Yuri Kharlov
The inclusive spectrum of π^0 production has been measured in pp collisions at \sqrt{s} = 900 GeV and 7 TeV with the ALICE experiment. The preliminary results of these measurements are presented, and perspectives for π^0 measurements with heavy ions are discussed.
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ALICE (A Large Ion Collider Experiment) at the LHC is designed for studies of nuclear matter at extreme temperatures and energy densities, so called Quark-Gluon Plasma (QGP). Two detectors for measurements of electromagnetic signals, high-granularity photon spectrometer PHOS and large acceptance electromagnetic calorimeter EMCal/DCal, are incorporated into the ALICE apparatus. In order to enhance the data sample of the high-energy part of the spectra, a dedicated triggers on high energetic photons or jets are used. High precision measurements of neutral mesons require fine energy and timing ca…
The performance of prototypes for the ALICE electromagnetic sampling calorimeter has been studied in test beam measurements at FNAL and CERN. A $4\times4$ array of final design modules showed an energy resolution of about 11% /$\sqrt{E(\mathrm{GeV})}$ $\oplus$ 1.7 % with a uniformity of the response to electrons of 1% and a good linearity in the energy range from 10 to 100 GeV. The electromagnetic shower position resolution was found to be described by 1.5 mm $\oplus$ 5.3 mm /$\sqrt{E \mathrm{(GeV)}}$. For an electron identification efficiency of 90% a hadron rejection factor of $>600$ was obt…
The ALICE experiment at the LHC is equipped with an electromagnetic calorimeter (EMCal) designed to enhance its capabilities for jet measurement. In addition, the EMCal enables triggering on high energy jets. Based on the previous development made for the Photon Spectrometer (PHOS) level-0 trigger, a specific electronic upgrade was designed in order to allow fast triggering on high energy jets (level-1). This development was made possible by using the latest generation of FPGAs which can deal with the instantaneous incoming data rate of 26 Gbit/s and process it in less than 4 μs.
A forward electromagnetic calorimeter (FoCal) based on SiW technology is being considered as a possible upgrade to the ALICE detector. This device should in particular feature an extremely high granularity allowing gamma/pi0 discrimination out to very high momenta. The main option considered for the high granularity layers is the use of CMOS pixel sensors. We will discuss the motivation and design principles of the proposed calorimeter and will then focus on the experience gained with a full CMOS-pixel calorimeter prototype. Preliminary results of this device show very good capabilities for sh…
ALICE measures the J/psi production at mid-rapidity (|y| < 0.9) in the di-electron decay channel as well as at forward rapidity (2.5 < y < 4.0) in the di-muon decay channel. In both channels the acceptance goes down to zero transverse momentum. We present the rapidity dependence of the inclusive J/psi production cross-section and transverse momentum spectra.
The ALICE experiment at LHC studies the strong interaction sector of the Standard Model with pp, pA and AA collisions. Within the scope of the physics program, measurements of photons, neutral mesons and jets in ALICE are performed by two electromagnetic calorimeters. Precise and high-granularity photon spectrometer (PHOS) composed of lead-tungstate crystals, along with a wide-aperture lead-scintillator sampling calorimeter (EMCal) provide complementary measurements of photon observables in a wide kinematic range. The calorimeter trigger system allows the experiment to utilize efficiently the …
ALICE FoCal overview
本文概述了 ALICE 前向量热器 FoCal 的物理目标、探测器结构及性能，旨在通过测量前向区域胶子密度探索非线性 QCD 演化。
Performance of the ALICE Electromagnetic Calorimeter
本文评估ALICE电磁量能器在2010–2018年LHC运行中的性能，系统阐述其校准、修正、重建与验证方法，并利用测试束流和13 TeV质子-质子碰撞数据验证其对光子、轻介子、电子和喷注的测量能力。
Physics program and performance of the ALICE Forward Calorimeter upgrade (FoCal)
本研究介绍ALICE实验升级用高粒度前向量能器FoCal的物理计划与性能，该探测器由电磁和强子量能器组成，可拓展低x区胶子分布等非线性QCD研究，原型测试与模拟验证了其设计可靠性与物理潜力。
