We present the current status of the measurement of jets that contain a D meson (D-tagged jets) with ALICE. D-meson candidates, identified via their hadronic decay channels, were combined with the other charged tracks reconstructed with the central tracking system, using the anti-$k_{\rm T}$ jet-finding algorithm. The yield of D-tagged jets was extracted through an invariant mass analysis of the D-meson candidates. A Monte Carlo simulation was used to determine the detector performance and validate the signal extraction techniques.
A Monte Carlo study of two jet observables that can be used to obtain jet samples enhanced in quark or gluon content is presented. We compare the performance of one of these methods on pure Monte Carlo events with that after the transport of events through the full simulation of the ALICE experiment. It is shown that the performance of the method is not deteriorated by experimental effects like resolution and inefficiency.
ALICE measured transverse momentum spectra of pi0 and eta mesons via the two photon decay in pp collisions at sqrt(s)=0.9, 2.76 and 7 TeV and Pb-Pb collisions at sqrt(sNN)=2.76 TeV. NLO pQCD calculations agree with p-p measurements at 0.9 TeV, but overestimate the data at 2.76 and 7 TeV. The nuclear modification factor for neutral pions shows a strong suppression of high-pt particle production in central Pb-Pb collisions. Raw spectra of charged particle jets have been measured in Pb-Pb collisions. Detailed studies of background fluctuations have been performed and will allow us to unfold the s…
Jets and direct photons are used to probe the formation and the properties of the Quark-Gluon Plasma (QGP) by the ALICE Collaboration. The results shown here will present the measurements obtained from Pb$-$Pb and p$-$Pb collisions. It is observed that in Pb$-$Pb collisions jets are collimated and hadron yields ($π^{0}$ and $η$) at high transverse momentum undergo strong suppression due to the interaction of the patrons with the QGP. On the other hand, photons do not show any suppression in this region, and, in addition, an excess attributed to a thermal emission is observed at low transverse …
This contribution summarises the results on heavy-flavour correlations and jets measured with ALICE detector. Studies of D$^{0}$-tagged jets are presented in various collision systems and energies. The measurement of the fraction of jet momentum carried by the D$^{0}$ meson in the direction of the jet axis ($z_{\rm ||}^{\rm ch,jet}$) in pp collisions at $\sqrt{s}$ = 5.02 and 13 TeV as well as the nuclear modification factor in p--Pb and Pb--Pb collisions are presented. The measurements of the production of jets tagged by electrons from heavy-flavour decays in pp and p--Pb are compared to expec…
Measurements of jet yields in heavy-ion collisions can be used to constrain jet energy loss models, and in turn provide information about the physical properties of deconfined QCD matter. ALICE reconstructs charged particle jets ($\textit{charged jets}$) with high-precision tracking of charged particles down to $p_{\mathrm{T}}^{\mathrm{track}} = 150$ MeV/$c$, and jets ($\textit{full jets}$) with the addition of particle information from the electromagnetic calorimeter down to $E_{\mathrm{cluster}} = 300$ MeV. By including low momentum jet constituents, ALICE is uniquely positioned at the LHC t…
Jet quenching, a standard signature of quark--gluon plasma (QGP) formation in which jets lose energy by traversing the medium, comprises a well-studied set of observables in heavy-ion collisions. Significant questions remain, however, concerning the mechanisms driving this phenomenon. Theoretical work that attempts to address these open questions offers the path-length dependence of jet energy loss as one way to better understand the underlying mechanisms of jet quenching. It has proven challenging, however, to derive explicit values for the path-length dependence from experimental data. These…
We study the medium modification of jets correlated with large transverse momentum photons at the LHC via a transport and perturbative QCD hybrid model which incorporates the contributions from both elastic collisions and radiative energy loss experienced by the parton showers. Calculations are performed for the modification of the photon-tagged jet yield, the photon-jet energy imbalance, and the azimuthal distribution of away-side jets. The modifications of photon-tagged jets with different $x_T = p_{T, J}/p_{T, γ}$ values are studied and they exhibit different centrality and jet cone size de…
The large statistics accumulated during the LHC Run-1 and Run-2 have provided the unique opportunity to study the properties of the Quark-Gluon Plasma using rare hard probes. The ALICE Collaboration has presented new results on the jet shape observables in p--Pb and Pb--Pb collision. Using data from Run-2, the elliptic flow of open and hidden charm mesons have been measured with much better precision, confirming that charm quarks participate in the collective dynamic expansion with the medium. In p--Pb collisions the absence of jet quenching correlated with high event activity has been confirm…
