학술논문
Excess of charged over neutral $K$ meson production in high-energy collisions of atomic nuclei
Document Type
Working Paper
Author
Collaboration, NA61/SHINE; Adhikary, H.; Adrich, P.; Allison, K. K.; Amin, N.; Andronov, E. V.; Arsene, I. -C.; Bajda, M.; Balkova, Y.; Battaglia, D.; Bazgir, A.; Bhosale, S.; Bielewicz, M.; Blondel, A.; Bogomilov, M.; Bondar, Y.; Brandin, A.; Brylinski, W.; Brzychczyk, J.; Buryakov, M.; Camino, A. F.; Cirkovic, M.; Csanád, M.; Cybowska, J.; Czopowicz, T.; Dalmazzone, C.; Davis, N.; Dmitriev, A.; von Doetinchem, P.; Dominik, W.; Dumarchez, J.; Engel, R.; Feofilov, G. A.; Fields, L.; Fodor, Z.; Friend, M.; Gazdzicki, M.; Golosov, O.; Golovatyuk, V.; Golubeva, M.; Grebieszkow, K.; Guber, F.; Igolkin, S. N.; Ilieva, S.; Ivashkin, A.; Izvestnyy, A.; Kargin, N.; Karpushkin, N.; Kashirin, E.; Kiełbowicz, M.; Kireyeu, V. A.; Kolesnikov, R.; Kolev, D.; Koshio, Y.; Kovalenko, V. N.; Kowalski, S.; Kozłowski, B.; Krasnoperov, A.; Kucewicz, W.; Kuchowicz, M.; Kuich, M.; Kurepin, A.; László, A.; Lewicki, M.; Lykasov, G.; Lyubushkin, V. V.; Mackowiak-Pawłowska, M.; Majka, Z.; Makhnev, A.; Maksiak, B.; Malakhov, A. I.; Marcinek, A.; Marino, A. D.; Mathes, H. -J.; Matulewicz, T.; Matveev, V.; Melkumov, G. L.; Merzlaya, A.; Mik, Ł.; Morozov, S.; Nagai, Y.; Nakadaira, T.; Naskret, M.; Nishimori, S.; Olivier, A.; Ozvenchuk, V.; Panova, O.; Paolone, V.; Petukhov, O.; Pidhurskyi, I.; Płaneta, R.; Podlaski, P.; Popov, B. A.; Pórfy, B.; Prokhorova, D. S.; Pszczel, D.; Puławski, S.; Puzovic, J.; Renfordt, R.; Ren, L.; Ortiz, V. Z. Reyna; Röhrich, D.; Rondio, E.; Roth, M.; Rozpłochowski, Ł.; Rumberger, B. T.; Rumyantsev, M.; Rustamov, A.; Rybczynski, M.; Rybicki, A.; Rybka, D.; Sakashita, K.; Schmidt, K.; Seryakov, A. Yu.; Seyboth, P.; Shah, U. A.; Shiraishi, Y.; Shukla, A.; Słodkowski, M.; Staszel, P.; Stefanek, G.; Stepaniak, J.; Strikhanov, M.; Ströbele, H.; Šuša, T.; Swiderski, Ł.; Szewinski, J.; Szukiewicz, R.; Taranenko, A.; Tefelska, A.; Tefelski, D.; Tereshchenko, V.; Tsenov, R.; Turko, L.; Tveter, T. S.; Unger, M.; Urbaniak, M.; Valiev, F. F.; Veberic, D.; Vechernin, V. V.; Vitiuk, O.; Volkov, V.; Wickremasinghe, A.; Witek, K.; Wójcik, K.; Wyszynski, O.; Zaitsev, A.; Zherebtsova, E.; Zimmerman, E. D.; Zviagina, A.; Zwaska, R.
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Abstract
Collisions of atomic nuclei at relativistic velocities produce new particles, predominantly mesons containing one valence quark and one valence anti-quark. These particles are produced in strong interactions, which preserve an approximate symmetry between up ($u$) and down ($d$) quarks. In the case of $K$ meson production, if this symmetry were exact, it would result in equal numbers of charged ($K^+$ and $K^-$) and neutral ($K^0$ and $\overline K^0$) mesons in the final state. In this Letter, we report a measurement of the relative abundance of charged over neutral $K$ meson production in collisions of argon and scandium nuclei at a center-of-mass energy of 11.9~GeV per nucleon pair. We find that production of $\mathit{K^+}$ and $\mathit{K^-}$ mesons at mid-rapidity displays a significant excess of $(23.3\pm 5.5)\%$ relative to that of the neutral $K$ mesons. The origin of this unexpected excess remains to be elucidated.
Comment: 18 pages, 6 figures
Comment: 18 pages, 6 figures