# Presentation: 778079

## Charm Production In AuAu, dAu and pp Reactions from the PHENIX Experiment at RHIC

- Sean Kelly - University of Colorado
- for the PHENIX collaboration

##  12 Countries;  58 Institutions;  480 Participants*

**             ****Brookhaven National Laboratory, Upton, NY **
**             ****University of California - Riverside, Riverside, CA**
**             ****University of Colorado, Boulder, CO**
**             ****Columbia University, Nevis Laboratories, Irvington, NY**
**             ****Florida State University, Tallahassee, FL**
**             ****Florida Technical University, Melbourne, FL**
**             ****Georgia State University, Atlanta, GA**
**             ****University of Illinois Urbana Champaign, Urbana-Champaign, IL**
**             ****Iowa State University and Ames Laboratory, Ames, IA**
**             ****Los Alamos National Laboratory, Los Alamos, NM**
**             ****Lawrence Livermore National Laboratory, Livermore, CA**
**             ****University of New Mexico, Albuquerque, NM **
**             ****New Mexico State University, Las Cruces, NM**
**             ****Dept. of Chemistry, Stony Brook Univ., Stony Brook, NY**
**             ****Dept. Phys. and Astronomy, Stony Brook Univ., Stony Brook, NY  **
**             ****Oak Ridge National Laboratory, Oak Ridge, TN**
**             ****University of Tennessee, Knoxville, TN  **
**             ****Vanderbilt University, Nashville, TN****	**

**Brazil        University of São Paulo, São Paulo**
**China        Academia Sinica, Taipei, Taiwan**
**                  ****China Institute of Atomic Energy, Beijing**
**                  ****Peking University, Beijing**
**France      LPC, University de Clermont-Ferrand, Clermont-Ferrand**
**                  ****Dapnia, CEA Saclay, Gif-sur-Yvette**
**                  ****IPN-Orsay, Universite Paris Sud, CNRS-IN2P3, Orsay          **
**                  ****LLR, Ecòle Polytechnique, CNRS-IN2P3, Palaiseau**
**                  ****SUBATECH, Ecòle des Mines at Nantes, Nantes**
**Germany  University of M****ü****nster, M****ü****nster**
**Hungary   Central Research Institute for Physics (KFKI), Budapest**
**                  ****Debrecen University, Debrecen**
**                  ****Eötvös Loránd University (ELTE), Budapest **
**India         Banaras Hindu University, Banaras**
**                  ****Bhabha Atomic Research Centre, Bombay**
**Israel        Weizmann Institute, Rehovot**
**Japan       Center for Nuclear Study, University of Tokyo, Tokyo**
**                  ****Hiroshima University, Higashi-Hiroshima **
**                  ****KEK, Institute for High Energy Physics, Tsukuba **
**                  ****Kyoto University, Kyoto**
**                  ****Nagasaki Institute of Applied Science, Nagasaki**
**                  ****RIKEN, Institute for Physical and Chemical Research, Wako**
**                                               ****RIKEN-BNL Research Center, Upton, NY              **
**	****     ****Rikkyo University, Tokyo, Japan             **
**                  ****Tokyo Institute of Technology, Tokyo**
**                  ****University of Tsukuba, Tsukuba **
**                  ****Waseda University, Tokyo                    **
**S. Korea   Cyclotron Application Laboratory, KAERI, Seoul**
**                  ****Kangnung National University, Kangnung**
**                  ****Korea University, Seoul **
**                  ****Myong Ji University, Yongin City **
**                  ****System Electronics Laboratory, Seoul Nat. University, Seoul**
**                  ****Yonsei University, Seoul**
**Russia      Institute of High Energy Physics, Protovino **
**                  ****Joint Institute for Nuclear Research, Dubna **
**                  ****Kurchatov Institute, Moscow**
**                  ****PNPI, St. Petersburg Nuclear Physics Institute, St. Petersburg**
**                  ****St. Petersburg State Technical University, St. Petersburg**
**Sweden    Lund University, Lund**

*** ******12 Countries;  58 Institutions;  480 Participants****

***as of January 2004**

## Charm Probes The Initial State & The Medium 

- charm local time

- medium local time

-  = 1/mq~ 0.1 fm

-  = 1/mqv ~ 1 fm

- d-Au

- Au+Au

- precursor

## Outline 

**PHENIX Data**
-  Single Electron Spectra (pp, dAu, AuAu)
-  Electron v2
**The PHYSICS These Data Address**
-  Nuclear modifications to total charm production
-  Nuclear modifications to the charm spectrum
-  Charm dynamics in mediu, do charm quarks flow ?

## The PHENIX Experiment 

- The PHENIX Experiment

- The data I will show today is all from the central arm and therefore at  = 0

## Measuring Charm via Semi-leptonic D Meson Decay 

- Direct reconstruction of open charm is ideal, but difficult.
- Open charm and bottom can be measured via single leptons and lepton pairs.

## Single Electrons From pp Collisions at s =200 GeV

- PHENIX measures inclusive electron spectra
- The physics we are interested is in what's left over after we subtract.