The ALICE (A Large Ion Collider Experiment) detector yields a huge sample of data from different sub-detectors. On-line data processing is applied to select and reduce the volume of the stored data. ALICE applies a multi-level hardware trigger scheme where fast detectors are used to feed a three-level (L0, L1, and L2) deep chain. The High-Level Trigger (HLT) is a fourth filtering stage sitting logically between the L2 trigger and the data acquisition event building. The EMCal detector comprises a large area electromagnetic calorimeter that extends the momentum measurement of photons and neutra…
Machine Learning methods for simulating particle response in the Zero Degree Calorimeter at the ALICE experiment, CERN
针对LHC升级后中子零度量热器模拟计算负担重的问题，提出利用神经网络分类器和生成模型（含改进的GAN）直接模拟响应，速度提升两个数量级且保持高保真度。
The ALICE experiment is equipped with electromagnetic calorimeters of two different types: PHOS, the lead-tungstate photon spectrometer, and EMCAL, the sampling lead-scintillator calorimeter. These two detectors measure photon spectra in a wide kinematic range and allow the reconstruction of neutral mesons decaying into photons. The measurement of the inclusive spectra of neutral meson production in pp collisions will not only provide a test of perturbative QCD but also important reference data for future heavy-ion measurements. The status of the analysis of the data accumulated during the LHC…
We present multiplicity and pseudorapidity distributions of inclusive photons at forward rapidity in proton-lead (p-Pb) collisions at $\sqrt{s\rm_{NN}}$ = 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.
Fine-tuned Normalizing Flows for ALICE Zero Degree Calorimeter Fast Simulation
针对LHC上ALICE零度数量计模拟成本高的问题，提出结合归一化流、条件微调及物理驱动评估的框架，引入精细指标，其模型集成体在Wasserstein距离上优于基线。
A selection of recent jet measurements are presented from the ALICE experiment at the CERN LHC in proton-proton collisions at $\sqrt{s}=13$ TeV, focusing on substructure results for inclusive and charmed jets. The groomed jet momentum fractions ($z_g$) of inclusive full jets are shown for various jet resolution parameters, and $z_g$, the groomed splitting radius ($θ_g$) as well as the number of soft drops ($n_{\rm SD}$) of inclusive and charmed charged-particle jets are compared. The first direct measurement of the dead cone in heavy-flavor jets is also presented. Furthermore, the parallel mom…
We report measurement of the semi-inclusive distribution of charged-particle jets recoiling from a high transverse momentum ($p_{\rm T}$) hadron trigger, for p-Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV, in p-Pb events classified by event activity. This observable has been measured in pp and Pb-Pb collisions at the LHC, providing a new probe to measure quenching. Jets are reconstructed from charged particle tracks using anti-$k_{\rm t}$ with $R = 0.4$ and low IR cutoff of jet constituents ($p_{\rm T,track} > 0.15$ GeV/$c$). The complex uncorrelated jet background is corrected by a data-dr…
We report on the performance studies of two correction methods, namely the efficiency-purity method and the Bayesian unfolding method applied to the pseudorapidity distribution of photons. The pseudorapidity distribution of inclusive photons at forward rapidities in the range \mbox{\small $(2.3<η<3.9)$} in p\textendash Pb collisions at $\sqrt{\it{s}_{\rm{NN}}} = 8.16$ TeV is obtained with the HIJING Monte Carlo event generator. The simulated data samples were obtained from the Photon Multiplicity Detector (PMD) in ALICE.
Studying p-Pb collisions at LHC energies allows a quantitative evaluation of the cold nuclear matter (CNM) effects. Event activity dependence of the J/ψ production is under intense studies both theoretically and experimentally and is expected to provide important insights on the influence of CNM. This paper presents the first results on event activity dependence of the inclusive J/ψ production at backward (-4.46 < $y_{cms}$ < -2.96) and forward (2.03 < $y_{cms}$ < 3.53) rapidity in ALICE for p-Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV.
