WorldWideScience

Sample records for antikaons

  1. Antikaon condensation in neutron stars

    CERN Document Server

    Pal, S; Greiner, W

    2000-01-01

    We investigate the condensation of charged K sup - meson and neutral anti-K sup 0 meson in dense neutron star matter. Calculations are performed in relativistic mean field models in which both the baryon-baryon and (anti)kaon-baryon interactions are mediated by meson exchange. It is found that anti-K sup 0 condensation is quite sensitive to the antikaon optical potential and depends more strongly on the nucleonic equation of state. For moderate values of antikaon potential and a rather stiff equation of state, a significant region of maximum mass star will contain anti-K sup 0 meson. The critical density of anti-K sup 0 condensation is always higher than that of K sup - condensation. With the appearance of K sup - and anti-K sup 0 condensates, pairs of p-K sup - and n-Kbar sup 0 are produced with equal proportion leading to a perfectly symmetric matter of nucleons and antikaons in neutron stars. Along with K sup - condensate, anti-K sup 0 condensate makes the equation of state much softer resulting in smaller...

  2. Antikaon Condensation and In-medium Kaon and Antikaon Production in Protoneutron Stars

    Institute of Scientific and Technical Information of China (English)

    GU Jian-Fa; GUO Hua; LI Xi-Guo; LIU Yu-Xin; XU Fu-Rong

    2007-01-01

    Antikaon condensation and kaon and antikaon production in protoneutron stars are investigated in a chiral hadronic model (also referred to as the FST model in this paper). The effects of neutrino trapping on protoneutron stars are analyzed systematically. It is shown that neutrino trapping makes the critical density of K- condensation delay to higher density and Ko condensation not occur. The equation of state (EOS) of (proto)neutron star matter with neutrino trapping is stiffer than that without neutrino trapping. As a result, the maximum masses of (proto)neutron stars with neutrino trapping are larger than those without neutrino trapping. If hyperons are taken into account, antikaon does not form a condensate in (proto)neutron stars. Meanwhile, the corresponding EOS becomes much softer, and the maximum masses of (proto)neutron stars are smaller than those without hyprons. Finally, our results illustrate that the Q values for K+ and K- production in (proto)neutron stars are not sensitive to neutrino trapping and inclusion of hyperons.

  3. Antineutrino induced antikaon production off the nucleon

    CERN Document Server

    Alam, M Rafi; Athar, M Sajjad; Vacas, M J Vicente

    2011-01-01

    The charged current antikaon production off nucleons induced by antineutrinos is studied at low and intermediate energies. We extend here our previous calculation on kaon production induced by neutrinos. We have developed a microscopic model that starts from the SU(3) chiral Lagrangians and includes background terms and the resonant mechanisms associated to the lowest lying resonance in the channel, namely, the Sigma*(1385). Our results could be of interest for the background estimation of various neutrino oscillation experiments like MiniBooNE and SuperK. They can also be helpful for the planned antineutrino experiments like MINERvA, NOvA and T2K phase II and for beta-beam experiments with antineutrino energies around 1 GeV.

  4. Towards exclusive antikaonic nuclear cluster search with AMADEUS

    Energy Technology Data Exchange (ETDEWEB)

    Kienle, Paul [Stefan Meyer Institute of the Austrian Academy of Sciences, Vienna A-1090, Boltzmanngasse 3 (Austria); Physik Department Technische Universitaet Muenchen, D-85748 Garching (Germany)], E-mail: paul.kienle@ph.tum.de

    2008-05-15

    The recently proposed AMADEUS project makes use of mono energetic, low energy K{sup -} beams from the upgraded high luminosity DA{phi}NE (e{sup +}e{sup -})-collider of the LNF Frascati for the production of antikaon mediated deeply bound nuclear states using the (K{sub stopped}{sup -}, n/p) reaction. The existing KLOE detector with a target for stopping the K{sup -} surrounded by trigger detectors will be used for an exclusive detection of all particles in the production and decay processes of the antikaonic nuclei formed. Using missing mass and invariant mass spectroscopy a conclusive observation of these exotic objects should be in reach and then their properties, such as binding energies, total and partial widths, size and density could be determined, thus opening a new spectroscopy of exotic strongly bound nuclear systems.

  5. Low-energy Antikaon Interaction with Nuclei: The AMADEUS Challenge

    CERN Document Server

    Marton, Johann; Bellotti, Giovanni; Berucci, Carolina; Bosnar, Dimitri; Bragadireanu, Mario; Curceanu, Catalina; Clozza, Alberto; Cargnelli, Michael; Butt, Aslan; Del Grande, Raffaele; Fabbietti, Laura; Fiorini, Carlo; Ghio, Francesco; Guaraldo, Carlo; Iliescu, Mihai; Sandri, Paolo Levi; Pietreanu, Dorel; Piscicchia, Kristian; Vidal, Antonio Romero; Scordo, Alessandro; Shi, Hexi; Sirghi, Diana; Sirghi, Florin; Tucakovic, Ivana; Doce, Oton Vazquez; Widmann, Eberhard; Zmeskal, Johann

    2016-01-01

    The low-energy strong interaction of antikaons (K-) with nuclei has many facets and rep- resents a lively and challenging research ?eld. It is interconnected to the peculiar role of strangeness, since the strange quark is rather light, but still much heavier than the up and down quarks. Thus, when strangeness is involved one has to deal with spontaneous and explicit symmetry breaking in QCD. It is well known that the antikaon interaction with nucleons is attractive, but how strong ? Is the interaction strong enough to bind nucleons to form kaonic nuclei and, if so, what are the properties (binding energy, decay width)? There are controversial indications for such bound states and new results are expected to come soon. The existence of antikaon mediated bound states might have important consequences since it would open the possibility for the formation of cold baryonic matter of high density which might have a severe impact in astrophysics for the understanding of the composi- tion of compact (neutron) stars. ...

  6. Role of antikaon condensation in r-mode instability

    CERN Document Server

    Chatterjee, Debarati

    2007-01-01

    We investigate the effect of antikaon condensed matter on bulk viscosity in rotating neutron stars. We use relativistic field theoretical models to construct the equation of state of neutron stars with the condensate, where the phase transition from nucleonic to $K^-$ condensed phase is assumed to be of first order. We calculate the coefficient of bulk viscosity due to the non-leptonic weak interaction n --> p + K^-. The influence of antikaon bulk viscosity on the gravitational radiation reaction driven instability in the r-modes is investigated. We compare our results with the previously studied non-leptonic weak interaction $n + p --> p + \\Lambda$ involving hyperons on the damping of the r-mode oscillations. We find that the bulk viscosity coefficient due to the non-leptonic weak process involving the condensate is suppressed by several orders of magnitude in comparison with the non-superfluid hyperon bulk viscosity coefficient. Consequently, the antikaon bulk viscosity may not be able to damp the r-mode in...

  7. Bose–Einstein condensation of anti-kaons and neutron star twins

    Indian Academy of Sciences (India)

    Sarmistha Banik; Debades Bandyopadhyay

    2003-05-01

    We investigate the role of Bose–Einstein condensation (BEC) of anti-kaons on the equation of state (EoS) and other properties of compact stars. In the framework of relativistic mean field model we determine the EoS for -stable hyperon matter and compare it to the situation when anti-kaons condense in the system. We observe that anti-kaon condensates soften the EoS, thereby lowering the maximum mass of the stars. We also demonstrate that the presence of antikaon condensates in the high density core of compact stars may lead to a new mass sequence beyond white dwarf and neutron stars. The limiting mass of the new sequence stars is nearly equal to that of neutron star branch though they have distinctly different radii and compositions. They are called neutron star twins.

  8. Antikaon-nucleon interaction and Λ(1405) in chiral SU(3) dynamics

    Science.gov (United States)

    Kamiya, Yuki; Miyahara, Kenta; Ohnishi, Shota; Ikeda, Yoichi; Hyodo, Tetsuo; Oset, Eulogio; Weise, Wolfram

    2016-10-01

    The properties of the Λ (1405) resonance are key ingredients for determining the antikaon-nucleon interaction in strangeness nuclear physics, and the novel internal structure of the Λ (1405) is of great interest in hadron physics, as a prototype case of a baryon that does not fit into the simple three-quark picture. We show that a quantitative description of the antikaon-nucleon interaction with the Λ (1405) is achieved in the framework of chiral SU(3) dynamics, with the help of recent experimental progress. Further constraints on the K bar N subthreshold interaction are provided by analyzing πΣ spectra in various processes, such as the K- d → πΣn reaction and the Λc → ππΣ decay. The structure of the Λ (1405) is found to be dominated by an antikaon-nucleon molecular configuration, based on its wavefunction derived from a realistic K bar N potential and the compositeness criteria from a model-independent weak-binding relation.

  9. In-medium kaon and antikaon properties in the quark-meson coupling model

    CERN Document Server

    Tsushima, K; Thomas, A W; Wright, S V

    1998-01-01

    The properties of the kaon, $K$, and antikaon, $\\kbar$, in nuclear medium are studied in the quark-meson coupling (QMC) model. Employing a constituent quark-antiquark (MIT bag model) picture, their excitation energies in a nuclear medium at zero momentum are calculated within mean field approximation. The scalar, and the vector mesons are assumed to couple directly to the nonstrange quarks and antiquarks in the $K$ and $\\kbar$ mesons. It is demonstrated that the $\\rho$ meson induces different mean field potentials for each member of the isodoublets, $K$ and $\\kbar$, when they are embedded in asymmetric nuclear matter. Furthermore, it is also shown that this $\\rho$ meson potential is repulsive for the $K^-$ meson in matter with a neutron excess, and renders $K^-$ condensation less likely to occur.

