Presentation is loading. Please wait.

Presentation is loading. Please wait.

Lecture 07: particle production in AA collisions

Published byCleopatra Woods Modified over 8 years ago

Similar presentations

Presentation on theme: "Lecture 07: particle production in AA collisions"— Presentation transcript:

1 Lecture 07: particle production in AA collisions
Last lecture: soft particle production in pp collisions Linear QCD potential at large distances and classical string theory reproduce the main features of the data: Hadron masses and spins are related through the string constant Rapidity distribution MT scaling for particle spectra for low mT Today: AA collisions Multiplicity: number of particles produced per event (i.e. for one pp or AA collision) Differential multiplicity: dN/dh or dN/dy : # of particles produced per event in a certain kinematic region Centrality ( see next page) Rapidity, energy, system size dependence of particle multiplicity phys340a, Nov 5,2007 Julia Velkovska

2 Some definitions of terms
Participants Spectators Nuclei are extended objects Impact parameter Number of participants Centrality ( % from total inelastic cross-section) 100% % Julia Velkovska phys340a, Nov 5,2007

3 How to measure centrality (with PHENIX)
Beam-Beam Counters: 3.0<|h|<3.9,  = 2 Zero-Degree Calorimeters: |h| > 6, |Z|=18.25 m phys340a, Nov 5,2007 Julia Velkovska

4 Centrality Selection in PHENIX
ZDC vs BBC Define centrality classes: ZDC vs BBC Extract N participants: Glauber model ET EZDC b QBBC Nch Nch ET phys340a, Nov 5,2007 Julia Velkovska

5 An almost central collision
phys340a, Nov 5,2007 Julia Velkovska

6 PHOBOS 200 GeV Au+Au charged hadrons >99.5%
The bulk of the particles are produced with low momentum: turn off the magnet and count! PHOBOS 200 GeV Au+Au charged hadrons >99.5% phys340a, Nov 5,2007 Julia Velkovska

7 The Phobos experiment Phobos: Si based spectrometer, PID by TOF and dE/dx in Si, large rapidity coverage I’ll discuss pseudo-rapidity measurements of particle multiplicity phys340a, Nov 5,2007 Julia Velkovska

8 PHOBOS Silicon Detector Arrays
Partially Assembled Vertex Octagon Spectrometer Ring Multiplicity Arrays phys340a, Nov 5,2007 Julia Velkovska

9 Tracks in Spectrometer
Example of multiplicity measurement from PHOBOS Hits in Vertex Octagon Hits in Spectrometer Tracks in Spectrometer 130 AGeV 56 AGeV Sample of Events phys340a, Nov 5,2007 Julia Velkovska

10 Charged Multiplicity Measurements
Count tracks on a statistical basis (no explicit track reconstruction) Combine all hits in PC3 with all hits in PC1. Project resulting lines onto a plane through the beam line. Count tracks within a given radius. Determine combinatorial background by event mixing technique B=0 MC corrections for acceptance, detector effects, decays, background phys340a, Nov 5,2007 Julia Velkovska

11 Npart and Ncoll from Glauber MC simulations
Woods-Saxon nuclear density distributions. Put in the Lorentz boost Put in the NN inelastic cross section ( as parameterized from data) Straight line nucleon trajectories Throw the dice: see if the nucleon is a participant See if the nucleon will collide with another nucleon more than once Variety of ways to make correspondence with exp’t PHOBOS Glauber MC phys340a, Nov 5,2007 Julia Velkovska

12 More on Npart and Ncoll phys340a, Nov 5,2007 Julia Velkovska

13 Nch pseudo-rapidity dependence
Integrate the distribution to get total multiplicity – study the production as a function of energy Explore scaling behavior Is there longitudinal boost invariance ? Plateau around h = 0 increasing with energy. BUT, pseudo-rapidity maybe misleading…we’ll find out … phys340a, Nov 5,2007 Julia Velkovska

14 Total charged particle production
62.4 GeV 200 GeV PHOBOS Here: number of participants  100 Same multiplicity for same Npart G. Roland (QM’05) phys340a, Nov 5,2007 Julia Velkovska

