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Charged particle multiplicity in HI collisions at 2.76 TeV

Introduction

This page describes the histograms approved to show in the 2011 Quark Matter Conference for charged particle multiplicity measurement at 2.76 TeV.

$\Delta \phi$ vs $\Delta \eta$ for all layer-0 and layer-1 pixel clusters pairs
$\Delta \phi$ vs $\Delta \eta$ for all layer-0 and layer-1 pixel cluster pairs for Minbias events. $\Delta \eta$ and $\Delta \phi$ are defined as layer-0 cluster $\eta$ or $\phi$ minus layer-1 cluster $\eta$ or $\phi$ correspondingly. The black line shows the selection criteria for selecting tracklets candidates at $|\eta|=1$. Cluster pairs within the black line are selected as tracklet candidates. The $\eta$ dependent selection criteria is denoted by this formula:$ \Delta {\mathcal R} \equiv \frac{1}{\sqrt{2}} \sqrt{\left(\frac{\Delta \eta}{\sigma_\eta(\eta)}\right)^2 +                       \left(\frac{\Delta \phi}{\sigma_\phi(\eta)}\right)^2} <  3$.
https://twiki.cern.ch/twiki/pub/AtlasPublic/QM2011Multiplicity/a-9.png
APPROVED eps file

Occupancy variable used to match MC to data (|η|<1)
Distribution of occupancy variable $dn_{clus}^{0}/d\eta (|\eta|<1)/2$ for data. This variable is used to match data and MC. This variable divides events into 20 different occupant categories.
https://twiki.cern.ch/twiki/pub/AtlasPublic/QM2011Multiplicity/a-19.png
APPROVED eps file

Comparison of data and Monte Carlo with tracklets $\Delta \eta$ and $\Delta \phi$ distributions
Distribution of tracklets $\Delta \eta$ (left) and $\Delta \phi$ (right) from data (black line) and MC (yellow shaded) with tracklets from two $\eta$ range: $|\eta|<1.0$ (top) and $1<|\eta|<2$ (bottom) for the 0-10$\%$ centrality events. A pT re-weighting procedure was applied to MC samples.
https://twiki.cern.ch/twiki/pub/AtlasPublic/QM2011Multiplicity/paper_detadphi_v1.png
APPROVED eps file

Distribution of tracklets $\Delta \eta$ from data and MC
Distribution of tracklets $\Delta \eta$ from data and MC for the 0-10$\%$ centrality events. Top: data (black) and MC (yellow) overlay together. Bottom: Ratio of MC to data. A pT re-weighting procedure was applied to MC samples.
https://twiki.cern.ch/twiki/pub/AtlasPublic/QM2011Multiplicity/a-1.png
APPROVED eps file

Distribution of tracklets $\Delta \phi$ from data and MC
Distribution of tracklets $\Delta \phi$ from data and MC for the 0-10$\%$ centrality events. Top: data (black) and MC (yellow) overlay together. Bottom: Ratio of MC to data. A pT re-weighting procedure was applied to MC samples.
https://twiki.cern.ch/twiki/pub/AtlasPublic/QM2011Multiplicity/a-10.png
APPROVED eps file

Distribution of pixel tracks $d_{0}$ from data and MC
Distribution of pixel tracks $d_{0}$ from data and MC for the 0-10$\%$ centrality events. Top: data (black) and MC (yellow) overlay together. Bottom: Ratio of MC to data. A pT re-weighting procedure was applied to MC samples.
https://twiki.cern.ch/twiki/pub/AtlasPublic/QM2011Multiplicity/a-0.png
APPROVED eps file

Distribution of pixel tracks $z_{0}\sin(\theta)$ from data and MC
Distribution of pixel tracks $z_{0}\sin(\theta)$ from data and MC for the 0-10$\%$ centrality events. Top: data (black) and MC (yellow) overlay together. Bottom: Ratio of MC to data. A pT re-weighting procedure was applied to MC samples.
https://twiki.cern.ch/twiki/pub/AtlasPublic/QM2011Multiplicity/a-0.png
APPROVED eps file

