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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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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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Amer Physical Soc |
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English |
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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 |
Martinez Torres, A.; Oset, E. |
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Title |
Novel Interpretation of the “Theta(+)(1540) Pentaquark” Peak |
Type |
Journal Article |
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Year |
2010 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys. Rev. Lett. |
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Volume |
105 |
Issue |
9 |
Pages |
092001 - 4pp |
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Abstract |
We use a theoretical model of the gamma d --> K+K- np reaction adapted to the experiment done at LEPS where a peak was observed and associated with the Theta(+)(1540) pentaquark. The study shows that the method used in the experiment to assign momenta to the undetected proton and neutron, together with the chosen cuts, necessarily creates an artificial broad peak in the assumed K(+)n invariant mass in the region of the claimed Theta(+)(1540), such that the remaining strength seen for the experimental peak is compatible with a fluctuation of 2 sigma significance. |
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Address |
[Martinez Torres, A.] Univ Valencia, Ctr Mixto, CSIC, Inst Invest Paterna,Dept Fis Teor, Valencia 46071, Spain |
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Amer Physical Soc |
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English |
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ISSN |
0031-9007 |
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Notes |
ISI:000281272700005 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ elepoucu @ |
Serial |
387 |
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Author |
Xie, J.J.; Martinez Torres, A.; Oset, E.; Gonzalez, P. |
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Title |
Plausible explanation for the Delta(5/2)+(2000) puzzle |
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 |
5 |
Pages |
055204 - 11pp |
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Abstract |
From a Faddeev calculation for the pi-(Delta rho)(N5/2)-(1675) system we show the plausible existence of three dynamically generated I (J(P)) = 3/2(5/2(+)) baryon states below 2.3 GeV, whereas only two resonances, Delta(5/2)+ (1905)( ) and Delta(5/2)+(2000)(**), are cataloged in the Particle Data Book Review. Our results give theoretical support to data analyses extracting two distinctive resonances, Lambda(5/2)+(similar to 1740) and Lambda(5/2)+(similar to 2200), from which the mass of Delta(5/2)+ (2000) is estimated. We propose that these two resonances should be cataloged instead of Delta(5/2)+(2000). This proposal gets further support from the possible assignment of the other baryon states found in the approach in the I = 1/2, 3/2 with J(P) = 1/2(+), 3/2(+), 5/(2)+ sectors to known baryonic resonances. In particular, Delta(1/2)+(1750)(*) is naturally interpreted as a pi N-1/2-(1650) bound state. |
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Address |
[Xie, Ju-Jun; Oset, E.; Gonzalez, P.] 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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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:000290522200010 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
626 |
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Author |
Martinez Torres, A.; Garzon, E.J.; Oset, E.; Dai, L.R. |
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Title |
Limits to the fixed center approximation to Faddeev equations: The case of the phi(2170) |
Type |
Journal Article |
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Year |
2011 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
83 |
Issue |
11 |
Pages |
116002 - 9pp |
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Keywords |
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Abstract |
The fixed center approximation to the Faddeev equations has been used lately with success in the study of bound systems of three hadrons. It is also important to set the limits of the approach in those problems to prevent proliferation of inaccurate predictions. In this paper, we study the case of the phi(2170), which has been described by means of Faddeev equations as a resonant state of phi and K (K) over bar, and show the problems derived from the use of the fixed center approximation in its study. At the same time, we also expose the limitations of an alternative approach recently proposed. |
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Address |
[Martinez Torres, A.] Kyoto Univ, Yukawa Inst Theoret Phys, Kyoto 6068502, Japan |
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Publisher |
Amer Physical Soc |
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English |
Summary Language |
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Series Editor |
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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 |
1550-7998 |
ISBN |
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Area |
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Conference |
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Notes |
ISI:000291151000015 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
637 |
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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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Keywords |
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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 |
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 |
0556-2813 |
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 |
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.; Dai, L.R.; Koren, C.; Jido, D.; Oset, E. |
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Title |
KD, eta Ds interaction in finite volume and the Ds*0(2317) resonance |
Type |
Journal Article |
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Year |
2012 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
85 |
Issue |
1 |
Pages |
014027 - 11pp |
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Keywords |
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Abstract |
