first experimental results on third-order cumulants of the net-proton distributions in Pb–Pb collisions at a center-of-mass energy √sNN=5.02 TeV recorded by the ALICE detector. The results on the second-order cumulants of net-proton distributions at √sNN=2.76 and 5.02 TeV are also discussed in view of effects due to the global and local baryon number conservation. The results demonstrate the presence of long-range rapidity correlations between protons and antiprotons. Such correlations originate from the early phase of the collision. The experimental results are compared with HIJING and EPOS model calculations, and the dependence of the fluctuation measurements on the phase-space coverage is examined in the context of lattice quantum chromodynamics (LQCD) and hadron resonance gas (HRG) model estimations. The measured third-order cumulants are consistent with zero within experimental uncertainties of about 4% and are described well by LQCD and HRG predictions.
In March 2019 the HADES experiment recorded 14 billion Ag+Ag collisions at √sNN = 2.55 GeV as a part of the FAIR phase-0 physics program. In this contribution, we present and investigate our capabilities to reconstruct and analyze weakly decaying strange hadrons and hypernuclei emerging from these collisions. The focus is put on measuring the mean lifetimes of these particles.
This article presents the first measurement of the interaction between charm hadrons and nucleons. The two-particle momentum correlations of pD− and ¯pD+ pairs are measured by the ALICE Collaboration in high-multiplicity pp collisions at √s=13 TeV. The data are compatible with the Coulomb-only interaction hypothesis within (1.1–1.5)σ. The level of agreement slightly improves if an attractive nucleon (N)¯D strong interaction is considered, in contrast to most model predictions which suggest an overall repulsive interaction. This measurement allows for the first time an estimation of the 68% confidence level interval for the isospin I=0 inverse scattering length of the N¯D state f−10, I=0∈[−0.4,0.9] fm−1, assuming negligible interaction for the isospin I=1 channel.
The first measurement of the e+e− pair production at low lepton pair transverse momentum (pT,ee) and low invariant mass (mee) in non-central Pb−Pb collisions at sNN−−−√=5.02 TeV at the LHC is presented. The dielectron production is studied with the ALICE detector at midrapidity (|ηe|<0.8) as a function of invariant mass (0.4≤mee<2.7 GeV/c2) in the 50−70% and 70−90% centrality classes for pT,ee<0.1 GeV/c, and as a function of pT,ee in three mee intervals in the most peripheral Pb−Pb collisions. Below a pT,ee of 0.1 GeV/c, a clear excess of e+e− pairs is found compared to the expectations from known hadronic sources and predictions of thermal radiation from the medium. The mee excess spectra are reproduced, within uncertainties, by different predictions of the photon−photon production of dielectrons, where the photons originate from the extremely strong electromagnetic fields generated by the highly Lorentz-contracted Pb nuclei. Lowest-order quantum electrodynamic (QED) calculations, as well as a model that takes into account the impact-parameter dependence of the average transverse momentum of the photons, also provide a good description of the pT,ee spectra. The measured ⟨p2T,ee⟩−−−−−√ of the excess pT,ee spectrum in peripheral Pb−Pb collisions is found to be comparable to the values observed previously at RHIC in a similar phase-space region.
The inclusive production of the charm-strange baryon Ω0c is measured for the first time via its hadronic decay into Ω−π+ at midrapidity (|y|<0.5) in proton-proton (pp) collisions at the centre-of-mass energy s√=13 TeV with the ALICE detector at the LHC. The transverse momentum (pT) differential cross section multiplied by the branching ratio is presented in the interval 2<pT<12 GeV/c. The pT dependence of the Ω0c-baryon production relative to the prompt D0-meson and to the prompt Ξ0c-baryon production is compared to various models that take different hadronisation mechanisms into consideration. In the measured pT interval, the ratio of the pT-integrated cross sections of Ω0c and prompt Λ+c baryons multiplied by the Ω−π+ branching ratio is found to be larger by a factor of about 20 with a significance of about 4σ when compared to e+e− collisions.