Number of tracklets from Method 2 vs FCal ET (1<|η|<2)
Number of tracklets from method 2 in $|\eta|<1.0$ normalized by $\eta$ coverage vs the forward calorimeter transverse energy distribution. The red points are from signal events, the black points are from flipped events, and the blue points are signal events subtracted by flipped events.
https://twiki.cern.ch/twiki/pub/AtlasPublic/QM2011Multiplicity/a-7.png
APPROVED eps file

Raw tracklets $\eta$ distribution from Method 1
Raw two-point tracklet $1/N_{evt} dN_{trkl}/d\eta$ distribution in 2.76 TeV Pb+Pb collisions from Method 1 for 8 different centrality selections.
https://twiki.cern.ch/twiki/pub/AtlasPublic/QM2011Multiplicity/a-20.png
APPROVED eps file

Distribution of $dn/d\eta/(N_{part}/2)$ vs $N_{part}$
Distribution of $dn/d\eta/(N_{part}/2)$ vs $N_{part}$. The error bar on each point shows the combined statistical and systematic uncertainty from the $dn/d\eta$ measurement, the shaded band shows the total statisical and systematic uncertainty including the uncertainties on $N_{part}$.
https://twiki.cern.ch/twiki/pub/AtlasPublic/QM2011Multiplicity/a-5.png
APPROVED eps file

Charged particle multiplicity collision energy dependence and $N_{part}$ dependence
Top: Collision energy dependence of $dn/d\eta$ per colliding nucleon pair, $N_{part}$/2, from a variety of measurements in proton-proton and central nuclear nucelar collisions including the 0-6\% reported here for $|\eta|<0.5$ and the previous 0-5$\%$ ALICE measurement (point shifted horizontally for clarity). The curves show different expectations for the collision energy dependence of $dn/d\eta/(N_{part}/2)$ in nuclear nuclear collisions: dotted - results of a Landau hydrodynamics calculation , dashed - a $\sqrt{s}^{0.15}$ extrapolation of RHIC and SPS data proposed by ALICE, dot-dashed - a logarithmic extrapolation of RHIC and SPS data. Bottom: $dn/d\eta/(N_{part}/2)$ evaluated over $|\eta| < 0.5$ vs $N_{part}$ for 2$\%$ centrality intervals over 0-20$\%$ and 5$\%$ centrality intervals over 20-80$\%$. Error bars represent combined statistical and systematic uncertainties on the \dndetamid\ measurement, the shaded band represents the total systematic uncertainty including $N_{part}$ uncertainties. The RHIC measurements have been multiplied by 2.15 to allow comparison with the $\sqrt{s}$ = 2.76 TeV results. }
https://twiki.cern.ch/twiki/pub/AtlasPublic/QM2011Multiplicity/paper_dndetaNpart_v10.png
APPROVED eps file

Distribution of $dn/d\eta/(N_{part}/2)$ vs $N_{part}$
Distribution of $dn/d\eta/(N_{part}/2)$ vs $N_{part}$ from ATLAS (circle points). The error bar on each point shows the combined statistical and systematic uncertainty from the $dn/d\eta$ measurement, the shaded band shows the total statisical and systematic uncertainty including the uncertainties on $N_{part}$. Also shown in the figure are measurement from ALICE (star points), RHIC results averaged over four experiments (square), and PHOBOS results (triangle). RHIC and PHOBOS results are scaled up by a factor of 2.15 to match central ATLAS data.
https://twiki.cern.ch/twiki/pub/AtlasPublic/QM2011Multiplicity/a-6.png
APPROVED eps file

Distribution of $dn/d\eta$ vs $\eta$ compared with CGC calculation
Distribution of $dn/d\eta$ vs $\eta$ from ATLAS (circle points) for 0-6$\% $ centrality interval. Shaded band shows the combined systematic and statistical uncertainties. Also shown is the prediction from CGC calculation [arXiv:1011.3591v1 [hep-ph]] for 0-5$\%$ (line).
https://twiki.cern.ch/twiki/pub/AtlasPublic/QM2011Multiplicity/a-4.png
APPROVED eps file