  10. Recent developments in antikaon-nucleon dynamics

    CERN Document Server

    Hyodo, Tetsuo

    2012-01-01

    Stimulated by various experimental achievements, the study of Kbar N dynamics now enters a new phase. The two-body Kbar N interaction is largely constrained by recent experimental data, and the nature of the Lambda(1405) resonance is being unveiled by several theoretical analyses. These findings provide a basic tool for applications to KbarK-nuclear systems. We summarize the current status of the Kbar N phenomenology and outline the future direction in this field.

  11. Recoil corrections in antikaon-deuteron scattering

    Directory of Open Access Journals (Sweden)

    Mai Maxim

    2016-01-01

    Full Text Available Using the non-relativistic effective field theory approach for K−d scattering, it is demonstrated that a systematic perturbative expansion of the recoil corrections in the parameter ξ = MK/mN is possible in spite of the fact that K−d scattering at low energies is inherently non-perturbative due to the large values of the K̄N scattering lengths. The first order correction to the K−d scattering length due to single insertion of the retardation term in the multiple-scattering series is calculated. The recoil effect turns out to be reasonably small even at the physical value of MK/mN ≃ 0:5.

  12. Antikaon induced Ξ production from a chiral model at NLO

    Directory of Open Access Journals (Sweden)

    Feijoo A.

    2014-01-01

    Full Text Available We study the meson-baryon interaction in the strangeness S = −1 sector using a chiral unitary approach, paying particular attention to the K̄N → KΞ reaction, especially important for constraining the next-to-leading order chiral terms, and considering also the effect of high spin hyperonic resonances. We also present results for the production of Ξ hyperons in nuclei

  13. Analysis Of The Semileptonic Neutral D Meson Decays To Neutral Antikaon Pion Muon Neutrino

    CERN Document Server

    Segoni, I M

    2004-01-01

    This thesis describes the analysis of the semileptonic decay D0→K0p- m+n using FOCUS data. FOCUS is a fixed target experiment at Fermilab that studies the physics of the charm quark. Particles containing charm are produced by photon-gluon fusion from the collision of a photon beam on a BeO target. The experiment is characterized by excellent vertex resolution and particle identification. The spectrometer consists of three systems for track reconstruction (two silicon systems and one multiwire proportional chamber system) and two magnets of opposite polarity. The polarity of the magnet is such that the events of e+e− pairs produced in the target (which constitutes the main background) travel through a central opening in the detectors without interactions. Particle momentum is measured from the deflection angle in the magnets. Three multi-cell Čerenkov counters are used for charged particle identification (for e, p , K, and p). Two different tracking systems located after se...

  14. a Study of Negative Kaon-Proton Interactions at 6.5 Gev/c: Final States with Neutral Anti-Kaon and Neutral Anti-Kaon Mesonic Resonance Production.

    Science.gov (United States)

    Herder, Leland Earl

    In this dissertation, we present a study of K(' -) p interactions at 6.5 GeV/c, using the 12-foot bubble chamber at the Argonne ZGS. This study is based upon events from the two-prong-plus-Vee topology, where the Vee fits a K(,s)('0) decay. Resonance production in the following final states was studied:. K('-) p (--->) K('0) (pi)('-) p (7C-fit) (I). K('-) p (--->) K('0) (pi)('0) (pi)('-) p (4C -fit) (II). K('-) p (--->) K('0) (pi)('+) (pi)('-) n (4C -fit) (III). For the 7C reaction (I), we found signals for K*(892), K*(1430), and K*(1780) with cross sections 181 (+OR-) 22, 41.2 (+OR-) 6, and 8.4 (+OR-) 2.9 (mu)b, respectively. Production of the K*(2080) was not significant in our data. The partial waves contributing to the production of the K('0(' ))(pi)(' -) system from threshold up to 1.7 GeV were studied. The principal conclusions are: (i) K*(892) and K*(1430) production is dominated by natural parity exchange, (ii) the ratio of unnatural- to natural-parity exchange increases with the resonance mass, consistent with the predictions of a triple Regge model, (iii) there is evidence for a broad 0('+) (K(pi)) S-wave enhancement, with considerable S-D and S-P interference, centered at 1.2 GeV, and (iv) the m = 2 amplitudes of (K(pi)) production are negligible. The two 4C reactions (II and III) were found to have considerably more background and ambiguities than reaction I, as expected. Cross sections for various two -body resonances were measured and compared with results obtained at neighboring energies. The m = 0 amplitudes for the production of K*(892) resonance at low t' were found to be large for both reactions II and III. Reaction II shows evidence for double peripheral production of the K* resonance from an analysis of slope parameters of the differential cross sections. The K*(pi) systems of reactions II and III were studied and cross sections were obtained. The K(rho) channels do not exhibit any significant signals. The spin and parity of the K*(pi) systems over the mass range 1.0 - 1.5 GeV were found to be consistent with J('P) = 1('+), 2('+) and contributions from a 0('-) state were also detected. In reaction II, the K*(pi) system is produced mainly by the Deck mechanism, while for reaction III, the K*(pi) system is for the most part resonant with a peak around 1.43 GeV. We also examined K*(DELTA) double resonance production in reactions II and III. The m = 0 amplitudes are large. Our results of the transversity decay distributions gave agreement with the additive quark model predictions of Bia l as and Zalewski for joint resonance decays.

  15. Development of liquid helium-3 target for experimental studies of antikaon-nucleon interaction at J-PARC

    CERN Document Server

    Iio, M; Sato, M; Enomoto, S; Hashimoto, T; Suzuki, S; Iwasaki, M; Hayano, R S

    2012-01-01

    A liquid helium-3 target system was developed for experimental studies of kaonic atoms and kaonic nuclei at J-PARC. helium-3 gas is liquefied in a heat exchanger cooled below 3.2 K by decompression of liquid helium-4. To maintain a large acceptance of the cylindrical detector system for decay particles of kaonic nuclei, efficient heat transport between the separate target cell and the main unit is realized using circulation of liquid helium-3. To minimize the amount of material, a vacuum vessel containing a carbon fiber reinforced plastic cylinder having an inside diameter of 150 mm and a thickness of 1 mm was produced. A target cell made of pure beryllium and beryllium-aluminum alloy was developed not only to minimize the amount of material but to obtain also high x-ray transmission. During a cooling test, the target cell was kept at 1.3 K at a pressure of 33 mbar. The total estimated heat load to the components including the target cell and heat exchanger cooled by liquid helium-4 decompression, was 0.21 W,...

  16. A Cloudy Quark Bag Model of S, P, and D wave interactions for the coupled channel antikaon-nucleon system

    Energy Technology Data Exchange (ETDEWEB)

    He, Guangliang.

    1992-05-15

    The Cloudy Quark Bag Model is extended from S-wave to P- and D-wave. The parameters of the model are determined by K{sup {minus}}p scattering cross section data, K{sup {minus}}p {yields}{Sigma}{pi}{pi}{pi} production data, K{sup {minus}}p threshold branching ratio data, and K{sup {minus}}p {yields}{Lambda}{pi}{pi}{pi} production data. The resonance structure of the {Lambda}(1405), {Sigma}(1385), and {Lambda}(1520) are studied in the model. The shift and width of kaonic hydrogen are calculated using the model.

  17. Cross sections for inelastic meson-meson scattering via quark-antiquark annihilation

    CERN Document Server

    Shen, Zhen-Yu; Weber, H J

    2015-01-01

    We study inelastic meson-meson scattering that is governed by quark-antiquark annihilation and creation involving a quark and an antiquark annihilating into a gluon, and subsequently the gluon creating another quark-antiquark pair. The resultant hadronic reactions include for I=1: pion + pion to rho + rho, kaon + antikaon to kaon* + antikaon*, kaon + antikaon* to kaon* + antikaon*, kaon* + antikaon to kaon* + antikaon*, as well as pion + pion to kaon + antikaon, pion + rho to kaon + antikaon*, pion + rho to kaon* + antikaon, and kaon + antikaon to rho + rho. In each reaction, one or two Feynman diagrams are involved in the Born approximation. We derive formulas for the unpolarized cross section, the transition amplitude, and the transition potential for quark-antiquark annihilation and creation. The unpolarized cross sections for the reactions are calculated at six temperatures, and prominent temperature dependence is found. It is due to differences among mesonic temperature dependence in hadronic matter.

