# Presentation: 382747

## Charged Particle Production in the Constituent Quarks Framework 

- Rachid Nouicer
- Brookhaven National Laboratory (BNL)
- Hot Quarks Workshop
- Ultrarelativistic nucleus-nucleus collisions
- May 15-20, 2006, Villasimius, Sardinia, Italy

**Notes:**
Wu tao for ICHEP04 meetings, 25 pages.

## Outline

- What can we learn from charged particles productionin Cu+Cu compared to Au+Au?
- Motivation for Constituent Quarks Participants
- Calculation Procedure of Number of Constituent Quarks Participants
- Global Observables in Constituent Quarks and Nucleons Frameworks
- Summary

## Beams/Energies Delivered by RHIC @ BNL

- sNN = 200 GeV

- sNN = 200 and 410 GeV

- Energies:

-  Systems:

- Au+Au

- sNN=19.6,56 ,62.4,130 and 200 GeV

- d+Au

- sNN = 22.4, 62.4 and 200 GeV

**Notes:**
Java vs PHP

## Four Complementary Experiments @ RHIC

** ****(+h’s, ********’s)**
**High rate,**
**Sophisticated**
**triggering **

** ****Large solid**
**angle tracking**
** ****~ Complete **
**     ****events**

## h Coverage @RHIC

- QM2005Gábor Veres

**Notes:**
Plan

## Pseudorapidity Distributions of Charged Particles  

- Pseudorapidity Distributions of Charged Particles ** **

- There is no evidence for two separate regions  “mid-rapidity and fragmentation regions” in any of the RHIC energies
-   “Continuous distributions”

**           ****references for the data:**
** ****Au+Au : PRL  91, 052303 (2003)****                 PRC: nucl-ex/0509034 **
** ****d+Au   :  PRL 93, 082301 (2004)**
** ****Cu+Cu :  nucl-ex/0510042 & nucl-ex/0601026**

- See Talks R. NOUICER at ISMD, DNP & PANIC : nucl-ex/0512044, nucl-ex/0601026

**Au+Au at 200 GeV**

**Au+Au at 130 GeV**

**Au+Au at 62.4 GeV**

**Au+Au at 19.6 GeV**

**Cu+Cu at 200 GeV**

**Cu+Cu at 62.4 GeV**

**d+Au at 200 GeV**

**p+p at 200 GeV**

- Prel.

- Prel.

- Prel.

**Notes:**
XML vs HTML

HTML – Langage de balises restreint

Les données sont mélangées aux informations concernant la mise en forme (look)
Lorsque le HTML est généré dynamiquement, il devient très compliqué de faire évoluer le look

## Pseudorapidity Distributions of Charged Particles  

- Pseudorapidity Distributions of Charged Particles ** **

**           ****references for the data:**
** ****Au+Au : PRL  91, 052303 (2003)****                 PRC: nucl-ex/0509034 **
** ****d+Au   :  PRL 93, 082301 (2004)**
** ****Cu+Cu :  nucl-ex/0510042 & nucl-ex/0601026**

- See Talks R. NOUICER at ISMD, DNP & PANIC : nucl-ex/0512044, nucl-ex/0601026

- We define the mid-rapidity region:  || < 1

**Au+Au at 200 GeV**

**Au+Au at 130 GeV**

**Au+Au at 62.4 GeV**

**Au+Au at 19.6 GeV**

**Cu+Cu at 200 GeV**

**Cu+Cu at 62.4 GeV**

**d+Au at 200 GeV**

**p+p at 200 GeV**

- There is no evidence for two separate regions  “mid-rapidity and fragmentation regions” in any of the RHIC energies
-   “Continuous distributions”

- Prel.

- Prel.

- Prel.

