Parton energy loss in heavy-ion collisions via direct-photon and charged-particle azimuthal correlations
- University of Illinois at Chicago, Chicago, Illinois 60607 (United States)
- Panjab University, Chandigarh 160014 (India)
- Variable Energy Cyclotron Centre, Kolkata 700064 (India)
Charged-particle spectra associated with direct photon ({gamma}{sub dir}) and {pi}{sup 0} are measured in p+p and Au+Au collisions at center-of-mass energy {radical}(s{sub N{sub N}})=200 GeV with the STAR detector at the Relativistic Heavy Ion Collider. A shower-shape analysis is used to partially discriminate between {gamma}{sub dir} and {pi}{sup 0}. Assuming no associated charged particles in the {gamma}{sub dir} direction (near side) and small contribution from fragmentation photons ({gamma}{sub frag}), the associated charged-particle yields opposite to {gamma}{sub dir} (away side) are extracted. In central Au+Au collisions, the charged-particle yields at midrapidity (|{eta}|<1) and high transverse momentum (3<p{sub T}{sup assoc}<16 GeV/c) associated with {gamma}{sub dir} and {pi}{sup 0} (|{eta}|<0.9, 8<p{sub T}{sup trig}<16 GeV/c) are suppressed by a factor of 3-5 compared with p+p collisions. The observed suppression of the associated charged particles is similar for {gamma}{sub dir} and {pi}{sup 0} and independent of the {gamma}{sub dir} energy within uncertainties. These measurements indicate that, in the kinematic range covered and within our current experimental uncertainties, the parton energy loss shows no sensitivity to the parton initial energy, path length, or color charge.
- OSTI ID:
- 21419549
- Journal Information:
- Physical Review. C, Nuclear Physics, Vol. 82, Issue 3; Other Information: DOI: 10.1103/PhysRevC.82.034909; (c) 2010 The American Physical Society; ISSN 0556-2813
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ATOM-ATOM COLLISIONS
BROOKHAVEN RHIC
CENTER-OF-MASS SYSTEM
CHARGED PARTICLES
COLLISIONS
COLOR MODEL
CORRELATIONS
ENERGY LOSSES
FRAGMENTATION
GEV RANGE 100-1000
GOLD
HEAVY ION REACTIONS
PHOTONS
PIONS NEUTRAL
PROTON-PROTON INTERACTIONS
SENSITIVITY
SPECTRA
TRANSVERSE MOMENTUM
ACCELERATORS
ATOM COLLISIONS
BARYON-BARYON INTERACTIONS
BOSONS
COMPOSITE MODELS
ELEMENTARY PARTICLES
ELEMENTS
ENERGY RANGE
GEV RANGE
HADRON-HADRON INTERACTIONS
HADRONS
HEAVY ION ACCELERATORS
INTERACTIONS
LINEAR MOMENTUM
LOSSES
MASSLESS PARTICLES
MATHEMATICAL MODELS
MESONS
METALS
NUCLEAR REACTIONS
NUCLEON-NUCLEON INTERACTIONS
PARTICLE INTERACTIONS
PARTICLE MODELS
PIONS
PROTON-NUCLEON INTERACTIONS
PSEUDOSCALAR MESONS
QUARK MODEL
STORAGE RINGS
TRANSITION ELEMENTS