Evidence of isospin-symmetry violation in high-energy collisions of atomic nuclei

Strong interactions preserve an approximate isospin symmetry between up (u) and down (d) quarks, part of the more general flavor symmetry. In the case of K meson production, if this isospin symmetry were exact, it would result in equal numbers of charged (K<sup>+</sup> and K<sup>-</sup>) and neutral (K<sup>0</sup> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mrow> <mml:mover><mml:mrow><mml:mi>K</mml:mi></mml:mrow> <mml:mo>¯</mml:mo></mml:mover> </mml:mrow> <mml:mrow><mml:mn>0</mml:mn></mml:mrow> </mml:msup> </mml:math> ) mesons produced in collisions of isospin-symmetric atomic nuclei. Here, we report results on the relative abundance of charged over neutral K meson production in argon and scandium nuclei collisions at a center-of-mass energy of 11.9 GeV per nucleon pair. We find that the production of K<sup>+</sup> and K<sup>-</sup> mesons at mid-rapidity is (18.4 ± 6.1)% higher than that of the neutral K mesons. Although with large uncertainties, earlier data on nucleus-nucleus collisions in the collision center-of-mass energy range <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mn>2.6</mml:mn> <mml:mspace></mml:mspace> <mml:mo><</mml:mo> <mml:mspace></mml:mspace> <mml:msqrt> <mml:mrow> <mml:msub><mml:mrow><mml:mi>s</mml:mi></mml:mrow> <mml:mrow><mml:mi>N</mml:mi> <mml:mi>N</mml:mi></mml:mrow> </mml:msub> </mml:mrow> </mml:msqrt> <mml:mspace></mml:mspace> <mml:mo><</mml:mo> <mml:mspace></mml:mspace> <mml:mn>200</mml:mn></mml:math> GeV are consistent with the present result. Using well-established models for hadron production, we demonstrate that known isospin-symmetry breaking effects and the initial nuclei containing more neutrons than protons lead only to a small (few percent) deviation of the charged-to-neutral kaon ratio from unity at high energies. Thus, they cannot explain the measurements. The significance of the flavor-symmetry violation beyond the known effects is 4.7σ when the compilation of world data with uncertainties quoted by the experiments is used. New systematic, high-precision measurements and theoretical efforts are needed to establish the origin of the observed large isospin-symmetry breaking.

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Journal
Nature Communications
Published
2025-03-23
DOI
https://doi.org/10.1038/s41467-025-57234-6
Citations
9
Primary Topic
High-Energy Particle Collisions Research
Type
article
Field-Weighted Citation Impact
16.83

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article

Evidence of isospin-symmetry violation in high-energy collisions of atomic nuclei

V. Golovatyuk, O. Wyszyński, P. von Doetinchem, R. Engel et al.
9 citations
Nature Communications
High-Energy Particle Collisions Research
16.83
article

Evidence of isospin-symmetry violation in high-energy collisions of atomic nuclei

V. Golovatyuk, O. Wyszyński, P. von Doetinchem, R. Engel, R. Szukiewicz, G. I. Lykasov, M. Rumyantsev, H. Adhikary, I. Pidhurskyi, P. Staszel, Ł. Rozpłochowski, A. Ivashkin, Ł. Świderski, B. T. Rumberger, M. Gaździcki, M. Buryakov, K. Schmidt, A. Shukla, M. Roth, P. Podlaski, M. Strikhanov, A. Zaitsev, F. Guber, E. Zherebtsova, M. M. Kielbowicz, A. Rustamov, J. Brzychczyk, T. Šuša, M. Słodkowski, A. Olivier, Darko Veberič, M. Urbaniak, H. Ströbele, V. Vechernin, Y. Balkova, Evgeny Andronov, L. Ren, M. P. Lewicki, V. Paolone, D. Pszczel, Y. Bondar, P. Seyboth, Y. Nagai, M. Rybczyński, E. Kashirin, M. Naskręt, Francesco Giacosa, Y. Shiraishi, T. Matulewicz, M. Kuich, Д. С. Прохорова, Ł. Mik, O. Vitiuk, W. Kucewicz, K. Sakashita, V. Ozvenchuk, D. A. Wickremasinghe, M. I. Gorenstein, W. Bryliński, D. Rybka, S. Kowalski, M. Friend, O. Panova, D. Tefelski, T. S. Tveter, A. Zviagina, B. Kozłowski, G. L. Melkumov, B. Pórfy, U. A. Shah, A. Brandin, M. Ćirković, Hermann-Josef Mathes, R. Tsenov, V. A. Kireyeu, L. Turko, J. Steṕaniak, N. Karpushkin, V. Z. Reyna Ortiz, B. Popov, Roman V. Poberezhnyuk, K. K. Allison, J. Cybowska, A. Taranenko, Jarosław Szewiński, Y. Koshio, P. Adrich, A. Dmitriev, M. Bielewicz, F. F. Valiev, M. Bajda, S. Puławski, S. Ilieva, A. Blondel, R. Płaneta, A. Malakhov, Г. Феофилов, V. Kovalenko, A. Bazgir, M. Bogomilov, W. Dominik, K. Grebieszkow, A. Yu. Seryakov, C. Dalmazzone, M. Golubeva, M. Kuchowicz, M. Maćkowiak-Pawłowska, A. F. Camino, R. Zwaska, A. Makhnev, Subhasis Samanta, M. Unger, E. Rondio, V. Matveev, J. Dumarchez, A. D. Marino, V. Volkov, E. D. Zimmerman, N. Amin, G. Stefanek, Z. Majka, L. Fields, A. Marcinek, A. Tefelska, N. Davis, O. Golosov, A. Rybicki, S. N. Igolkin, Á. László, I. C. Arsene, D. Röhrich, V. Lyubushkin, D. Kolev, T. Czopowicz, K. Witek, A. Kurepin, R. Renfordt, T. Nakadaira, A. Krasnoperov, A. Merzlaya, A. Izvestnyy, O. Petukhov, J. Puzović, V. Tereshchenko, Zoltán Fodor, Н. И. Каргин, M. Csanád, B. Maksiak, S. Bhosale, S. Nishimori, D. Battaglia, Roman A. Kolesnikov, K. Wójcik, S. Morozov
article en
9 citations

