Symmetry energy investigation with pion production from Sn+Sn systems

  • In the past two decades, pions created in the high density regions of heavy ion collisions have been predicted to be sensitive at high densities to the symmetry energy term in the nuclear equation of state, a property that is key to our understanding of neutron stars. In a new experiment designed to study the symmetry energy, the multiplicities of negatively and positively charged pions have been measured with high accuracy for central 132Sn+124Sn, 112Sn+124Sn, and 108Sn+112Sn collisions at E/A = 270 MeV with the SπRIT Time Projection Chamber. While individual pion multiplicities are measured to 4% accuracy, those of the charged pion multiplicity ratios are measured to 2% accuracy. We compare these data to predictions from seven major transport models. The calculations reproduce qualitatively the dependence of the multiplicities and their ratios on the total neutron and proton number in the colliding systems. However, the predictions of the transport models from different codes differ too much to allow extraction of reliable constraints on the symmetry energy from the data. This finding may explain previous contradictory conclusions on symmetry energy constraints obtained from pion data in Au+Au system. These new results call for still better understanding of the differences among transport codes, and new observables that are more sensitive to the density dependence of the symmetry energy.

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Author:Genie JhangORCiD, Justin Estee, Jonathan Barney, Giordano Cerizza, Masanori KanekoORCiD, Jung Woo Lee, William G. LynchORCiD, Tadaaki IsobeORCiD, Mizuki Kurata-NishimuraORCiD, Tetsuya MurakamiORCiD, Chun Yuen Tsang, Betty Tsang, Rensheng Wang, Deuk Soon Ahn, Leyla AtarORCiDGND, Thomas AumannORCiDGND, Hidetada BabaORCiD, Konstanze BoretzkyORCiD, Janusz BrzychczykORCiD, Nobuyuki Chiga, Naoki FukudaORCiD, Igor GašparićORCiD, Byungsik HongORCiD, Andrea HorvatORCiDGND, Kazuo IekiORCiD, Naohito Inabe, Y.J. Kim, Taizo Kobayashi, Yosuke KondoORCiD, Pawel LaskoORCiD, H.S. Lee, Yvonne LeifelsORCiDGND, Jerzy ŁukasikORCiD, Juan ManfrediORCiD, Alan B. McIntoshORCiD, Pierre MorfouaceORCiD, Takashi NakamuraORCiD, N. Nakatsuka, Shunji NishimuraORCiD, Robert Olsen, Hideaki OtsuORCiD, Piotr PawłowskiORCiD, Krzysztof PelczarORCiD, Dominic M. RossiORCiDGND, Hiroyoshi SakuraiORCiD, Clementine SantamariaORCiD, Hiromi SatoORCiD, Heiko ScheitORCiDGND, Rebecca ShaneORCiD, Yohei Shimizu, Haik SimonGND, Aleksandra Snoch, Anna SochockaORCiD, Zbigniew Sosin, Toshiyuki SumikamaORCiD, Hiroshi Suzuki, Daisuke Suzuki, Hiroshi Takeda, Suwat Tangwancharoen, Hans Toshihide TörnqvistORCiD, Yasuhiro Togano, Zhi-Gang Xiao, Sherry J. YennelloORCiD, John Yurkon, Youhong Zhang, Maria Colonna, Dan Cozma, Paweł DanielewiczORCiDGND, Hannah ElfnerORCiDGND, Natsumi IkenoORCiD, Che Ming KoORCiD, Justin MohsORCiD, Dmytro OliinychenkoORCiDGND, Akira OnoORCiD, Jun Su, Yong Jia Wang, Hermann Wolter, Jun XuORCiD, Ying-Xun Zhang, Zhen Zhang
Parent Title (English):Physics Letters B
Place of publication:Amsterdam
Document Type:Article
Date of Publication (online):2020/12/15
Date of first Publication:2020/12/15
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Creating Corporation:TMEP collaboration
Contributing Corporation:the SπRIT Collaboration
Release Date:2022/10/01
Page Number:7
Institutes:Physik / Physik
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 53 Physik / 530 Physik
Licence (German):License LogoCreative Commons - Namensnennung 4.0