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Author Ikeno, N.; Kimura, R.; Yamagata-Sekihara, J.; Nagahiro, H.; Jido, D.; Itahashi, K.; Geng, L.S.; Hirenzaki, S. url  doi
openurl 
  Title Precision Spectroscopy of Deeply Bound Pionic Atoms and Partial Restoration of Chiral Symmetry in Medium Type Journal Article
  Year 2011 Publication (down) Progress of Theoretical Physics Abbreviated Journal Prog. Theor. Phys.  
  Volume 126 Issue 3 Pages 483-509  
  Keywords  
  Abstract We study theoretically the formation spectra of deeply bound pionic atoms expected to be observed by experiments with high energy resolution at RIBF/RIKEN, and we discuss in detail the possibilities to extract new information on the pion properties at finite density from the observed spectra, which may provide information on partial restoration of chiral symmetry in medium. We find that the non-yrast pionic states such as 2s are expected to be seen in the (d,(3)He) spectra, which will be helpful to reduce uncertainties of the theoretical calculations in the neutron wave functions in nucleus. The observation of the 2s state with the ground is state is also helpful to reduce the experimental uncertainties associated in the calibration of the absolute excitation energy. We find that the nuclear densities probed by atomic pions are quite stable and almost constant for various atomic states and various nuclei. Effects of the pion wave function renormalization to the formation spectra are also evaluated.  
  Address [Ikeno, N; Kimura, R; Nagahiro, H; Hirenzaki, S] Nara Womens Univ, Dept Phys, Nara 6308506, Japan  
  Corporate Author Thesis  
  Publisher Progress Theoretical Physics Publication Office Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0033-068x ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000295760400008 Approved no  
  Is ISI no International Collaboration yes  
  Call Number IFIC @ elepoucu @ Serial 784  
Permanent link to this record
 

 
Author Molina, R.; Geng, L.S.; Oset, E. url  doi
openurl 
  Title Comments on the dispersion relation method to vector-vector interaction Type Journal Article
  Year 2019 Publication (down) Progress of Theoretical and Experimental Physics Abbreviated Journal Prog. Theor. Exp. Phys.  
  Volume Issue 10 Pages 103B05 - 16pp  
  Keywords  
  Abstract We study in detail the method proposed recently to study the vector-vector interaction using the N/D method and dispersion relations, which concludes that, while, for J = 0, one finds bound states, in the case of J = 2, where the interaction is also attractive and much stronger, no bound state is found. In that work, approximations are done for N and D and a subtracted dispersion relation for D is used, with subtractions made up to a polynomial of second degree in s – s(th), matching the expression to 1 – VG at threshold. We study this in detail for the rho rho interaction and to see the convergence of the method we make an extra subtraction matching 1 – VG at threshold up to (s – s(th))(3). We show that the method cannot be used to extrapolate the results down to 1270 MeV where the f(2)(1270) resonance appears, due to the artificial singularity stemming from the “on-shell” factorization of the rho exchange potential. In addition, we explore the same method but folding this interaction with the mass distribution of the rho, and we show that the singularity disappears and the method allows one to extrapolate to low energies, where both the (s – s(th))(2) and (s – s(th))(3) expansions lead to a zero of Re D(s), at about the same energy where a realistic approach produces a bound state. Even then, the method generates a large Im D(s) that we discuss is unphysical.  
  Address [Molina, R.] Univ Complutense Madrid, Fac Fis, Dept Fis Teor 2, Plaza Ciencias 1, E-28040 Madrid, Spain, Email: ramolinape@gmail.com  
  Corporate Author Thesis  
  Publisher Oxford Univ Press Inc Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2050-3911 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000493500800006 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4190  
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Author Ren, X.L.; Alvarez-Ruso, L.; Geng, L.S.; Ledwig, T.; Meng, J.; Vicente Vacas, M.J. url  doi
openurl 
  Title Consistency between SU(3) and SU(2) covariant baryon chiral perturbation theory for the nucleon mass Type Journal Article
  Year 2017 Publication (down) Physics Letters B Abbreviated Journal Phys. Lett. B  
  Volume 766 Issue Pages 325-333  
  Keywords Baryon chiral perturbation theory; Lattice QCD; Nucleon mass and sigma term  
  Abstract Treating the strange quark mass as a heavy scale compared to the light quark mass, we perform a matching of the nucleon mass in the SU(3) sector to the two-flavor case in covariant baryon chiral perturbation theory. The validity of the 19low-energy constants appearing in the octet baryon masses up to next-to-next-to-next-to-leading order[1] is supported by comparing the effective parameters (the combinations of the 19couplings) with the corresponding low-energy constants in the SU(2) sector[2]. In addition, it is shown that the dependence of the effective parameters and the pion-nucleon sigma term on the strange quark mass is relatively weak around its physical value, thus providing support to the assumption made in Ref.[2] that the SU(2) baryon chiral perturbation theory can be applied to study n(f) = 2 + 1lattice QCD simulations as long as the strange quark mass is close to its physical value.  
  Address [Ren, Xiu-Lei; Geng, Li-Sheng; Meng, Jie] Beihang Univ, Sch Phys & Nucl Energy Engn, Beijing 100191, Peoples R China, Email: lisheng.geng@buaa.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 0370-2693 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000396438300043 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 3003  
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Author Molina, R.; Xie, J.J.; Liang, W.H.; Geng, L.S.; Oset, E. url  doi
openurl 
  Title Theoretical interpretation of the D-s(+) -> pi(+)pi(0)eta decay and the nature of a(0)(980) Type Journal Article
  Year 2020 Publication (down) Physics Letters B Abbreviated Journal Phys. Lett. B  
  Volume 803 Issue Pages 135279 - 4pp  
  Keywords  
  Abstract In a recent paper [I], the BESIII Collaboration reported the so-called first observation of pure W-annihi- lation decays D-s(+) -> a(0)(+) (980)pi(0) and D-s(+) -> a(0)(0)(980)pi(+). The measured absolute branching fractions are, however, puzzlingly larger than those of other measured pure W-annihilation decays by at least one order of magnitude. In addition, the relative phase between the two decay modes is found to be about 0 degrees. In this letter, we show that all these can be easily understood if the a(0)(980) is a dynamically generated state from (K) over barK and pi eta interactions in coupled channels. In such a scenario, the D-s(+) decay proceeds via internal W emission instead of W-annihilation, which has a larger decay rate than W-annihilation. The proposed decay mechanism and the molecular nature of the a(0)(980) also provide a natural explanation to the measured negative interference between the two decay modes.  
  Address [Molina, Raquel; Liang, Wei-Hong; Oset, Eulogio] Guangxi Normal Univ, Dept Phys, Guilin 541004, Peoples R China, Email: raqumoli@ucm.es;  
  Corporate Author Thesis  
  Publisher Elsevier 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:000521730300066 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4356  
Permanent link to this record
 