Highly energetic jets and photons are complementary probes for the kinematics and the topology of nuclear collisions. Jets are collimated sprays of charged and neutral particles, which are produced in the fragmentation of hard scattered partons in an early stage of the collision. While traversing the medium formed in nuclear collisions, they lose energy and therefore carry information about the interaction of partons with the medium. The jet substructure is particularly interesting to learn about in-medium modification of the jets and several observables exists to probe it. In contrast to jets…
Highly energetic jets are sensitive probes for the kinematics and the topology of nuclear collisions. Jets are collimated sprays of charged and neutral particles, which are produced in the fragmentation of hard scattered partons in the early stage of the collision. The measurement of nuclear modification of charged jet spectra in p-Pb collisions provides an important way of quantifying the effects of cold nuclear matter in the initial state on jet production, fragmentation, and hadronization. Unlike in Pb-Pb collisions, modifications of jet production due to hot nuclear matter effects are not …
In these proceedings, we report on recent results related to vector boson-tagged jet production in heavy ion collisions and the related modification of jet substructure, such as jet shapes and jet momentum sharing distributions. $Z^0$-tagging and $γ$-tagging of jets provides new opportunities to study parton shower formation and propagation in the quark-gluon plasma and has been argued to provide tight constrains on the energy loss of reconstructed jets. We present theoretical predictions for isolated photon-tagged and electroweak boson-tagged jet production in Pb+Pb collisions at $\sqrt{s_{NN…
Highly energetic jets are sensitive probes for the kinematics and the topology of nuclear collisions. Jets are collimated sprays of charged and neutral particles, which are produced in the fragmentation of hard scattered partons in an early stage of the collision. The measurement of jet spectra in p-Pb collisions provides an important way of quantifying the effects of cold nuclear matter in the initial state on jet production, fragmentation, and hadronization. Unlike in Pb-Pb collisions, strong hot nuclear matter effects - e.g. from quark-gluon plasma formation - are not expected to occur in p…
Highly energetic jets are sensitive probes for the kinematics and the topology of nuclear collisions. Jets are produced in an early stage of the collision from hard-scattered partons, which fragment into a spray of charged and neutral particles. The measurement of jet spectra in p-Pb collisions provides an important way to quantify the effects of cold nuclear matter on jet production, fragmentation and hadronization. This is possible because the hot, dense medium produced in Pb-Pb collisions is not expected to form. Proton-Lead collisions also provide an important constraint for the nuclear pa…
Measurements of the suppression of high-pT particles and the away-side jets from heavy-ion collisions at RHIC have shown that medium-induced energy loss affects partons produced in the early stage of a heavy-ion collision. At LHC energies the initial production cross-section is much higher, which allows jets to be reconstructed with a wide kinematic range. Measuring fully reconstructed jets by taking advantage of the ALICE Electromagnetic Calorimeter allows for a more differential investigation of the parton energy loss. Parton energy loss will allow us to access key observables of the hot, de…
Measurements of high-pT particle production in heavy-ion collisions at RHIC have shown that medium-induced energy loss affects the partons produced in the early stage of a heavy-ion col- lision. The increased initial production cross section for partons at LHC energies makes fully reconstructed jets available in a wide kinematic range, which allows for a more differential in- vestigation of parton energy loss. Partonic energy loss allows us to access key observables of the hot deconfined nuclear matter produced in heavy-ion collisions. The inclusive cross-section of reconstructed jets using th…
The large center-of-mass energies available to the heavy-ion program at the LHC and recent experimental advances at RHIC will enable QCD matter at very high temperatures and energy densities, that is, the quark-gluon plasma (QGP), to be probed in unprecedented ways. Fully-reconstructed inclusive jets and the away-side hadron showers associated with electroweak bosons, that is, tagged jets, are among these exciting new probes. Full jet reconstruction provides an experimental window into the mechanisms of quark and gluon dynamics in the QGP which is not accessible via leading particles and leadi…
