hadronization from dis at clas
DESCRIPTION
Hadronization from DIS at CLAS. K. Hicks * (CLAS Collaboration) DIS 2009 Conference, Madrid April 27, 2009. *working with Aji Daniel and the eg2 run-group. Introduction. Goal: measure observables of quark propagation through cold QCD matter. Pions: PhD work of H. Hakobyan (Yerevan) - PowerPoint PPT PresentationTRANSCRIPT
Hadronization from Hadronization from DIS at CLASDIS at CLASK. HicksK. Hicks** (CLAS Collaboration) (CLAS Collaboration)
DIS 2009 Conference, MadridDIS 2009 Conference, Madrid
April 27, 2009April 27, 2009*working with Aji Daniel and the eg2 run-group.
Ken Hicks, Ohio U.Ken Hicks, Ohio U. DIS 2009, April 27DIS 2009, April 27 22
IntroductionIntroduction
Goal: measure observables of quark Goal: measure observables of quark propagation through cold QCD matter.propagation through cold QCD matter.
Pions: PhD work of H. Hakobyan (Yerevan)Pions: PhD work of H. Hakobyan (Yerevan) Kaons: work of postdoc A. Daniel (Ohio)Kaons: work of postdoc A. Daniel (Ohio)
Do kaons hadronize differently than pions?Do kaons hadronize differently than pions? Heavy s-quarks could affect the hadronization.Heavy s-quarks could affect the hadronization.
KK++ and K and K-- attenuation ratios differ (HERMES). attenuation ratios differ (HERMES). No difference between No difference between ++, , -- or or 00.. New: KNew: K00 attenuation ratios (not done by HERMES). attenuation ratios (not done by HERMES).
Ken Hicks, Ohio U.Ken Hicks, Ohio U. DIS 2009, April 27DIS 2009, April 27 33
Deep Inelastic ScatteringRelativistic Heavy-Ion Collisions
e e’
Initial quark energy is knownProperties of medium are known
Relevance to RHICRelevance to RHIC
These experiments try to recreate conditions of the early universe.
Graphics by Will Brooks
Ken Hicks, Ohio U.Ken Hicks, Ohio U. DIS 2009, April 27DIS 2009, April 27 44
ObservablesObservables
Hadronic multiplicity ratio: Transverse momentum:
DIS
DT
DIS
ATT ppp 222
Binning:
Q2 (range 1.0-2.5 GeV2) (range 2.6-4.3 GeV) z (range 0.1-1.0)
Ken Hicks, Ohio U.Ken Hicks, Ohio U. DIS 2009, April 27DIS 2009, April 27 55
Theoretical ModelsTheoretical Models
No (dynamical) lattice calculations yet.No (dynamical) lattice calculations yet. Accardi et al. (nucl-th/0211011):Accardi et al. (nucl-th/0211011):
gluon radiation and absorption included.gluon radiation and absorption included. good agreement with HERMES data.good agreement with HERMES data. increased increased deconfinementdeconfinement in nuclei. in nuclei.
Many other phenomenological models.Many other phenomenological models.
Ken Hicks, Ohio U.Ken Hicks, Ohio U. DIS 2009, April 27DIS 2009, April 27 66
Inside the ModelsInside the Models
HERMES: K+ and K- different.
Ken Hicks, Ohio U.Ken Hicks, Ohio U. DIS 2009, April 27DIS 2009, April 27 77
CLAS – the CEBAF Large Acceptance Spectrometer
Ken Hicks, Ohio U.Ken Hicks, Ohio U. DIS 2009, April 27DIS 2009, April 27 88
eg2: pion attenuationeg2: pion attenuation
H. Hakobyan analysis: one of ~50 bins
Ken Hicks, Ohio U.Ken Hicks, Ohio U. DIS 2009, April 27DIS 2009, April 27 99
Examples of multi-variable Examples of multi-variable (preliminary) CLAS data(preliminary) CLAS data
zh dependence
Q2 dependence
pT2 dependence
dependence
Ken Hicks, Ohio U.Ken Hicks, Ohio U. DIS 2009, April 27DIS 2009, April 27 1010
ppTT Broadening and Quark Broadening and Quark Energy LossEnergy Loss
nucleus
propagating quark
quarks in nuclei
gluons
L
Quarks lose energy by Quarks lose energy by gluon emissiongluon emission as they propagate within a mediumas they propagate within a medium
Medium-stimulated losscalculation by BDMPS
ThisThisenergy loss is manifested by energy loss is manifested by pT2
pT2 gives the production time p
E ~ L dominates in QEDE ~ L dominates in QED
E ~ LE ~ L22 dominates in QCD? dominates in QCD?
