In this manuscript, various beauty production measurements using the ALICE detector will be presented. We will show new measurements of non-prompt D$^0$ mesons in pp collisions at $\sqrt{s} = 5.02$ TeV and beauty-tagged jet production in p--Pb collisions at $\sqrt{s_{\mathrm{NN}}} = 5.02$ TeV. The $R_{\mathrm{AA}}$ of beauty-hadron decay electrons in central Pb--Pb collisions and the $v_{2}$ of beauty-hadron decay electrons in semi-central Pb--Pb collisions at $\sqrt{s_{\mathrm{NN}}} = 5.02$ TeV will also be discussed.
This contribution summarizes a selection of recent results from the ALICE experiment. We show the cross-section of beauty jets in pp collisions, as well as the charmed baryon-to-meson production ratios, down to unprecedentedly low momenta, at $\sqrt{s_{\rm NN}} = 5.02$ and 13 TeV collision energies. We present the nuclear modification of ${\rm D}^0$-jets and the $v_2$ of non-prompt ${\rm D}^0$ in Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV. We also discuss the implications and constraints from comparing these data to some of the most recent theoretical models.
We present the expected ALICE performance for the measurement of the p_t-differential cross section of electrons from beauty decays in central Pb-Pb collisions at the LHC.
Electron spectra measured with ALICE at mid-rapidity are used to study the production of hadrons carrying a charm or a beauty quark. The production cross section of electrons from heavy-flavour hadron decays is measured in pp collisions at $\sqrt{s}$=7 TeV. Electrons from the beauty decays are identified via the displacement from the interaction vertex. From the electron spectra measured in Pb--Pb collisions, we determine the nuclear modification factor, which is sensitive to the heavy-quark energy loss in a hot strongly interacting medium.
At LHC energy, heavy quarks will be abundantly produced and the design of the ALICE detector will allow us to study their production using several channels. The expected heavy-quark in-medium energy loss in nucleus-nucleus collisions at the LHC is calculated within a model, that is compared to the available heavy-quark quenching measurements at RHIC. The nuclear modification factors and heavy-to-light ratios of charm and beauty mesons are considered. The capability of the ALICE experiment for addressing this phenomenology is discussed.
Measurements of heavy (charm and beauty) quarks provide useful insights into the properties of the quark--gluon plasma. The good particle identification capabilities of ALICE make a measurement based on the electrons from semi-leptonic decays of heavy-flavour hadrons feasible. This approach makes use of the large branching ratios ($\approx 10-20\%$) of heavy--flavour hadrons into electrons. Separation of the contribution from beauty-hadron decay electrons was achieved by utilizing the large decay length of the associated hadrons, making the investigation of beauty quarks in the medium possible…
The hot and dense nuclear matter, that is produced in heavy-ion collisions, could be studied by jets originating from beauty quarks. In-medium energy loss of these quarks provides information on several properties of the quark-gluon plasma, produced in ultra-relativistic heavy-ion collisions. Reconstructed jets are powerful tools, since they offer access to kinematics of these hard-scattered partons. Beauty hadrons are specific for their long lifetime, large mass and large-multiplicity decays. Due to the long lifetime beauty hadrons decay at displaced secondary vertices. In the ALICE experimen…
The ALICE experiment has measured at mid-rapidity electrons from heavy-flavour decays in pp collisions at $\sqrt{s}$ = 2.76 and 7 TeV, and in Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV. In pp collisions, electrons from charm-hadron and from beauty-hadron decays are identified by applying cuts on displaced vertices. The relative yield of electrons from beauty-hadron decays to those from heavy-flavour decays is extracted using electron-hadron correlations. Results are compared to pQCD-based calculations. In Pb-Pb collisions, the $p_{\rm T}$ dependence of the nuclear modification factor o…
The ALICE Collaboration at the LHC studies heavy-ion collisions to investigate the properties of the Quark-Gluon Plasma (QGP). Heavy quarks (charm and beauty) are effective probes for this purpose. Both their energy loss in the medium as well as their possible thermalization yield information about the medium properties. Experimentally, the reconstruction of hadrons with charm valence quarks is possible. For hadrons with beauty valence quarks a promising strategy is the measurement of their decay electrons. To separate these from the background electrons (mainly from charm hadron decays, photo…