We report on the first measurement of the charged hadron composition in charged jets from pp collisions. The ALICE detector at the LHC was used to study charged pion, kaon and (anti-)proton production in jets. The results were extracted from $2 \times 10^8$ minimum bias events at a centre-of-mass energy of $\sqrt{s} = 7$ TeV. We present the transverse momentum ($p_{\mathrm{T}}$) spectra and reduced momentum spectra ($z^{\mathrm{ch}} \equiv p_{\mathrm{T}}^{\mathrm{track}} / p_{\mathrm{T, jet}}^{\mathrm{ch}}$) of $π$, K and p in charged jets with $p_{\mathrm{T, jet}}^{\mathrm{ch}}$ between 5 and…
We report the first measurement of charged pion, kaon and (anti-)proton production in jets from hadron colliders. The measurement was carried out with the ALICE detector using $2\times10^8$ minimum bias pp collisions at a centre-of-mass energy of $\sqrt{s}=7$ TeV at the LHC. We present the $π$, K and p transverse momentum ($p_\textrm{T}$) spectra, as well as the spectra of the reduced momentum (${z^\textrm{ch}\equiv p_\textrm{T}^\textrm{track}/p_\textrm{T, jet}^\textrm{ch}}$), in charged jets of $p_\textrm{T}$ between 5--20 $\textrm{GeV}/c$. The measurement is compared to Monte Carlo calculati…
Measurements of spectra of identified particles produced in jets represent an important tool for understanding the interplay of various hadronisation mechanisms which contribute to particle production in the hot and dense medium created in ultra-relativistic heavy-ion collisions. In this contribution, we present the measurements of the pT spectra of Λ baryons and K0S mesons produced in charged jets in Pb--Pb collisions at sqrt(sNN) = 2.76 TeV and in p--Pb collisions at sqrt(sNN) = 5.02 TeV. The results are obtained with the ALICE detector at the LHC, exploiting the excellent particle identific…
Tagged jet measurements in high energy hadronic and nuclear reactions provide constraints on the energy and parton flavor origin of the parton shower that recoils against the tagging particle. Such additional insight can be especially beneficial in illuminating the mechanisms of heavy flavor production in proton-proton collisions at the LHC and their modification in the heavy ion environment, which are not fully understood. With this motivation, we present theoretical results for isolated-photon-tagged and B-meson-tagged b-jet production at center-of-mass energy 5.1 TeV for comparison to the u…
Jets are generated in hard interactions in high-energy nuclear collisions. Jets propagate through the quark-gluon plasma (QGP) as the jet shower evolves; their interaction with the QGP, known as jet quenching, generates observable phenomena that provide incisive probes of the structure and dynamics of the QGP. For instance, medium-induced modification of jet substructure probes color coherence, and may be sensitive to differences in quark and gluon energy loss due to their different Casimir factors. Jet grooming can be used to focus on specific regions of phase space, isolating medium-induced …
We study the production of ${\rm K}_{\rm S}^{0}$ mesons and $Λ$ baryons in jets in p--Pb collisions at $\sqrt{s_{\rm NN}}=5.02$ TeV with ALICE at the LHC. The $p_{\rm T}$-differential density of the particles produced in jets is compared to the inclusive distributions and the $Λ/{\rm K}_{\rm S}^{0}$ ratio is reported in bins of multiplicity of the collisions. The hard scatterings are selected on an event-by-event basis using the anti-$k_{\rm T}$ clustering algorithm with resolution parameter $R=0.2,~0.3$ and $0.4$, reconstructed from charged particles with a minimum $p_{\rm T,jet}$ of $10$ (or…
Recent experimental advances at the Relativistic Heavy Ion Collider (RHIC) and the large center-of-mass energies available to the heavy-ion program at the Large Hadron Collider (LHC) will enable strongly interacting matter at high temperatures and densities, that is, the quark-gluon plasma (QGP), to be probed in unprecedented ways. Among these exciting new probes are fully-reconstructed inclusive jets and the away-side hadron showers associated with a weakly or electromagnetically interacting boson, or, tagged jets. Full jet reconstruction provides an experimental window into the mechanisms of…
Jets correlated with isolated photons are a promising channel to study jet quenching in heavy-ion collisions, as photons do not interact strongly and therefore constrain the $Q^2$ of the initial hard scattering. We present the isolated photon-jet correlations measured in Pb--Pb collisions at $\sqrt{s_{\text{NN}}}$ = 5.02 TeV by the ALICE collaboration. We study correlations of isolated photons above 20 GeV/$c$ with charged-particle jets above 10 GeV/$c$, reconstructed with the anti-$k_\text{T}$ algorithm. The correlations probe the lowest jet $p_\text{T}$ range ever measured at LHC energies, a…
