energy and centrality dependence of mid-rapidity charged particle multiplicity measured with
DESCRIPTION
DNP02. Energy and Centrality Dependence of Mid-Rapidity Charged Particle Multiplicity Measured with. Aneta Iordanova University of Illinois at Chicago. Collaboration. ARGONNE NATIONAL LABORATORY Birger Back, Alan Wuosmaa - PowerPoint PPT PresentationTRANSCRIPT
Energy and Centrality Dependence of Mid-Rapidity Charged Particle
Multiplicity Measured with
DNP02
Aneta Iordanova
University of Illinois at Chicago
Collaboration
ARGONNE NATIONAL LABORATORYBirger Back, Alan Wuosmaa
BROOKHAVEN NATIONAL LABORATORY Mark Baker, Donald Barton, Alan Carroll, Nigel George, Stephen Gushue, George Heintzelman, Burt Holzman, Robert Pak, Louis Remsberg, Peter Steinberg, Andrei Sukhanov
INSTITUTE OF NUCLEAR PHYSICS, KRAKOWAndrzej Budzanowski, Roman Hołyński, Jerzy Michałowski, Andrzej Olszewski, Pawel Sawicki, Marek Stodulski, Adam Trzupek, Barbara Wosiek, Krzysztof Woźniak
MASSACHUSETTS INSTITUTE OF TECHNOLOGYMaartin Ballintijn, Wit Busza (Spokesperson), Patrick Decowski, Kristjan Gulbrandsen, Conor Henderson, Jay Kane, Judith Katzy, Piotr Kulinich, Jang Woo Lee, Heinz Pernegger, Corey Reed, Christof Roland, Gunther Roland, Leslie Rosenberg, Pradeep Sarin, Stephen Steadman, George Stephans, Carla Vale, Gerrit van Nieuwenhuizen, Gábor Veres, Robin Verdier, Bernard Wadsworth, Bolek Wysłouch
NATIONAL CENTRAL UNIVERSITY, TAIWANChia Ming Kuo, Willis Lin, Jaw-Luen Tang
UNIVERSITY OF ILLINOIS AT CHICAGORussell Betts, Edmundo García, Clive Halliwell, David Hofman, Richard Hollis, Aneta Iordanova, Wojtek Kucewicz, Don McLeod, Rachid Nouicer, Michael Reuter, Joe Sagerer
UNIVERSITY OF MARYLANDAbigail Bickley, Richard Bindel, Alice Mignerey,
Marguerite Belt Tonjes
UNIVERSITY OF ROCHESTERJoshua Hamblen, Erik Johnson, Nazim Khan, Steven Manly, Inkyu Park, Wojtek Skulski, Ray Teng, Frank Wolfs
•4 Multiplicity Array
Octagon, Vertex and Ring Counters
•Mid-rapidity Spectrometer
•TOF wall for high momentum PID
•Triggering
Scintillator Paddle Counters
Zero Degree Calorimeter (ZDC)
Čerenkov Counters
DNP02 Aneta Iordanova
Vertex Detector8192 silicon channels • Outer Layer: 2 × 2048 channels, 0.47mm × 24.1mm• Inner Layer: 2 × 2048 channels, 0.47mm × 12.0mm
Top
Bottom
62.1mm
50.4mm
Z,
Beam pipe
1 channel
Y
X
Used for• reconstruction of collision location (“vertex”)• multiplicity measurement
DNP02 Aneta Iordanova
Inner Layer
Outer Layer
TrackletTwo-hit combinations from Outer and Inner Vertex (Top or Bottom), pointing to the reconstructed vertex.
ReconstructedVertex
hit
hit
Top VertexTop Vertex
DNP02 Aneta Iordanova
First Pass
Second Pass
Tracklet Reconstruction
Seed Layer
Search Layer
Reconstructed Vertex
hit
hit
Search ,Search
Extrapolate Seed ,Seed
• || = |Search – Seed| < 0.3
• || =|Search – Seed| < 0.1
• smallest combination.
Tracklets with a common hit in the “Search Layer”
•smallest combination.
Top VertexTop Vertex
DNP02 Aneta Iordanova
etsted_tracklreconstruc1||charged 1
1N
d
dN
Multiplicity Determination using Vertex detector
DNP02 Aneta Iordanova
Efficiency Correction
Factor
Combinatorial Background
depends on:•Azimuthal acceptance of detector• Z vertex position
• Multiplicity in detector (hits)
Inner Layer
Inner Layer
Outer Layer
Outer Layer
Nominal vertex position
Bottom
Top
Efficiency Correction Factor ((from Monte Carlo)
~ 0.4 (Z=0cm) to 0.25 (Z=10cm)
DNP02 Aneta Iordanova
Efficiency Correction Factor for three different Zvertex positions19.6 GeV
DNP02 Aneta Iordanova
Combinatorial Background Tracklets ()
Nbackground_tracklets= Nreconstructed_tracklets
etsted_tracklreconstruc1||charged 1
1N
d
dN
T R U E
Z,
Beam pipe
Tracklets from hits by rotating Inner layers 1800 about the beam pipe.
DNP02 Aneta Iordanova
Monte CarloData
Background Tracklets for 80 to 100 Hits in Outer Vertex Layer 19.6 GeV
DNP02 Aneta Iordanova
Cou
nts
Cou
nts
Scaled charged-particle multiplicity as a function of Npart for Au+Au collisions
DNP02 Aneta Iordanova
200GeV
130GeV
19.6GeVPRELIMINAR
Y
||<1
Scaled charged-particle multiplicity as a function of Npart for Au+Au collisions(Two component fit)
DNP02 Aneta Iordanova
200GeV
130GeV
19.6GeVPRELIMINAR
Y
||<1
DNP02 Aneta Iordanova
Scaled charged-particle multiplicity as a function of Npart for Au+Au collisions
(Normalized by the corresponding pp value for each energy)
200GeV
130GeV
19.6GeVPRELIMINAR
Y
||<1
Errors from Au+Au only
Scaled charged-particle multiplicity as a function of Npart for Au+Au collisions
(KLN saturation model)
DNP02 Aneta Iordanova
200GeV
130GeV
19.6GeVPRELIMINAR
Y
||<1
PHOBOS 19.6 GeV
Comparison of central charged-particle multiplicity for different energies.
PRELIMINARY
DNP02 Aneta Iordanova
Conclusion
• Phobos has measured charged-particle multiplicity dependence on centrality and energy in Au-Au collisions at √sNN of 200,130 and 19.6GeV.
• The mid-rapidity scaled charged-particle multiplicity shows evidence for deviation from Npart scaling over the studied centrality range.
• The mid-rapidity scaled charged-particle multiplicity dependence on energy follows the logarithmic rise.
DNP02 Aneta Iordanova