  18. Effective Mass of Kaon in Asymmetrici Nuclear Matter

    Institute of Scientific and Technical Information of China (English)

    LiXiguo; GaoYuan; LiuZiyu; ZuoWei

    2003-01-01

    The properties of kaon at very high baryon density has been a fascinating subject since 1986. Of particular importance is the modification of effective mass of antikaon in-medium. This is expected to not only help us to understander the chiral symmetry restoration but also effect the composition and structure of neutron star.. The modification of kaon and antikaon mass in medium might be a new mechanism of production at energies below the threshold. Based on the mean-field approximation to the effective SU(3)L×SU(3)n chiral Lagrangian, the kaon and anti kaon mass in medium, defined as the energy of a kaon (or antikaon) with zero three momentum,are then given by[1

  19. Weak Strangeness and Eta Production

    CERN Document Server

    Alam, M Rafi; Alvarez-Ruso, Luis; Simo, I Ruiz; Vacas, M J Vicente; Singh, S K

    2013-01-01

    We have studied strange particle production off nucleons through $\\Delta S =0 $ and $|\\Delta S| = 1$ channels, and specifically single kaon/antikaon, eta, associated particle production for neutrino/antineutrino induced processes as well as antineutrino induced single hyperon production processes. We have developed a microscopical model based on the SU(3) chiral Lagrangians. The basic parameters of the model are $f_\\pi$, the pion decay constant, Cabibbo angle, the proton and neutron magnetic moments and the axial vector coupling constants for the baryons octet. For antikaon production we have also included $\\Sigma^*(1385)$ resonance and for eta production $S_{11}(1535)$ and $S_{11}(1650)$ resonances are included.

  20. Hadrons in compact stars

    Indian Academy of Sciences (India)

    Debades Bandyopadhyay

    2006-05-01

    We discuss -equilibrated and charge neutral matter involving hyperons and $\\bar{K}$ condensates within relativistic models. It is observed that populations of baryons are strongly affected by the presence of antikaon condensates. Also, the equation of state including $\\bar{K}$ condensates becomes softer resulting in a smaller maximum mass neutron star.

  1. Strong interaction studies with kaonic atoms

    CERN Document Server

    Marton, J; Beer, G; Berucci, C; Bosnar, D; Bragadireanu, A M; Cargnelli, M; Clozza, A; Curceanu, C; d'Uffizi, A; Fiorini, C; Ghio, F; Guaraldo, C; Hayano, R; Iliescu, M; Ishiwatari, T; Iwasaki, M; Sandri, P Levi; Okada, S; Pietreanu, D; Piscicchia, K; Ponta, T; Quaglia, R; Vidal, A Romero; Sbardella, E; Scordo, A; Shi, H; Sirghi, D L; Sirghi, F; Tatsuno, H; Doce, O Vazquez; Widmann, E; Zmeskal, J

    2016-01-01

    The strong interaction of antikaons with nucleons and nuclei in the low-energy regime represents an active research field connected intrinsically with few-body physics. There are important open questions like the question of antikaon nuclear bound states. A unique and rather direct experimental access to the antikaon-nucleon scattering lengths is provided by precision X-ray spectroscopy of transitions in low-lying states of light kaonic atoms like kaonic hydrogen isotopes. In the SIDDHARTA experiment at the electron-positron collider DAFNE of LNF-INFN we measured the most precise values of the strong interaction observables, i.e. the strong interaction on the 1s ground state of the electromagnetically bound kaonic hydrogen atom leading to a hadronic shift and a hadronic broadening of the 1s state. The SIDDHARTA result triggered new theoretical work which achieved major progress in the understanding of the low-energy strong interaction with strangeness. Antikaon-nucleon scattering lengths have been calculated ...

  2. Strong interaction studies with kaonic atoms

    CERN Document Server

    Marton, J; Beer, G; Berucci, C; Bosnar, D; Bragadireanu, A M; Cargnelli, M; Clozza, A; Curceanu, C; d'Uffizi, A; Fiorini, C; Ghio, F; Guaraldo, C; Hayano, R; Iliescu, M; Ishiwatari, T; Iwasaki, M; Sandri, P Levi; Okada, S; Pietreanu, D; Piscicchia, K; Ponta, T; Quaglia, R; Vidal, A Romero; Sbardella, E; Scordo, A; Shi, H; Sirghi, D L; Sirghi, F; Tatsuno, H; Doce, O Vazquez; Widmann, E; Zmeskal, J

    2015-01-01

    The strong interaction of antikaons (K-) with nucleons and nuclei in the low energy regime represents an active research field connected intrinsically with few-body physics. There are important open questions like the question of antikaon nuclear bound states - the prototype system being K-pp. A unique and rather direct experimental access to the antikaon-nucleon scattering lengths is provided by precision X-ray spectroscopy of transitions in low-lying states of light kaonic atoms like kaonic hydrogen isotopes. In the SIDDHARTA experiment at the electron-positron collider DA?NE of LNF-INFN we measured the most precise values of the strong interaction observables, i.e. the strong interaction on the 1s ground state of the electromagnetically bound K-p atom leading to a hadronic shift and a hadronic broadening of the 1s state. The SIDDHARTA result triggered new theoretical work which achieved major progress in the understanding of the low-energy strong interaction with strangeness. Antikaon-nucleon scattering le...

  3. Weak production of strange particles and η mesons off the nucleon

    Energy Technology Data Exchange (ETDEWEB)

    Alam, M. Rafi; Athar, M. Sajjad [Department of Physics, Aligarh Muslim University, Aligarh-202 002 (India); Simo, I. Ruiz [Departamento de Física Atómica, Moleculary Nuclear, and Instituto de Física Teórica y Computacional Carlos I, Universidad de Granada, Granada 18071 (Spain); Alvarez-Ruso, L.; Vacas, M. J. Vicente [Departamento de Física Teórica and Instituto de Física Corpuscular, Centro Mixto Universidad de Valencia-CSIC, E-46071 Valencia (Spain)

    2015-10-15

    The strange particle production induced by (anti)neutrino off nucleon has been studied for |ΔS| = 0 and |ΔS| = 1 channels. The reactions those we have considered are for the production of single kaon/antikaon, eta and associated particle production processes. We have developed a microscopical model based on the SU(3) chiral Lagrangian. The basic parameters of the model are f{sub π}, the pion decay constant, Cabibbo angle, the proton and neutron magnetic moments and the axial vector coupling constants for the baryons octet. For antikaon production we have also included Σ*(1385) resonance and for eta production S{sub 11}(1535) and S{sub 11}(1650) resonances are included.

  4. Weak Production of Strange Particles and $\\eta$ Mesons off the Nucleon

    CERN Document Server

    Alam, M Rafi; Alvarez-Ruso, L; Athar, M Sajjad; Vacas, M J Vicente

    2015-01-01

    The strange particle production induced by (anti)neutrino off nucleon has been studied for $|\\Delta S|=0$ and $|\\Delta S|=1$ channels. The reactions those we have considered are for the production of single kaon/antikaon, eta and associated particle production processes. We have developed a microscopical model based on the SU(3) chiral Lagrangian. The basic parameters of the model are $f_\\pi$, the pion decay constant, Cabibbo angle, the proton and neutron magnetic moments and the axial vector coupling constants for the baryons octet. For antikaon production we have also included $\\Sigma^*$(1385) resonance and for eta production $S_{11}$(1535) and $S_{11}$(1650) resonances are included.

  5. (K)0 Condensation in Hyperonic Neutron Star Matter

    Institute of Scientific and Technical Information of China (English)

    DING Wen-Bo; LIU Guang-Zhou; ZHU Ming-Feng; YU Zi; ZHAO En-Guang

    2008-01-01

    In the framework of the relativistic mean field theory,we investigate (K)0 condensation along with Kˉcondensation occur well in the core of the maximum mass stars for relatively shallow optical potentials of (K) in the range of-100 MeV~-160 MeV.With the increasing optical potential of (K),the critical densities of (K) decrease and the species of baryons appearing in neutron stars become fewer.The main role of (K)0 condensation is to make the abundances of particles become identical leading to isospin saturated symmetric matter including antikaons,state,which leads to a large reduction in the maximum masses of neutron stars.In the core of massive neutron stars,neutron star matter including rich particle species,such as antikaons,nucleons and hyperons,may exist.

  6. Low-energy kaon-nucleon/nuclei interaction studies at DAΦNE by AMADEUS

    Directory of Open Access Journals (Sweden)

    Tucaković Ivana

    2015-01-01

    Full Text Available The AMADEUS experiment deals with the investigation of the low-energy kaon-nuclei hadronic interaction at the DAΦNE collider at LNF-INFN, fundamental to respond to longstanding open questions in the non-perturbative QCD in the strangeness sector. One of the most interesting aspects is to understand how hadron masses and interactions change in the nuclear environment. The antikaon-nucleon potential is investigated searching for signals from possible bound kaonic clusters, which would imply a strongly attractive antikaon-nucleon potential. AMADEUS step 0 consists in the analysis of 2004/2005 KLOE data, exploring K− absorptions in H, 4He, 9Be and 12C present in setup materials. The status of the various preliminary analyses is presented, together with future perspectives.

  7. Chiral unitary theory: Application to nuclear problems

    Indian Academy of Sciences (India)

    E Oset; D Cabrera; H C Chiang; C Garcia Recio; S Hirenzaki; S S Kamalov; J Nieves; Y Okumura; A Ramos; H Toki; M J Vicente Vacas

    2001-08-01

    In this talk we briefly describe some basic elements of chiral perturbation theory, , and how the implementation of unitarity and other novel elements lead to a better expansion of the -matrix for meson–meson and meson–baryon interactions. Applications are then done to the interaction in nuclear matter in the scalar and vector channels, antikaons in nuclei and - atoms, and how the meson properties are changed in a nuclear medium.

  8. Catalytic Reactions in Heavy-ion Collisions

    CERN Document Server

    Kolomeitsev, E E

    2011-01-01

    We discuss a new type of reactions of a phi meson production on hyperons, pi Y--> phi Y and anti-kaons bar-K N --> phi Y. These reactions are not suppressed according to Okubo-Zweig-Iizuka rule and can be a new efficient source of phi mesons in a nucleus-nucleus collision. We discuss how these reactions can affect the centrality dependence and the rapidity distributions of the phi yield.

