Indian Institute of Technology Indore

About: Indian Institute of Technology Indore is a education organization based out in Indore, Madhya Pradesh, India. It is known for research contribution in the topics: Fading & Support vector machine. The organization has 1606 authors who have published 4803 publications receiving 66500 citations.

Energy dependence and fluctuations of anisotropic flow in Pb-Pb collisions at √sNN = 5.02 and 2.76 TeV

Abstract: Measurements of anisotropic flow coefficients with two- and multi-particle cumulants for inclusive charged particles in Pb-Pb collisions at $ \sqrt{s_{\mathrm{NN}}}=5.02 $ and 2.76 TeV are reported in the pseudorapidity range |η| < 0.8 and transverse momentum 0.2 < p$_{T}$ < 50 GeV/c. The full data sample collected by the ALICE detector in 2015 (2010), corresponding to an integrated luminosity of 12.7 (2.0) μb$^{−1}$ in the centrality range 0-80%, is analysed. Flow coefficients up to the sixth flow harmonic (v$_{6}$) are reported and a detailed comparison among results at the two energies is carried out. The p$_{T}$ dependence of anisotropic flow coefficients and its evolution with respect to centrality and harmonic number n are investigated. An approximate power-law scaling of the form v$_{n}$(p$_{T}$) ∼ p$_{T}^{n}^{/3}$ is observed for all flow harmonics at low p$_{T}$ (0.2 < p$_{T}$ < 3 GeV/c). At the same time, the ratios v$_{n}$/v$_{m}^{n}^{/ }^{m}$ are observed to be essentially independent of p$_{T}$ for most centralities up to about p$_{T}$ = 10 GeV/c. Analysing the differences among higher-order cumulants of elliptic flow (v$_{2}$), which have different sensitivities to flow fluctuations, a measurement of the standardised skewness of the event-by-event v$_{2}$ distribution P(v$_{2}$) is reported and constraints on its higher moments are provided. The Elliptic Power distribution is used to parametrise P(v$_{2}$), extracting its parameters from fits to cumulants. The measurements are compared to different model predictions in order to discriminate among initial-state models and to constrain the temperature dependence of the shear viscosity to entropy-density ratio.

Measurement of charged jet suppression in Pb-Pb collisions at √s NN = 2.76 TeV

Abstract: A measurement of the transverse momentum spectra of jets in Pb-Pb collisions at √sNN = 2.76TeV is reported. Jets are reconstructed from charged particles using the anti-k T jet algorithm with jet resolution parameters R of 0.2 and 0.3 in pseudo-rapidity |η| < 0.5. The transverse momentum p T of charged particles is measured down to 0.15 GeV/c which gives access to the low p T fragments of the jet. Jets found in heavy-ion collisions are corrected event-by-event for average background density and on an inclusive basis (via unfolding) for residual background fluctuations and detector effects. A strong suppression of jet production in central events with respect to peripheral events is observed. The suppression is found to be similar to the suppression of charged hadrons, which suggests that substantial energy is radiated at angles larger than the jet resolution parameter R = 0.3 considered in the analysis. The fragmentation bias introduced by selecting jets with a high p T leading particle, which rejects jets with a soft fragmentation pattern, has a similar effect on the jet yield for central and peripheral events. The ratio of jet spectra with R = 0.2 and R = 0.3 is found to be similar in Pb-Pb and simulated PYTHIA pp events, indicating no strong broadening of the radial jet structure in the reconstructed jets with R < 0.3. [Figure not available: see fulltext.] © 2014 The Author(s).