Bulk Properties of Pb-Pb collisions at sqrt(sNN) = 2.76 TeV measured by ALICE
Alberica Toia
备注：
Proceedings of the XXII International Conference on Ultrarelativistic Nucleus-Nucleus Collisions Quark Matter 2011, submitted to J. Phys. G: Nucl. Part. Phys. 8 pages, 7 (multi)figures
Global variables, such as the charged particle multiplicity and the transverse energy are important observables to characterize Relativistic Heavy Ion collisions and to constrain model calculations. The charged particle multiplicity dNch/deta and transverse energy dET/deta are measured at sqrt(sNN) = 2.76 TeV in Pb-Pb collisions as a function of centrality and in pp collisions. The fraction of inelastic cross section seen by the ALICE detector is calculated either using a Glauber model or the data corrected by simulations of nuclear and electromagnetic processes, or data collected with a minimum bias interaction trigger. The centrality, defined by the number of nucleons participating in the collision, is obtained, via the Glauber model, by relating the multiplicity distributions of various detectors in the ALICE Central Barrel and their correlation with the spectator energy measured by the Zero-Degree Calorimeters. The results are compared to corresponding results obtained at the significantly lower energies of the BNL AGS, the CERN SPS, and the BNL RHIC, and with models based on different mechanisms for particle production in nuclear collisions. Particular emphasis will be given to a discussion on systematic studies of the dependence of the centrality determination on the details of the Glauber model, and the validity of the Glauber model at unprecedented collision energies.
Measurement of the nuclear modification factor of electrons from heavy-flavour hadron decays in Pb-Pb collisions at {\surd}sNN = 2.76 TeV with ALICE at the LHC
Measurements of the nuclear modification factor and elliptic flow of leptons from heavy-flavour hadron decays in Pb--Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76 and 5.02 TeV with ALICE
Measurement of the nuclear modification factor of electrons from heavy-flavour decays at mid-rapidity in Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV with ALICE
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…
These proceedings report on measurements of the jet spectrum and nuclear modification factor for inclusive full jets (containing both charged and neutral constituents) in Pb-Pb and pp collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV recorded with the ALICE detector. These measurements use a machine learning based background correction, which reduces residual fluctuations. This method allows for measurements to lower transverse momenta and larger jet resolution parameter (R) than previously possible in ALICE. In this method, machine learning techniques are used to correct the jet transverse momentu…
Inclusive jet spectra in 2.76 TeV collisions from ALICE
在RHIC上对重离子碰撞中高pT粒子产生的测量表明，介质引起的能量损失影响重离子碰撞早期产生的部分子。在LHC能量下，部分子初始产生截面的增加使得完全重构的喷流在很宽的运动学范围内可用，这允许对部分子能量损失进行更多的差分研究。部分子能量损失使我们能够获得在重离子碰撞中产生的热的非限定核物质的关键观测值。利用ALICE跟踪探测器和电磁量能器重建的喷流的包含截面是从2.76 TeV pp运行期间收集的数据中给出的。用于重建喷流和提取它们从铅铅碰撞的波动背景的程序进行了讨论。
We present the analysis of the semi-inclusive distribution of reconstructed charged particle jets recoiling from a high pT hadron trigger in central Pb Pb collisions at $\sqrt{s_{NN}}=2.76$ TeV. We measure, subtract and unfold the large underlying event background in such collisions, utilizing a novel technique that does not impose fragmentation bias on the measured jet population. The Pb Pb measurements are compared to a pp PYTHIA reference distribution generated at the same $\sqrt{s}$. Modification of jet structure due to quenching is explored by varying the cone radius $R$ (0.2, 0.4) and th…
Full Jet Reconstruction in 2.76 TeV pp and Pb-Pb collisions in the ALICE experiment
在RHIC上对重离子碰撞产生的高pT粒子和远离侧喷流的测量表明，介质引起的能量损失影响了重离子碰撞早期产生的部分子。在大型强子对撞机的能量下，初始产生的截面要高得多，这使得喷流可以在很宽的运动学范围内重建。利用ALICE电磁量热计测量完全重构的喷流，可以对部分子能量损失进行更多的微分研究。部分子能量损失将使我们能够获得在重离子碰撞中产生的热的、致密的物质的关键观测值。所呈现的数据是在2.76 TeV Pb-Pb运行期间收集的，以及来自2.76 TeV pp运行的基线测量。将讨论用于重建射流并从波动背景中提取它们的程序。还将讨论在有限接受度下对背景进行定量的程序。这些结果进行了比较，PP的测量和模拟。
ALICE mesurements of heavy-flavour production in pp and p-Pb collisions at the LHC
本文给出了$\sqrt{s}=7$ TeV pp碰撞和$\sqrt{s_{\mathrm{NN}}}=5.02$ TeV p-Pb碰撞中D介子产额与带电粒子多重数的关系。在$\sqrt{s_{\mathrm{NN}}}=5.02$ TeV的p-Pb碰撞中，重味强子衰变的电子产额作为带电粒子多重性的函数的测量也被显示。本文还测量了$\sqrt{s}=7$ TeV pp碰撞和$\sqrt{s_{\mathrm{NN}}}=5.02$ TeV p-Pb碰撞中的瞬发D介子和带电强子的方位角关联。结果与模型的预期进行了比较。