15 Total multiplicity per participant pair
Total multiplicity ( fixed energy/system) scales with Npart . With the change in centrality – change the system size and Ncoll , Npart Au+Au : increase in particle production with the available energy d+Au : not all “participants” are equal phys340a, Nov 5,2007 Julia Velkovska

16 Nch as a function of centrality:comparison to models
NOTE: this is at central rapidity HIJING – pQCD based model with soft and hard component of particle production X.N.Wang and M.Gyulassy, PRL 86, 3498 (2001) KLN – gluon saturation in the initial state D.Kharzeev and M. Nardi, Phys.Lett. B503, 121 (2001) D.Kharzeev and E.Levin, Phys.Lett. B523, 79 (2001) EKRT – saturation in the final state K.J.Eskola et al, Nucl Phys. B570, 379 and Phys.Lett. B 497, 39 (2001) phys340a, Nov 5,2007 Julia Velkovska

17 And a full pallet of Nch to theory comparison from PHOBOS
phys340a, Nov 5,2007 Julia Velkovska

18 Longitudinal scaling Particles near beam and target rapidity governed by limiting fragmentation Projectile hadron viewed in the rest frame of the target is highly Lorenz contracted. It passes through the target leaving it in an excited state which is independent of energy. It then fragments to produce hadrons phys340a, Nov 5,2007 Julia Velkovska

19 Longitudinal scaling: Adding Cu+Cu into the picture
Longitudinal scaling is independent even of the identity of the projectile! phys340a, Nov 5,2007 Julia Velkovska

20 Summary Particle production grows logarithmically with cm energy
Total multiplicity is ~ Npart At mid-rapidity: multiplicity per participant grows slowly – consistent with gluon saturation in the initial state Near beam and target rapidity: universal scaling of multiplicity Limiting fragmentation phys340a, Nov 5,2007 Julia Velkovska

Download ppt "Lecture 07: particle production in AA collisions"

Similar presentations

Quark Matter 2006 (2006.11.18) Excitation functions of baryon anomaly and freeze-out properties at RHIC-PHENIX Tatsuya Chujo (University of Tsukuba) for.

Quark Matter 2006 ( ) Excitation functions of baryon anomaly and freeze-out properties at RHIC-PHENIX Tatsuya Chujo (University of Tsukuba) for.
1 Zakopane, June 06, HB Wounded Nucleons, Wounded Quarks, and Relativistic Ion Collisions Helena Białkowska Institute for Nuclear Studies Warsaw.

1 Zakopane, June 06, HB Wounded Nucleons, Wounded Quarks, and Relativistic Ion Collisions Helena Białkowska Institute for Nuclear Studies Warsaw.
Ultra Peripheral Collisions at RHIC Coherent Coupling Coherent Coupling to both nuclei: photon~Z 2, Pomeron~A 4/3 Small transverse momentum p t ~ 2h 

Ultra Peripheral Collisions at RHIC Coherent Coupling Coherent Coupling to both nuclei: photon~Z 2, Pomeron~A 4/3 Small transverse momentum p t ~ 2h 
Results from PHENIX on deuteron and anti- deuteron production in Au+Au collisions at RHIC Joakim Nystrand University of Bergen for the PHENIX Collaboration.

Results from PHENIX on deuteron and anti- deuteron production in Au+Au collisions at RHIC Joakim Nystrand University of Bergen for the PHENIX Collaboration.
Julia Velkovska Selected CMS Results from pp collisions 27th Winter Workshop on Nuclear Dynamics Winter Park, Colorado Feb 6-13, 2011.

Julia Velkovska Selected CMS Results from pp collisions 27th Winter Workshop on Nuclear Dynamics Winter Park, Colorado Feb 6-13, 2011.
Julia VelkovskaMoriond QCD, March 27, 2015 Geometry and Collective Behavior in Small Systems from PHENIX Julia Velkovska for the PHENIX Collaboration Moriond.

Julia VelkovskaMoriond QCD, March 27, 2015 Geometry and Collective Behavior in Small Systems from PHENIX Julia Velkovska for the PHENIX Collaboration Moriond.
Semin.IFD/IPJ 06.10.06 1 Zakopane, June 06, HB Wounded Nucleons, Wounded Quarks, and Relativistic Ion Collisions Helena Białkowska Institute for Nuclear.