Deep inelastic inclusive and diffractive scattering at $Q^2$ values from 25 to 320 GeV$^2$ with the ZEUS forward plug calorimeter
在HERA用ZEUS探测器研究了深度非弹性散射及其衍射分量$ep \to e^{\prime}γ^* p \to e^{\prime}XN$，使用的积分光度为52.4 pb $ep \to e^{\prime}γ^* p \to e^{\prime}XN$。$M_X$方法已被用来提取衍射贡献。覆盖了质心能量$W$（37 - 245 GeV）、光子虚$Q^2$（20 - 450 GeV $^2$）和质量$M_X$（0.28 - 35 GeV）的宽范围。$2 < M_X < 15$ GeV的衍射截面随着$W$的增大而增大，随着$Q^2$的增大，衍射截面的增大幅度更大.的数据也提出了在衍射结构函数，$F^{\rm D(3)}_2$，质子。对于固定的$Q^2$和固定的$M_X$，$\xpom F^{\rm D(3)}_2$显示出与$\xpom \to 0$一样的强烈上升，其中$\xpom$是坡密子携带的质子动量的分数。对于Bjorken- $x < 1 \cdot 10^{-3}$，$\xpom F^{\rm D(3)}_2$显示正的$\log Q^2$比例违反，而对于$x \ge 5 \cdot 10^{-3}$，观察到负的比例违反。衍射结构的功能与超前扭转是相容的。数据表明，Regge因子分解被破坏了。
Study of deep inelastic inclusive and diffractive scattering with the ZEUS forward plug calorimeter
HERA使用ZEUS探测器研究了深度非弹性散射及其衍射分量ep -> e 'gamma *p -> e' XN，其积分亮度为4.2 pb-1。测量范围很广，伽马 *p c.m.。能量W（37 - 245 GeV），光子虚度Q2（2.2 - 80 GeV 2）和质量Mx。衍射截面Mx > 2 GeV的强烈上升与W，上升是陡峭的增加Q2。后者的观察排除了衍射深非弹性散射的描述，在一个单一的坡密子的交换。衍射截面与总截面之比是W的函数，这与Regge现象学结合对伽马 *p散射的光学定理的天真扩展的预期相矛盾。高于8 GeV的Mx，该比率与Q2是平坦的，表明衍射截面的主导扭转行为。这些数据也以质子的衍射结构函数F2 D（3）（beta，xpom，Q2）的形式给出。对于固定的beta，xpom F2 D（3）的Q2依赖性随着xpom而改变，违反了Regge因子分解。对于固定的xpom，xpom F2 D（3）随着β-> 0而上升，上升随着Q2的增加而加速。这些积极的标度违规表明衍射DIS截面中的扰动效应的实质性贡献。
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…
In order to disentangle CNM effects from the ``hot'' QGP effects, quarkonium production is studied in p--Pb collisions in which QGP formation is not expected. ALICE has measured the $Υ$ production in p--Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV at backward ($-$4.46 $<y_{\rm cms}<$ $-$2.96) and forward (2.03 $< y_{\rm cms}<$ 3.53) rapidity down to zero transverse momentum. At forward rapidity, a suppression of $Υ$(1S) production in p--Pb collisions is observed compared to the binary-scaled yield in pp collisions in the same kinematic domain while at backward rapidity no significant suppre…
ALICE Upgrades
本文介绍ALICE在LHC Run 4及以后的探测器升级：FoCal与新型内层像素径迹层支持低x胶子、重味和双电子测量，ALICE 3则面向QGP重味探针、热辐射及手征对称性恢复研究。
The ALICE Collaboration has studied inclusive J/$ψ$ and $ψ$(2S) production in p-Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV with the Muon Spectrometer. The measurement was performed at forward (2.03 $<$ $y_{\rm cms}$ $<$ 3.53) and backward ($-$4.46 $<$ $y_{\rm cms}$ $<$ $-$2.96) centre of mass rapidities. The nuclear modification factor of J/$ψ$ and $ψ$(2S) has been measured as a function of transverse momentum and event activity. Theoretical models based on nuclear shadowing, coherent energy loss or both are in reasonable agreement with the J/$ψ$ results but cannot describe the $ψ$(2S) be…
We report a measurement of high-p_T inclusive pi^0, eta, and direct photon production in p+p and d+Au collisions at sqrt(s_NN) = 200 GeV at midrapidity (0 < eta < 1). Photons from the decay pi^0 -> gamma gamma were detected in the Barrel Electromagnetic Calorimeter of the STAR experiment at the Relativistic Heavy Ion Collider. The eta -> gamma gamma decay was also observed and constituted the first eta measurement by STAR. The first direct photon cross section measurement by STAR is also presented, the signal was extracted statistically by subtracting the pi^0, eta, and omega(782) decay backgr…