**Notes:**
XML vs HTML

HTML – Langage de balises restreint

Les données sont mélangées aux informations concernant la mise en forme (look)
Lorsque le HTML est généré dynamiquement, il devient très compliqué de faire évoluer le look

## Does this factorization work and can we predict the dN/d distributions of Cu+Cu based on Au+Au? 

- System Size Independence of Pseudorapidity Shapes

- Factorization of dN/d Shapes: R. Nouicer nucl-ex/0512044

**Au+Au **

**Cu+Cu**

- dNFact.(CuCu: x %) =  RAu (0-6%) dNMeas.(AuAu: x %)

- d

- d

- Cu

***Does this factorization work and can we predict the dN/d********** distributions of Cu+Cu based on Au+Au?***** **

## It thus appears that dN/d shapes are independent of the overall size of  the colliding nuclei, at least between the Cu+Cu and Au+Au at 200 GeV. 

- System Size Independence of Pseudorapidity Shapes

- Similarity of the dN/d Shapes of AuAu and CuCu: R. Nouicer nucl-ex/0512044

***It thus appears that dN/d********** shapes are independent of the overall size of  the colliding nuclei, at least between the Cu+Cu and Au+Au at 200 GeV.***** **

-  Factorized Au+Au =  RAu (0-6%) dNMeas.(Au+Au: x %)

- Cu

- d

- 200 GeV

## It thus appears that dN/d shapes are independent of the overall size of  the colliding nuclei, at least between the Cu+Cu and Au+Au at 200 GeV. 

- System Size Independence of Pseudorapidity Shapes

- Similarity of the dN/d Shapes of AuAu and CuCu: R. Nouicer nucl-ex/0512044

***It thus appears that dN/d********** shapes are independent of the overall size of  the colliding nuclei, at least between the Cu+Cu and Au+Au at 200 GeV.***** **

-  Factorized Au+Au =  RAu (0-6%) dNMeas.(Au+Au: x %)

- Cu

- d

- 200 GeV

## dN/d shapes are independent of the overall size of  the colliding nuclei CuCu/AuAu at 200 GeV but NOT at 62.4 GeV: spectators contribution important at low energy 

- System Size Independence of Pseudorapidity Shapes

-      dN/d**** Shapes between AuAu and CuCu

***dN/d********** shapes are independent of the overall size of  the colliding nuclei CuCu/AuAu at 200 GeV but ******NOT****** at 62.4 GeV: ******spectators contribution important at low energy***** **

-  Factorized Au+Au =  RAu (0-6%)  dNMeas.(Au+Au: x %)

- Cu

-  d

**62.4 GeV**

## Motivation for Constituent Quarks Participants

- This increase in the number of produced particles/Nn-part is still not understood.
- Common explanation: hard process.
- But we know that hard processes cross section is smaller than soft collisions!

- Nucleon Participants Framework: Scaled to Nn-part** **

## Motivation for Constituent Quarks Participants

- This increase in the number of produced particles/Nn-part is still not understood.
- Common explanation: hard process.
- But we know that hard processes cross section is smaller than soft collisions!

- R. Nouicer for PHOBOS Collaboration:
- International Europhysics Conference     on High Energy Physics 2003

## Motivation for Constituent Quarks Participants

- Until today, there is no clean description of how AA and pp differ
- at mid-rapidity region

- Talks: R. Nouicer @ISMD 2005 and R. Nouicer for  PHOBOS Collaboration PANIC 2005 ** **

- Au+Au :    PRL  91, 052303 (2003)                 PRC: nucl-ex/0509034
- Cu+Cu:     nucl-ex/0510042                    nucl-ex/0601026

- Nucleon Participants Framework: Scaled to Nn-part** **

## Moivation: Charged Particle Production in forward Regions 

**p+p Collisions**** **

**Au+Au Central Collisions**** **

**Cu+Cu Central **
**Collisions**** **

- The extended longitudinal scaling
- is present for all systems
- and it grows as function of energy

**Using PHOBOS (Prel.) QM2005:  Cu+Cu at 200 and 62.4 GeV**

**Using data: PRL 93, 082302 (2004) for AuAu**

**Au+Au peripheral Collisions**** **

- See Talk R. NOUICER at ISMD 2005

- Moivation: Charged Particle Production in forward Regions

- Extended Longitudinal Scaling “Limiting Fragmentation” Scenario

**Notes:**
XML vs HTML

XSL – Sous espace de XML (certains noms de balise sont réservés, ils sont tous préfixés par xsl: )

XSL est destiné à la transformation d'arbres XML.
Le langage de sortie après la transformation est quelconque. On peut trouver du XML (ainsi que ses sous-espaces, XML, XSL, HTML...) ou des langages complètement différents (FO pour la création de fichiers PDF, PS pour l'impression directe ...)
Dans tous les cas, XSL ne modifie jamais la sémantique des données, il se contente de les mettre en forme.