  9. Catalytic reactions in heavy-ion collisions

    Science.gov (United States)

    Kolomeitsev, E. E.; Tomášik, B.

    2012-06-01

    We discuss a new type of reactions of a ϕ-meson production on hyperons, πY → ϕY and antikaons -KN → ϕY. These reactions are not suppressed according to Okubo-Zweig-Iizuka rule and can be a new efficient source of ϕ mesons in a nucleus-nucleus collision. We discuss how these reactions can affect the centrality dependence and the rapidity distributions of the ϕ yield.

  10. Measurement of the strong interaction induced shift and width of the 1s state of kaonic deuterium at J-PARC

    CERN Document Server

    Zmeskal, J; Ajimura, S; Bazzi, M; Beer, G; Berucci, C; Bhang, H; Bosnar, D; Bragadireanu, M; Buehler, P; Busso, L; Cargnelli, M; Choi, S; Clozza, A; Curceanu, C; D'uffizi, A; Enomoto, S; Fabbietti, L; Faso, D; Fiorini, C; Fujioka, H; Ghio, F; Golser, R; Guaraldo, C; Hashimoto, T; Hayano, R S; Hiraiwa, T; Iio, M; Iliescu, M; Inoue, K; Ishimoto, S; Ishiwatari, T; Itahashi, K; Iwai, M; Iwasaki, M; Kawasaki, S; Lachner, J; Sandri, P Levi; Ma, Y; Marton, J; Matsuda, Y; Mizoi, Y; Morra, O; Moskal, P; Nagae, T; Noumi, H; Ohnishi, H; Okada, S; Outa, H; Pietreanu, D; Piscicchia, K; Lener, M Poli; Vidal, A Romero; Sada, Y; Sakaguchi, A; Sakuma, F; Sbardella, E; Scordo, A; Sekimoto, M; Shi, H; Silarski, M; Sirghi, D; Sirghi, F; Suzuki, K; Suzuki, S; Suzuki, T; Tanida, K; Tatsuno, H; Tokuda, M; Toyoda, A; Tucakovic, I; Tsukada, K; Doce, O Vazquez; Widmann, E; Yamaga, T; Yamazaki, T; Zhang, Q

    2015-01-01

    The antikaon-nucleon interaction close to threshold provides crucial information on the interplay between spontaneous and explicit chiral symmetry breaking in low-energy QCD. In this context the importance of kaonic deuterium X-ray spectroscopy has been well recognized, but no experimental results have yet been obtained due to the difficulty of the measurement. We propose to measure the shift and width of the kaonic deuterium 1s state with an accuracy of 60 eV and 140 eV respectively at J-PARC. These results together with the kaonic hydrogen data (KpX at KEK, DEAR and SIDDHARTA at DAFNE) will then permit the determination of values of both the isospin I=0 and I=1 antikaon-nucleon scattering lengths and will provide the most stringent constraints on the antikaon-nucleon interaction, promising a breakthrough. Refined Monte Carlo studies were performed, including the investigation of background suppression factors for the described setup. These studies have demonstrated the feasibility of determining the shift a...

  11. New boundaries for the “ppK−” production in p+p collisions

    Directory of Open Access Journals (Sweden)

    Epple Eliane

    2014-01-01

    Full Text Available The HADES collaboration has searched for the anti-kaonic nuclear cluster “ppK−” in p+p collisions by its decay into pΛ. In the course of this analysis several cross checks had to be performed. This report discusses two examples thereof. In one test it was checked whether the presence of background events could introduce a bias on the applied partial wave analysis. The second item discussed here is the extraction of the total pK+Λ production cross section necessary to derive the absolute upper limit on the “ppK−” production cross section.

  12. Charged kaon production by coherent scattering of neutrinos and antineutrinos on nuclei

    CERN Document Server

    Alvarez-Ruso, L; Simo, I Ruiz; Valverde, M; Vacas, M J Vicente

    2012-01-01

    With the aim of achieving a better and more complete understanding of neutrino interactions with nuclear targets, the coherent production of charged kaons induced by neutrinos and antineutrinos is investigated in the energy range of some of the current neutrino experiments. We follow a microscopic approach which, at the nucleon level, incorporates the most important mechanisms allowed by the chiral symmetry breaking pattern of QCD. The distortion of the outgoing (anti)kaon is taken into account by solving the Klein-Gordon equation with realistic optical potentials. Angular and momentum distributions are studied, as well as the energy and nuclear dependence of the total cross section.

  13. New boundaries for the "ppK-" production in p+p collisions

    Science.gov (United States)

    Epple, Eliane

    2014-11-01

    The HADES collaboration has searched for the anti-kaonic nuclear cluster "ppK-" in p+p collisions by its decay into pΛ. In the course of this analysis several cross checks had to be performed. This report discusses two examples thereof. In one test it was checked whether the presence of background events could introduce a bias on the applied partial wave analysis. The second item discussed here is the extraction of the total pK+Λ production cross section necessary to derive the absolute upper limit on the "ppK-" production cross section.

  14. Precision X-ray measurements on kaonic atoms at LNF

    CERN Document Server

    Marton, J

    2007-01-01

    After the successfully performed DEAR experiment at DAFNE - resulting in the most precise data on the hadronic shift and width in kaonic hydrogen up-to-now - the next step will be the measurement at the percent level using new X-ray detectors. These detectors (silicon drift detectors) are developed within the SIDDHARTA project. The asynchronous background will be suppressed using the time correlation between the kaon and the X-ray by 2-3 orders of magnitude. These measurements will lead to precise values of the isospin-dependent antikaon-nucleon scattering lengths, thus opening a new insight in the low-energy kaon nucleon interaction.

  15. Kaon condensation and multi-strange matter

    Science.gov (United States)

    Gazda, D.; Friedman, E.; Gal, A.; Mareš, J.

    2010-04-01

    We report on dynamical calculations of multi- K¯ hypernuclei, which were performed by adding K¯ mesons to particle-stable configurations of nucleons, Λ and Ξ hyperons. The K¯ separation energy as well as the baryonic densities saturate with the number of antikaons. We demonstrate that the saturation is a robust feature of multi- K¯ hypernuclei. Because the K¯ separation energy B does not exceed 200 MeV, we conclude that kaon condensation is unlikely to occur in finite strong-interaction self-bound {N,Λ,Ξ} strange hadronic systems.

  16. X-ray spectroscopy of light kaonic atoms – new results and perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Marton, J. [Stefan-Meyer-Institut für subatomare Physik, Boltzmanngasse 3, 1090 Wien (Austria); Bazzi, M. [INFN, Laboratori Nazionali di Frascati, C.P. 13, Via E. Fermi 40, I-00044 Frascati (Roma) (Italy); Beer, G. [Dep. of Physics and Astronomy, University of Victoria, P.O.Box 3055, Victoria B.C. Canada V8W3P6 (Canada); Berucci, C. [INFN, Laboratori Nazionali di Frascati, C.P. 13, Via E. Fermi 40, I-00044 Frascati (Roma) (Italy); Bombelli, L. [Politecnico di Milano, Dip. di Elettronica e Informazione, Piazza L. da Vinci, 32 I-20133 Milano (Italy); Bragadireanu, A.M. [INFN, Laboratori Nazionali di Frascati, C.P. 13, Via E. Fermi 40, I-00044 Frascati (Roma) (Italy); IFIN-HH, P.O. box MG-6, R76900 Magurele, Bucharest (Romania); Cargnelli, M. [Stefan-Meyer-Institut für subatomare Physik, Boltzmanngasse 3, 1090 Wien (Austria); Curceanu, C. [INFN, Laboratori Nazionali di Frascati, C.P. 13, Via E. Fermi 40, I-00044 Frascati (Roma) (Italy); D' Uffizi, A.; Fiorini, C.; Frizzi, T. [Politecnico di Milano, Dip. di Elettronica e Informazione, Piazza L. da Vinci, 32 I-20133 Milano (Italy); Ghio, F. [INFN Sez. di Roma I and Instituto Superiore di Sanita I-00161, Roma (Italy); Guaraldo, C. [INFN, Laboratori Nazionali di Frascati, C.P. 13, Via E. Fermi 40, I-00044 Frascati (Roma) (Italy); Hayano, R. [University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo (Japan); Iliescu, M. [INFN, Laboratori Nazionali di Frascati, C.P. 13, Via E. Fermi 40, I-00044 Frascati (Roma) (Italy); Ishiwatari, T. [Stefan-Meyer-Institut für subatomare Physik, Boltzmanngasse 3, 1090 Wien (Austria); Iwasaki, M. [RIKEN, Institute of Physical and Chemical Research, Saitama (Japan); and others

    2012-12-15

    The antikaon interaction on nucleons and nuclei in the low-energy regime is neither simple nor well understood. Rather direct access to this field is provided by x-ray spectroscopy of light kaonic atoms like kaonic hydrogen, deuterium and helium isotopes. A series of precision measurements on kaonic atoms was performed very successfully by the SIDDHARTA Collaboration at the DAΦNE electron-positron collider at LNF-INFN (Frascati, Italy). Consequently, new precision data on the strong interaction observables (i.e. energy shift and broadening of low-lying atomic states) were delivered having an important impact on the theory of low-energy QCD with strangeness. Presently, the follow-up experiment, SIDDHARTA-2, is in preparation, aiming at a determination of the strong interaction observables in kaonic deuterium as the highest priority; other type of measurements (light and heavier kaonic atoms) are as well foreseen. With the kaonic deuterium data the antikaon-nucleon isospin-resolved scattering lengths can be extracted for the first time. An overview of the progress and present status of experimental studies and an outlook to future perspectives in this fascinating research field is given.