The ALICE collaboration at the LHC has measured the transverse momentum spectra of neutral pions via their two photon decay in pp and Pb$-$Pb collisions at $\sqrt{s_{NN}}=2.76$ TeV over a broad transverse momentum range with different subsystems: with the electromagnetic calorimeters PHOS and EMCAL and with photon conversions in the inner material of the detectors using $e^{+}e^{-}$ pairs reconstructed with the Central Tracking System. In this report, neutral pions production is compared between pp and Pb$-$Pb collisions measured with conversion photons in terms of the nuclear modification fac…
Jet reconstruction and jet fragmentation variables provide important information to study the interaction between hard scattered partons and the Quark-Gluon Plasma. This paper presents the measurement of the inclusive cross section for fully reconstructed jets in pp collisions at sqrt(s) = 2.76 TeV, which provides an essential reference for jet measurements in Pb-Pb collisions at the same sqrt(s_NN). In addition, we report jet fragmentation measurements for charged particle jets in pp collisions at sqrt(s) = 7 TeV. These measurements utilize the ALICE central barrel tracking system to detect c…
We report on the inclusive J/psi nuclear modification factor in p-Pb collisions at sqrt(s_NN) = 5.02 TeV as a function of rapidity y and transverse momentum p_T. The experimental coverage extends down to p_T = 0 GeV/c in the three rapidity ranges accessible by ALICE (-4.46 < y_cms < -2.96, -1.37 < y_cms < 0.46, 2.03 < y_cms < 3.53). The obtained results as a function of rapidity are in agreement with theory predictions based only on shadowing or on coherent energy loss. At forward and backward rapidity, the psi(2S) measurement complements the J/psi results. The ratio between the psi(2S) and J/…
Expected performance of the ALPIDE pixel layers in ALICE FoCal
本文介绍了ALICE FoCal-E的预期性能，提出并验证了反向偏置、网格掩蔽和区域触发等策略，有效缓解像素层占用率与BUSY违规，提升高亮度下探测器性能。
We report recent ALICE results on primary charged particle and neutral meson production in pp, p--Pb, Pb--Pb and Xe--Xe collisions at LHC energies. In this article, measurements of the nuclear modification factors $R_{\rm AA}$ of primary charged particles and of light neutral mesons in Pb--Pb, in Xe--Xe and in p--Pb collisions in a wide $p_{\rm T}$ range and different centrality classes are discussed. We compare the nuclear modification factors obtained for different collision systems as a function of transverse momentum, collision centrality as well as charged particle multiplicity (${\rm d}N…
The low-x gluon density in the proton and, in particular, in nuclei is only very poorly constrained, while a better understanding of the low-x structure is crucial for measurements at the LHC and also for the planning of experiments at future hadron colliders. In addition, deviations from linear QCD evolution are expected to appear at low x, potentially leading to gluon saturation and a universal state of hadronic matter, the color-glass condensate. However, these effects have not been unambiguously proven to date. Fortunately, data from the LHC can be used directly to provide better constrain…
The relative rates of single- and double- diffractive processes were measured with the ALICE detector by studying properties of gaps in the pseudorapidity distribution of particles produced in proton-proton collisions at $\sqrt{s}$ = 0.9 TeV, 2.76 TeV and 7 TeV. ALICE triggering efficiencies are determined for various classes of events, using a detector simulation validated with data on inclusive particle production. Cross-sections are determined using van der Meer scans to measure beam properties and obtain a measurement of the luminosity.
