# Presentation: 400222

## Charming Measurements in E866/NuSea

**Mike Leitch - Los Alamos National Laboratory**
***leitch@lanl.gov***

***Charm Production: from Threshold via SPS to RHIC and LHC ***
***European Center for Theory, June 17-22, 2002***

**Introduction to Physics of Drell-Yan & Charmonium suppression in nuclei**
**E866/NuSea & comparison to NA50**
** ****p****T**** broadening & polarization**
**Summary**

- E772 - 1991

- Mike Leitch - LANL

## Nuclear modification of parton level structure & dynamics

-  e.g. shadowing – depletion of low-momentum partons. Process dependent?
**Nuclear effects on parton “dynamics”**
-  energy loss of partons as they propagate through nuclei
-  and (associated?) multiple scattering effects
**Production of heavy vector mesons, e.g. J/****Ψ****, ****Ψ ', ******
-  production: color singlet or octet      (     ) and color neutralization timescale
-  hadronization time:
- Coherence length for cc fluctuations:
-  absorption on nucleons or co-movers
-  feed-down from higher mass resonances, e.g. χc

_**Nuclear modification of parton level structure & dynamics**_

**Drell-Yan**

**E866 R(W/Be)**

**E772 R(W/D)**

**Ratio(W/Be)**

**1.0**

**0.9**

**0.8**

**0.7**

**NMC  DIS**

***Drell-Yan Process***

- Mike Leitch - LANL

## J/Ψ suppression – an effective signature of Quark-gluon plasma (QGP) formation?

_**J/**__**Ψ**__** suppression – an effective signature of Quark-gluon plasma (QGP) formation?**_
-  **Color screening in a QGP would destroy      pairs before they can hadronize into charmonium**
** ****But ordinary nuclear effects also absorb or modify J/****Ψ’s**
**We need a comprehensive understanding of charmonium production in nuclei**
**Competing effects may be identified in p-A collisions by their strong kinematic dependencies, together with complementary studies of Drell-Yan scattering and open-charm production**** **

**DY**

****

**J/******

**Peng et al, PLB 344 (1995) 1-5.**

- Mike Leitch - LANL

## FNAL E866/NuSea Collaboration

***Abilene Christian University***
**Donald Isenhower, Mike Sadler, Rusty Towell, Josh Willis**
***Argonne National Laboratory***
**Don Geesaman, Sheldon Kaufman, Bryon Mueller**
***Fermi National Accelerator Laboratory***
**Chuck Brown, Bill Cooper**
***Georgia State University*****Gus Petitt, Xiao-chun He, Bill Lee*****Illinois Institute of Technology***
**Dan Kaplan*****Los Alamos National Laboratory*****Tom Carey, Gerry Garvey, Mike Leitch, Pat McGaughey,****Joel Moss, Jen-Chieh Peng, Paul Reimer, Walt Sondheim**
***New Mexico State University***
**Mike Beddo, Ting Chang, Vassili Papavassiliou, Jason Webb*****Oak Ridge National Laboratory***
**Paul Stankus, Glenn Young*****Texas A & M University*****Carl Gagliardi, Bob Tribble, Eric Hawker, Maxim Vasiliev*****Valparaiso University*****Don Koetke**

- Mike Leitch - LANL

##  Forward xF, high-mass spectrometer

-  Solid Be, Fe, W and empty targets
-  Thick absorber wall to filter out all but μ’s
-  Two acceptance defining magnets
-  Four tracking stations and one momentum analyzing magnet
-  Scale 60m long, 3m x 3m at back

_**FNAL E866/NuSea**_

- Mike Leitch - LANL

## Scaling of J/ Suppression?

- Comparison of 800 GeV (E866) and 200 GeV (NA3) -appears to scale only with xF

_**E866/NuSea: **_**800 GeV p-A (Fermilab)**
***PRL 84, 3256 (2000)***

-  J/Ψ and Ψ’ similar at large xF where they both correspond to a     traversing the nucleus
- but Ψ’ absorbed more strongly than J/Ψ  near mid-rapidity (xF ~ 0) where the resonances are beginning to be hadronized in nucleus.