$dn/d\eta$ vs $\eta$ distribution
Left: Top: raw track/tracklet $1/\Nevt dN_{\mathrm{trkl}}/d\eta$ distribution from tracklet Method 1 ( points), tracklet Method 2 (squares) and pixel tracking (blue triangles) for 0-10$\%$ centrality events. Middle: corrected tracklet and track $dn/d\eta$ distributions (same symbol scheme), bottom: ratio of $dn/d\eta$ from the tracklet Method 2 (squares) and pixel tracking ( triangles) to tracklet Method 1 respectively. Right: Final $dn/d\eta$ distributions from tracklet Method 1 for eight 10$\%$ centrality intervals. Total systematic errors on $1/\Nevt dN_{\mathrm{ch}}/d\eta$ are shown as a shaded band.
https://twiki.cern.ch/twiki/pub/AtlasPublic/QM2011Multiplicity/paper_dndeta_v7.png
APPROVED eps file

$dn/d\eta/(N_{part}/2)$ vs $\eta$
Left: $dn/d\eta/(N_{part}/2)$ measured by ATLAS at $\sqrt{s}=2.76$ TeV compared to similar measurements over $|\eta|<5.4$ by PHOBOS at RHIC for 19.6 and 200 GeV. Right: The same data as in the other figure, but with the PHOBOS data shifted such that one of the projectiles has the LHC Pb+Pb per-nucleon beam rapidity.
https://twiki.cern.ch/twiki/pub/AtlasPublic/QM2011Multiplicity/a-22.png
APPROVED eps file

$dn/d\eta$ vs $\eta$ from three different methods
Distributions of $dn/d\eta$ measured by three different methods: Pixel tracking (trigangle), tracklet Method 1(point) and tracklet Method 2(square). Low panel shows the ratio of pixel tracking and Method2 to Method 1 ratio. This shows for 0-10\% centrality interval.
https://twiki.cern.ch/twiki/pub/AtlasPublic/QM2011Multiplicity/a-11.png
APPROVED eps file

$dn/d\eta$ vs $\eta$ from three different methods
Distributions of $dn/d\eta$ measured by three different methods: Pixel tracking (trigangle), tracklet Method 1(point) and tracklet Method 2(square). Low panel shows the ratio of pixel tracking and Method2 to Method 1 ratio. This shows for 10-20\% centrality interval.
https://twiki.cern.ch/twiki/pub/AtlasPublic/QM2011Multiplicity/a-12.png
APPROVED eps file

$dn/d\eta$ vs $\eta$ from three different methods
Distributions of $dn/d\eta$ measured by three different methods: Pixel tracking (trigangle), tracklet Method 1(point) and tracklet Method 2(square). Low panel shows the ratio of pixel tracking and Method2 to Method 1 ratio. This shows for 20-30\% centrality interval.
https://twiki.cern.ch/twiki/pub/AtlasPublic/QM2011Multiplicity/a-13.png
APPROVED eps file

$dn/d\eta$ vs $\eta$ from three different methods
Distributions of $dn/d\eta$ measured by three different methods: Pixel tracking (trigangle), tracklet Method 1(point) and tracklet Method 2(square). Low panel shows the ratio of pixel tracking and Method2 to Method 1 ratio. This shows for 30-40\% centrality interval.
https://twiki.cern.ch/twiki/pub/AtlasPublic/QM2011Multiplicity/a-14.png
APPROVED eps file

$dn/d\eta$ vs $\eta$ from three different methods
Distributions of $dn/d\eta$ measured by three different methods: Pixel tracking (trigangle), tracklet Method 1(point) and tracklet Method 2(square). Low panel shows the ratio of pixel tracking and Method2 to Method 1 ratio. This shows for 40-50\% centrality interval.
https://twiki.cern.ch/twiki/pub/AtlasPublic/QM2011Multiplicity/a-15.png
APPROVED eps file

$dn/d\eta$ vs $\eta$ from three different methods
Distributions of $dn/d\eta$ measured by three different methods: Pixel tracking (trigangle), tracklet Method 1(point) and tracklet Method 2(square). Low panel shows the ratio of pixel tracking and Method2 to Method 1 ratio. This shows for 50-60\% centrality interval.
https://twiki.cern.ch/twiki/pub/AtlasPublic/QM2011Multiplicity/a-16.png
APPROVED eps file