Heavy quarks produced in pp and heavy ion collisions are studied using heavy-flavour decay electrons and heavy-flavour mesons. Detailed understanding of the production processes and fragmentation of heavy quarks can be obtained by studying the azimuthal angular correlation of heavy-flavour hadrons. The azimuthal angular correlations of heavy-flavour mesons and charged hadrons can be used to disentangle charm and beauty-hadrons in pp collisions. In this contribution the fraction of electrons from beauty-hadron decays in the heavy-flavour decay electron yield is shown as well as the beauty produ…
In this contribution, the final measurements of the centrality dependence of the nuclear modification factor ($R_{\rm AA}$) of non-prompt $\rm D^0$ in Pb--Pb collisions at $\sqrt{s_{\scriptscriptstyle \rm NN}}$ = 5.02 TeV will be presented. These measurements provide important constraints to the in-medium mass dependent of energy loss and hadronisation of the beauty quark. The $p_{\rm T}$-integrated non-prompt $\rm D^0$ $R_{\rm AA}$ will be presented for the first time and will be compared to the prompt $\rm D^0$ one. This comparison will shed light on possible different shadowing effects betw…
The ALICE detector is well suited to measure heavy-flavour (charm and beauty) production via hadronic and semi-leptonic decay channels of heavy-flavour particles. Here an overview of heavy-flavour measurements made with the ALICE detector during Run 1 in pp and p--Pb collisions is presented and discussed.
During the second long shutdown of the LHC in 2018, the ALICE Collaboration plans to install an upgrade of the ALICE Inner Tracking System (ITS) in the central barrel with seven layers of silicon detectors starting at 2.2 cm radial distance from the interaction region and a material budget as low as 0.3% radiation length per layer. A single-hit resolution of $\mathrm{4 μm}$ and a readout rate capability of up to 50 kHz in Pb--Pb collisions will allow new and unique measurements in the heavy-quark sector, i.e. charm and beauty. Using detailed Monte Carlo simulations of pp and Pb--Pb collisions …
We report recent results from the ALICE experiment the Large Hadron Collider on open charmed hadron production in pp collisions at $\sqrt{s} = 2.76$ and 7 TeV, and Pb-Pb collisions at $\sqrt{\mathrm{s}_{_{\mathrm{NN}}}} = 2.76$ TeV. Open charmed hadrons are kinematically fully reconstructed in the hadronic decay channels \DtoKpi, \DtoKpipi, and \DstartoDpi %$D^0\rightarrow K^-π^+$, $D^+\rightarrow K^-π^+ π^+$, and $D^{*+} \rightarrow D^0 (K^-π^+) + π^+$ and identified through their invariant mass. Combinatorial background is minimized by selecting a displaced vertex topology. Inclusive charm a…
The measurements of open heavy-flavours, i.e. D mesons at central rapidity and leptons from charm and beauty decays at central and forward rapidity was studied in p-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 5.02 TeV using the ALICE detector. The results are presented and compared to model predictions including cold nuclear matter effects.
In ultra-relativistic heavy-ion collisions heavy quarks (charm and beauty) are produced in hard scattering processes and thus carry relevant information on the properties of the created hot and dense medium. Heavy-flavour hadrons can be measured using electrons from their semileptonic decay channels. The relative contribution of charm and beauty hadrons can be estimated from the study of the near side azimuthal angular correlations between these electrons and charged hadrons. We present the measurement of azimuthal angular correlations between electrons and charged hadrons in pp collisions at …
Charm and beauty quark production measurement represents a fundamental means to access the initial stage of hadronic collisions. Being produced almost exclusively in initial hard partonic scatterings due to their large masses, $m_{\text{c}}=$ 1.3 $ \text{GeV}/c^2$ and $m_{\text{b}} =$ 4.1 $ \text{GeV}/c^2$, charm and beauty quarks are ideal tools to investigate various QCD aspects. In addition, the corresponding measurements in pp collisions represent a baseline for cold nuclear matter studies in p--A collisions as well as for the characterization of the hot and dense interacting nuclear matte…
These proceedings summarize the LHCb measurements of charm- and beauty-hadron production in pPb collisions. The studies are made down to very low-\pt of the observed heavy-flavor hadrons using fully reconstructed decays. Nuclear matter effects are quantified via nuclear modification factors and forward-backward production ratios. A strong suppression is observed at positive rapidity (proton beam direction), while a modest or no suppression is seen for the backward rapidity (lead beam direction). The nuclear parton distributions of the lead nucleus is constrained down to Bjorken-$x\sim10^{-5}$,…
The ALICE experiment at LHC is mainly dedicated to heavy-ion physics. An overview of its performances, some predictions related to its first measurements and QGP observable measurements will be given.