## Motivation for Constituent Quarks Participants

- in the limiting fragmentation region

- Centrality: 0-6%

- Nucleon Participants Framework: Scaled to Nn-part** **

- See Talks R. NOUICER at ISMD 2005 & DNP 2005: nucl-ex/0512044

- Centrality: 0-6%

## Number of Constituent Quark Participants: “ Nq-part” 

-      Made from nucleons

- Number of Constituent Quark Participants: “ Nq-part”** **

-      S. Goldhaber, Phys. Rev. Lett. 33, 47 (1974).
-       A. Bialas et al., Acta, Phys. Pol. B8, 585 (1977).
-       S. Eremin and S. Voloshin Phys. Rev. C67, 06490 (2003)
-       R. Nouicer AIP  828, 11 (2006).

- 1) the density is three times that of nucleon density with
- 2) the cross sections
- 3) the mass numbers of the colliding nuclei are three times their values, keeping the size of the nuclei same as in the case of Nn-part

- Nucleon Participants Framework Nn-part         Constituents Quarks Framework Nq-part

**Notes:**
Plan

## Number of Constituent Quark Participants: “ Nq-part” 

- Number of Constituent Quark Participants: “ Nq-part”** **

- See Talks R. NOUICER at ISMD 2005 & DNP 2005: nucl-ex/0512044

**Notes:**
Plan

## Multiparticle Production at Midrapidity || <1  

- See Talk R. NOUICER at ISMD 2005: nucl-ex/0512044

- Multiparticle Production at Midrapidity || <1 ** **

- Density per Nucleon and Density per Constituent Quarks** **

**Notes:**
XML vs HTML

XSL – Sous espace de XML (certains noms de balise sont réservés, ils sont tous préfixés par xsl: )

XSL est destiné à la transformation d'arbres XML.
Le langage de sortie après la transformation est quelconque. On peut trouver du XML (ainsi que ses sous-espaces, XML, XSL, HTML...) ou des langages complètement différents (FO pour la création de fichiers PDF, PS pour l'impression directe ...)
Dans tous les cas, XSL ne modifie jamais la sémantique des données, il se contente de les mettre en forme.

## Charged Particle Production in forward Regions 

- If we Scale by the Constituent Quark Participants,
-   AA and pp Collisions are the SAME.

- Constituent Quarks Participants Framework: Scaled to Nq-part

- Charged Particle Production in forward Regions

- See Talks R. NOUICER at ISMD 2005 & DNP 2005: nucl-ex/0512044

- Extended Longitudinal Scaling “Limiting Fragmentation” Scenario

- Centrality: 0-6%

## Increase of dN/d per nucleon participant pair with centrality can be explained by the relative increase in the number of interacting constituent quarks in more central collisions   

- Hard Process vs Interacting Constituent Quarks  ** **

- Multiparticle Production at Midrapidity || <1  ** **

- Increase of dN/d per nucleon participant pair with centrality can be explained by the relative increase in the number of interacting constituent quarks in more central collisions**   **

**PRC 70, 027901 (2004)**

- PHENIX
-   DATA

- Scaled to Nn-part** **

- Scaled to Nq-part** **

## Summary I

- What we can learn from charged hadron production       in Cu+Cu compared to Au+Au?

- For the same fraction of overall cross section and at the same energy, Cu+Cu and Au+Au are very similar:
-  Particle Density
-  Extended Longitudinal Scaling
-  dN/d Shapes @ 200 GeV

- Do these “Scaling and Factorization” observations
- in charged particle production persist to HIC at LHC?

## Summary II

-  My main points are very simple:
-  In the Constituent Quarks Framework (CQF):    *the initial states in A+A and p+p collisions are SIMILAR*
-  The most relevant degrees of freedom early in the collision may be constituents quarks

_*Nothing is written in stone yet,*_

_*you have time for questions*_