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Author Roca, L.; Oset, E. url  doi
openurl 
  Title Lambda(1405) poles obtained from pi(0)Sigma(0) photoproduction data Type Journal Article
  Year 2013 Publication Physical Review C Abbreviated Journal (down) Phys. Rev. C  
  Volume 87 Issue 5 Pages 055201 - 8pp  
  Keywords  
  Abstract We present a strategy to extract the position of the two Lambda(1405) poles from experimental photoproduction data measured recently at different energies in the gamma p -> K+pi(0)Sigma(0) reaction at Jefferson Laboratory. By means of a chiral dynamics motivated potential with free parameters, we solve the Bethe-Salpeter equation in the coupled channels (K) over barN and pi Sigma in isospin I = 0 and parametrize the amplitude for the photonuclear reaction in terms of a linear combination of the pi Sigma -> pi Sigma and (K) over barN -> pi Sigma scattering amplitudes in I = 0, with a different linear combination for each energy. Good fits to the data are obtained with some sets of parameters, by means of which one can also predict the cross section for the K- p -> pi(0)Sigma(0) reaction. These later results help us decide among the possible solutions. The result is that the different solutions lead to two poles similar to those found in the chiral unitary approach. With the best result we find the two Lambda(1405) poles at 1385 – 68i MeV and 1419 – 22i MeV.  
  Address Univ Murcia, Dept Fis, E-30100 Murcia, 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 0556-2813 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000318527400004 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 1442  
Permanent link to this record
 

 
Author Roca, L.; Oset, E. url  doi
openurl 
  Title Isospin 0 and 1 resonances from pi Sigma photoproduction data Type Journal Article
  Year 2013 Publication Physical Review C Abbreviated Journal (down) Phys. Rev. C  
  Volume 88 Issue 5 Pages 055206 - 7pp  
  Keywords  
  Abstract Recently we presented a successful strategy to extract the position of the two Lambda ( 1405) poles from experimental photoproduction data on the gamma p -> K+pi(0)Sigma(0) reaction at Jefferson Lab. Following a similar strategy, we extend the previous method to incorporate also the isospin 1 component which allows us to consider in addition the experimental data on gamma p -> K+pi(+/-)Sigma(-/+). The idea is based on considering a production mechanism as model independent as possible and implementing the final state interaction of the final meson-baryon pair based on small modifications of the unitary chiral perturbation theory amplitudes. Good fits to the data are obtained with this procedure, by means of which we can also predict the cross sections for the K- p -> (K) over barN, pi Sigma, and pi Lambda reactions for the different charge channels. Besides the two poles found for the Lambda(1405) resonance, we discuss the possible existence of an isospin 1 resonance in the vicinity of the (K) over barN threshold.  
  Address [Roca, L.] Univ Murcia, Dept Fis, E-30100 Murcia, 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 0556-2813 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000327315800008 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 1655  
Permanent link to this record
 

 
Author Aceti, F.; Oset, E.; Roca, L. url  doi
openurl 
  Title Composite nature of the Lambda (1520) resonance Type Journal Article
  Year 2014 Publication Physical Review C Abbreviated Journal (down) Phys. Rev. C  
  Volume 90 Issue 2 Pages 025208 - 8pp  
  Keywords  
  Abstract Recently, the Weinberg compositeness condition of a bound state was generalized to account for resonant states and higher partial waves. We apply this extension to the case of the Lambda (1520) resonance and quantify the weight of the meson-baryon components in contrast to other possible genuine building blocks. This resonance was theoretically obtained from a coupled channels analysis using the s-wave pi Sigma* and K Xi* and the d-wave (K) over bar N and pi Sigma channels, applying the techniques of the chiral unitary approach. We obtain the result that this resonance is essentially dynamically generated from these meson-baryon channels, leaving room for only 15% weight of other kinds of components in its wave function.  
  Address [Aceti, F.; Oset, E.] Univ Valencia, CSIC, Ctr Mixto, Inst Invest Paterna,Dept Fis Teor, 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 0556-2813 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000341271300006 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 1907  
Permanent link to this record
 

 
Author Roca, L.; Oset, E. url  doi
openurl 
  Title Role of a triangle singularity in the pi Delta decay of N(1700)(3/2(-)) Type Journal Article
  Year 2017 Publication Physical Review C Abbreviated Journal (down) Phys. Rev. C  
  Volume 95 Issue 6 Pages 065211 - 8pp  
  Keywords  
  Abstract We show the important role played by the pi Delta(1232) channel in the build up of the N(1700)(3/2(-)) resonance due to the nontrivial enhancement produced by a singularity of a triangular loop. The N(1700) is one of the dynamically generated resonances produced by the coupled-channel vector-baryon interaction. The pi Delta channel was neglected in previous works but we show that it has to be incorporated into the coupled-channel formalism due to an enhancement produced by a singularity in the triangular loop with., nucleon, and p as internal loop lines and pi and Delta as external ones. The enhancement is of nonresonant origin but it contributes to the dynamical generation of the N(1700) resonance due to the nonlinear dynamics involved in the coupled-channel mechanisms. We obtain an important increase of the total width of the N(1700) resonance when the pi Delta channel is included and provide predictions for the partial widths of the N(1700) decays into VB and pi Delta.  
  Address [Roca, L.] Univ Murcia, Dept Fis, E-30100 Murcia, 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 2469-9985 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000404022100005 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 3177  
Permanent link to this record
 

 
Author Oset, E.; Roca, L. url  doi
openurl 
  Title Triangle mechanism in tau -> f(1)(1285)pi nu(tau) decay Type Journal Article
  Year 2018 Publication Physics Letters B Abbreviated Journal (down) Phys. Lett. B  
  Volume 782 Issue Pages 332-338  
  Keywords  
  Abstract We show that the tau(-) decay into f(1)(1285) pi(-)nu(tau) is dominated by a triangle loop mechanism with K*, (K) over bar* and K( or (K) over bar) as internal lines, which manifests a strong enhancement reminiscent of a nearby singularity present in the narrow K* limit and the near (K) over bar* K* threshold of the internal K* propagators. The f1(1285) is then produced by its coupling to the K* (K) over bar and (K) over bar* K which is obtained from a previous model where this resonance was dynamically generated as a molecular K* (K) over bar (or (K) over bar* K) state using the techniques of the chiral unitary approach. We make predictions for the f(1)pi mass distribution which significantly deviates from the phase-space shape, due to the distortion caused by the triangle mechanism and the K* (K) over bar threshold. We find a good agreement with the experimental value within uncertainties for the integrated partial decay width, which is a clear indication of the importance of the triangle mechanism in this decay and supports the dynamical origin of the f(1)(1285) as a K* (K) over bar and (K) over bar* K molecular state.  
  Address [Oset, E.] Univ Valencia, CSIC, Inst Invest Paterna, Dept Fis Teor,Ctr Mixto, Aptdo 22085, Valencia 46071, Spain, Email: luisroca@um.es  
  Corporate Author Thesis  
  Publisher Elsevier Science Bv Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0370-2693 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000438486900054 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 3663  
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