**open charm: no A-dep**
**at mid-rapidity**

**Hadronized**
**J/******

- Mike Leitch - LANL

## PT Broadening at 800 GeV

_**P**__**T**__** Broadening at 800 GeV**_

- (pT) shape is independent of xF & same for NA3 at a lower energy
- (curves are                                                   with *A* slightly different for each)

**E772 & E866: p-A at 800 *****GeV***

**Drell-Yan**

**J/******** & ********’**

**Upsilons**

- Mike Leitch - LANL

## Comparison to NA50 J/Ψ Nuclear Dependence

_**Comparison to NA50 J/**__**Ψ**__** Nuclear Dependence**_

| Expt. | E(GeV) | YCM | J/Ψ | J/Ψ - Ψ  |
| --- | --- | --- | --- | --- |
| E866 | 800 | -0.4 to 1.0 | .954 ±  .001 | .027 ± .006* |
| NA50 | 450 | -0.4 to 0.6 | .925 ± .018 | .029 ± .014 |
| NA38 | 200 | 0 to 1.0 | .911 ± .034 |  |

- -0.4

- 1.0

- yCM :

- * mid-rapidity part of E866 data

_****__** **__**y~0**__**        dependence?**_
**gluon  shadowing?**
**change in production, e.g. octet vrs singlet balance?**
**(Both experiments have good p****T**** coverage, so strong p****T****-dependence of α not the cause)**

**Charmonia cross sections from NA50/51**
** ****for p-A collisions at 450 GeV/c**

**NA50/51**
**450 GeV**

**E866**
**800 GeV**

**p-p & p-d**

******’**

**J/******

- Mike Leitch - LANL

## J/Deuterium/Hydrogen Ratios

***A = 1.35***

***A = 1.2***

***A = 2***

***A = 2***

**Using fits to E866/NuSea p + Be, Fe, W data:**

***Preliminary***

***Preliminary***

- Mike Leitch - LANL

## Gluon Shadowing for J/Ψ’s

_**Gluon Shadowing for J/**__**Ψ’s**_

***Kopeliovich, Tarasov, & Hufner***
***hep-ph/0104256***

***Eskola, Kolhinen, Vogt hep-ph/0104124***

***J.C.Peng, LANL***

**E866/NuSea**

**PHENIX**
**μ****+****μ****-**

**e****+****e****-**

- PHENIX μ+μ-  (Au)

**In PHENIX ****μ acceptance**** for Au-Au collisions?**
***Eskola...***** : ~ 0.8**
***Kopeliovich...***** : ~ 0.4**
***Strikman...***** *****[hep-ph/9812322]***** : ~ 0.4**

**PHENIX ****μ**
**PHENIX ****e**
**E866 (mid-rapidity)**
**NA50**

- Mike Leitch - LANL

## PT Broadening for different energies and probes – other data

_**P**__**T**__** Broadening for different energies and probes – other data**_

**NA10 140,286 GeV ********- ****DY**
***PLB ***_***193***_***, 368 (1987)***

**E288 400 GeV p DY**
***PRD ***_***23***_***, 604 (1981)***

**Antipov, 43 GeV ********- ****J/******
***PL***_***76B***_***, 235 (1978)***

**E537 125 GeV p,********-**** J/******
***PRL ***_***60***_***, 2121 (1988)***

**Omega 39.5 GeV ********- ****J/******
***PL***_***110B***_***, 415 (1982)***

- Mike Leitch - LANL

## Systematics of PT Broadening 

_**Systematics of P**__**T**__** Broadening**_** **

- Mike Leitch - LANL

## Feeding of J/Ψ’s from Decay of Higher Mass Resonances

***E705 @ 300 GeV/c, PRL ***_***70***_***, 383 (1993)***

-  Large fraction of J/Ψ’s are not produced directly

-  Nuclear dependence of parent resonance, e.g. χC is probably different than that of the J/Ψ
-  e.g. in proton production ~30% of J/Ψ’s will have effectively stronger absorption because they were actually more strongly absorbed (larger size) χC’s while in the nucleus

|  | Proton | Pion |
| --- | --- | --- |
| χ,1,2  J/Ψ | 30% | 37% |
| Ψ ́  J/Ψ  | 5.5% | 7.6% |

| Meson | M(GeV) | R(Fm) | BE
(MeV) |
| --- | --- | --- | --- |
| J/Ψ | 3.1 | .45 | ~640 |
| Ψ ́ | 3.7 | .88 | ~52 |
| χC | 3.5 | .70 |  |