$dn/d\eta$ vs $\eta$ from three different methods
Distributions of $dn/d\eta$ measured by three different methods: Pixel tracking (trigangle), tracklet Method 1(point) and tracklet Method 2(square). Low panel shows the ratio of pixel tracking and Method2 to Method 1 ratio. This shows for 60-70\% centrality interval.
https://twiki.cern.ch/twiki/pub/AtlasPublic/QM2011Multiplicity/a-17.png
APPROVED eps file

$dn/d\eta$ vs $\eta$ from three different methods
Distributions of $dn/d\eta$ measured by three different methods: Pixel tracking (trigangle), tracklet Method 1(point) and tracklet Method 2(square). Low panel shows the ratio of pixel tracking and Method2 to Method 1 ratio. This shows for 70-80\% centrality interval.
https://twiki.cern.ch/twiki/pub/AtlasPublic/QM2011Multiplicity/a-18.png
APPROVED eps file


Major updates:
-- Main.YujiaoChen - 15-Jun-2011

Responsible: Main.YujiaoChen
Subject: public

Topic attachments
ISorted ascending Attachment History Action Size Date Who Comment
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Unknown file formateps auxi_detaM1_Run169866vsHijing_3sigma_Reweight.eps r1 manage 21.0 K 2011-06-15 - 18:58 YujiaoChen  
Unknown file formateps auxi_dndEtaRatio_errorBand.eps r1 manage 21.0 K 2011-06-15 - 18:50 YujiaoChen  
Unknown file formateps auxi_dndeta0to6CompareCGC.eps r1 manage 14.8 K 2011-06-15 - 18:50 YujiaoChen  
Unknown file formateps auxi_dndetaNpartScale_ATLAS.eps r1 manage 13.8 K 2011-06-15 - 18:57 YujiaoChen  
Unknown file formateps auxi_dndetaNpart_phobos.eps r1 manage 25.0 K 2011-06-15 - 18:04 YujiaoChen  
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Unknown file formateps auxi_dphiDetaClus_Run169866_ellipse.eps r1 manage 478.1 K 2011-06-15 - 18:52 YujiaoChen  
Unknown file formateps auxi_dphiM1_Run169866vsHijing_3sigma_Reweight.eps r1 manage 22.1 K 2011-06-15 - 18:57 YujiaoChen  
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Unknown file formateps auxi_eta_pt0MagOff_m1m2tm_3sigma_tm16_2_1_5_cent4.eps r1 manage 29.5 K 2011-06-15 - 21:17 YujiaoChen  
Unknown file formateps auxi_eta_pt0MagOff_m1m2tm_3sigma_tm16_2_1_5_cent5.eps r1 manage 29.9 K 2011-06-15 - 18:55 YujiaoChen  
Unknown file formateps auxi_eta_pt0MagOff_m1m2tm_3sigma_tm16_2_1_5_cent6.eps r1 manage 28.7 K 2011-06-15 - 18:54 YujiaoChen  
Unknown file formateps auxi_eta_pt0MagOff_m1m2tm_3sigma_tm16_2_1_5_cent7.eps r1 manage 28.7 K 2011-06-15 - 18:54 YujiaoChen  
Unknown file formateps auxi_occupancy_20bins.eps r1 manage 15.6 K 2011-06-15 - 18:51 YujiaoChen  
Unknown file formateps auxi_rawDndetaM1_Run169866_3sigma.eps r1 manage 31.9 K 2011-06-15 - 18:54 YujiaoChen  
Unknown file formateps auxi_z0sinTrackPix_run169866vsHijing_ReWeight_cent0.eps r1 manage 16.9 K 2011-06-15 - 18:53 YujiaoChen  
