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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 (down) Physical Review C Abbreviated Journal 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 Debastiani, V.R.; Sakai, S.; Oset, E. url  doi
openurl 
  Title Role of a triangle singularity in the pi N(1535) contribution to gamma p -> p pi(0) eta Type Journal Article
  Year 2017 Publication (down) Physical Review C Abbreviated Journal Phys. Rev. C  
  Volume 96 Issue 2 Pages 025201 - 7pp  
  Keywords  
  Abstract We have studied the gamma p -> p pi(0) eta reaction paying attention to the two main mechanisms at low energies, the gamma p ->Delta(1700) -> eta Delta(1232) and the gamma p -> Delta(1700) -> pi N(1535). Both are driven by the photoexcitation of the Delta (1700) and the second one involves a mechanism that leads to a triangle singularity. We are able to evaluate quantitatively the cross section for this process and show that it agrees with the experimental determination. Yet there are some differences with the standard partial wave analysis which does not include explicitly the triangle singularity. The exercise also shows the convenience of exploring possible triangle singularities in other reactions and how a standard partial wave analysis can be extended to accommodate them.  
  Address [Debastiani, V. R.] Univ Valencia, Ctr Mixto, CSIC, Inst Invest Paterna,Dept Fis Teor, Apartado 22085, Valencia 46071, Spain, Email: vinicius.rodrigues@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 2469-9985 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000406755100005 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 3227  
Permanent link to this record
 

 
Author Samart, D.; Liang, W.H.; Oset, E. url  doi
openurl 
  Title Triangle mechanisms in the build up and decay of the N*(1875) Type Journal Article
  Year 2017 Publication (down) Physical Review C Abbreviated Journal Phys. Rev. C  
  Volume 96 Issue 3 Pages 035202 - 14pp  
  Keywords  
  Abstract We studied the N*(1875)(3/ 2-) resonance with a multichannel unitary scheme, considering the Delta pi and Sigma * K, with their interaction extracted from chiral Lagrangians, and then added two more channels, the N*(1535) p and N sigma, which proceed via triangle diagrams involving the Sigma * K and Delta pi respectively in the intermediate states. The triangle diagram in the N*(1535) p case develops a singularity at the same energy as the resonance mass. We determined the couplings of the resonance to the different channels and the partial decay widths. We found a very large decay width to Sigma * K, and also observed that, due to interference with other terms, the N sigma channel has an important role in the pi pi mass distributions at low invariant masses, leading to an apparently large N sigma decay width. We discuss justifying the convenience of an experimental reanalysis of this resonance, in light of the findings of the paper, using multichannel unitary schemes.  
  Address [Samart, Daris] Rajamangala Univ Technol Isan, Fac Sci & Liberal arts, Dept Appl Phys, Nakhon Ratchasima 30000, Thailand, Email: daris.sa@rmuti.ac.th;  
  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:000409256500008 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 3283  
Permanent link to this record
 

 
Author Bayar, M.; Pavao, R.; Sakai, S.; Oset, E. url  doi
openurl 
  Title Role of the triangle singularity in Lambda(1405) production in the pi(-) p -> K-0 pi Sigma and pp -> pK(+) pi Sigma processes Type Journal Article
  Year 2018 Publication (down) Physical Review C Abbreviated Journal Phys. Rev. C  
  Volume 97 Issue 3 Pages 035203 - 12pp  
  Keywords  
  Abstract We have investigated the cross section for the pi(-) p -> K-0 pi Sigma and pp -> pK(+) pi Sigma reactions, paying attention to a mechanism that develops a triangle singularity. The triangle diagram is realized by the decay of a N* to K* Sigma and the K* decay into pi K, and the pi Sigma finally merges into Lambda (1405). The mechanism is expected to produce a peak around 2140 MeV in the K Lambda (1405) invariant mass. We found that a clear peak appears around 2100 MeV in the K Lambda (1405) invariant mass, which is about 40 MeV lower than the expectation, and that is due to the resonance peak of a N* resonance which plays a crucial role in the K* Sigma production. The mechanism studied produces the peak of the Lambda (1405) around or below 1400 MeV, as is seen in the pp -> pK(+) pi Sigma HADES experiment.  
  Address [Bayar, M.] Kocaeli Univ, Dept Phys, TR-41380 Izmit, Turkey, Email: melahat.bayar@kocaeli.edu.tr  
  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:000426780000004 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 3510  
Permanent link to this record
 

