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Author Tolos, L.; Molina, R.; Oset, E.; Ramos, A. url  doi
openurl 
  Title (K)over-bar* mesons in dense matter Type Journal Article
  Year 2010 Publication Physical Review C Abbreviated Journal Phys. Rev. C  
  Volume 82 Issue 4 Pages 045210 - 12pp  
  Keywords  
  Abstract We study the properties of (K) over bar* mesons in nuclear matter using a unitary approach in coupled channels within the framework of the local hidden gauge formalism and incorporating the (K) over bar pi decay channel in matter. The in-medium (K) over bar *N interaction accounts for Pauli blocking effects and incorporates the (K) over bar* self-energy in a self-consistent manner. We also obtain the (K) over bar* (off-shell) spectral function and analyze its behavior at finite density and momentum. At a normal nuclear matter density, the (K) over bar* meson feels a moderately attractive potential, while the (K) over bar* width becomes five times larger than in free space. We estimate the transparency ratio of the gamma A -> K+K*(-) A` reaction, which we propose as a feasible scenario at the present facilities to detect changes in the properties of the (K) over bar* meson in nuclear medium.  
  Address [Tolos, L.] Univ Groningen, Theory Grp KVI, NL-9747 AA Groningen, Netherlands, Email: tolos@kvi.nl  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (up) 0556-2813 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000283648400011 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ elepoucu @ Serial 335  
Permanent link to this record
 

 
Author Magas, V.K.; Yamagata-Sekihara, J.; Hirenzaki, S.; Oset, E.; Ramos, A. url  doi
openurl 
  Title Proton emission off nuclei induced by kaons in flight Type Journal Article
  Year 2010 Publication Physical Review C Abbreviated Journal Phys. Rev. C  
  Volume 81 Issue 2 Pages 024609 - 10pp  
  Keywords  
  Abstract We study the (K-, p) reaction on nuclei with a 1 GeV/c momentum kaon beam, paying special attention to the region of emitted protons having kinetic energy above 600 MeV, which was used to claim a deeply attractive kaon nucleus optical potential. Our model describes the nuclear reaction in the framework of a local density approach and the calculations are performed following two different procedures: one is based on a many-body method using the Lindhard function and the other is based on a Monte Carlo simulation. The simulation method offers flexibility to account for processes other than kaon quasielastic scattering, such as K- absorption by one and two nucleons, producing hyperons, and allows consideration of final-state interactions of the K-, the p, and all other primary and secondary particles on their way out of the nucleus, as well as the weak decay of the produced hyperons into pi N. We find a limited sensitivity of the cross section to the strength of the kaon optical potential. We also show a serious drawback in the experimental setup-the requirement for having, together with the energetic proton, at least one charged particle detected in the decay counter surrounding the target-as we find that the shape of the original cross section is appreciably distorted, to the point of invalidating the claims made in the experimental paper on the strength of the kaon nucleus optical.  
  Address [Magas, V. K.; Ramos, A.] Univ Barcelona, Dept Estructura & Constituents Mat, E-08028 Barcelona, Spain, Email: vladimir@ecm.ub.es  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (up) 0556-2813 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000278341300014 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ elepoucu @ Serial 432  
Permanent link to this record
 

 
Author Martinez Torres, A.; Oset, E. url  doi
openurl 
  Title The gamma d -> K(+)K(-)np reaction and an alternative explanation for the “Theta(+)(1540) pentaquark” peak Type Journal Article
  Year 2010 Publication Physical Review C Abbreviated Journal Phys. Rev. C  
  Volume 81 Issue 5 Pages 055202 - 16pp  
  Keywords  
  Abstract We present a calculation of the gamma d -> K(+)K(-)np reaction with the aim of seeing whether the experimental peak observed in the K(+)n invariant mass around 1526 MeV, from where evidence for the existence of the Theta(+) has been claimed, can be obtained without this resonance as a consequence of the particular dynamics of the process and the cuts applied in the experimental setup. We find that a combination of facts leads indeed to a peak around 1530 MeV for the invariant mass of K(+)n without the need to invoke any new resonance around this energy. This, together with statistical fluctuations that we prove to be large with the statistics of the experiment, is likely to produce the narrower peak observed there.  
  Address [Martinez Torres, A.] Univ Politecn Valencia, CSIC, Ctr Mixto, Dept Fis Teor, E-46071 Valencia, Spain, Email: amartine@ific.uv.es  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (up) 0556-2813 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000278144800057 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ elepoucu @ Serial 443  
Permanent link to this record
 

 
Author Xie, J.J.; Martinez Torres, A.; Oset, E. url  doi
openurl 
  Title Faddeev fixed-center approximation to the N K K(bar) system and the signature of a N*(1920)(1/2+) state Type Journal Article
  Year 2011 Publication Physical Review C Abbreviated Journal Phys. Rev. C  
  Volume 83 Issue 6 Pages 065207 - 8pp  
  Keywords  
  Abstract We perform a calculation for the three-body N (K) over barK scattering amplitude by using the fixed-center approximation to the Faddeev equations, taking the interaction between N and (K) over bar, N and K, and (K) over bar and K from the chiral unitary approach. The resonant structures show up in the modulus squared of the three-body scattering amplitude and suggest that a N (K) over barK hadron state can be formed. Our results are in agreement with others obtained in previous theoretical works, which claim a new N* resonance around 1920 MeV with spin-parity J(P) = 1/2(+). The existence of these previous works allows us to test the accuracy of the fixed center approximation in the present problem and sets the grounds for possible application in similar problems, as an explorative tool to determine bound or quasibound three-hadron systems.  
  Address [Xie, Ju-Jun; Oset, E.] Univ Valencia, Ctr Mixto CSIC, Inst Fis Corpuscular IFIC, Inst Invest Paterna, E-46071 Valencia, Spain, Email: xiejujun@ific.uv.es  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (up) 0556-2813 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000291984800004 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ elepoucu @ Serial 665  
Permanent link to this record
 

 
Author Bayar, M.; Yamagata-Sekihara, J.; Oset, E. url  doi
openurl 
  Title K-bar NN system with chiral dynamics Type Journal Article
  Year 2011 Publication Physical Review C Abbreviated Journal Phys. Rev. C  
  Volume 84 Issue 1 Pages 015209 - 9pp  
  Keywords  
  Abstract We have performed a calculation of the scattering amplitude for the three-body system (K) over bar NN assuming (K) over bar scattering against a NN cluster using the fixed center approximation to the Faddeev equations. The (K) over bar N amplitudes, which we take from chiral unitary dynamics, govern the reaction and we find a (K) over bar NN amplitude that peaks around 40 MeV below the (K) over bar NN threshold, with a width in |T|(2) of the order of 50 MeV for spin 0 and has another peak around 27 MeV with similar width for spin 1. The results are in line with those obtained using different methods but implementing chiral dynamics. The simplicity of the approach allows one to see the important ingredients responsible for the results. In particular, we show the effects from the reduction of the size of the NN cluster due to the interaction with the (K) over bar and those from the explicit consideration of the pi Sigma N channel in the three-body equations.  
  Address [Bayar, M; Yamagata-Sekihara, J; Oset, E] Inst Invest Paterna, Inst Fis Corpuscular, Ctr Mixto CSIC UV, E-46071 Valencia, Spain  
  Corporate Author Thesis  
  Publisher Amer Physical Soc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (up) 0556-2813 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000292825800007 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 686  
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