Probing late-stage hadronic interactions at high baryon density via K^⁎0 production in the RHIC beam energy scan program

Authors

• B. E. Aboona, Texas AandM University
• J. Adam, Czech Technical University in Prague
• G. Agakishiev, Joint Institute for Nuclear Research, Dubna
• I. Aggarwal, Panjab University
• M. M. Aggarwal, Panjab University
• Z. Ahammed, Variable Energy Cyclotron Centre
• A. Aitbayev, Joint Institute for Nuclear Research, Dubna
• I. Alekseev, Alikhanov Institute for Theoretical and Experimental Physics
• E. Alpatov, Moscow Engineering Physics Institute
• A. K. Alshammri, Kent State University
• A. Aparin, Joint Institute for Nuclear Research, Dubna
• S. Aslam, Fudan University
• J. Atchison, Abilene Christian University
• G. S. Averichev, Joint Institute for Nuclear Research, Dubna
• V. Bairathi, Universidad de Tarapaca
• X. Bao, Shandong University
• P. Barik, Indian Institute of Science Education and Research (IISER)
• K. Barish, University of California Riverside
• S. Behera, Indian Institute of Science Education and Research (IISER) Tirupati
• P. Bhagat, University of Jammu
• A. Bhasin, University of Jammu
• S. Bhatta, Stony Brook University
• I. G. Bordyuzhin, Alikhanov Institute for Theoretical and Experimental Physics
• J. D. Brandenburg, Ohio State University
• A. V. Brandin, Moscow Engineering Physics Institute
• C. Broodo, University of Houston
• X. Z. Cai, Chinese Academy of Sciences
• H. Caines, Yale University
• M. Calderón de la Barca Sánchez, University of California Davis
• D. Cebra, University of California Davis
• J. Ceska, Czech Technical University in Prague

Abstract

A precision measurement of the K ^⁎0 meson yield is reported in Au+Au collisions at s_NN=7.7,11.5,14.6,19.6, and 27 GeV using the high-statistics data sample collected by the STAR experiment during the Beam Energy Scan II (BES-II) program at RHIC. The transeverse momentum ( p_T )-integrated yield ratios (K^*0+K^*0‾)/(K⁺+K⁻) in central collisions show a suppression relative to peripheral collisions at the (1.7–3.6) σ level, while a thermal model without final-stage rescattering overpredicts this ratio with a deviation of (6.9–8.2) σ . These results indicate a loss of the measured K ^⁎0 signal in central collisions due to re-scattering of its hadronic decay products in the hadronic phase. The p_T -integrated yield of charged kaons exhibits an approximate scaling with charged-particle multiplicity, independent of collision energy and system size. A similar trend is observed for the short-lived K ^⁎0 resonance, although significant deviations emerge at lower energies. At BES energies, the K ^⁎0/ K ratio shows stronger suppression than at the highest RHIC and LHC energies within a given multiplicity bin, particularly in central and mid-central collisions. This behavior is consistent with changes in the effective hadronic interaction cross section and is supported by transport model calculations, which indicate dominant meson–baryon interactions at lower energies and meson–meson interactions at higher energies.

Document Type

Article

Publication Date

5-1-2026

Notes/Citation Information

Publisher Copyright: Copyright © 2026. Published by Elsevier B.V.

Digital Object Identifier (DOI)

10.1016/j.physletb.2026.140389

Archival?

Archival

Repository Citation

Aboona, B. E.; Adam, J.; Agakishiev, G.; Aggarwal, I.; Aggarwal, M. M.; Ahammed, Z.; Aitbayev, A.; Alekseev, I.; Alpatov, E.; Alshammri, A. K.; Aparin, A.; Aslam, S.; Atchison, J.; Averichev, G. S.; Bairathi, V.; Bao, X.; Barik, P.; Barish, K.; Behera, S.; Bhagat, P.; Bhasin, A.; Bhatta, S.; Bordyuzhin, I. G.; Brandenburg, J. D.; Brandin, A. V.; Broodo, C.; Cai, X. Z.; Caines, H.; Calderón de la Barca Sánchez, M.; Cebra, D.; and Ceska, J., "Probing late-stage hadronic interactions at high baryon density via K^⁎0 production in the RHIC beam energy scan program" (2026). Physics and Astronomy Faculty Publications. 779.
https://uknowledge.uky.edu/physastron_facpub/779