- Mike Leitch - LANL

## Open Charm Nuclear Dependence : xF Dependence?

_**Open Charm Nuclear Dependence : x**__**F**__** Dependence?**_

*E769 250 GeV ****± ** PRL *_*70*_*,722 (1993)*

*WA82 340 GeV ****- ** PRB *_*284*_*,453 (1992)*

*Vogt et al., NP *_*383*_*,643 (1992)*

- E769 250 GeV ***-*

- WA78 320 GeV ***- *
*(Beam dump)*

**E789 : PRL 72, 2542 (1994)**
**800 GeV***** ***** p + A, <x****F****> = 0.03**
****** ****= 1.02****±****.03****±****.02**

- Mike Leitch - LANL

## Ψ’ to J/Ψ ratio (in +- channel)

_**Ψ**__**’ to J/**__**Ψ ratio (in **__****__**+**__****__**-**__** channel)**_

**E789 – 800 GeV p-Au**
***PRD***_***52***_***, 1307 (1995)***

**NA50 – 200 & 450 GeV p-A**
***PLB ***_***444***_***, 516 (1998)***

- Independent of      and rapidity?

- Mike Leitch - LANL

## J/Ψ Polarization

_**J/**__**Ψ**__** Polarization**_

***E866/NuSea***

**CDF**

- NRQCD based predictions *[Braaten & Fleming, PRL *_*74*_*, 3327 (1995)]* necessary to explain CDF charm cross sections
- E866 measurement not in agreement with NRQCD based predictions *[**Beneke & Rothstein, PRD *_*54*_*, 2005 (1996)**]* which give 0.31 < λ < 0.63
- or with color-singlet models *[PRD *_*51*_*, 3332 (1995)]*
- Complicated by feedown (~40%) from higher mass states.
**No clear information on production mechanism!**

- Mike Leitch - LANL

## Upsilon Polarization – E866/NuSea,  Phys. Rev. Lett. 86,  2529 (2001)

_**Upsilon Polarization – E866/NuSea,  **__***Phys. Rev. Lett. 86,  2529 (2001)***_

** ****Υ****2S+3S**** has maximal polarization,**
**like Drell-Yan**
**Y****1S**** has very small polarization**

**Y****1S**

**Υ****2S+3S**

**Y****1S**

**Υ****2S+3S**

**DY**

**DY**

**Υ****2S+3S**

**Y****1S**

- Mike Leitch - LANL

## Summary:

**Charmonium suppression involves a non-trivial interplay between different effects and involves several timescales including that for hadronizaton and for the coherence of a      pair.**
**It has large variations with x****F**** and p****T**** that help reveal the underlying mechanisms**

**p-A (or d-A) measurements serve as a basis for understanding what is seen in nucleus-nucleus collisions and are a must at RHIC. **
**Shadowing is certainly very important at RHIC and must be measured in d-A collisions as soon as possible**

***Eskola, Kolhinen, Vogt hep-ph/0104124***

***PRL 84, 3256 (2000)***

- Mike Leitch - LANL

## Summary continued – PT broadening:

**               ****is ~5 times larger for J/******** than for Drell-Yan; cause?**
**gluons interact more strongly than quarks by 9/4 color factor**
**resonances can multiple scatter in final state**
**J/********                grows with  **
**Radiative energy loss associated with Drell-Yan p****T**** broadening in the BDMS model is tiny**

_**Summary continued – P**__**T**__** broadening:**_

- Mike Leitch - LANL