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Author |
Martinez Torres, A.; Oset, E. |
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Title |
The gamma d -> K(+)K(-)np reaction and an alternative explanation for the “Theta(+)(1540) pentaquark” peak |
Type |
Journal Article |
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Year |
2010 |
Publication |
Physical Review C |
Abbreviated Journal  |
Phys. Rev. C |
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Volume |
81 |
Issue |
5 |
Pages |
055202 - 16pp |
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Keywords |
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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. |
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Address |
[Martinez Torres, A.] Univ Politecn Valencia, CSIC, Ctr Mixto, Dept Fis Teor, E-46071 Valencia, Spain, Email: amartine@ific.uv.es |
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Publisher |
Amer Physical Soc |
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English |
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ISSN |
0556-2813 |
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Notes |
ISI:000278144800057 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ elepoucu @ |
Serial |
443 |
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Author |
Xie, J.J.; Martinez Torres, A.; Oset, E. |
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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 |
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Year |
2011 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
83 |
Issue |
6 |
Pages |
065207 - 8pp |
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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. |
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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 |
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Publisher |
Amer Physical Soc |
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English |
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ISSN |
0556-2813 |
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Conference |
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Notes |
ISI:000291984800004 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
665 |
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Author |
Martinez Torres, A.; Bayar, M.; Jido, D.; Oset, E. |
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Title |
Strategy to find the two Lambda (1405) states from lattice QCD simulations |
Type |
Journal Article |
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Year |
2012 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
86 |
Issue |
5 |
Pages |
055201 - 13pp |
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Abstract |
Theoretical studies within the chiral unitary approach, and recent experiments, have provided evidence of the existence of two isoscalar states in the region of the Lambda(1405). In this paper we use the same chiral approach to generate energy levels in a finite box. In a second step, assuming that these energies correspond to lattice QCD results, we devise the best strategy of analysis to obtain the two states in the infinite-volume case, with sufficient precision to distinguish them. We find out that by using energy levels obtained with asymmetric boxes and/or with a moving frame, with reasonable errors in the energies, one has a successful scheme to get the two Lambda(1405) poles. |
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Address |
[Torres, A. Martinez; Jido, D.] Kyoto Univ, Yukawa Inst Theoret Phys, Kyoto 6068502, Japan |
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Amer Physical Soc |
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English |
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Series Volume |
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Edition |
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ISSN |
0556-2813 |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000310685400008 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1226 |
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Author |
Martinez Torres, A.; Khemchandani, K.P.; Oset, E. |
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Title |
Theoretical study of the gamma d -> pi(0)eta d reaction |
Type |
Journal Article |
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Year |
2023 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
107 |
Issue |
2 |
Pages |
025202 - 24pp |
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Keywords |
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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. |
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Address |
[Torres, A. Martinez] Univ Sao Paulo, Inst Fis, BR-05389970 Sao Paulo, Brazil, Email: amartine@if.usp.br; |
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Publisher |
Amer Physical Soc |
Place of Publication |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9985 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000981821500002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5563 |
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| Permanent link to this record |
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Author |
Martinez Torres, A.; Khemchandani, K.P.; Navarra, F.S.; Nielsen, M.; Oset, E. |
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Title |
The role of f(0)(1710) in the phi omega threshold peak of J/Psi -> gamma phi omega |
Type |
Journal Article |
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Year |
2013 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
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Volume |
719 |
Issue |
4-5 |
Pages |
388-393 |
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Keywords |
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Abstract |
We study the process J/Psi -> gamma phi omega, measured by the BES experiment, where a neat peak close to the phi omega threshold is observed and is associated to a scalar meson resonance around 1800 MeV. We make the observation that a scalar resonance coupling to phi omega unavoidably couples strongly to K (K) over bar, but no trace of a peak is seen in the K (K) over bar spectrum of the J/Psi -> gamma K (K) over bar at this energy. This serves us to rule out the interpretation of the observed peak as a signal of a new resonance. After this is done, a thorough study is performed on the production of a pair of vector mesons and how its interaction leads necessarily to a peak in the J/Psi -> gamma phi omega reaction close to the phi omega threshold, due to the dynamical generation of the f(0)(1710) resonance by the vector-vector interaction. We then show that both the shape obtained for the phi omega mass distribution, as well as the strength are naturally reproduced by this mechanism. The work also explains why the phi omega peak is observed in the BES experiment and not in other reactions, like B-+/- -> K-+/-phi omega of Belle. |
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Address |
[Martinez Torres, A.; Khemchandani, K. P.; Navarra, F. S.; Nielsen, M.; Oset, E.] Univ Sao Paulo, Inst Fis, BR-05389970 Sao Paulo, Brazil, Email: amartine@if.usp.br |
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Corporate Author |
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Publisher |
Elsevier Science Bv |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0370-2693 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000315316900020 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1377 |
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Author |
Martinez Torres, A.; Khemchandani, K.P.; Jido, D.; Kanada-En'yo, Y.; Oset, E. |
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Title |
Three-body hadron systems with strangeness |
Type |
Journal Article |
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Year |
2013 |
Publication |
Nuclear Physics A |
Abbreviated Journal |
Nucl. Phys. A |
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Volume |
914 |
Issue |
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Pages |
280-288 |
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Keywords |
Unitary chiral theories; Few-body systems |
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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). |
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Address |
[Torres, A. Martinez; Khemchandani, K. P.] Univ Sao Paulo, Inst Fis, BR-05314970 Sao Paulo, Brazil, Email: amartine@if.usp.br; |
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Corporate Author |
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Publisher |