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…
CASTOR: The ALICE forward detector for identification of Centauros and Strangelets in Nucleus-Nucleus Collisions at the LHC
讨论了欧洲核子研究中心（CERN）大型强子对撞机（LHC）ALICE重离子实验中采用超前向探测器的物理动机。提出了一个描述核-核碰撞中半人马座火球形成和衰变的唯象模型。本文描述了CASTOR探测器，它的目的是测量相互作用的强子和光子含量，并以逐事件模式识别非常向前的、富含重子的相空间5.6 < eta < 7.2中的深穿透物体。的量热计的预期响应的模拟结果，特别是奇异的通道，提出。
A measurement of the cross section for the inclusive production of isolated prompt photons in proton-proton collisions at a centre-of-mass energy of $\sqrt{s} = 8$ TeV is presented. The measurement covers the pseudo rapidity ranges $|η^γ| < 1.37$ and $1.56 \leq |η^γ| < 2.37$ in the transverse energy range $25 < E_{\rm T}^γ < 1500$ GeV. The results are based on an integrated luminosity of 20.2 fb$^{-1}$, recorded by the ATLAS detector at the LHC. Photon candidates are identified by combining information from the calorimeters and the inner tracker. The background is subtracted using a data-drive…
Charmonia, bound states of charm and anti-charm quarks, represent an interesting probe for the study of Quantum Chromodynamics (QCD) since their production involves both hard and soft energy scales. Several effective models are available to describe the production of charmonia, but so far none have been able to describe all experimental observables simultaneously. ALICE has studied the production of charmonia in different collision systems at all available LHC energies at both mid- and forward-rapidity down to zero transverse momentum. In this contribution, different measurements performed in …
The ALICE Collaboration studies the production of J/psi meson in pp collisions at the center-of-mass energies of 2.76 and 7 TeV at mid- and forward-rapidity. Inclusive production cross-sections are presented as a function of the collision energy, rapidity and transverse-momentum. The J/psi polarization measurements in the helicity and Collins-Soper frames are discussed. A novel result on the correlation between the collision charged particle multiplicity and J/psi yield is also shown.
Measurement of the Inclusive Isolated Photon Cross Section at CDF
我们目前的初步结果包括直接光子生产$p\bar{p}$碰撞在$\sqrt{s}$ =1.96 TeV，使用升级后的对撞机探测器在费米实验室在运行II收集的数据，对应于451铅$^{-1}$的积分亮度。测量作为光子横向动量的函数与$p_{T}>$ 30 GeV和$|η|<$ 1.0的光子。光子需要在量热计中被隔离。测量被校正到强子水平，并与NLO pQCD预测进行比较。
The ALICE Collaboration completed the upgrade of the detector and is now commissioning for the beginning of the data taking during LHC Run 3. In parallel, R&D activities and simulation studies are being performed to define the future of the experiment beyond LHC Run 3. Two detector upgrades are foreseen for the next long shutdown (LS3). The first is the replacement of the three layers of the inner tracking system closest to the beam with a novel vertex detector consisting of curved wafer-scale ultra-thin silicon sensors arranged in perfectly cylindrical layers to improve impact parameter resol…
The production of direct photons, not coming from hadron decays, at large transverse momentum pT > 2 GeV/c in proton-proton collisions at the LHC, is an interesting process to test the predictions of perturbative Quantum Chromodynamics at the highest energies ever and to put constraints on the gluon density in the proton. Furthermore, they provide a baseline reference for quark-gluon-plasma studies in Pb-Pb collisions. We will present the experimental capabilities of the ALICE electromagnetic calorimeter EMCal to reconstruct the direct and isolated photon spectra in p-p and Pb-Pb collisions.
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.