The first measurement of the e+e− pair production at low lepton pair transverse momentum (pT,ee) and low invariant mass (mee) in non-central Pb−Pb collisions at sNN−−−√=5.02 TeV at the LHC is presented. The dielectron production is studied with the ALICE detector at midrapidity (|ηe|<0.8) as a function of invariant mass (0.4≤mee<2.7 GeV/c2) in the 50−70% and 70−90% centrality classes for pT,ee<0.1 GeV/c, and as a function of pT,ee in three mee intervals in the most peripheral Pb−Pb collisions. Below a pT,ee of 0.1 GeV/c, a clear excess of e+e− pairs is found compared to the expectations from known hadronic sources and predictions of thermal radiation from the medium. The mee excess spectra are reproduced, within uncertainties, by different predictions of the photon−photon production of dielectrons, where the photons originate from the extremely strong electromagnetic fields generated by the highly Lorentz-contracted Pb nuclei. Lowest-order quantum electrodynamic (QED) calculations, as well as a model that takes into account the impact-parameter dependence of the average transverse momentum of the photons, also provide a good description of the pT,ee spectra. The measured ⟨p2T,ee⟩−−−−−√ of the excess pT,ee spectrum in peripheral Pb−Pb collisions is found to be comparable to the values observed previously at RHIC in a similar phase-space region.
We report about the properties of the underlying event measured with ALICE at the LHC in pp and p−Pb collisions at sNN−−−√=5.02 TeV. The event activity, quantified by charged-particle number and summed-pT densities, is measured as a function of the leading-particle transverse momentum (ptrigT). These quantities are studied in three azimuthal-angle regions relative to the leading particle in the event: toward, away, and transverse. Results are presented for three different pT thresholds (0.15, 0.5, and 1 GeV/c) at mid-pseudorapidity (|η|<0.8). The event activity in the transverse region, which is the most sensitive to the underlying event, exhibits similar behaviour in both pp and p−Pb collisions, namely, a steep increase with ptrigT for low ptrigT, followed by a saturation at ptrigT≈5 GeV/c. The results from pp collisions are compared with existing measurements at other centre-of-mass energies. The quantities in the toward and away regions are also analyzed after the subtraction of the contribution measured in the transverse region. The remaining jet-like particle densities are consistent in pp and p−Pb collisions for ptrigT>10 GeV/c, whereas for lower ptrigT values the event activity is slightly higher in p−Pb than in pp collisions. The measurements are compared with predictions from the PYTHIA 8 and EPOS LHC Monte Carlo event generators.
We report about the properties of the underlying event measured with ALICE at the LHC in pp and p−Pb collisions at sNN−−−√=5.02 TeV. The event activity, quantified by charged-particle number and summed-pT densities, is measured as a function of the leading-particle transverse momentum (ptrigT). These quantities are studied in three azimuthal-angle regions relative to the leading particle in the event: toward, away, and transverse. Results are presented for three different pT thresholds (0.15, 0.5, and 1 GeV/c) at mid-pseudorapidity (|η|<0.8). The event activity in the transverse region, which is the most sensitive to the underlying event, exhibits similar behaviour in both pp and p−Pb collisions, namely, a steep increase with ptrigT for low ptrigT, followed by a saturation at ptrigT≈5 GeV/c. The results from pp collisions are compared with existing measurements at other centre-of-mass energies. The quantities in the toward and away regions are also analyzed after the subtraction of the contribution measured in the transverse region. The remaining jet-like particle densities are consistent in pp and p−Pb collisions for ptrigT>10 GeV/c, whereas for lower ptrigT values the event activity is slightly higher in p−Pb than in pp collisions. The measurements are compared with predictions from the PYTHIA 8 and EPOS LHC Monte Carlo event generators.
The production of K∗(892)0 and ϕ(1020) resonances has been measured in p-Pb collisions at sNN−−−√ = 8.16 TeV using the ALICE detector. Resonances are reconstructed via their hadronic decay channels in the rapidity interval −0.5 < y < 0 and the transverse momentum spectra are measured for various multiplicity classes up to pT = 20 GeV/c for K∗(892)0 and pT = 16 GeV/c for ϕ(1020). The pT -integrated yields and mean transverse momenta are reported and compared with previous results in pp, p-Pb and Pb-Pb collisions. The xT scaling for K∗(892)0 and ϕ(1020) resonance production is newly tested in p-Pb collisions and found to hold in the high-pT region at Large Hadron Collider energies. The nuclear modification factors (RpPb) as a function of pT for K∗0 and ϕ at sNN−−−−√ = 8.16 TeV are presented along with the new RpPb measurements of K∗0, ϕ , Ξ, and Ω at sNN−−−√ = 5.02 TeV. At intermediate pT (2-8 GeV/c), RpPb of Ξ, Ω show a Cronin-like enhancement, while K∗0 and ϕ show no or little nuclear modification. At high pT (> 8 GeV/c), the RpPb values of all hadrons are consistent with unity within uncertainties. The RpPb of K∗(892)0 and ϕ(1020) at sNN−−−√ = 8.16 and 5.02 TeV show no significant energy dependence.