Abstract

Strong interactions preserve an approximate isospin symmetry between up (u) and down (d) quarks, part of the more general flavor symmetry. In the case of K meson production, if this isospin symmetry were exact, it would result in equal numbers of charged (K<sup>+</sup> and K<sup>-</sup>) and neutral (K<sup>0</sup> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mrow> <mml:mover><mml:mrow><mml:mi>K</mml:mi></mml:mrow> <mml:mo>¯</mml:mo></mml:mover> </mml:mrow> <mml:mrow><mml:mn>0</mml:mn></mml:mrow> </mml:msup> </mml:math> ) mesons produced in collisions of isospin-symmetric atomic nuclei. Here, we report results on the relative abundance of charged over neutral K meson production in argon and scandium nuclei collisions at a center-of-mass energy of 11.9 GeV per nucleon pair. We find that the production of K<sup>+</sup> and K<sup>-</sup> mesons at mid-rapidity is (18.4 ± 6.1)% higher than that of the neutral K mesons. Although with large uncertainties, earlier data on nucleus-nucleus collisions in the collision center-of-mass energy range <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mn>2.6</mml:mn> <mml:mspace></mml:mspace> <mml:mo><</mml:mo> <mml:mspace></mml:mspace> <mml:msqrt> <mml:mrow> <mml:msub><mml:mrow><mml:mi>s</mml:mi></mml:mrow> <mml:mrow><mml:mi>N</mml:mi> <mml:mi>N</mml:mi></mml:mrow> </mml:msub> </mml:mrow> </mml:msqrt> <mml:mspace></mml:mspace> <mml:mo><</mml:mo> <mml:mspace></mml:mspace> <mml:mn>200</mml:mn></mml:math> GeV are consistent with the present result. Using well-established models for hadron production, we demonstrate that known isospin-symmetry breaking effects and the initial nuclei containing more neutrons than protons lead only to a small (few percent) deviation of the charged-to-neutral kaon ratio from unity at high energies. Thus, they cannot explain the measurements. The significance of the flavor-symmetry violation beyond the known effects is 4.7σ when the compilation of world data with uncertainties quoted by the experiments is used. New systematic, high-precision measurements and theoretical efforts are needed to establish the origin of the observed large isospin-symmetry breaking.

Nature CommunicationsVol. 16(1)
Karlsruhe Institute of Technology (DE), Eötvös Loránd University (HU), University of Notre Dame (US), Warsaw University of Technology (PL), Goethe University Frankfurt (DE), University of Hawaiʻi at Mānoa (US), Jagiellonian University (PL), Centre National de la Recherche Scientifique (FR), Fermi National Accelerator Laboratory (US), Okayama University (JP), Jan Kochanowski University (PL), University of Pittsburgh (US), University of Oslo (NO), University of Colorado Boulder (US), University of Wrocław (PL), Frankfurt Institute for Advanced Studies (DE), Sorbonne Université (FR), University of Belgrade (RS), National Centre for Nuclear Research (PL), Laboratoire de Physique Nucléaire et de Hautes Énergies (FR), Institute of Nuclear Physics, Polish Academy of Sciences (PL), Ruđer Bošković Institute (HR), HUN-REN Wigner Research Centre for Physics (HU), National Nuclear Research Center (AZ), Bogolyubov Institute for Theoretical Physics (UA), University of Bergen (NO), University of Houston (US), University of Warsaw (PL), Sofia University "St. Kliment Ohridski" (BG), KIIT University (IN), AGH University of Krakow (PL), University of Silesia in Katowice (PL)
National Science Foundation, U.S. Department of Energy, Alexander von Humboldt-Stiftung, CERN, Strong, European Commission, Deutsche Forschungsgemeinschaft, Ministry of Education, Culture, Sports, Science and Technology, Hungarian Scientific Research Fund, Centre National de la Recherche Scientifique, Uniwersytet Jana Kochanowskiego w Kielcach, Nemzeti Kutatási Fejlesztési és Innovációs Hivatal, Narodowa Agencja Wymiany Akademickiej, Office of Science, Institut National de Physique Nucléaire et de Physique des Particules, Fermilab
Openalex Percentile: Top 1%
High-Energy Particle Collisions Research
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