 
Author Pavao, R.; Sakai, S.; Oset, E. url  doi
openurl 
  Title Production of N*(1535) and N*(1650) in Lambda(c)-> (K)over-bar(0)eta p (pi N) decay Type Journal Article
  Year 2018 Publication (down) Physical Review C Abbreviated Journal Phys. Rev. C  
  Volume 98 Issue 1 Pages 015201 - 8pp  
  Keywords  
  Abstract To study the properties of the N*(1535) and N*(1650), we calculate the mass distributions of MB in the Lambda(c) -> (K) over bar (MB)-M-0 decay, with MB = pi N(I = 1/2), eta p, and K Sigma(I = 1/2). We do this by calculating the tree-level and loop contributions, mixing pseudoscalar-baryon and vector-baryon channels using the local hidden gauge formalism. The loop contributions for each channel are calculated using the chiral unitary approach. We observe that for the eta N mass distribution only the N* (1535) is seen, with the N* (1650) contributing to the width of the curve, but for the pi N mass distribution both resonances are clearly visible. In the case of MB = K Sigma, we found that the strength of the K E mass distribution is smaller than that of the mass distributions of the pi N and eta p in the Lambda(+)(c)-> (K) over bar (0)pi N and Lambda(+)(c) -> (K) over bar (0)eta p processes, in spite of this channel having a large coupling to the N* (1650). This is because the K Sigma pair production is suppressed in the primary production from the Lambda(c) decay.  
  Address [Pavao, R.] Ctr Mixto Univ Valencia, CSIC Inst Invest Paterna, Dept Fis Teor, Valencia 46071, Spain, Email: rpavao@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 2469-9985 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000436940200003 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 3643  
Permanent link to this record
 

 
Author Ikeno, N.; Molina, R.; Oset, E. url  doi
openurl 
  Title Triangle singularity mechanism for the pp -> pi(+)d fusion reaction Type Journal Article
  Year 2021 Publication (down) Physical Review C Abbreviated Journal Phys. Rev. C  
  Volume 104 Issue 1 Pages 014614 - 16pp  
  Keywords  
  Abstract We develop a model for the pp -> pi(+)d reaction based on the pp -> Delta(1232)N transition followed by Delta(1232) -> pi N' decay and posterior fusion of NN' to give the deuteron. We show that the triangle diagram depicting this process develops a triangle singularity leading to a large cross section of this reaction compared to ordinary fusion reactions. The results of the calculation also show that the process is largely dominated by the pp system in L = 2 and S = 0, which transfers J = 2 to the final pi(+)d system. This feature is shown to be well suited to provide L = 2, S = 1, and J(tot) = 3 for np in the np(I = 0) pi(-)pp reaction followed by the pp -> pi(+)d reaction, which has been proposed recently, as a means of describing the so far assumed dibaryon d* (2380) peak.  
  Address [Ikeno, Natsumi] Tottori Univ, Dept Agr Life & Environm Sci, Tottori 6808551, Japan, Email: ikeno@tottori-u.ac.jp;  
  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:000677555100001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4908  
Permanent link to this record
 

 
Author Martinez Torres, A.; Khemchandani, K.P.; Oset, E. url  doi
openurl 
  Title Theoretical study of the gamma d -> pi(0)eta d reaction Type Journal Article
  Year 2023 Publication (down) Physical Review C Abbreviated Journal Phys. Rev. C  
  Volume 107 Issue 2 Pages 025202 - 24pp  
  Keywords  
  Abstract We have done a theoretical study of the gamma d -> pi(0)eta d reaction starting with a realistic model for the gamma N -> pi(0)eta N reaction that reproduces cross sections and polarization observables at low energies and involves the gamma N -> Delta(1700) -> eta Delta(1232) -> eta pi N-0 process. For the coherent reaction in the deuteron we considered the impulse approximation together with the rescattering of the pions and the eta on a different nucleon than the one where they are produced. We found this second mechanism very important since it helps share between two nucleons the otherwise large momentum transfer of the reaction. Other contributions to the gamma d -> pi(0)eta d reaction, involving the gamma N -> pi(+/-)pi N-0' process, followed by the rescattering of the pi(+/-) with another nucleon to give eta and a nucleon, have also been included. We find a natural explanation, tied to the dynamics of our model, for the shift of the eta-d mass distribution to lower invariant masses, and of the pi(0)-d mass distribution to larger invariant masses, compared to a phase space calculation. We also study theoretical uncertainties related to the large momenta of the deuteron wave function involved in the process as well as to the couplings present in the model. Striking differences are found with the experimental angular distribution and further theoretical investigations might be necessary.  
  Address [Torres, A. Martinez] Univ Sao Paulo, Inst Fis, BR-05389970 Sao Paulo, Brazil, Email: amartine@if.usp.br;  
  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:000981821500002 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5563  
Permanent link to this record
 