An SU(4) extrapolation of the chiral unitary theory in coupled channels done to study the scalar mesons in the charm sector is extended to produce results in finite volume. The theory in the infinite volume produces dynamically the D-s*0(2317) resonance by means of the coupled channels KD, eta D-s. Energy levels in the finite box are evaluated and, assuming that they would correspond to lattice results, the inverse problem of determining the bound states and phase shifts in the infinite volume from the lattice data is addressed. We observe that it is possible to obtain accurate KD phase shifts and the position of the D-s*0(2317) state, but it requires the explicit consideration of the two coupled channels in the analysis if one goes close to the eta D-s threshold. We also show that the finite volume spectra look rather different in case the D-s*0(2317) is a composite state of the two mesons, or if it corresponds to a non molecular state with a small overlap with the two meson system. We then show that a careful analysis of the finite volume data can shed some light on the nature of the D-s*0(2317) resonance as a KD molecule or otherwise. |
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Address |
[Torres, A. Martinez; Dai, L. R.; Koren, C.; Jido, D.; Oset, E.] Kyoto Univ, Yukawa Inst Theoret Phys, Kyoto 6068502, Japan |
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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 |
1550-7998 |
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:000299926800004 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
898 |
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Author |
Sekihara, T.; Martinez Torres, A.; Jido, D.; Oset, E. |
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Title |
Theoretical study of incoherent phi photoproduction on a deuteron target |
Type |
Journal Article |
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Year |
2012 |
Publication |
European Physical Journal A |
Abbreviated Journal |
Eur. Phys. J. A |
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Volume |
48 |
Issue |
1 |
Pages |
10 - 17pp |
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Keywords |
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Abstract |
We study the photoproduction of phi mesons in deuteron, paying attention to the modification of the cross-section from bound protons to the free ones. For this purpose we take into account Fermi motion in single scattering and rescattering of phi to account for phi absorption on a second nucleon as well as the rescattering of the proton on the neutron. We find that the contribution of the double scattering for phi is much smaller than the typical cross-section of gamma p -> phi p in free space, which implies a very small screening of the phi production in deuteron. The contribution from the proton rescattering, on the other hand, is found to be not negligible compared to the cross-section of gamma p -> phi p in free space, and leads to a moderate reduction of the phi photoproduction cross-section on a deuteron at forward angles if the LEPS set-up is taken into account. The Fermi motion allows contribution of the single scattering in regions forbidden by phase-space in the free case. In particular, we find that for momentum transfer squared close to the maximum value, the Fermi motion changes drastically the shape of d sigma/dt, to the point that the ratio of this cross-section to the free one becomes very sensitive to the precise value of t chosen, or the size of the bin used in an experimental analysis. Hence, this particular region of t does not seem to be the most indicated to find effects of a possible phi absorption in the deuteron. This reaction is studied theoretically as a function of t and the results are contrasted with recent experiments at LEPS and Jefferson Lab. The effect of the experimental angular cuts at LEPS is also discussed, providing guidelines for future experimental analyses of the reaction. |
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Address |
[Sekihara, T.] Kyoto Univ, Grad Sch Sci, Dept Phys, Kyoto 6068502, Japan, Email: sekihara@th.phys.titech.ac.jp |
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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 |
1434-6001 |
ISBN |
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Notes |
WOS:000300285400001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
912 |
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Author |
Oset, E.; Martinez Torres, A.; Khemchandani, K.P.; Roca, L.; Yamagata-Sekihara, J. |
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Title |
Two, three, many body systems involving mesons |
Type |
Journal Article |
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Year |
2012 |
Publication |
Progress in Particle and Nuclear Physics |
Abbreviated Journal |
Prog. Part. Nucl. Phys. |
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Volume |
67 |
Issue |
2 |
Pages |
455-460 |
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Keywords |
Meson many body; Chiral dynamics; Dynamically generated resonances |
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Abstract |
In this talk we show recent developments on few body systems involving mesons. We report on an approach to Faddeev equations using chiral unitary dynamics, where an explicit cancellation of the two body off shell amplitude with three body forces stemming from the same chiral Lagrangians takes place. This removal of the unphysical off shell part of the amplitudes is most welcome and renders the approach unambiguous, showing that only on shell two body amplitudes need to be used. Within this approach, systems of two mesons and one baryon are studied, reproducing properties of the low lying 1/2(+) states. On the other hand we also report on multirho and K* multirho states which can be associated to known meson resonances of high spin. |
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Address |
[Oset, E.; Yamagata, J.] Ctr Mixto CSIC UV, Inst Fis Corpuscular, Inst Invest Paterna, Valencia 46071, Spain, Email: oset@ific.uv.es |
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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 |
0146-6410 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000303282200060 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
998 |
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| Permanent link to this record |
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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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Keywords |
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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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Publisher |
Amer Physical Soc |
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 |
0556-2813 |
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: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.; 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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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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| Permanent link to this record |