- Light hadron cocktail from decay generator

## Non-Photonic Electrons

- We call electrons **that are not from**
-  0 Dalitz
-   conversions
-   Dalitz

- (for the balance of this talk)

## Subtracting The Photonic Electrons

**Cocktail subtraction method**
- Light hadron cocktail.  Dominant input is taken from PHENIX measured  0 + - spectra.
- Other mesons from mt scaling assumption and asymptotic ratios from lower energy data.
- Photon conversion from material budget in PHENIX acceptance.
**Converter method**
- Comparison of e+/- spectra with and without converter allows separation of photonic and non-photonic sources of single electrons.
**Direct measurement via ********-e coincidences**
- Yield of -e in vicinity of  mass with mixed event subtraction & PHENIX measured  correction

##  Data is excess of  PYTHIA charm + bottom above pt=1.5 GeV/c

- PHENIX Non-Photonic Single Electron Spectra pp s = 200 GeV

- 200 GeV pp non-photonic single electron spectrum from cocktail subtraction method
- PYTHIA tuned to low energy data1
-  Data is excess of  PYTHIA charm + bottom above pt=1.5 GeV/c

- PHENIX PRELIMINARY

- 1Phys. Rev. Lett. 88, 192303 (2002)

- Poster by Sergey Butsyk

## Comparison With PYTHIA   

- Comparison With PYTHIA

- PYTHIA charm alone under predicts the data by a factor of 2-5 at moderated pt

- PYTHIA charm + bottom under predict the tail by a factor of ~2-3

- PHENIX PRELIMINARY

- PHENIX PRELIMINARY

## PYTHIA Heads For the Florida Keys In a Winnebago

- PHENIX pp fit baseline for dAu and AuAu data

- PHENIX PRELIMINARY

## Independent -e Analysis 

- Mixed event subtraction of the  -e invariant mass spectrum in the vicinity of the pion mass - eta from the cocktail
- Direct measurement of the single electrons from  pion and eta conversions/Dalitz
- Data shows good agreement with the cocktail subtraction

- Poster by        Xinhua Li

## Deuteron Gold Collisions at s = 200 GeV / nucleon

- Deuteron Gold Collisions at s = 200 GeV / nucleon

- 200 GeV dAu non-photonic single electron spectrum from converter method
- Data divided by TAB
- Spectacular agreement within stated errors

- PHENIX PRELIMINARY

**1/T****AB**

- Poster by Sergey Butsyk

- 1/TABEdN/dp3 [mb GeV-2]

## Centrality Dependence In Deuteron Au Collisions

- PHENIX PRELIMINARY

- PHENIX PRELIMINARY

- PHENIX PRELIMINARY

- PHENIX PRELIMINARY

**1/T****AB**

**1/T****AB**

**1/T****AB**

**1/T****AB**

- 1/TABEdN/dp3 [mb GeV-2]

- 1/TABEdN/dp3 [mb GeV-2]

- 1/TABEdN/dp3 [mb GeV-2]

- 1/TABEdN/dp3 [mb GeV-2]

## Single Electron Spectra Au+Au s = 200 GeV

- 200 GeV Au+Au non-photonic single electron spectrum from converter method
- Data is divided by TAA and overlaid with PHENIX pp fit
- At low pt the pp fit is in good agreement

**1/T****AA**

- 1/TABEdN/dp3 [mb GeV-2]

## Centrality Dependence Au+Au

**1/T****AA**

**1/T****AA**

**1/T****AA**

**1/T****AA**

**1/T****AA**

- 1/TABEdN/dp3 [mb GeV-2]

- 1/TABEdN/dp3 [mb GeV-2]

- 1/TABEdN/dp3 [mb GeV-2]

- 1/TABEdN/dp3 [mb GeV-2]

- 1/TABEdN/dp3 [mb GeV-2]

- 1/TABEdN/dp3 [mb GeV-2]

## Ncollision Scaling In Au+Au 

- Ncollision Scaling In Au+Au

- We have quantified the extent to which the Au+Au data exhibits Ncoll scaling
- Yellow band represents the set of alpha values consistent with the data at 90% Confidence Level
**dN/dy = A (N****coll****)******

**0.906 < ******** < 1.042**

## Since You Asked - Total Charm Cross Section s = pp 200 GeV 

- PYTHIA comes out of retirement - Matches the line shape in the region that matters for the determination of the cross section, hence we use it to extrapolate over all phase space

- PYTHIA charm + bottom line-shapes with independent floating normalizations that best fit the data
- Systematic error is determined by offsetting the data by the upper and lower systematic and extracting the cross section

- PHENIX PRELIMINARY

- N

## Back To The Dynamics of Charm In Media  

- Back To The Dynamics of Charm In Media

- D from PYTHIA

- D from Hydro

- B from PYTHIA

- B from Hydro

- e from PYTHIA

- e from Hydro

- 130 GeV Au+Au (0-10%)

- Upper West-Side Sopranos Plot
- (S. Batsouli, S.Kelly, M.Gyulassy, J.Nagle) Phys.Lett. B557 (2003) 26-32

- The measurement of v2 of charm is a way to discriminate between these contrasting dynamical scenarios

- Data indicate non-zero charm flow

- PHENIX PRELIMINARY

## Summary & Conclusions  

- PHENIX has measured inclusive single electrons in pp, d+Au, and Au+Au at 200 GeV/nucleon.
- The measured yield of non-photonic electrons is consistent with binary scaling in d+Au and Au+Au collisions. Indicating no strong enhancement or suppression of the charm cross section in nuclear systems.
- We are statistics limited regarding the presence of spectral modifications in the Au+Au data.
- With anticipated Run 4 statistics the indications for spectral modifications in Au+Au and v2 should be definitive.  Run 4 is **the** run for closed **and** open charm physics in Au+Au collisions.

## Single Electron pp, d+Au, Au+Au  

- Single Electron pp, d+Au, Au+Au

## Backup  

## Nothing Dramatic Going On  

- CTEQ5L + EKS98

- CTEQ5L

- Au+Au  e + X  (0-10%) 130 GeV

- Point here is that central arm single electrons are not sensitive to shadow+antishadow - These plots need to re-made for 200 GeV data