We overview recent jet measurements in pp and Pb-Pb collisions with the ALICE detector. ALICE reconstructs jets at midrapidity using the anti-$k_{\mathrm{T}}$ algorithm, including both charged particle jets from the ALICE tracking detectors, and full jets from the combination of the ALICE electromagnetic calorimeter with the tracking system. We focus on inclusive and semi-inclusive jet measurements as well as jet substructure measurements, including a variety of groomed and ungroomed observables. In pp collisions, these results test pQCD techniques at $p_{\mathrm{T,\;jet}}<140$ GeV$/c$ in a lo…
The production of charm jets in proton-proton collisions at a center-of-mass energy of $\sqrt{s}=7$ TeV was measured with the ALICE detector at the CERN Large Hadron Collider. The measurement is based on a data sample corresponding to a total integrated luminosity of $6.23$ ${\rm nb}^{-1}$, collected using a minimum-bias trigger. Charm jets are identified by the presence of a D$^0$ meson among their constituents. The D$^0$ mesons are reconstructed from their hadronic decay D$^0\rightarrow$K$^{-}π^{+}$. The D$^0$-meson tagged jets are reconstructed using tracks of charged particles (track-based…
Jet reconstruction in heavy-ion collisions is strongly affected by soft background from the underlying event. For an appropriate interpretation of the jet observables it is essential to understand the influence of the background and its fluctuations on the reconstructed jets. With this purpose we study random cones and the response of a known probe embedded in a heavy-ion events. The embedded probe can be a single high-p_T track or a jet from a simulated or real pp event. This allows a detailed study of background fluctuations and verification of the performance of background subtraction metho…
Full jet reconstruction in ALICE uses the combined information from charged and neutral particles. Essentially all jet constituents can be measured with large efficiency down to very low transverse momenta (pT > 150 MeV/c). This has the advantage to introduce a minimum bias on the jet fragmentation, in particular for low jet momenta and in the presence of quenching. In this article, we present preliminary results from reconstruction of charged jets in Pb-Pb collisions at sqrt(s_NN) = 2.76 TeV. The inclusive charged jet spectrum, the jet nuclear modification factors (R_AA, R_CP), the ratio of s…
Electroweak bosons produced in conjunction with jets in high-energy collider experiments is one of the principle final-state channels that can be used to test the accuracy of perturbative Quantum Chromodynamics calculations and to assess the potential to uncover new physics through comparison between data and theory. In this paper we present results for the $Z^0/γ^*$+jet production cross sections at the LHC at leading and next-to-leading orders. In proton-proton reactions we elucidate up to ${\cal O}(G_Fα_s^2)$ the constraints that jet tagging via the $Z^0/γ^*$ decay dileptons provides on the …
Studies of jet production can provide information about the properties of the hot and dense strongly interacting matter created in ultra-relativistic heavy-ion collisions. Specifically, measurement of strange particles in jets may clarify the role of fragmentation processes in the anomalous baryon to meson ratio at intermediate particle pT that was observed in PbPb and, to a lesser extent, in pPb collisions. In this contribution, measurements of the pT spectra of Lambda and Antilambda baryons and K0s mesons produced in association with charged jets in PbPb collisions at sqrt(sNN)=2.76 TeV and …
The effect of recoils on soft-drop-groomed observables in $γ$-tagged jets in a multistage approach
Akita International University（秋田国际大学）；Duke University（杜克大学）；Wayne State University（韦恩州立大学）；Lawrence Livermore National Laboratory（劳伦斯利弗莫尔国家实验室）；Vanderbilt University（范德堡大学）；Massachusetts Institute of Technology（麻省理工学院）；McGill University（麦吉尔大学）；University of California, Berkeley（加州大学伯克利分校）；Lawrence Berkeley National Laboratory（劳伦斯伯克利国家实验室）
We report a measurement of transverse momentum spectra of jets detected with the ALICE detector in Pb-Pb collisions at sqrt(sNN)=2.76 TeV. Jets are reconstructed from charged particles using the anti-kt jet algorithm. The background from soft particle production is determined for each event and subtracted. The remaining influence of underlying event fluctuations is quantified by embedding different probes into heavy-ion data. The reconstructed transverse momentum spectrum is corrected for background fluctuations by unfolding. We compare the inclusive jet spectra reconstructed with R=0.2 and R=…