 
Author Liang, W.H.; Dias, J.M.; Debastiani, V.R.; Oset, E. url  doi
openurl 
  Title Molecular Omega(b) states Type Journal Article
  Year 2018 Publication (down) Nuclear Physics B Abbreviated Journal Nucl. Phys. B  
  Volume 930 Issue Pages 524-532  
  Keywords  
  Abstract Motivated by the recent finding of five Omega(c) states by the LHCb collaboration, and the successful reproduction of three of them in a recent approach searching for molecular states of meson-baryon with the quantum numbers of Omega(c), we extend these ideas and make predictions for the interaction of meson-baryon in the beauty sector, searching for poles in the scattering matrix that correspond to physical states. We find several Omega(b) states: two states with masses 6405 MeV and 6465 MeV for J(P) = 1/2(-) ; two more states with masses 6427 MeV and 6665 MeV for 3/4(-) ; and three states between 6500 and 6820 MeV, degenerate with J(P) = 1/2(-), 3/4(-), stemming from the interaction of vector-baryon in the beauty sector.  
  Address [Liang, Wei-Hong] Guangxi Normal Univ, Dept Phys, Guilin 541004, Peoples R China, Email: liangwh@gxnu.edu.cn;  
  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 0550-3213 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000435647100019 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 3636  
Permanent link to this record
 

 
Author Bayar, M.; Oset, E. url  doi
openurl 
  Title Improved fixed center approximation of the Faddeev equations for the (K)over-bar N N system with S=0 Type Journal Article
  Year 2012 Publication (down) Nuclear Physics A Abbreviated Journal Nucl. Phys. A  
  Volume 883 Issue Pages 57-68  
  Keywords Fixed center approximation; (K)over-bar N N system  
  Abstract We extend the Fixed Center Approximation (FCA) to the Faddeev equations for the (K) over bar N N system with S = 0, including the charge exchange mechanisms in the (K) over bar rescattering which have been ignored in former works within the FCA. We obtain similar results to those found before, but the binding is reduced by 6 MeV. At the same time we also evaluate the explicit contribution the pi N Sigma intermediate state in the three body system and find that it produces and additional small decrease in the binding of about 3 MeV. The system appears bound by about 35 MeV and the width omitting two body absorption, is about 50 MeV.  
  Address [Bayar, M.; Oset, E.] Inst Invest Paterna, Inst Fis Corpuscular, Ctr Mixto, CSIC,UV, Valencia 46071, Spain, Email: melahat@ific.uv.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 0375-9474 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000304628900005 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 1042  
Permanent link to this record
 

 
Author Martinez Torres, A.; Khemchandani, K.P.; Jido, D.; Kanada-En'yo, Y.; Oset, E. url  doi
openurl 
  Title Three-body hadron systems with strangeness Type Journal Article
  Year 2013 Publication (down) Nuclear Physics A Abbreviated Journal Nucl. Phys. A  
  Volume 914 Issue Pages 280-288  
  Keywords Unitary chiral theories; Few-body systems  
  Abstract Recently, many efforts are being put in studying three-hadron systems made of mesons and baryons and interesting results are being found. In this talk, we summarize the main features of the formalism used to study such three hadron systems with strangeness S = -1, 0 within a framework built on the basis of unitary chiral theories and solution of the Faddeev equations. In particular, we present the results obtained for the pi(K) over barN, K (K) over barN and KK (K) over bar systems and their respective coupled channels. In the first case, we find four Sigma's and two A's with spin-parity J(P) = 1/2(+), in the 1500-1800 MeV region, as two meson-one baryon s-wave resonances. In the second case, a 1/2(+) N* around 1900 MeV is found. For the last one a kaon close to 1420 MeV is formed, which can be identified with K(1460).  
  Address [Torres, A. Martinez; Khemchandani, K. P.] Univ Sao Paulo, Inst Fis, BR-05314970 Sao Paulo, Brazil, Email: amartine@if.usp.br;  
  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 0375-9474 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000324847700036 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 1596  
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