Elsevier Science Bv |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0375-9474 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000324847700036 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1596 |
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| Permanent link to this record |
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Author |
Martinez Torres, A.; Oset, E.; Prelovsek, S.; Ramos, A. |
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Title |
Reanalysis of lattice QCD spectra leading to the Ds0*(2317) and Ds1*(2460) |
Type |
Journal Article |
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Year |
2015 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
05 |
Issue |
5 |
Pages |
153 - 22pp |
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Keywords |
Lattice QCD; Phenomenological Models; QCD |
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Abstract |
We perform a reanalysis of the energy levels obtained in a recent lattice QCD simulation, from where the existence of bound states of KD and KD* are induced and identified with the narrow D-s0*(2317) and D-s1*(2460) resonances. The reanalysis is done in terms of an auxiliary potential, employing a single-channel basis KD(*()), and a two-channel basis KD(*()), eta D-s(()*()). By means of an extended Luscher method we determine poles of the continuum t-matrix, bound by about 40 MeV with respect to the KD and KD* thresholds, which we identify with the D-s0*(2317) and D-s1*(2460) resonances. Using a sum rule that reformulates Weinberg compositeness condition we can determine that the state D-s0*(2317) contains a KD component in an amount of about 70%, while the state D-s1*(2460) contains a similar amount of KD*. We argue that the present lattice simulation results do not still allow us to determine which are the missing channels in the bound state wave functions and we discuss the necessary information that can lead to answer this question. |
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Address |
[Martinez Torres, A.] Univ Sao Paulo, Inst Fis, BR-05389970 Sao Paulo, SP, Brazil, Email: amartine@if.usp.br; |
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Corporate Author |
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Thesis |
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Publisher |
Springer |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1029-8479 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000355346500002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2258 |
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| Permanent link to this record |
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Author |
Martinez Torres, A.; Prelovsek, S.; Oset, E.; Ramos, A. |
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Title |
Effective Field Theories in a Finite Volume |
Type |
Journal Article |
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Year |
2018 |
Publication |
Few-Body Systems |
Abbreviated Journal |
Few-Body Syst. |
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Volume |
59 |
Issue |
6 |
Pages |
139 - 5pp |
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Keywords |
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Abstract |
In this talk I present the formalism we have used to analyze Lattice data on two meson systems by means of effective field theories. In particular I present the results obtained from a reanalysis of the lattice data on the KD(*()) systems, where the states D-s0*(2317) and D-s1*(2460) are found as bound states of KD and KD *, respectively. We confirm the presence of such states in the lattice data and determine the contribution of the KD channel in the wave function of D-s0*(2317) and that of KD* in the wave function of D-s1*(2460). Our findings indicate a large meson-meson component in the two cases. |
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Address |
[Martinez Torres, A.] Univ Sao Paulo, Inst Fis, Rua Matao 1371, BR-05508090 Sao Paulo, SP, Brazil, Email: amartine@if.usp.br |
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Corporate Author |
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Thesis |
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Publisher |
Springer Wien |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0177-7963 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000448041400002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3772 |
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| Permanent link to this record |
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Author |
Martinez Torres, A.; Khemchandani, K.P.; Roca, L.; Oset, E. |
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Title |
Few-body systems consisting of mesons |
Type |
Journal Article |
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Year |
2020 |
Publication |
Few-Body Systems |
Abbreviated Journal |
Few-Body Syst. |
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Volume |
61 |
Issue |
4 |
Pages |
35 - 16pp |
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Keywords |
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Abstract |
We present a work which is meant to inspire the few-body practitioners to venture into the study of new, more exotic, systems and to hadron physicists, working mostly on two-body problems, to move in the direction of studying related few-body systems. For this purpose we devote the discussions in the introduction to show how the input two-body amplitudes can be easily obtained using techniques of the chiral unitary theory, or its extensions to the heavy quark sector. We then briefly explain how these amplitudes can be used to solve the Faddeev equations or a simpler version obtained by treating the three-body scattering as that of a particle on a fixed center. Further, we give some examples of the results obtained by studying systems involving mesons. We have also addressed the field of many meson systems, which is currently almost unexplored, but for which we envisage a bright future. Finally, we give a complete list of works dealing with unconventional few-body systems involving one or several mesons, summarizing in this way the findings on the topic, and providing a motivation for those willing to investigate such systems. |
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Address |
[Martinez Torres, A.] Univ Sao Paulo, Inst Fis, BR-05389970 Sao Paulo, Brazil, Email: amartine@if.usp.br; |
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Corporate Author |
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Thesis |
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Publisher |
Springer Wien |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0177-7963 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000572646500001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4546 |
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| Permanent link to this record |
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Author |
Bayar, M.; Martinez Torres, A.; Khemchandani, K.P.; Molina, R.; Oset, E. |
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Title |
Exotic states with triple charm |
Type |
Journal Article |
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Year |
2023 |
Publication |
European Physical Journal C |
Abbreviated Journal |
Eur. Phys. J. C |
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Volume |
83 |
Issue |
1 |
Pages |
46 - 9pp |
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Keywords |
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Abstract |
In this work we investigate the possibility of the formation of states from the dynamics involved in the D* D* D* system by considering that two D*'s generate a JP = 1+ bound state, with isospin 0, which has been predicted in an earlier theoretical work. We solve the Faddeev equations for this system within the fixed center approximation and find the existence of J(P) = 0(-), 1(-) and 2(-) states with charm 3, isospin 1/2, masses similar to 6000 MeV, which are manifestly exotic hadrons, i.e., with a multiquark inner structure. |
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Address |
[Bayar, M.] Kocaeli Univ, Dept Phys, TR-41380 Izmit, Turkey, Email: melahat.bayar@kocaeli.edu.tr; |
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Thesis |
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Publisher |
Springer |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1434-6044 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000918220000006 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5473 |
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| Permanent link to this record |