In this work we are studying the relative beauty to charm production in pp collisions at \sqrt{s} = 2.76 TeV, through correlations between electrons from heavy-flavour decay and charged hadrons, with the ALICE detector at the LHC. This study represents a baseline for the analysis in heavy-ion collisions where heavy flavour production is a powerful tool to study the Quark Gluon Plasma (QGP).
The ALICE experiment at the Large Hadron Collider (LHC) at CERN consists of a central barrel, a muon spectrometer and additional detectors for trigger and event classification purposes. The low transverse momentum threshold of the central barrel gives ALICE a unique opportunity to study the low mass sector of central exclusive production at the LHC.
Measurements of charm and beauty production in pp collisions, using the ALICE detector system, at LHC energies ($\sqrt{s} = 2.76$ and 7.0 TeV) can test perturbative QCD down to very low Björken-x. They are also critical as a reference to ALICE's heavy ion program. The ALICE detector system allows measurements not covered by the other LHC experiments in addition to covering complementary regions. A description of the ALICE detector system, in relation to ATLAS and CMS, are presented. Results from both leptonic and hadronic decay channels will be shown along with comparisons to other measurement…
The production cross section of electrons from semileptonic decays of beauty hadrons was measured at mid-rapidity (|y| < 0.8) in the transverse momentum range $1 < p_{\rm T} < 8$ Gev/$c$ with the ALICE experiment at the CERN LHC in pp collisions at a center of mass energy $\sqrt{s} = 7$ TeV using an integrated luminosity of 2.2 nb$^{-1}$. Electrons from beauty hadron decays were selected based on the displacement of the decay vertex from the collision vertex. A perturbative QCD calculation agrees with the measurement within uncertainties. The data were extrapolated to the full phase space to d…
In high-energy hadronic collisions, hard parton scatterings with large momentum transfers are prerequisites for the formation of hard and rare probes. In heavy-ion collisions, these probes---final state particles related to the early hard-parton scatterings---serve as a powerful tool to explore the whole evolution of the medium including the quark--gluon plasma (QGP) stage. Hard probes in proton-proton (pp) collisions test perturbative quantum chromodynamics (pQCD) processes and hadronization, and provide a reference for the nuclear collision systems. High-multiplicity pp collisions provide a …
The measurement of D-meson production in heavy-ion collisions at LHC energy provides insights into the mechanisms of interaction of charm quarks in the hot and dense medium formed in these collisions. ALICE results on the D-meson nuclear modification factor and azimuthal anisotropy in Pb-Pb collisions at $\sqrt{s_{\rm NN}}=2.76$ TeV are presented.
The ALICE experiment has measured charm and beauty production in pp and Pb-Pb collisions at sqrt(s) = 2.76 and 7 TeV and sqrt(sNN) = 2.76 TeV, respectively, via the exclusive reconstruction of hadronic D meson decays and semi-leptonic D and B meson decays. In this contribution, recent results on the nuclear modification factor for open charmed mesons and heavy-flavour decay electrons at central rapidity and muons at forward rapidity are presented and discussed.