Quarkonia states are expected to provide essential information on the properties of the high-density strongly-interacting system formed in the early stages of high-energy heavy-ion collisions. ALICE is the LHC experiment dedicated to the study of nucleus-nucleus collisions and can study charmonia at forward rapidity (2.5 < y < 4) via the mu+ mu- decay channel and at mid rapidity (|y| < 0.9) via the e+ e- decay channel. In both cases charmonia are measured down to zero transverse momentum. The inclusive J/psi production as a function of transverse momentum and rapidity in pp collisions at sqrt{…
Charmonium is a prominent probe of the Quark-Gluon Plasma (QGP), expected to be formed in ultrarelativistic heavy-ion (A-A) collisions. It has been predicted that the J/psi(c-cbar) particle is dissolved in the deconfined medium created in A-A systems. However this suppression can be counterbalanced via regeneration of the charm/anti-charm bound state in QGP or via statistical production at the phase boundary. At LHC energies, the latter mechanisms are expected to play a more important role, due to a charm production cross section significantly larger than at lower energies. Measurements obtain…
We present a state-of-the-art computation for the production of forward dijets in proton-proton and proton-lead collisions at the LHC, in rapidity domains covered by the ATLAS calorimeter and the planned FoCal extension of the ALICE detector. We use the small-x improved TMD (ITMD) formalism, together with collinearly improved TMD gluon distributions and full b-space Sudakov resummation, and discuss nonperturbative corrections due to hadronization and showers using the Pythia event generator. We observe that forward dijets in proton-nucleus collisions at moderately low pT are excellent probes o…
In this new energy regime, quarkonium provides a unique probe to study the properties of the high-density, strongly interacting system formed in the early stages of high-energy heavy-ion collisions. In ALICE, quarkonium states are reconstructed down to p_T=0 via their mu+mu- decay channel in the muon spectrometer (2.5<y<4.0) and via their e+e- channel in the central barrel (|y|<0.9). Measurement of the transverse momentum and rapidity distributions of inclusive J/psi production cross section in proton-proton collisions at sqrt{s}=2.76 and 7 TeV will be presented. We will discuss the dependence…
For Run 4, ALICE is pioneering the construction of truly cylindrical tracking layers, which will improve the measurements of heavy-flavour hadrons and dielectrons. In addition, a Forward Calorimeter (FoCal) for the measurement of direct photons is being developed to access the gluon distributions of nucleons and nuclei at low $x$. For Run 5 and beyond, ALICE 3 is proposed. It combines a unique high-resolution vertex detector with a silicon pixel tracker and modern particle identification solutions over a large acceptance. This will permit heavy-flavour and dielectron measurements with unpreced…
Jets are produced by processes involving high momentum transfer of initial partons at high energies. Comparing jet production in pp and nucleus-nucleus collisions will allow us to study the jet-quenching effect caused by the hot and dense QCD medium produced in nucleus-nucleus collisions when energetic partons traverse the medium. In particular, systematic studies of jet production in different multiplicity environments will provide in-depth understanding of the medium properties and their evolution from small to large systems. In small systems and high multiplicity events, the bulk properties…
We present results from the ALICE experiment on the inclusive J/Psi production in pp collisions at sqrt(s)=2.76 and 7 TeV. The integrated and differential cross sections are evaluated down to pT=0 in two rapidity ranges, |y|<0.9 and 2.5<y<4, in the dielectron and dimuon decay channel respectively. The measurement at sqrt(s)=2.76 TeV, the same energy as Pb-Pb collisions, provides a crucial reference for the study of hot nuclear matter effects on J/Psi production. The J/Psi yield in pp collisions at sqrt(s)=7 TeV has also been studied as a function of the charged particle multiplicity and first …
Among the probes used to investigate the properties of the Quark-Gluon Plasma, the measurement of the energy loss of high-energy partons can be used to put constraints on energy-loss models and to ultimately access medium characteristics, such as the energy density or the temperature. The study of two-particle correlations allows us to obtain very different constraints compared to the nuclear modification factor. In particular, the correlation of charged hadrons with high energy $π^{0}$ or direct photons is believed to give a measurement of the parton energy loss and insights into the medium-i…
The latest results on charm-tagged jets and open-charm production obtained with \mbox{ALICE} at the LHC are presented. The baryon-to-meson ratios for $\mathrm{Λ^+_c}$, $\mathrm{Σ^{0,+,++}_c}$ and $\mathrm{Ξ^{0,+}_c}$ measured in pp collisions at $\sqrt{s}=13\ \mathrm{TeV}$ are discussed. The measurements of the jet-momentum fraction carried by the $\mathrm{D^0}$ meson and $\mathrm{Λ^+_c}$ baryon in pp collisions at $\sqrt{s}=13\ \mathrm{TeV}$ are reported, and the number of leading-parton splittings $n_{SD}$ for $\mathrm{D^0}$-tagged and inclusive jets in pp collisions at $\sqrt{s}=13\ \mathrm…