Semin.IFD/IPJ Zakopane, June 06, HB Wounded Nucleons, Wounded Quarks, and Relativistic Ion Collisions Helena Białkowska Institute for Nuclear.
Winter Workshop on Nuclear Dynamics, 2007 1 Heavy Ion Physics with CMS: Day-One Measurements Olga Barannikova for the CMS Collaboration.

Winter Workshop on Nuclear Dynamics, Heavy Ion Physics with CMS: Day-One Measurements Olga Barannikova for the CMS Collaboration.
The fundamental nature of matter and forces Physics 114 Spring 2004 – S. Manly.

The fundamental nature of matter and forces Physics 114 Spring 2004 – S. Manly.
11/21/05Ali Hanks - Journal Club1 Determining Centrality at PHENIX Ali Hanks Journal Club November 21, 2005.

11/21/05Ali Hanks - Journal Club1 Determining Centrality at PHENIX Ali Hanks Journal Club November 21, 2005.
12-17 February 2007 Winter Workshop on Nuclear Dynamics STAR identified particle measurements at large transverse momenta in Cu+Cu collisions at RHIC Richard.

12-17 February 2007 Winter Workshop on Nuclear Dynamics STAR identified particle measurements at large transverse momenta in Cu+Cu collisions at RHIC Richard.
Mid-Rapidity Hadron Production Studied with the PHENIX detector at RHIC Joakim Nystrand Universitetet i Bergen for the PHENIX Collaboration.

Mid-Rapidity Hadron Production Studied with the PHENIX detector at RHIC Joakim Nystrand Universitetet i Bergen for the PHENIX Collaboration.
Sourav Tarafdar Banaras Hindu University For the PHENIX Collaboration Hard Probes 2012 Measurement of electrons from Heavy Quarks at PHENIX.

Sourav Tarafdar Banaras Hindu University For the PHENIX Collaboration Hard Probes 2012 Measurement of electrons from Heavy Quarks at PHENIX.
Computational Lab in Physics: Final Project Monte Carlo Nuclear Collisions: Glauber Model.

Computational Lab in Physics: Final Project Monte Carlo Nuclear Collisions: Glauber Model.
Tatsuya Chujo (BNL) for the PHENIX Collaboration

Tatsuya Chujo (BNL) for the PHENIX Collaboration
Measurement of the Centrality Dependence of Charged Particle Pseudorapidity Density with the PHOBOS Detector Michael Reuter University of Illinois at Chicago.

Measurement of the Centrality Dependence of Charged Particle Pseudorapidity Density with the PHOBOS Detector Michael Reuter University of Illinois at Chicago.
Richard Bindel, UMDDivision of Nuclear Physics, Maui, 2005 System Size and Energy Dependence of Elliptical Flow Richard Bindel University of Maryland For.

Richard Bindel, UMDDivision of Nuclear Physics, Maui, 2005 System Size and Energy Dependence of Elliptical Flow Richard Bindel University of Maryland For.
High p T  0 Production in p+p, Au+Au, and d+Au Stefan Bathe UC Riverside for the Collaboration Topics in Heavy Ion Collisions McGill University, Montreal,

High p T  0 Production in p+p, Au+Au, and d+Au Stefan Bathe UC Riverside for the Collaboration Topics in Heavy Ion Collisions McGill University, Montreal,
Identified Particle Ratios at large p T in Au+Au collisions at  s NN = 200 GeV Matthew A. C. Lamont for the STAR Collaboration - Talk Outline - Physics.

Identified Particle Ratios at large p T in Au+Au collisions at  s NN = 200 GeV Matthew A. C. Lamont for the STAR Collaboration - Talk Outline - Physics.
Nov2,2001High P T Workshop, BNL Julia Velkovska High pt Hadrons from  sNN = 130 GeV Au-Au collisions measured in PHENIX Julia Velkovska (BNL) for PHENIX.

Nov2,2001High P T Workshop, BNL Julia Velkovska High pt Hadrons from  sNN = 130 GeV Au-Au collisions measured in PHENIX Julia Velkovska (BNL) for PHENIX.

Similar presentations

Ads by Google