  17. Kaon Production and Interaction

    CERN Document Server

    Wolke, B M; Budzanowski, A; Czyzykiewicz, R; Grzonka, D; Jarczyk, L; Kamys, B; Khoukaz, A; Kilian, K; Kowina, P; Lister, T A; Moskal, P; Oelert, Walter; Rozek, T; Santo, R; Schepers, G; Sefzick, T; Siemaszko, M; Smyrski, J; Steltenkamp, S; Strzalkowski, A; Winter, P; Wüstner, P; Zipper, W; Wolke, By M.

    2003-01-01

    Exclusive data on both the elementary kaon and antikaon production channels have been taken at the cooler synchrotron COSY in proton-proton scattering. In the kaon--hyperon production an enhancement by one order of magnitude of the Lambda/Sigma0 ratio has been observed at excess energies below Q=13 MeV compared to data at higher excess energies (Q>300 MeV). New results obtained at the COSY-11 facility explore the transition region between the regime of this low-energy Sigma0 suppression and excess energies of 60 MeV. A comparison of the energy dependence of the Lambda and Sigma0 total cross sections exhibits distinct qualitative differences between both hyperon production channels. Studies of kaon-antikaon production have been motivated especially by the ongoing discussion about the nature of the scalar resonances f0(980) and a0(980) coupling to the K anti-K channel. For the reaction pp->ppK+K- a first total cross section value is reported at an excess energy of Q=17 MeV, i.e. below the phi threshold. Calcula...

  18. In-medium and isospin effects on particle production near threshold energies in heavy-ion collisions

    CERN Document Server

    Feng, Zhao-Qing; Chen, Peng-Hui; Chen, Jie; Jin, Gen-Ming

    2015-01-01

    Dynamics of pseudoscalar mesons ($\\pi$, $\\eta$, $K$ and $\\overline{K}$ ) and hyperons ($\\Lambda$ and $\\Sigma$) produced in heavy-ion collisions near threshold energies has been investigated within the Lanzhou quantum molecular dynamics (LQMD) transport model. The in-medium modifications on particle production in dense nuclear matter are implemented in the model through corrections on the elementary cross sections and by inclusion of the meson (hyperon)-nucleon potentials, in which the isospin effects are considered. It is found that the transportation of particles are influenced with the in-medium corrections. The total number of pions is reduced with an isospin, density and momentum dependent pion-nucleon potential. However, the ratios of charged pions is enhanced with inclusion of the potential. The production of eta in the domain of mid-rapidities and high momenta is sensitive to the $\\eta$-nucleon potential, but weakly depends on symmetry energy. The attractive antikaon-nucleon potential enhances the subt...

  19. Fast Equilibration of Hadrons in an Expanding Fireball

    CERN Document Server

    Noronha-Hostler, J; Shovkovy, I A

    2007-01-01

    Due to long chemical equilibration times within standard hadronic reactions during the hadron gas phase in relativistic heavy ion collisions it has been suggested that the hadrons are "born" into equilibrium after the quark gluon plasma phase. Here we develop a dynamical scheme in which possible Hagedorn states contribute to fast chemical equilibration times of baryon anti-baryon pairs (as well as kaon anti-kaon pairs) inside a hadron gas and just below the critical temperature. Within this scheme, we use master equations and derive various analytical estimates for the chemical equilibration times. Applying a Bjorken picture to the expanding fireball, the kaons and baryons as well as the bath of pions and Hagedorn resonances can indeed quickly chemically equilibrate for both an initial overpopulation or underpopulation of Hagedorn resonances. Moreover, a comparison of our results to $(B+\\bar{B})/\\pi^{+}$ and $K/\\pi^{+}$ ratios at RHIC, indeed, shows a close match.

  20. On the pole content of coupled channels chiral approaches used for the K bar N system

    Science.gov (United States)

    Cieplý, A.; Mai, M.; Meißner, Ulf-G.; Smejkal, J.

    2016-10-01

    Several theoretical groups describe the antikaon-nucleon interaction at low energies within approaches based on the chiral SU(3) dynamics and including next-to-leading order contributions. We present a comparative analysis of the pertinent models and discuss in detail their pole contents. It is demonstrated that the approaches lead to very different predictions for the K- p amplitude extrapolated to subthreshold energies as well as for the K- n amplitude. The origin of the poles generated by the models is traced to the so-called zero coupling limit, in which the inter-channel couplings are switched off. This provides new insights into the pole contents of the various approaches. In particular, different concepts of forming the Λ (1405) resonance are revealed and constraints related to the appearance of such poles in a given approach are discussed.

  1. Antinucleon-nucleus interaction near threshold from the Paris $\\bar NN$ potential

    CERN Document Server

    Friedman, E; Loiseau, B; Wycech, S

    2015-01-01

    A general algorithm for handling the energy dependence of hadron-nucleon amplitudes in the nuclear medium, consistently with their density dependence, has been recently applied to antikaons, eta mesons and pions interacting with nuclei. Here we apply this approach to antiprotons below threshold, analyzing experimental results for antiprotonic atoms across the periodic table. It is also applied to antiproton and antineutron interaction with nuclei up to 400~MeV/c, comparing with elastic scattering and annihilation cross sections. The underlying $\\bar pN$ scattering amplitudes are derived from the Paris $\\bar NN$ potential, including modifications in the medium. Emphasis is placed on the role of the $P$-wave amplitudes with respect to the repulsive $S$-wave amplitudes.

  2. Aspects of thermal and chemical equilibration of hadronic matter

    CERN Document Server

    Bratkovskaya, E L; Greiner, C; Effenberger, M; Mosel, U; Sibirtsev, A A

    2000-01-01

    We study thermal and chemical equilibration in 'infinite' hadron matter as well as in finite size relativistic nucleus-nucleus collisions using a BUU cascade transport model that contains resonance and string degrees-of-freedom. The 'infinite' hadron matter is simulated within a cubic box with periodic boundary conditions. The various equilibration times depend on baryon density and energy density and are much shorter for particles consisting of light quarks then for particles including strangeness. For kaons and antikaons the chemical equilibration time is found to be larger than $\\simeq$ 40 fm/c for all baryon and energy densities considered. The inclusion of continuum excitations, i.e. hadron 'strings', leads to a limiting temperature of $T_s\\simeq$ 150 MeV. We, furthermore, study the expansion of a hadronic fireball after equilibration. The slope parameters of the particles after expansion increase with their mass; the pions leave the fireball much faster then nucleons and accelerate subsequently heavier ...

  3. Thermal and chemical equilibration of hadronic matter

    CERN Document Server

    Bratkovskaya, E L; Greiner, C; Effenberger, M; Mosel, U; Sibirtsev, A A

    2001-01-01

    We study thermal and chemical equilibration in 'infinite' hadron matter as well as in finite size relativistic nucleus-nucleus collisions using a BUU cascade transport model with resonance and string degrees-of-freedom. The 'infinite' hadron matter is simulated within a cubic box employing periodic boundary conditions. The various equilibration times depend on baryon density and energy density and are much shorter for particles consisting of light quarks then for particles including strangeness. For kaons and antikaons the chemical equilibration time is found to be larger than $\\simeq$ 40 fm/c for all baryon and energy densities considered. The inclusion of continuum excitations, i.e. hadron 'strings', leads to a limiting temperature of $T_s\\simeq$ 150 MeV.

  4. On the pole content of coupled channels chiral approaches used for the $\\bar{K}N$ system

    CERN Document Server

    Cieplý, A; Meißner, Ulf-G; Smejkal, J

    2016-01-01

    Several theoretical groups describe the antikaon-nucleon interaction at low energies within approaches based on the chiral SU(3) dynamics and including next-to-leading order contributions. We present a comparative analysis of the pertinent models and discuss in detail their pole contents. It is demonstrated that the approaches lead to very different predictions for the $K^{-}p$ amplitude extrapolated to subthreshold energies as well as for the $K^{-}n$ amplitude. The origin of the poles generated by the models is traced to the so-called zero coupling limit, in which the inter-channel couplings are switched off. This provides new insights into the pole contents of the various approaches. In particular, different concepts of forming the $\\Lambda(1405)$ resonance are revealed and constraints related to the appearance of such poles in a given approach are discussed.

  5. Golden Jubilee photos: LEAR

    CERN Document Server

    2004-01-01

    Extraction lines that carried the antiprotons from LEAR to the experiments. Beam-splitters and a multitude of beam-lines allowed several users to be supplied simultaneously. Particle physicists don't always need ever more powerful accelerators to study interesting physics. LEAR, the Low Energy Antiproton Ring, was designed to help explore the properties of antimatter, with the annihilation of protons and antiprotons becoming the main theme. LEAR was commissioned in 1983 and contributed to more than 30 experiments with great success. LEAR took part in the discovery of a 'glueball', a particle composed entirely of gluons, the carriers of the strong nuclear force. LEAR also observed that neutral kaons and antikaons decay at a slightly different rate, offering physicists another insight into the mystery about why matter prevails over antimatter in the Universe. Uniquely, LEAR combined both the electron and stochastic beam cooling techniques, used to control and refine the beams. It also pioneered a technique usin...