The ALICE detector at the LHC (A Large Ion Collider Experiment) will carry out comprehensive measurements of high energy nucleus-nucleus collisions, in order to study QCD matter under extreme conditions and the phase transtion between conïned matter and the Quark-Gluon Plasma (QGP). This report presents our current state of understanding of the Physics Performance of the large acceptance Electromagnetic Calorimeter (EMCal) in the ALICE central detector. The EMCal enhances ALICE's capabilities for jet measurements. The EMCal enables triggering and full reconstruction of high energy jets in ALIC…
We present a measurement of the Pi0 transverse momentum spectrum and of the Eta/Pi0 ratio in proton-proton collisions at sqrt(s) = 7 TeV at the CERN LHC. In this analysis the reconstruction of Pi0 and Eta mesons has been done via photon conversions in the central tracking system of ALICE. Therefore, this method is completely independent from the electromagnetic calorimeters. It makes the Pi0 (Eta) measurement possible down to pt = 0.4 (0.6) GeV/c with a very good resolution and a very small background. For 100 Mio. pp collisions the pt reach is 7 GeV/c. The results are compared to NLO pQCD cal…
A forward electromagnetic and hadronic calorimeter (FoCal) was proposed as an upgrade to the ALICE experiment, to be installed during LS3 for data-taking in 2027--2029 at the LHC. The FoCal extends the scope of ALICE, which was designed for the comprehensive study of hot and dense partonic matter, by adding new capabilities to explore the small-$x$ parton structure of nucleons and nuclei. The primary objective of the FoCal is high-precision inclusive measurement of direct photons and jets, as well as coincident gamma-jet and jet-jet measurements, in pp and p--Pb collisions. These measurements …
We report recent results from the ALICE experiment at the LHC for minimum bias pp collisions. This overview includes results on inelastic cross section, with analysis of single and double diffractive events; the study of hadron production mechanisms, both for inclusive and identified particles; Bose-Einstein correlations; and fluctuations in $<p_T>$
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 ($-3.4~<~η~<~5.0$), combining the data from the Silicon Pixel Detector (SPD) and the Forward Multiplicity Detector (FMD). The inclusive photons are measured at forward…
In heavy-ion collisions at the LHC, the ALICE Collaboration is studying Quantum Chromodynamics (QCD) matter at very high energy density where the formation of a Quark Gluon Plasma (QGP) is expected. Quarkonium production is an important probe to characterize the QGP properties. High precision data in pp collisions provide the baseline of Pb-Pb measurements and p-Pb collisions serve to quantify the amount of initial and/or final state effects, related to cold nuclear matter, that are largely unknown at the LHC energy. Since 2010, the LHC provided Pb-Pb collisions at sqrt{s_{NN}} = 2.76 TeV, pp …
The study of jets, collimated sprays of particles associated with hard partons, is an important tool in testing perturbative quantum chromodynamics (pQCD) and probing hot and dense nuclear matter created in high energy heavy-ion collisions. Jets enable the study of hard scatterings, fragmentation and hadronisation and their modification in the presence of a nuclear medium with respect to baseline vacuum measurements, which is acquired from jet measurements in proton-proton collisions. We have analysed data from proton-proton collisions at s= \sqrt{s} = 7 TeV measured by the ALICE experiment at…
Precise measurements and calculations of the internal structure of hadronic jets produced in high energy proton or lead collisions have become a prominent research area in recent years. Jet substructure provides information about quantum chromodynamics (QCD) and plays an important role in the study of the evolution of the quark-gluon plasma. The ALICE experiment is uniquely suited to provide insight into the smallest splitting angles due to high efficiency in the reconstruction of charged particles. In this proceeding, we present an overview of recent ALICE results on jet substructure in pp co…
Measurements of the semi-inclusive distribution of charged jets recoiling from a trigger hadron in pp and Pb--Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV are presented. This technique provides precise, data-driven subtraction of the large uncorrelated background in jet measurements. It uniquely enables the exploration of medium-induced modification of jet production and acoplanarity over wide phase space, including low transverse momentum ($p_\mathrm{T}$) and large resolution parameter ($R$) jets. This proceeding reports the measurements of medium-induced jet energy redistribution thr…
The study of energy and multiplicity dependence of strange hadron production in proton-proton collisions provides a powerful tool to understand similarities and differences between small and large collision systems. In order to better understand the origin of strangeness enhancement in pp new multi-differential analyses have been performed. The first separates the contribution of soft and hard processes, such as jets, to strange hadron production through two-particle correlation techniques. The second exploits the concept of the effective energy available for particle production in the event, …
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