The production of open heavy-flavour particles was studied in p-Pb collisions at $\sqrt{s_\mathrm{NN}}=5.02$ TeV using the ALICE detector. Three separate observables were used: the hadronic decays of D mesons at mid-rapidity, and semileptonic decays of heavy-flavour hadrons to electrons and muons at mid-rapidity and forward rapidity, respectively. The most recent ALICE measurements of the nuclear modification factor, $R_\mathrm{pPb}$, of open charm and beauty are reported, along with the centrality and multiplicity dependence of D-meson production in p-Pb collisions.
After close to 20 years of preparation, the dedicated heavy ion experiment ALICE took first data with proton collisions at the LHC starting in November 2009 and first Pb-Pb data in November 2010. This article summarizes initial operation and performance of ALICE as well as first results from both pp and Pb-Pb collisions.
Results on open heavy-flavour production in Pb-Pb collisions at sqrt{s_NN} = 2.76 TeV measured with ALICE at the LHC are presented. The nuclear modification factors, extracted in three different channels, show a strong suppression in central collisions. The measured D-meson azimuthal anisotropy indicates a non-zero v2, which is similar to the one of charged hadrons.
The pseudorapidity density and multiplicity distributions of charged particles have been the first measurements carried out with the ALICE detector at the LHC. After an introduction on the experiment and some details on the subdetectors relevant for these measurements, results from minimum bias proton-proton collisions at 0.9, 2.36 and 7 TeV are presented. Comparisons with other measurements and model predictions are also discussed.
After 20 years of preparation, the dedicated heavy ion experiment ALICE took first data at the CERN LHC accelerator with proton collisions at the end of 2009 and with lead beams at the end of 2010. This article will give a brief overview of the main results presented at the Quark Matter 2011 conference.
After a short review of the physics motivations for the study of open heavy flavour production in proton-proton, proton-nucleus and nucleus-nucleus collisions at the LHC, we present results on the expected performance of the ALICE experiment for charm and beauty production measurements.
Reference cross sections have been measured with the ALICE detector in both pp and Pb-Pb collisions, in dedicated luminosity calibration experiments (van der Meer scans) at the LHC. The results and their uncertainties are discussed, together with a few selected applications.
ALICE is the LHC experiment dedicated to the study of Heavy-Ion collisions. Many observables related to the properties of the medium created in such collisions rely on the excellent capabilities of the detector in terms of Particle Identification (PID) of particles. In the following, the various PID techniques used for the different ALICE analyses will be described. Focus will be given to the detectors' performance, and selected results will be presented on pp data collected at sqrt(s) = 7 TeV and PbPb collisions at sqrt(s_NN) = 2.76 TeV.
We present here recent open heavy-flavour results from the ALICE experiment, including measurements of D-meson, $\mathrm{Λ_{c}^{+}}$ baryon and $\mathrm{Ξ_c^0}$ baryon production in pp collisions at $\sqrt{s} = 7~\mathrm{TeV}$ and p-Pb collisions at $\sqrt{s_{\mathrm{NN}}} = 5.02~\mathrm{TeV}$.
The ALICE detector at the LHC recorded first Pb-Pb collisions at 2.76 TeV in November and December of 2010. We report on the measurements of anisotropic flow for charged and identified particles. From the comparison with measurements at lower energies and with model predictions we find that the system created at these collision energies is described well by hydrodynamical model calculations and behaves like an almost perfect fluid.
We report on the pseudo-rapidity dependence of the charged particle anisotropic flow in Pb-Pb collisions at 2.76 TeV. The measurement is done over a wide range of pseudo-rapidity, |η|<5 using the forward detectors of ALICE at the LHC. Results are obtained from two- and multi-particle correlation techniques with the latter being less sensitive to non-flow effects. Elliptic flow longitudinal scaling, comparison with RHIC data and AMPT model calculations for the LHC are discussed.