  6. Nuclear in-medium effects of strange particles in proton-nucleus collisions

    CERN Document Server

    Feng, Zhao-Qing

    2014-01-01

    Dynamics of strange particles produced in proton induced nuclear reactions near threshold energies has been investigated within the Lanzhou quantum molecular dynamics (LQMD) transport model. The in-medium modifications on particle production in dense nuclear matter are considered through corrections on the elementary cross sections via the effective mass and the mean-field potentials. It is found that the attractive antikaon-nucleon potential enhances the subthreshold $\\overline{K}$ production and also influences the structure of inclusive spectra. The strangeness production is strongly suppressed in proton induced reactions in comparison to heavy-ion collisions. The measured K$^{-}$/K$^{+}$ ratios in the $^{12}$C+$^{12}$C and p+$^{12}$C collisions from KaoS collaboration have been well explained with inclusion of the in-medium potentials.

  7. Particle production in antiproton induced nuclear reactions

    CERN Document Server

    Feng, Zhao-Qing

    2014-01-01

    The quantum molecular dynamics model has been improved to investigate the reaction dynamics induced by antiprotons. The reaction channels of elastic scattering, annihilation, charge exchange and inelastic collisions have been included in the model. Dynamics on particle production, in particular pions, kaons, antikaons and hyperons, is investigated in collisions of $\\overline{p}$ on $^{12}$C, $^{20}$Ne, $^{40}$Ca, $^{112}$Sn, $^{181}$Ta, $^{197}$Au and $^{238}$U from a low to high incident momentum. The rapidity and momentum distributions of $\\pi^{+}$ and protons from the LEAR measurements can be well reproduced. The impacts of system size and incident momentum on particle emissions are investigated from the inclusive spectra, transverse momentum and rapidity distributions. It is found that the annihilations of $\\overline{p}$ on nucleons are of importance on the particle production. Hyperons are mainly produced via meson induced reactions on nucleons and strangeness exchange collisions when the incident moment...

  8. Nuclear dynamics induced by antiprotons

    CERN Document Server

    Feng, Zhao-Qing

    2015-01-01

    Reaction dynamics in collisions of antiprotons on nuclei is investigated within the Lanzhou quantum molecular dynamics model. The reaction channels of elastic scattering, annihilation, charge exchange and inelastic collisions of antiprotons on nucleons have been included in the model. Dynamics on particle production, in particular pions, kaons, antikaons and hyperons, is investigated in collisions of $\\overline{p}$ on $^{12}$C, $^{20}$Ne, $^{40}$Ca and $^{181}$Ta from a low to high incident momenta. It is found that the annihilations of $\\overline{p}$ on nucleons are of importance on the dynamics of particle production in phase space. Hyperons are mainly produced via meson induced reactions on nucleons and strangeness exchange collisions, which lead to the delayed emission in antiproton-nucleus collisions.

  9. Constraints on the chiral unitary $\\bar KN$ amplitude from $\\pi\\Sigma K^+$ photoproduction data

    CERN Document Server

    Mai, Maxim

    2014-01-01

    A chiral unitary approach for antikaon-nucleon scattering in on-shell factorization is studied. We find multiple sets of parameters for which the model describes all existing hadronic data similarly well. We confirm the two-pole structure of the $\\Lambda (1405)$. The narrow $\\Lambda(1405)$ pole appears at comparable positions in the complex energy plane, whereas the location of the broad pole suffers from a large uncertainty. In the second step, we use a simple model for photoproduction of $K^+\\pi\\Sigma$ off the proton and confront it with the experimental data from the CLAS collaboration. It is found that only a few of the hadronic solutions allow for a consistent description of the CLAS data within the assumed reaction mechanism.

  10. Constraints on the chiral unitary $\\bar KN$ amplitude from ${\\pi}{\\Sigma}K^+$ photoproduction data

    CERN Document Server

    Mai, Maxim

    2015-01-01

    A chiral unitary approach for antikaon-nucleon scattering in on-shell factorization is studied. We find multiple sets of parameters for which the model describes all existing hadronic data similarly well. We confirm the two-pole structure of the ${\\Lambda}(1405)$. The narrow ${\\Lambda}(1405)$ pole appears at comparable positions in the complex energy plane, whereas the location of the broad pole suffers from a large uncertainty. In the second step, we use a simple model for photoproduction of $K^+{\\pi}{\\Sigma}$ off the proton and confront it with the experimental data from the CLAS collaboration. It is found that only a few of the hadronic solutions allow for a consistent description of the CLAS data within the assumed reaction mechanism.

  11. Strange Baryonic Matter and Kaon Condensation

    Science.gov (United States)

    Gazda, D.; Friedman, E.; Gal, A.; Mareš, J.

    In this contribution we address the question whether kaon condensation could occur in strongly interacting self-bound strange hadronic matter. In our comprehensive dynamical relativistic mean-field (RMF) calculations of nuclear and hypernuclear systems containing several antikaons we found saturation of bar K separation energy as well as the associated nuclear and bar K density distributions upon increasing the number of bar K mesons. The saturation pattern was found to be a universal feature of these multi-strangeness configurations. Since in all cases the bar K separation energy does not exceed 200 MeV, we conclude that bar K mesons do not provide the physical "strangeness" degrees of freedom for self-bound strange hadronic matter.

  12. Testing in-medium πN dynamics on pionic atoms

    Science.gov (United States)

    Friedman, E.; Gal, A.

    2014-08-01

    A general algorithm for handling the energy dependence of meson-nucleon amplitudes in the nuclear medium has been recently applied to antikaons and to eta mesons. Here we test this approach on πN amplitudes in pionic atoms where direct comparison can be made with ample experimental results. Applying this algorithm to a large-scale fit of 100 pionic-atom data points across the periodic table, which also include the ‘deeply-bound' states in Sn and Pb, reaffirms earlier conclusions on the density-dependent renormalization of the πN threshold isovector amplitude b1, or equivalently the renormalization of the pion decay constant fπ in the nuclear medium.

  13. MULTI-bar K (hyper)nuclei and Kaon Condensation

    Science.gov (United States)

    Gazda, D.; Mareš, J.; Friedman, E.; Gal, A.

    2010-10-01

    We report on recent relativistic mean-field calculations of multi-bar K nuclei1,2 which were performed fully and self-consistently across the periodic table. The bar K separation energy B{bar K} as well as the nuclear and bar K-meson densities were found to saturate with the number of antikaons in the nuclear medium. Saturation appears robust against a wide range of variations, including the nuclear model used and the type of boson fields mediating the strong interactions. In addition, we have explored properties of kaonic hypernuclei - strange systems made of nucleons, hyperons and K- mesons. We observed saturation also in these objects. Since the bar K separation energy B{bar K} does not exceed 200 MeV, multi-bar K nuclei lie energetically well above multi-hyperonic nuclei and it is unlikely that kaon condensation could occur in strong-interaction self-bound hadronic matter.

  14. Multi-kaonic Hypernuclei and Kaon Condensation

    Science.gov (United States)

    Gazda, D.; Friedman, E.; Gal, A.; Mareš, J.

    2011-09-01

    This contribution reports on dynamical, self-consistent calculations of multi-bar K hypernuclei, which were performed by adding antikaons to particle-stable nuclear configurations of nucleons, Λ and Ξ hyperons. Our results show a robust pattern of saturation of the bar K separation energy Bbar K as a function of the number of bar K mesons, with Bbar K bounded from above by 200 MeV. The associated baryon densities saturate at values 2-3 times nuclear-matter density. The main reason for saturation is the repulsion induced by the vector meson fields between bar K mesons, similarly to what was found for multi-bar K nuclei. The calculations confirm that strangeness in finite strong-interaction self-bound systems is realized through hyperons, with no room for kaon condensation.

  15. Antinucleon-nucleus interaction near threshold from the Paris N bar N potential

    Science.gov (United States)

    Friedman, E.; Gal, A.; Loiseau, B.; Wycech, S.

    2015-11-01

    A general algorithm for handling the energy dependence of hadron-nucleon amplitudes in the nuclear medium, consistently with their density dependence, has been recently applied to antikaons, eta mesons and pions interacting with nuclei. Here we apply this approach to antiprotons below threshold, analyzing experimental results for antiprotonic atoms across the periodic table. It is also applied to antiproton and antineutron interactions with nuclei up to 400 MeV/c, comparing with elastic scattering and annihilation cross sections. The underlying p bar N scattering amplitudes are derived from the Paris N bar N potential, including in-medium modifications. Emphasis is placed on the role of the P-wave amplitudes with respect to the repulsive S-wave amplitudes.

  16. Parton/hadron dynamics in heavy-ion collisions at FAIR energies

    CERN Document Server

    Cassing, W; Palmese, A; Toneev, V D; Bratkovskaya, E L

    2014-01-01

    Recent STAR data for the directed flow of protons, antiprotons and charged pions obtained within the beam energy scan program are analyzed within the Parton-Hadron-String-Dynamics (PHSD/HSD) transport models. Both versions of the kinetic approach are used to clarify the role of partonic degrees of freedom. The PHSD results, simulating a partonic phase and its coexistence with a hadronic one, are roughly consistent with the STAR data. Generally, the semi-qualitative agreement between the measured data and model results supports the idea of a crossover type of quark-hadron transition which softens the nuclear EoS but shows no indication of a first-order phase transition. Furthermore, the directed flow of kaons and antikaons is evaluated in the PHSD/HSD approachesfrom $\\sqrt{s_{NN}} \\approx$ 3 - 200 GeV which shows a high sensitivity to hadronic potentials in the FAIR/NICA energy regime $\\sqrt{s_{NN}} \\le$ 8 GeV.