The production of K∗(892)0 and ϕ(1020) resonances has been measured in p-Pb collisions at sNN−−−√ = 8.16 TeV using the ALICE detector. Resonances are reconstructed via their hadronic decay channels in the rapidity interval −0.5 < y < 0 and the transverse momentum spectra are measured for various multiplicity classes up to pT = 20 GeV/c for K∗(892)0 and pT = 16 GeV/c for ϕ(1020). The pT -integrated yields and mean transverse momenta are reported and compared with previous results in pp, p-Pb and Pb-Pb collisions. The xT scaling for K∗(892)0 and ϕ(1020) resonance production is newly tested in p-Pb collisions and found to hold in the high-pT region at Large Hadron Collider energies. The nuclear modification factors (RpPb) as a function of pT for K∗0 and ϕ at sNN−−−−√ = 8.16 TeV are presented along with the new RpPb measurements of K∗0, ϕ , Ξ, and Ω at sNN−−−√ = 5.02 TeV. At intermediate pT (2-8 GeV/c), RpPb of Ξ, Ω show a Cronin-like enhancement, while K∗0 and ϕ show no or little nuclear modification. At high pT (> 8 GeV/c), the RpPb values of all hadrons are consistent with unity within uncertainties. The RpPb of K∗(892)0 and ϕ(1020) at sNN−−−√ = 8.16 and 5.02 TeV show no significant energy dependence.
This article reports on the inclusive production cross section of several quarkonium states, J/ψ, ψ(2S), Υ(1S), Υ(2S), and Υ(3S), measured with the ALICE detector at the LHC, in pp collisions at s√=5.02 TeV. The analysis is performed in the dimuon decay channel at forward rapidity (2.5<y<4). The integrated cross sections and transverse-momentum (pT) and rapidity (y) differential cross sections for J/ψ, ψ(2S), Υ(1S), and the ψ(2S)-to-J/ψ cross section ratios are presented. The integrated cross sections, assuming unpolarized quarkonia, are: σJ/ψ(pT<20 GeV/c) = 5.88 ± 0.03 ± 0.34 μb, σψ(2S)(pT<12 GeV/c) = 0.87 ± 0.06 ± 0.10 μb, σΥ(1S)(pT<15 GeV/c) = 45.5 ± 3.9 ± 3.5 nb, σΥ(2S)(pT<15 GeV/c) = 22.4 ± 3.2 ± 2.7 nb, and σΥ(3S)(pT<15 GeV/c) = 4.9 ± 2.2 ± 1.0 nb, where the first (second) uncertainty is the statistical (systematic) one. For the first time, the cross sections of the three Υ states, as well as the ψ(2S) one as a function of pT and y, are measured at s√=5.02 TeV at forward rapidity. These measurements also significantly extend the J/ψ pT reach and supersede previously published results. A comparison with ALICE measurements in pp collisions at s√=2.76, 7, 8, and 13 TeV is presented and the energy dependence of quarkonium production cross sections is discussed. Finally, the results are compared with the predictions from several production models.
This article reports on the inclusive production cross section of several quarkonium states, J/ψ, ψ(2S), Υ(1S), Υ(2S), and Υ(3S), measured with the ALICE detector at the LHC, in pp collisions at s√=5.02 TeV. The analysis is performed in the dimuon decay channel at forward rapidity (2.5<y<4). The integrated cross sections and transverse-momentum (pT) and rapidity (y) differential cross sections for J/ψ, ψ(2S), Υ(1S), and the ψ(2S)-to-J/ψ cross section ratios are presented. The integrated cross sections, assuming unpolarized quarkonia, are: σJ/ψ(pT<20 GeV/c) = 5.88 ± 0.03 ± 0.34 μb, σψ(2S)(pT<12 GeV/c) = 0.87 ± 0.06 ± 0.10 μb, σΥ(1S)(pT<15 GeV/c) = 45.5 ± 3.9 ± 3.5 nb, σΥ(2S)(pT<15 GeV/c) = 22.4 ± 3.2 ± 2.7 nb, and σΥ(3S)(pT<15 GeV/c) = 4.9 ± 2.2 ± 1.0 nb, where the first (second) uncertainty is the statistical (systematic) one. For the first time, the cross sections of the three Υ states, as well as the ψ(2S) one as a function of pT and y, are measured at s√=5.02 TeV at forward rapidity. These measurements also significantly extend the J/ψ pT reach and supersede previously published results. A comparison with ALICE measurements in pp collisions at s√=2.76, 7, 8, and 13 TeV is presented and the energy dependence of quarkonium production cross sections is discussed. Finally, the results are compared with the predictions from several production models.