ALICE at the LHC has a unique potential to study proton-proton collisions with the goal to probe Quantum ChromoDynamics (QCD). The apparatus was designed to reconstruct particles over a large range in transverse momentum and rapidity. In particular, quarkonia are very interesting probes of QCD, because their production mechanisms are governed by both perturbative and non-perturbative QCD processes. In ALICE, quarkonia are reconstructed via their dilepton decay channel down to zero transverse momentum. This contribution gives a short overview of quarkonium production results in proton-proton co…
The ALICE Collaboration measured dielectron production as a function of the invariant mass ($m_{\rm ee}$), the pair transverse momentum ($p_{\rm T,ee}$) and the pair distance of closest approach ($\rm DCA_{ee}$) in pp collisions at $\sqrt{s} = 7$ TeV. Prompt and non-prompt dielectron sources can be separated with the $\rm DCA_{ee}$, which will give the opportunity in heavy-ion collisions to identify thermal radiation from the medium in the intermediate-mass range dominated by contributions from open-charm and beauty hadron decays. The charm and beauty total cross sections are extracted from th…
Hadronic resonances $\mathrm{K}^{*}(892)^{0}$, $ϕ$(1020) and $Σ(1385)^{\pm}$ have been measured by the ALICE experiment in pp collisions at $\sqrt{s}=7$ TeV and in Pb-Pb collisions at $\sqrt{s_{_\mathrm{NN}}}=2.76$ TeV. Transverse momentum spectra, particle ratios, nuclear modification factor and comparison with model predictions are discussed. In addition, ALICE results are compared with data obtained at RHIC energy.
ALICE is the heavy-ion experiment at the CERN Large Hadron Collider. The experiment continuously took data during the first physics campaign of the machine from fall 2009 until early 2013, using proton and lead-ion beams. In this paper we describe the running environment and the data handling procedures, and discuss the performance of the ALICE detectors and analysis methods for various physics observables.
ALICE measured electrons from inclusive heavy-flavour hadron decays and beauty-hadron decays at mid-rapidity in pp collisions at \sqrt{s} = 7 TeV and 2.76 TeV and p-Pb collisions at \sqrt{s_{NN}} = 5.02 TeV. For both pp collision energies, p_T-differential electron production cross sections are presented and compared to pQCD predictions. For p-Pb collisions, the p_T-dependent nuclear modification factor of electrons from inclusive heavy-flavour hadron decays is presented.
Probes for the small-x parton densities and predicted effects of gluon saturation are discussed. At very low x and intermediate Q, only results on hadronic observables at the LHC are available, which do not provide unambiguous information. It is shown that the measurement of direct photons at forward rapidity at the LHC is particularly promising to provide a unique signal. We further discuss the possibilities to perform such measurements with a detector upgrade in the ALICE experiment and present the R&D activities ongoing.
Measurements of the second Fourier harmonic coefficient ($v_2$) of the azimuthal distributions of prompt and nonprompt D$^0$ mesons produced in pp and pPb collisions are presented. Nonprompt D$^0$ mesons come from beauty hadron decays. The data samples are collected by the CMS experiment at nucleon-nucleon center-of-mass energies of 13 and 8.16 TeV, respectively. In high multiplicity pp collisions, $v_2$ signals for prompt charm hadrons are reported for the first time, and are found to be comparable to those for light-flavor hadron species over a transverse momentum ($p_\mathrm{T}$) range of 2…
These proceedings describe the charged-particle pseudorapidity densities and multiplicity distributions measured by the ALICE detector in pp collisions at $\sqrt{s} = 0.9$ and 7 TeV in specific phase space regions. The pseudorapidity range $|η| < 0.8$, together with $p_{\rm T}$ cuts at 0.15, 0.5 and 1 GeV/$c$ is considered. The classes of events considered are those having at least one charged particle in the kinematical ranges just described. The results obtained by ALICE are compared to Monte Carlo predictions.
We present measurements of charged jet cross sections and jet shape observables in leading jet in proton-proton (pp) collisions at sqrt(s) = 2.76 TeV with the ALICE detector at LHC. Jets are reconstructed at the midrapidity from charged particle using sequential recombination anti-kT jet finding algorithm for various R values. The results are compared to measurements from HERWIG, PHOJET and different tunes of PYTHIA6 and earlier measurements at 7 TeV.
