Enhanced Out-of-Plane Emission of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi mathvariant="italic">K</mml:mi></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msup></mml:mrow></mml:math>Mesons Observed in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>Au</mml:mi><mml:mi /><mml:mo>+</mml:mo><mml:mi /><mml:mi>Au</mml:mi></mml:math>Collisions at<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" dis

Shin, Y.; Ahner, W.; Barth, Rolf F.; Beckerle, P.; Brill, Dieter R.; Cieślak, M.; Dębowski, M.; Grosse, E.; Koczoń, P.; Kohlmeyer, B.; Mang, M.; Miśkowiec, D.; Müntz, C.; Oeschler, H.; Pühlhofer, F.; Schwab, E.; Schicker, R.; Senger, P.; Speer, John G.; Ströbele, H.; Sturm, C.; Völkel, K.; Wagner, A.; Waluś, W.

doi:10.1103/physrevlett.81.1576

Cited by 87 publications

(32 citation statements)

References 21 publications

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“…a promising probe of the kaon potential in dense matter, since it should push the K + mesons away from the nucleons and attract K − mesons towards the nucleons. The analysis of KaoS [106,107,[116][117][118][119], FOPI [120][121][122] and ANKE [123] on K + production in heavy-ion and proton-nucleus reactions established in the framework of transport approaches [34,103,124,125,126] and [28,44,111] that the K + meson indeed feels a moderately repulsive nuclear potential of about 20-30 MeV at normal nuclear matter density ρ 0 , in agreement with the above theoretical estimates. As an example of such analysis, Fig.…”

Section: Determination Of the K + -Nucleus Real Potentialsupporting

confidence: 83%

Meson–nucleus potentials and the search for meson–nucleus bound states

Metag

Nanova

Paryev

2017

Progress in Particle and Nuclear Physics

103

102

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Recent experiments studying the meson-nucleus interaction to extract meson-nucleus potentials are reviewed. The real part of the potentials quantifies whether the interaction is attractive or repulsive while the imaginary part describes the meson absorption in nuclei. The review is focused on mesons which are sufficiently long-lived to potentially form meson-nucleus quasi-bound states. The presentation is confined to meson production off nuclei in photon-, pion-, proton-, and lightion induced reactions and heavy-ion collisions at energies near the production threshold. Tools to extract the potential parameters are presented. In most cases, the real part of the potential is determined by comparing measured meson momentum distributions or excitation functions with collision model or transport model calculations. The imaginary part is extracted from transparency ratio measurements. Results on K + , K 0 , K − , η, η , ω, and φ mesons are presented and compared with theoretical predictions. The interaction of K + and K 0 mesons with nuclei is found to be weakly repulsive, while the K − , η, η , ω and φ meson-nucleus potentials are attractive, however, with widely different strengths. Because of meson absorption in the nuclear medium the imaginary parts of the meson-nucleus potentials are all negative, again with a large spread. An outlook on planned experiments in the charm sector is given. In view of the determined potential parameters, the criteria and chances for experimentally observing meson-nucleus quasi-bound states are discussed. The most promising candidates appear to be the η and η mesons.

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Section: Determination Of the K + -Nucleus Real Potentialsupporting

confidence: 83%

Meson–nucleus potentials and the search for meson–nucleus bound states

Metag

Nanova

Paryev

2017

Progress in Particle and Nuclear Physics

103

102

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“…All experiments have shown that kaons have very small, if not zero, flow, i.e., both the kaon average in-plane transverse momentum as a function of rapidity and its slope at mid-rapidity are consistent with zero within the experimental error bars [15]. For example, both the FOPI [16,17] and the KaoS [18] collaboration have found a negligible flow for K + in collisions of Ni+Ni at E beam /A=1.93 GeV and Au+Au at 1 GeV, respectively. Several collaborations at the AGS/BNL have also carried out the flow analysis for K + , K − , and K 0 s in Au+Au collisions at beam energies from 2 to 12 GeV/nucleon, and no statistically significant kaon transverse flow has been seen either [19][20][21][22].…”

