Strong Absorption of Hadrons with Hidden and Open Strangeness in Nuclear Matter

Adamczewski-Musch, J.; Arnold, O.; Atomssa, E. T.; Behnke, C.; Belounnas, A.; Belyaev, A.; Berger-Chen, J. C.; Biernat, J.; Blanco, A.; Blume, C.; Bohmer, M.; Chernenko, S.; Chlad, L.; Chudoba, P.; Ciepal, I.; Deveaux, C.; Dittert, D.; Dreyer, J.; Epple, E.; Fabbietti, L.; Fateev, O.; Fonte, P.; Franco, C.; Friese, J.; Frohlich, I.; Galatyuk, T.; Garzon, J. A.; Gernhauser, R.; Golubeva, M.; Greifenhagen, R.; Guber, F.; Gumberidze, M.; Harabasz, S.; Heinz, T.; Hennino, T.; Hohne, C.; Holzmann, R.; Ierusalimov, A.; Ivashkin, A.; Kampfer, B.; Kardan, B.; Koenig, I.; Koenig, W.; Kolb, B. W.; Korcyl, G.; Kornakov, G.; Kornas, F.; Kotte, R.; Kubos, J.; Kugler, A.; Kunz, T.; Kurepin, A.; Kurilkin, A.; Kurilkin, P.; Ladygin, V.; Lalik, R.; Lapidus, K.; Lebedev, A.; Linev, S.; Lopes, L.; Lorenz, M.; Mahmoud, T.; Maier, L.; Malige, A.; Markert, J.; Maurus, S.; Metag, V.; Michel, J.; Mihaylov, D. M.; Mikhaylov, V.; Morozov, S.; Muntz, C.; Munzer, R.; Naumann, L.; Nowakowski, K.; Parpottas, Y.; Pechenov, V.; Pechenova, O.; Petukhov, O.; Pietraszko, J.; Prozorov, A. P.; Przygoda, W.; Ramstein, B.; Rathod, N.; Reshetin, A.; Rodriguez-Ramos, P.; Rost, A.; Sadovsky, A.; Salabura, P.; Scheib, T.; Schmidt-Sommerfeld, K.; Schuldes, H.; Schwab, E.; Scozzi, F.; Seck, F.; Sellheim, P.; Siebenson, J.; Silva, L.; Smyrski, J.; Spataro, S.; Spies, S.; Strobele, H.; Stroth, J.; Strzempek, P.; Sturm, C.; Svoboda, O.; Szala, M.; Tlusty, P.; Traxler, M.; Tsertos, H.; Ungethum, C.; Vazquez Doce, O.; Wagner, V.; Wendisch, C.; Wiebusch, M. G.; Wirth, J.; Wojcik, D.; Zanevsky, Y.; Zumbruch, P.; Curceanu, C.; Piscicchia, K.; Scordo, A.

doi:10.1103/PhysRevLett.123.022002

We present the first observation of K- and φ absorption within nuclear matter by means of π - induced reactions on C and W targets at an incident beam momentum of 1.7 GeV/c studied with HADES at SIS18/GSI. The double ratio (K-/K+)W/(K-/K+)C is found to be 0.319±0.009(stat)-0.012+0.014(syst) indicating a larger absorption of K- in heavier targets as compared to lighter ones. The measured φ/K- ratios in π-+C and π-+W reactions within the HADES acceptance are found to be equal to 0.55±0.04(stat)-0.07+0.06(syst) and to 0.63±0.06(stat)-0.11+0.11(syst), respectively. The similar ratios measured in the two different reactions demonstrate for the first time experimentally that the dynamics of the φ meson in nuclear medium is strongly coupled to the K- dynamics. The large difference in the φ production off C and W nuclei is discussed in terms of a strong φN in-medium coupling. These results are relevant for the description of heavy-ion collisions and the structure of neutron stars.