The ALICE experiment is equipped with a wide range of detectors providing excellent tracking and particle identification in the central region, as well as forward detectors with extended pseudorapidity coverage, which are well suited for studying diffractive processes. Cross section measurements of single and double diffractive processes performed by ALICE in pp collisions at $\sqrt{s}=0.9,~2.76,~7$~TeV will be reported. Currently, ALICE is studying double-gap events in pp collisions at $\sqrt{s}=7$~TeV, which give an insight into the central diffraction processes: current status and future pe…
Strange quark and particle production is studied at the LHC with unprecedented high beam energies in both heavy-ion and proton-proton collisions: on the one hand, strangeness is used for investigating chemical equilibration and bulk properties; on the other hand, strange particles contribute to probe different kinematical domains, from the one where collective phenomena are at play up to the region dominated by pQCD-calculable processes. We highlight the suitability of the ALICE experiment for this topic, presenting our latest measurements and comparing them to models.
We report on the studies of two-particle angular correlations measured in proton-proton collisions at a center-of-mass energy of sqrt(s) = 7 TeV recorded by ALICE at the LHC. Two-particle correlations in relative azimuth (Δϕ) and pseudorapidity (Δη) are expected to exhibit several structures which arise from different physics mechanisms and allow us to study the wide landscape of correlations. The results include the dependence of the correlation function on the event multiplicity, the charge combination and species (pions, kaons or protons) of particles in the pair.
Long-range correlations between particles separated by a pseudorapidity gap are a powerful tool to explore the initial stages and evolution of the medium created in hadron-hadron collisions. An overview of the long-range correlations measured by the ALICE detector in pp, p-Pb and Pb-Pb will be presented. This includes analyses of forward-backward, two- and multi-particle correlations with the use of the central barrel and forward detectors.
In November 2010 the ALICE experiment at CERN has collected the first Pb--Pb collisions at $\sqrt{s_{NN}}$ = 2.76 TeV produced by the LHC. A first characterization of the hot and dense state of matter produced in this new energy domain became available shortly after the run. In this paper we present the results on charged-particle multiplicity, Bose-Einstein correlations, elliptic flow and their dependence on the collision centrality. Results from first measurements of strange and identified particle production and suppression of high-momentum hadrons with respect to $pp$ collisions are also r…
The excellent capabilities of the ALICE experiment for particle identification allow to measure the identified hadron production in a wide range of transverse momentum. In this work we present some results on identified particle spectra, strange particle production and particle contents measured in pp collisions at \sqrt{s} = 0.9, 2.76 and 7 TeV. The results are compared with Monte Carlo event generators predictions.
Two-particle azimuthal correlations of electrons from heavy-flavour hadron decays with charged particles can give insight into the properties of heavy-quark production and hadronization into heavy-flavour jets.\\ In this contribution, the ALICE results measured in pp collisions at 5.02 TeV, collected in the LHC Run 2, are presented. The yields of charged particles in the near and away-side correlation peaks and the peak width are compared with PYTHIA calculations.
Charm and beauty production are probed with the ALICE experiment at the LHC by studying the single lepton transverse momentum distribution (electrons at mid-rapidity, muons at large-rapidities) and D mesons reconstructed in their hadronic decays. The differential production cross sections in proton proton interactions show a good agreement with perturbative QCD calculations at both sqrt(s) = 2.76 and 7 TeV. The measurements in lead lead reactions at sqrt(s_{NN})= 2.76 TeV evidence a reduction (or suppression) of the production rate at intermediate and high pt in the most central collisions wit…
We present an analysis on the heavy flavor hadron decay electrons with charm and beauty contributions decomposed via a data driven method in p+p and Pb+Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV at LHC. The transverse momentum $p_{\mathrm{T}}$ spectra, nuclear modification factor $R_{\mathrm{AA}}$ and azimuthal anisotropic flow $v_2$ distributions of electrons from charm and beauty decays are obtained. We find that the electron $R_{\mathrm{AA}}$ from charm ($R_{\mathrm{AA}}^{\mathrm{c\rightarrow e}}$) and beauty ($R_{\mathrm{AA}}^{\mathrm{b\rightarrow e}}$) decays are suppressed at $…