Highly energetic jets are sensitive probes for the kinematic properties and the topology of high energy hadron collisions. Jets are collimated sprays of charged and neutral particles, which are produced in fragmentation of hard scattered partons from an early stage of the collision. In ALICE, jets have been measured in pp, p-Pb, and Pb-Pb collisions at several collision energies. While analyses of Pb-Pb events unveil properties of the hot and dense medium formed in heavy-ion collisions, pp and p-Pb collisions can shed light on hadronization and cold nuclear matter effects in jet production. Ad…
We report results on jet production in pp and Pb-Pb collisions at the LHC from the ALICE collaboration. The jet cross section in pp collisions at $\sqrt{s}$=2.76 TeV is presented, as well as the charged particle jet production cross section and measurements of the jet fragmentation and jet shape in pp collisions at $\sqrt{s}$=7 TeV. NLO pQCD calculations and simulations from MC event generators agree well with the data. Measurements of jets with a resolution parameter $R$=0.2 in Pb-Pb collisions at $\sqrt{s}_{NN}$=2.76 TeV show a strong, momentum dependent suppression in central events with re…
The modification of jet shapes in PbPb collisions, relative to those in pp collisions, is studied for jets associated with an isolated photon. The data were collected with the CMS detector at the LHC at a nucleon-nucleon center-of-mass energy of 5.02 TeV. Jet shapes are constructed from charged particles with track transverse momenta ($p_\mathrm{T}$) above 1 GeV/c in annuli around the axes of jets with $p^\mathrm{jet}_\mathrm{T}$ $>$ 30 GeV/c associated with an isolated photon with $p^γ_\mathrm{T}$ $>$ 60 GeV/c. The jet shape distributions are consistent between peripheral PbPb and pp collisio…
We report a measurement of transverse momentum spectra of jets detected with the ALICE detector in Pb-Pb collisions at $\sNN=2.76$ TeV. Jets are reconstructed from charged particles using the anti-\kt jet algorithm. The transverse momentum of tracks is measured down to 150 MeV/$c$ which gives access to the low \pt fragments of the jet. The background from soft particle production is determined for each event and subtracted. The remaining influence of underlying event fluctuations is quantified by embedding different probes into heavy-ion data. The reconstructed transverse momentum spectrum is …
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.
Probing flavor effects in the QCD parton shower using $\mathbf{{\rm D}^0}$-tagged jet angularities in proton$-$proton collisions at $\mathbf{ \sqrt{s} = 5.02}$ TeV
EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH（欧洲核子研究组织）
Reconstruction of jets in high-energy heavy-ion collisions is challenging due to the large and fluctuating background coming from the underlying event. We report results on full jet reconstruction, obtained from data collected in 2011 by the ALICE detector at LHC for Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=2.76~\mathrm{TeV}$. The analysis makes use of the tracking system and the electromagnetic calorimeter. Signal jets, which come from hard scattered partons, are reconstructed using the anti-$k_{\mathrm{T}}$ jet finder algorithm. The average background is subtracted on a jet-by-jet basis t…
We investigate properties of jets in proton-proton collisions using two-particle angular correlations. By choosing an analysis approach based on two-particle angular correlations, also the properties of low-energetic jets can be accessed. Observing the strength of the correlation as a function of the charged particle multiplicity reveals jet fragmentation properties as well as the contribution of jets to the overall charged particle multiplicity. Furthermore, the analysis discloses information on the underlying multiple parton interactions. We present results from proton-proton collisions at t…
The measurement of jets recoiling from a trigger hadron in heavy-ion collisions can be used to understand the properties of the Quark Gluon Plasma. Jet-medium interactions cause jets to lose energy in the medium and may modify the jet structure. Jet deflection towards large angles due to scattering off of quasi-particles in the Quark-Gluon Plasma may also occur, which can be studied through a measurement of the hadron-jet acoplanarity. These phenomena can be studied through the semi-inclusive distribution of track-based jets recoiling from a trigger hadron. This contribution presents the lates…
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…
Charged-particle fragmentation functions for jets azimuthally balanced by a high-transverse-momentum, prompt, isolated photon are measured in $25$ pb$^{-1}$ of $pp$ and $0.49$ nb$^{-1}$ of Pb+Pb collision data at $5.02$ TeV per nucleon pair recorded with the ATLAS detector at the Large Hadron Collider. The measurements are compared to predictions of Monte Carlo generators and to measurements of inclusively selected jets. In $pp$ collisions, a different jet fragmentation function in photon-tagged events from that in inclusive jet events arises from the difference in fragmentation between light …