mentioning

confidence: 91%

Kaon differential flow in relativistic heavy-ion collisions

Zhang

Sustich

et al. 1999

Phys. Rev. C

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Using a relativistic transport model, we study the azimuthal momentum asymmetry of kaons with fixed transverse momentum, i.e., the differential flow, in heavy-ion collisions at beam momentum of 6 GeV/c per nucleon, available from the Alternating Gradient Synchrotron ͑AGS͒ at the Brookhaven National Laboratory ͑BNL͒. We find that in the absence of kaon potential the kaon differential flow is positive and increases with transverse momentum as that of nucleons. The repulsive kaon potential as predicted by theoretical models, however, reduces the kaon differential flow, changing it to negative for kaons with low transverse momenta. Cancellation between the negative differential flow at low momenta and the positive one at high momenta is then responsible for the experimentally observed nearly vanishing in-plane transverse flow of kaons in heavyion experiments. ͓S0556-2813͑99͒02109-3͔ PACS number͑s͒: 25.75. Ld, 13.75.Jz, 21.65.ϩf Since the work of Kaplan and Nelson ͓1͔ on the possibility of a kaon condensation in the core of neutron stars, there have been many theoretical studies of kaon properties in dense matter ͓2͔. It is now generally agreed that a kaon has a weak repulsive potential in nuclear matter while an antikaon has instead a strong attractive one. The latter is responsible for the existence of the kaon condensation that was originally proposed in Ref. ͓1͔. Brown and Bethe ͓3͔ have further argued that because of the softening of the nuclear equation of state due to the kaon condensation, the maximum mass of neutron stars would decrease, hence allowing for the existence of mini black holes.Since a hot dense matter can be created in the initial stage of high energy heavy ion collisions, a unique opportunity thus exists for studying the kaon in-medium properties ͓4-7͔. Indeed, Li et al. ͓8͔ have shown that it is possible to extract the information on kaon potential or dispersion relation in dense matter from the kaon collective flow in heavy ion collisions. Specifically, they have found, based on the relativistic transport model, that the repulsive kaon potential in nuclear medium would reduce its flow relative to that of nucleons, while the flow of antikaons would be similar to that of nucleons due to their attractive potential ͓9͔. Since then, many theoretical studies ͓10-14͔ have been carried out, and all have reached the same conclusion. These theoretical studies have stimulated a number of experiments at both GSI and AGS. All experiments have shown that kaons have very small, if not zero, flow, i.e., both the kaon average in-plane transverse momentum as a function of rapidity and its slope at midrapidity are consistent with zero within the experimental error bars ͓15͔. For example, both the FOPI and KAOS Collaborations at SIS/GSI ͓16-18͔ have found a negligible flow for K ϩ in collisions of NiϩNi at E beam /Aϭ1.93 GeV and AuϩAu at 1 GeV, respectively. Several collaborations at the AGS/BNL have also carried out the flow analysis for K ϩ , K Ϫ , and K s 0 in AuϩAu collisions at beam energies from 2 to 12...

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“…Recent experimental studies of kaon and antikaon production in Ni+Ni collisions found a large K − yield at 1.8 AGeV [13,14], a vanishing in-plane flow of K + mesons [15] and an enhanced out-of-plane emission of K + mesons [16]. These observations are indications for in-medium modifications of the K meson properties [10,11,17,18].…”

mentioning

confidence: 97%

Medium Effects in Kaon and Antikaon Production in Nuclear Collisions at Subthreshold Beam Energies

Laue¹,

Sturm

Böttcher³

et al. 1999

Phys. Rev. Lett.

Self Cite

187

211

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Production cross sections of K 1 and K 2 mesons have been measured in C 1 C collisions at beam energies per nucleon below and near the nucleon-nucleon threshold. At a given beam energy, the spectral slopes of the K 2 mesons are significantly steeper than the ones of the K 1 mesons. The excitation functions for K 1 and K 2 mesons nearly coincide when correcting for the threshold energy. In contrast, the K 1 yield exceeds the K 2 yield by a factor of about 100 in proton-proton collisions at beam energies near the respective nucleon-nucleon thresholds. [S0031-9007 (99)08547-6] PACS numbers: 25.75.DwThe properties of strange mesons in a medium of finite baryon density are essential for our understanding of the strong interaction. According to various theoretical approaches, antikaons feel strong attractive forces in the nuclear medium, whereas the in-medium kaon-nucleon potential is expected to be slightly repulsive [1][2][3][4][5].Predictions have been made that the effective mass of the K 2 meson decreases with increasing nuclear density leading to K 2 condensation in neutron stars above 3 times saturation density r 0 . This effect is expected to influence significantly the evolution of supernova explosions: the K 2 condensate softens the nuclear equation of state and thus causes a core with 1.5-2 solar masses to collapse into a black hole rather than to form a neutron star [6,7].Experimental evidence for the attractive in-medium K 2 N potential was found in K 2 nucleus scattering [8] and kaonic atoms [9]. Strong effects are expected in relativistic nucleus-nucleus collisions where baryonic densities of several times the saturation density r o can be reached. Under these conditions the K 2 effective mass will be reduced and thus the kinematical threshold for the process NN ! K 2 1 K 1 1 NN (which in free space corresponds to a kinetic beam energy of 2.5 GeV) will be lowered. As a consequence, the K 2 yield in A 1 A collisions at bombarding energies below the NN threshold will be enhanced significantly as compared to the case without in-medium mass reduction. In contrast, the yield of K 1 mesons is predicted to be decreased as the K 1 effective mass and thus the in-medium K 1 production threshold is slightly increased [3,10,11]. The in-medium KN potentials are also expected to affect the propagation of kaons and antikaons, hence modifying their emission pattern in nucleus-nucleus collisions.According to these considerations, the K 2 ͞K 1 ratio observed in nucleus-nucleus collisions at beam energies below the NN threshold is sensitive to the in-medium properties of kaons and antikaons. Moreover, relativistic transport calculations find distinct differences in the K 1 and K 2 spectral slopes, again due to medium effects. In particular, these calculations predict that the K 2 spectra fall off steeper than the K 1 spectra due to the decrease of the K 2 effective mass in the nuclear medium [12].Recent experimental studies of kaon and antikaon production in Ni 1 Ni collisions found a large K 2 yield at 1.8A GeV [13,14], a...

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Enhanced Out-of-Plane Emission ofK+Mesons Observed inAu+AuCollisions at

Cited by 87 publications

References 21 publications

Meson–nucleus potentials and the search for meson–nucleus bound states

Meson–nucleus potentials and the search for meson–nucleus bound states

Kaon differential flow in relativistic heavy-ion collisions

Medium Effects in Kaon and Antikaon Production in Nuclear Collisions at Subthreshold Beam Energies

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