Unknown file formateps limfrag_comp_v6.eps r1 manage 15.7 K 2011-06-15 - 18:06 YujiaoChen  
Unknown file formateps paper_dndetaNpart_bottom.eps r1 manage 21.3 K 2011-06-15 - 18:07 YujiaoChen  
PDFpdf paper_detadphi_v1.pdf r1 manage 40.6 K 2011-06-15 - 18:52 YujiaoChen  
PDFpdf paper_dndetaNpart_v10.pdf r1 manage 25.2 K 2011-06-15 - 18:52 YujiaoChen  
PDFpdf paper_dndeta_v7.pdf r1 manage 40.9 K 2011-06-15 - 18:53 YujiaoChen  
PNGpng a-0.png r1 manage 42.3 K 2011-06-15 - 19:19 YujiaoChen d0
PNGpng a-1.png r1 manage 40.4 K 2011-06-15 - 19:20 YujiaoChen delta eta
PNGpng a-10.png r1 manage 41.8 K 2011-06-15 - 19:25 YujiaoChen Delta phi
PNGpng a-11.png r1 manage 55.7 K 2011-06-15 - 19:26 YujiaoChen dndeta, 3 methods, cent 1
PNGpng a-12.png r1 manage 52.4 K 2011-06-15 - 19:26 YujiaoChen dndeta, 3 methods, cent 2
PNGpng a-13.png r1 manage 54.6 K 2011-06-15 - 21:24 YujiaoChen  
PNGpng a-14.png r1 manage 51.6 K 2011-06-15 - 19:27 YujiaoChen dndeta, 3 methods, cent 3
PNGpng a-15.png r1 manage 55.4 K 2011-06-15 - 19:27 YujiaoChen dndeta, 3 methods, cent 4
PNGpng a-16.png r1 manage 57.0 K 2011-06-15 - 19:28 YujiaoChen dndeta, 3 methods, cent 5
PNGpng a-17.png r1 manage 54.0 K 2011-06-15 - 19:28 YujiaoChen dndeta, 3 methods, cent 6
PNGpng a-18.png r1 manage 53.1 K 2011-06-15 - 19:29 YujiaoChen dndeta, 3 methods, cent 7
PNGpng a-19.png r1 manage 22.0 K 2011-06-15 - 19:29 YujiaoChen occupancy
PNGpng a-20.png r1 manage 41.0 K 2011-06-15 - 19:31 YujiaoChen Raw
PNGpng a-21.png r1 manage 42.3 K 2011-06-15 - 19:31 YujiaoChen z0sin(theta)
PNGpng a-22.png r1 manage 24.7 K 2011-06-15 - 19:33 YujiaoChen  
PNGpng a-23.png r1 manage 38.3 K 2011-06-15 - 19:33 YujiaoChen dndeta ALICE
PNGpng a-24.png r1 manage 54.7 K 2011-06-15 - 19:34 YujiaoChen dndeta raw, corrected, ratio
PNGpng a-3.png r1 manage 39.1 K 2011-06-15 - 19:21 YujiaoChen dndeta ratio with error band
PNGpng a-4.png r1 manage 29.1 K 2011-06-15 - 19:22 YujiaoChen dndeta compared with CGC calculation
PNGpng a-5.png r1 manage 27.1 K 2011-06-15 - 19:22 YujiaoChen dndeta ATLAS
PNGpng a-6.png r1 manage 45.0 K 2011-06-15 - 19:23 YujiaoChen dndeta with PHOBOS
PNGpng a-7.png r1 manage 45.7 K 2011-06-15 - 19:23 YujiaoChen M2 signal, flipped, signal-flip
PNGpng a-9.png r1 manage 63.7 K 2011-06-15 - 19:24 YujiaoChen Detla phi vs Delta eta for layer-0 and layer-1 pixel clusters
PNGpng paper_detadphi_v1.png r1 manage 124.1 K 2011-06-15 - 19:50 YujiaoChen  
PNGpng paper_dndetaNpart_v10.png r1 manage 193.4 K 2011-06-15 - 20:34 YujiaoChen  
PNGpng paper_dndeta_v7.png r1 manage 189.3 K 2011-06-15 - 21:03 YujiaoChen  

This topic: AtlasPublic > WebHome > HeavyIonsPublicResults > QM2011Multiplicity
Topic revision: r1 - 2011-06-15 - YujiaoChen
 
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