  17. Preliminary study of kaonic deuterium X-rays by the SIDDHARTA experiment at DAΦNE.

    Science.gov (United States)

    Bazzi, M; Beer, G; Berucci, C; Bombelli, L; Bragadireanu, A M; Cargnelli, M; Curceanu Petrascu, C; Dʼuffizi, A; Fiorini, C; Frizzi, T; Ghio, F; Guaraldo, C; Hayano, R; Iliescu, M; Ishiwatari, T; Iwasaki, M; Kienle, P; Levi Sandri, P; Longoni, A; Marton, J; Okada, S; Pietreanu, D; Ponta, T; Romero Vidal, A; Sbardella, E; Scordo, A; Shi, H; Sirghi, D L; Sirghi, F; Tatsuno, H; Tudorache, A; Tudorache, V; Vazquez Doce, O; Widmann, E; Zmeskal, J

    2013-06-03

    The study of the [Formula: see text] system at very low energies plays a key role for the understanding of the strong interaction between hadrons in the strangeness sector. At the DAΦNE electron-positron collider of Laboratori Nazionali di Frascati we studied kaonic atoms with [Formula: see text] and [Formula: see text], taking advantage of the low-energy charged kaons from Φ-mesons decaying nearly at rest. The SIDDHARTA experiment used X-ray spectroscopy of the kaonic atoms to determine the transition yields and the strong interaction induced shift and width of the lowest experimentally accessible level (1s for H and D and 2p for He). Shift and width are connected to the real and imaginary part of the scattering length. To disentangle the isospin dependent scattering lengths of the antikaon-nucleon interaction, measurements of [Formula: see text] and of [Formula: see text] are needed. We report here on an exploratory deuterium measurement, from which a limit for the yield of the K-series transitions was derived: [Formula: see text] and [Formula: see text] (CL 90%). Also, the upcoming SIDDHARTA-2 kaonic deuterium experiment is introduced.

  18. Study of kaonic deuterium X-rays by the SIDDHARTA experiment at DAFNE

    CERN Document Server

    Bazzi, M; Berucci, C; Bombelli, L; Bragadireanu, A M; Cargnelli, M; Curceanu, C; d'Uffizi, A; Fiorini, C; Frizzi, T; Ghio, F; Guaraldo, C; Hayano, R; Iliescu, M; Ishiwatari, T; Iwasaki, M; Kienle, P; Sandri, P Levi; Longoni, A; Marton, J; Okada, S; Pietreanu, D; Ponta, T; Vidal, A Romero; Sbardella, E; Scordo, A; Shi, H; Sirghi, D L; Sirghi, F; Tatsuno, H; Tudorache, A; Tudorache, V; Doce, O Vazquez; Widmann, E; Zmeskal, J

    2013-01-01

    The study of the KbarN system at very low energies plays a key role for the understanding of the strong interaction between hadrons in the strangeness sector. At the DAFNE electron-positron collider of Laboratori Nazionali di Frascati we studied kaonic atoms with Z=1 and Z=2, taking advantage of the low-energy charged kaons from Phi-mesons decaying nearly at rest. The SIDDHARTA experiment used X-ray spectroscopy of the kaonic atoms to determine the transition yields and the strong interaction induced shift and width of the lowest experimentally accessible level (1s for H and D and 2p for He). Shift and width are connected to the real and imaginary part of the scattering length. To disentangle the isospin dependent scattering lengths of the antikaon-nucleon interaction, measurements of Kp and of Kd are needed. We report here on an exploratory deuterium measurement, from which a limit for the yield of the K-series transitions was derived: Y(K_tot)<0.0143 and Y(K_alpha)<0.0039 (CL 90%). Also, the upcoming ...

  19. An open quantum system approach to complementarity in neutral kaon interferometry

    CERN Document Server

    de Souza, Gustavo; Varizi, Adalberto D; Nogueira, Edson C; Sampaio, Marcos D

    2016-01-01

    In bipartite quantum systems, entanglement correlations between the parties exerts direct influence in the phenomenon of wave-particle duality. This effect has been quantitatively analyzed in the context of two qubits by M. Jakob and J. Bergou [Optics Communications 283(5) (2010) 827]. Employing a description of the K-meson propagation in free space where its weak decay states are included as a second party, we study here this effect in the kaon-antikaon oscillations. We show that a new quantitative "triality" relation similar to the one considered by Jakob and Bergou holds. In our case, it relates the distinguishability between the decay products states corresponding to the distinct kaon propagation modes $K_S $, $K_L $, the amount of wave-like path interference between these states, and the amount of entanglement given by the reduced von Neumann entropy. The inequality can account for the complementarity between strangeness oscillations and lifetime information previously considered in the literature, there...

  20. Unprecedented studies of the low-energy negatively charged kaons interactions in nuclear matter by AMADEUS

    CERN Document Server

    Curceanu, C; Bazzi, M; Berucci, C; Bosnar, D; Bragadireanu, A M; Clozza, A; Cargnelli, M; D'uffizi, A; Fabbietti, L; Fiorini, C; Ghio, F; Guaraldo, C; Iliescu, M; Sandri, P Levi; Marton, J; Pietreanu, D; Lener, M Poli; Quaglia, R; Vidal, A Romero; Sbardella, E; Scordo, A; Shi, H; Sirghi, D; Sirghi, F; Skurzok, M; Tucakovic, I; Doce, O Vazquez; Widmann, E; Zmeskal, J

    2015-01-01

    The AMADEUS experiment aims to provide unique quality data of $K^-$ hadronic interactions in light nuclear targets, in order to solve fundamental open questions in the non-perturbative strangeness QCD sector, like the controversial nature of the $\\Lambda(1405)$ state, the yield of hyperon formation below threshold, the yield and shape of multi-nucleon $K^-$ absorption, processes which are intimately connected to the possible existence of exotic antikaon multi-nucleon clusters. AMADEUS takes advantage of the DA$\\Phi$NE collider, which provides a unique source of monochromatic low-momentum kaons and exploits the KLOE detector as an active target, in order to obtain excellent acceptance and resolution data for $K^-$ nuclear capture on H, ${}^4$He, ${}^{9}$Be and ${}^{12}$C, both at-rest and in-flight. During the second half of 2012 a successful data taking was performed with a dedicated pure carbon target implemented in the central region of KLOE, providing a high statistic sample of pure at-rest $K^-$ nuclear i...

  1. Azimuthal angular distributions of K{sup +} and K{sup -} mesons from Au+Au collisions at a kinetic beam energy of 1.5 AGeV

    Energy Technology Data Exchange (ETDEWEB)

    Ploskon, M.

    2005-07-01

    The Kaon-Spectrometer (KaoS) at the heavy-ion synchrotron (SIS) at the Gesellschaft fuer Schwerionenforschung (GSI) in Darmstadt has been used to study production and propagation of K{sup +} and K{sup -} mesons from Au+Au collisions at a kinetic beam energy of 1.5 AGeV. The azimuthal angular distributions of particles as a function of the collision centrality and particle transverse momenta have been measured. We found a dependence of the K{sup -} meson azimuthal emission pattern on the transverse momentum. The antikaons registered with p{sub t}<0.5 GeV/c are preferentially emitted in the reaction plane and the particles with p{sub t} > 0.5 GeV/c show strong out-of-plane enhancement. The emission patterns of K{sup -} can be explained in terms of two competing phenomena: one of them is indeed the influence of the attractive K{sup -}N potential, however, the second one originates from the strangeness-exchange process. (orig.)

  2. Extended Statistical Thermal Model and Rapidity Spectra of Hadrons at 200 GeV/A

    CERN Document Server

    Uddin, Saeed; Shabir, Jan; Mir, M Farooq

    2009-01-01

    We use the extended statistical thermal model to describe various hadron rapidity spectra at the highest RHIC energy (200 GeV/A). The model assumes the formation of hot and dense regions moving along the beam axis with increasing rapidities, yFB. It has been earlier shown that this model can explain the net proton flow i.e. p minus pbar, ratio pbar/p and the pion rapidity spectra. In this paper we have attempted to show that in addition to these quantities, this model can also successfully describe the individual rapidity spectra of protons, antiprotons, Kaons, antiKaons, pions, the ratios lambdabar/lambda and cascadebar/cascade. The experimental data set on p, pbar, K, Kbar and Pion provided by BRAHMS collaboration at the highest energy of Relativistic Heavy Ion Collider, sqrt(SNN) = 200 GeV are used. The theoretical results fit quite well with mid-rapidity data (for y < 1) of the lambdabar/lambda and the cascadebar/cascade ratios available (from STAR). We have used single set of model parameters includin...

  3. Parton/hadron dynamics in heavy-ion collisions at FAIR energies

    Directory of Open Access Journals (Sweden)

    Cassing W.