Ken Hicks, Ohio U.Ken Hicks, Ohio U. DIS 2009, April 27DIS 2009, April 27 1111
eg2: pion peg2: pion pTT broadening broadening
H. Hakobyan analysis
Pb
Fe
C
pT
2
(GeV)
Ken Hicks, Ohio U.Ken Hicks, Ohio U. DIS 2009, April 27DIS 2009, April 27 1212
A-dependence of A-dependence of ppTT22
Only statistical errors shown
Only one of many bins of CLAS data
Ken Hicks, Ohio U.Ken Hicks, Ohio U. DIS 2009, April 27DIS 2009, April 27 1313
KK00 from M( from M(++--) at ) at z=0.55z=0.55
M(+-) [GeV]
LD2 target Fe target
Ken Hicks, Ohio U.Ken Hicks, Ohio U. DIS 2009, April 27DIS 2009, April 27 1414
z-dependence of Kz-dependence of K00 peakpeak
(CLAS PRELIMINARY)
Ken Hicks, Ohio U.Ken Hicks, Ohio U. DIS 2009, April 27DIS 2009, April 27 1515
KK00 Multiplicity Ratio Multiplicity Ratio
z = Eh/
(CLAS PRELIMINARY)
Ken Hicks, Ohio U.Ken Hicks, Ohio U. DIS 2009, April 27DIS 2009, April 27 1616
KK00 broadening of <p broadening of <ptt22>>
(CLAS PRELIMINARY)
Ken Hicks, Ohio U.Ken Hicks, Ohio U. DIS 2009, April 27DIS 2009, April 27 1717
KK00 Cronin Effect Cronin Effect
(CLAS PRELIMINARY)
Ken Hicks, Ohio U.Ken Hicks, Ohio U. DIS 2009, April 27DIS 2009, April 27 181812
GeV
Anti
cipate
d D
ata
12
GeV
Anti
cipate
d D
ata
Bins in yellow accessible at 5 GeV at CLAS
+
Ken Hicks, Ohio U.Ken Hicks, Ohio U. DIS 2009, April 27DIS 2009, April 27 1919
SummarySummary There is good statistical precision of the pion There is good statistical precision of the pion
data at 5 GeV.data at 5 GeV. Hadronization ratios, Hadronization ratios, ppTT
22, and Cronin effect. , and Cronin effect. Results are still preliminary but nearly final.Results are still preliminary but nearly final.
There is modest statistical precision for the KThere is modest statistical precision for the K00 data at 5 GeV.data at 5 GeV. From these data, we hope to learn about the quark From these data, we hope to learn about the quark
mass dependence of hadronization.mass dependence of hadronization. The JLab 12 GeV upgrade creates new The JLab 12 GeV upgrade creates new
possibilities to study quark-matter propagation.possibilities to study quark-matter propagation.
Ken Hicks, Ohio U.Ken Hicks, Ohio U. DIS 2009, April 27DIS 2009, April 27 2020
Backup SlidesBackup Slides
Ken Hicks, Ohio U.Ken Hicks, Ohio U. DIS 2009, April 27DIS 2009, April 27 2121
CLAS EG2CLAS EG2TargetsTargets
• Two targets in the beam simultaneously
• 2 cm LD2, upstream
• Solid target downstream
• Six solid targets:
-Carbon
-Aluminum (2 thicknesses)
-Iron
-Tin
-Lead
Al +emptytarget
Ken Hicks, Ohio U.Ken Hicks, Ohio U. DIS 2009, April 27DIS 2009, April 27 2222
Cronin Cronin EffectEffect
Carbon
Iron
Lead
Theoretical prediction:
CLAS preliminary dataz=0.5 and 0.7
Probes reaction mechanism