L. Adamczyk, AGH University of Science and Technology, Poland
James K. Adkins, University of KentuckyFollow
G. Agakishiev, Joint Institute for Nuclear Research, Russia
M. M. Aggarwal, Panjab University, India
Z. Ahammed, Variable Energy Cyclotron Centre, India
I. Alekseev, Alikhanov Institute for Theoretical and Experimental Physics, Russia
A. Aparin, Joint Institute for Nuclear Research, Russia
D. Arkhipkin, Brookhaven National Laboratory
E. C. Aschenauer, Brookhaven National Laboratory
A. Attri, Panjab University, India
G. S. Averichev, Joint Institute for Nuclear Research, Russia
X. Bai, Central China Normal University, China
V. Bairathi, National Institute of Science Education and Research, India
R. Bellwied, University of Houston
A. Bhasin, University of Jammu, India
A. K. Bhati, Panjab University, India
P. Bhattarai, University of Texas at Austin
J. Bielcik, Czech Technical University in Prague, Czech Republic
J. Bielcikova, Nuclear Physics Institute AS CR, Czech Republic
L. C. Bland, Brookhaven National Laboratory
I. G. Bordyuzhin, Alikhanov Institute for Theoretical and Experimental Physics, Russia
J. Bouchet, Kent State University
J. D. Brandenburg, Rice University
A. V. Brandin, National Research Nuclear Univeristy MEPhI, Russia
I. Bunzarov, Joint Institute for Nuclear Research, Russia
J. Butterworth, Rice University
H. Caines, Yale University
M. Calderón de la Barca Sánchez, University of California - Davis
J. M. Campbell, Ohio State University
D. Cebra, University of California - Davis
Renee H. Fatemi, University of KentuckyFollow
Suvarna Ramachandran, University of KentuckyFollow


We present results from a harmonic decomposition of two-particle azimuthal correlations measured with the STAR detector in Au + Au collisions for energies ranging from √sNN = 7.7 to 200 GeV. The third harmonic υ23 {2} = ⟨cos3(ϕ1ϕ2)⟩, where ϕ1ϕ2 is the angular difference in azimuth, is studied as a function of the pseudorapidity difference between particle pairs Δη = η1 η2. Nonzero υ23 {2} is directly related to the previously observed large-Δη narrow-Δϕ ridge correlations and has been shown in models to be sensitive to the existence of a low viscosity quark gluon plasma phase. For sufficiently central collisions, υ23 {2} persist down to an energy of 7.7 GeV, suggesting that quark gluon plasma may be created even in these low energy collisions. In peripheral collisions at these low energies, however, υ23 {2} is consistent with zero. When scaled by the pseudorapidity density of charged-particle multiplicity per participating nucleon pair, υ23 {2} for central collisions shows a minimum near √sNN = 20 GeV.

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Published in Physical Review Letters, v. 116, issue 11, 112302, p. 1-9.

© 2016 American Physical Society

The copyright holder has granted permission for posting the article here.

Due to the large number of authors, only the first 30 and the authors affiliated with the University of Kentucky are listed in the author section above. For the complete list of authors, please download this article.

The authors of this article are collectively known as STAR Collaboration.

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We thank the RHIC Operations Group and RCF at BNL, the NERSC Center at LBNL, the KISTI Center in Korea, and the Open Science Grid consortium for providing resources and support. This work was supported in part by the Office of Nuclear Physics within the U.S. DOE Office of Science, the U.S. NSF, the Ministry of Education and Science of the Russian Federation, NSFC, CAS, MoST, and MoE of China, the National Research Foundation of Korea, NCKU (Taiwan), GA and MSMT of the Czech Republic, FIAS of Germany, DAE, DST, and UGC of India, the National Science Centre of Poland, National Research Foundation, the Ministry of Science, Education and Sports of the Republic of Croatia, and RosAtom of Russia.

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