    2015-01-01

    Full Text Available Recent STAR data for the directed flow of protons, antiprotons and charged pions obtained within the beam energy scan program are analyzed within the Parton-Hadron-String-Dynamics (PHSD/HSD transport models. Both versions of the kinetic approach are used to clarify the role of partonic degrees of freedom. The PHSD results, simulating a partonic phase and its coexistence with a hadronic one, are roughly consistent with the STAR data. Generally, the semi-qualitative agreement between the measured data and model results supports the idea of a crossover type of quark-hadron transition which softens the nuclear EoS but shows no indication of a first-order phase transition. Furthermore, the directed flow of kaons and antikaons is evaluated in the PHSD/HSD approachesfrom √sNN ≈ 3 - 200 GeV which shows a high sensitivity to hadronic potentials in the FAIR/NICA energy regime √sNN ≤ 8 GeV.

  4. Open-quantum-systems approach to complementarity in neutral-kaon interferometry

    Science.gov (United States)

    de Souza, Gustavo; de Oliveira, J. G. G.; Varizi, Adalberto D.; Nogueira, Edson C.; Sampaio, Marcos D.

    2016-12-01

    In bipartite quantum systems, entanglement correlations between the parties exerts direct influence in the phenomenon of wave-particle duality. This effect has been quantitatively analyzed in the context of two qubits by Jakob and Bergou [Opt. Commun. 283, 827 (2010), 10.1016/j.optcom.2009.10.044]. Employing a description of the K -meson propagation in free space where its weak decay states are included as a second party, we study here this effect in the kaon-antikaon oscillations. We show that a new quantitative "triality" relation holds, similar to the one considered by Jakob and Bergou. In our case, it relates the distinguishability between the decay-product states corresponding to the distinct kaon propagation modes KS, KL, the amount of wave-like path interference between these states, and the amount of entanglement given by the reduced von Neumann entropy. The inequality can account for the complementarity between strangeness oscillations and lifetime information previously considered in the literature, therefore allowing one to see how it is affected by entanglement correlations. As we will discuss, it allows one to visualize clearly through the K0-K ¯0 oscillations the fundamental role of entanglement in quantum complementarity.

  5. Revisiting RG Flow for Kaon Condensation

    CERN Document Server

    Paeng, Won-Gi

    2014-01-01

    Kaon condensation in compact-star matter can be considered as a quantum critical phenomenon with the kaon mass tuned to zero by the baryon density plus the electron chemical potential that increases at the increase of the density. We approach this problem with a renormalization group flow at one loop of the system of anti-kaons considered as pseudo-Goldstone bosons coupled to nucleonic matter described as a Fermi liquid near its fixed point. While the Weinberg-Tomozawa term in chiral Lagrangians is of leading order in describing kaon-nucleon interactions in chiral perturbation theory, hence widely employed in the literature, it is irrelevant in the RG sense, therefore plays, if any, a less important role in the condensation process. The consequence is that the $\\Lambda (1405)$ resonance which is driven by the Weinberg-Tomozawa term is irrelevant for triggering kaon condensation. On the contrary, the $KN$ sigma term $\\Sigma_{KN}$, subleading in chiral counting, can play a more crucial role in renormalization g...

  6. A model-independent analysis of final-state interactions in \\bar B_{d/s}^0 --> J/psi pi pi

    CERN Document Server

    Daub, J T; Kubis, B

    2015-01-01

    Exploiting $B$-meson decays for Standard Model tests and beyond requires a precise understanding of the strong final-state interactions that can be provided model-independently by means of dispersion theory. This formalism allows one to deduce the universal pion-pion final-state interactions from the accurately known $\\pi\\pi$ phase shifts and, in the scalar sector, a coupled-channel treatment with the kaon-antikaon system. In this work an analysis of the decays $\\bar B_d^0 \\to J/\\psi \\pi^+\\pi^-$ and $\\bar B_s^0 \\to J/\\psi \\pi^+\\pi^-$ is presented. We find very good agreement with the data up to 1.05 GeV with a number of parameters reduced significantly compared to a phenomenological analysis. In addition, the phases of the amplitudes are correct by construction, a crucial feature when it comes to studies of $CP$ violation in heavy-meson decays.

  7. Catalytic phi meson production in heavy-ion collisions

    CERN Document Server

    Kolomeitsev, E E

    2009-01-01

    The phi meson production on hyperons, pi Y --> phi Y and anti-kaons bar-K N--> phi Y is argued to be a new efficient source of phi mesons in a nucleus-nucleus collision. These reactions are not suppressed according to Okubo-Zweig-Izuka rule in contrast to the processes with non-strange particles in the entrance channels, pi B and BB with B=N,Delta. A rough estimate of the cross sections within a simple hadronic model shows that the cross sections of pi Y-->phi Y and bar-K N-->phi Y reactions can exceed that of the pi N--> phi N reaction by factors 50 and 60, respectively. In the hadrochemical model for nucleus-nucleus collisions at SIS and lower AGS energies we calculate the evolution of strange particle populations and phi meson production rate due to the new processes. It is found that the catalytic reactions can be operative if the maximal temperature in nucleus-nucleus collisions is larger than 130 MeV and the collision time is larger than 10 fm. A possible influence of the catalytic reactions on the cent...

  8. Double-pole nature of Λ(1405) studied with coupled-channel complex scaling method using complex-range Gaussian basis

    Energy Technology Data Exchange (ETDEWEB)

    Doté, A., E-mail: dote@post.kek.jp [KEK Theory Center, Institute of Particle and Nuclear Studies (IPNS), High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); J-PARC Branch, KEK Theory Center, IPNS, KEK, 203-1 Shirakata, Tokai, Ibaraki 319-1106 (Japan); Myo, T. [General Education, Faculty of Engineering, Osaka Institute of Technology, Osaka 535-8585 (Japan); Research Center for Nuclear Physics (RCNP), Osaka University, Ibaraki 567-0047 (Japan)

    2014-10-15

    The excited hyperon Λ(1405) is the important building block for kaonic nuclei which are a nuclear many-body system with anti-kaons. We have been investigating the Λ(1405) resonance with the coupled-channel Complex Scaling Method (ccCSM) in which the Λ(1405) is treated as a hadron-molecular state of a K{sup ¯}N–πΣ coupled system. We use a K{sup ¯}N(–πY) potential based on the chiral SU(3) theory. In this article, we report the double-pole nature of the Λ(1405), which is a characteristic property predicted by many studies with chiral SU(3)-based models. With the help of the complex-range Gaussian basis in ccCSM, we have found successfully another pole besides a pole near the K{sup ¯}N threshold (called higher pole) which was found in our previous work with the real-range Gaussian basis. The new pole (called lower pole) is found far below K{sup ¯}N threshold: (M,−Γ/2)=(1395,−138) MeV when f{sub π}=110 MeV. In spite of so broad width of the lower-pole state, the state is clearly identified with good separation from continuum states, since the oscillatory behavior of the continuum states is improved owing to the complex-range Gaussian basis. Analyzing the ccCSM wave function of the lower pole, we have revealed explicitly that the lower-pole state is dominated by the πΣ component rather than the K{sup ¯}N component. We have confirmed that the ccCSM wave function is correctly connected to the asymptotic form of the resonance wave function. Estimating the meson–baryon mean distance for the lower-pole state which involves a large decay width, the obtained value has a large imaginary part comparable to a real part. Therefore, the mean-distance of the lower-pole state is difficult to be interpreted intuitively. Such a nature of the lower pole is different from that of the higher pole. In addition, we have investigated the origin of the appearance of the lower pole. The lower pole is confirmed to be generated by the energy dependence attributed to the

  9. In-medium nuclear interactions of low-energy hadrons

    Science.gov (United States)

    Friedman, E.; Gal, A.

    2007-11-01

    Exotic atoms provide a unique laboratory for studying strong interactions and nuclear medium effects at zero kinetic energy. Experimental and theoretical developments of the last decade in the study of exotic atoms and some related low-energy reactions are reviewed. The exotic atoms considered are of π-,K-,pbar,Σ-, and also the so far unobserved Ξ- atoms. The analysis of these atomic systems consists of fitting density-dependent optical potentials Vopt=t(ρ)ρ to comprehensive sets of data of strong-interaction level shifts, widths and yields across the periodic table. These provide information on the in-medium hadron-nucleon t matrix t(ρ) over a wide range of densities up to central nuclear densities. For pions, the review focuses on the extraction of the πN in-medium s-wave interaction from pionic atoms, which include also the deeply bound π- atomic states recently observed at GSI in isotopes of Sn and Pb. Also included are recent measurements at PSI of elastic scattering of π± on Si, Ca, Ni and Zr at 21.5 MeV. The experimental results are analyzed in the context of chirally motivated π-nuclear potentials, and the evidence for partial restoration of chiral symmetry in dense nuclear matter is critically discussed. For antikaons, we review the evidence from K- atoms, and also from low-energy K-p scattering and reaction data for and against a deepKbar-nucleus potential of 150-200 MeV attraction at nuclear matter density. The case for relatively narrow deeply bound K-atomic states is made, essentially independent of the potential-depth issue. Recent experimental suggestions from KEK and DA ΦNE (Frascati) for signals of Kbar-nuclear deeply bound states are reviewed, and dynamical models for calculating binding energies and widths of Kbar- nuclear states are discussed. For kaons we review the evidence, from K+ total and reaction cross section measurements at the AGS (BNL) on Li, C, Si and Ca at plab=500-700 MeV/c, for significant absorptivity of t