The production of strange~($K^0_S$, $Λ$) and multi-strange~($Ξ$ and $Ω$) hadrons in jets and underlying events in \pp and \pPb collisions is studied with ALICE at the LHC. Transverse momentum ($p_\rm{T}$) differential density distribution of particles produced in a jet is compared to that of inclusive particle production and that in underlying events. The particle yield ratios of $Λ/K^0_S$ and $Ξ/Λ$ as a function of $p_\rm{T}$ are also investigated in jets and underlying events.The production of the multi-strange hadrons, $Ξ$ and $Ω$, and the corresponding ratio in jets and underlying events a…
I will present physics measurements which are achievable in the ALICE experiment at the LHC through the inclusion of a new electromagnetic calorimeter. I will focus on jet measurements in proton proton and heavy ion collisions. Detailed simulations have been performed on jet reconstruction, jet triggering, heavy flavor jet reconstruction through electron identification, gamma-jet reconstruction and the measurements of identified hadrons and resonances in jets. I will show the physics capabilities which are made possible through the combination of calorimeter information with the other detector…
The ALICE experiment explores the properties of strongly interacting QCD matter at extremely high temperatures created in Pb-Pb collisions at LHC and provides further insight into small-system physics in (high-multiplicity) pp and p-Pb collisions. The ALICE collaboration presented 27 parallel talks, 50 posters, and 1 flash talk at Quark Matter 2015 and covered various topics including collective dynamics, correlations and fluctuations, heavy flavors, quarkonia, jets and high $p_{\rm T}$ hadrons, electromagnetic probes, small system physics, and the upgrade program. This paper highlights some o…
Measurements of fragmentation functions for jets associated with an isolated photon are presented for the first time in pp and PbPb collisions. The analysis uses data collected with the CMS detector at the CERN LHC at a nucleon-nucleon center-of-mass energy of 5.02 TeV. Fragmentation functions are obtained for jets with p$_\mathrm{T}^\text{jet} >$ 30 GeV in events containing an isolated photon with p$_\mathrm{T}^γ>$ 60 GeV, using charged tracks with transverse momentum p$_\mathrm{T}^\text{trk} >$ 1 GeV in a cone around the jet axis. The association with an isolated photon constrains the initia…
High-energy jets offer rich opportunities to study quantum chromodynamics, from investigating the limits of perturbative calculability to constraining the emergent properties of the quark-gluon plasma (QGP). In these proceedings, we present new measurements of the fragmentation properties of jets. We report distributions of the sub-jet momentum fraction $z_r$ measured in pp and Pb-Pb collisions with ALICE at the Large Hadron Collider. These measurements serve as input to test the universality of jet fragmentation in the QGP, and offer a path to elucidate jet quenching effects in the large-$z$ …
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.
The precise reconstruction of jet transverse momenta in heavy-ion collisions is a challenging task. A major obstacle is the large number of uncorrelated (mainly) low-$p_\mathrm{T}$ particles overlaying the jets. Strong region-to-region fluctuations of this background complicate the jet measurement and lead to significant uncertainties. We developed a novel approach to correct jet momenta (or energies) for the underlying background in heavy-ion collisions. The approach allows the measurement of jets down to extremely low transverse momenta and for large resolution $R$ by making use of common Ma…
We present the measurement of charged-particle jet properties in minimum bias p--Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV in ALICE. Jets are reconstructed from charged particles at midrapidity using the anti-$k_{\rm T}$ jet finding algorithm with jet resolution parameter $R$ = 0.4. The mean charged particle multiplicity and jet fragmentation function for leading charged-particle jets in the $p_{\rm T}$ interval 10 $< p_{\rm T, jet}^{\rm ch} <$ 100 GeV/$c$ are measured and compared with theoretical model predictions.
We present preliminary results of measurements of charged particle jet properties in proton-proton collisions at $\sqrt{s}$ = 7 TeV using the ALICE detector. Jets are reconstructed using $\rm anti-k_{T}, k_{T}$ and SISCone jet finding algorithms with resolution parameter $R=0.4$ in the range of transverse momentum from 20 to 100 GeV/$c$ in the midrapidity region ($\midη\mid\textless$ 0.5). The uncorrected charged jet spectra obtained using the three different jet finders show good agreement. The data are compared to predictions from PYTHIA-Perugia0, PYTHIA-Perugia2011, and PHOJET. The mean cha…