 
Author Martin Camalich, J.; Geng, L.S.; Vicente Vacas, M.J. url  doi
openurl 
  Title Lowest-lying baryon masses in covariant SU(3)-flavor chiral perturbation theory Type Journal Article
  Year 2010 Publication (down) Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 82 Issue 7 Pages 074504 - 7pp  
  Keywords  
  Abstract We present an analysis of the baryon-octet and -decuplet masses using covariant SU(3)-flavor chiral perturbation theory up to next-to-leading order. Besides the description of the physical masses we address the problem of the lattice QCD extrapolation. Using the PACS-CS Collaboration data we show that a good description of the lattice points can be achieved at next-to-leading order with the covariant loop amplitudes and phenomenologically determined values for the meson-baryon couplings. Moreover, the extrapolation to the physical point up to this order is found to be better than the linear one given at leading-order by the Gell-Mann-Okubo approach. The importance that a reliable combination of lattice QCD and chiral perturbation theory may have for hadron phenomenology is emphasized with the prediction of the pion-baryon and strange-baryon sigma terms.  
  Address [Martin Camalich, J.; Geng, L. S.; Vicente Vacas, M. J.] Univ Valencia, CSIC, 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 1550-7998 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000283121000002 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ elepoucu @ Serial 352  
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Author Geng, L.S.; Kaiser, N.; Martin Camalich, J.; Weise, W. url  doi
openurl 
  Title Low-energy interactions of Nambu-Goldstone bosons with D mesons in covariant chiral perturbation theory Type Journal Article
  Year 2010 Publication (down) Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 82 Issue 5 Pages 054022 - 7pp  
  Keywords  
  Abstract We calculate the scattering lengths of Nambu-Goldstone bosons interacting with D mesons in a covariant formulation of chiral perturbation theory, which satisfies heavy-quark spin symmetry and analytical properties of loop amplitudes. We compare our results with previous studies performed using heavy-meson chiral perturbation theory and show that recoil corrections are sizable in most cases.  
  Address [Geng, L. S.] Beihang Univ, Sch Phys & Nucl Energy Engn, Beijing 100191, Peoples R China  
  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 1550-7998 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000282045700003 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ elepoucu @ Serial 377  
Permanent link to this record
 

 
Author Garcia-Recio, C.; Geng, L.S.; Nieves, J.; Salcedo, L.L. url  doi
openurl 
  Title Low-lying even-parity meson resonances and spin-flavor symmetry Type Journal Article
  Year 2011 Publication (down) Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 83 Issue 1 Pages 016007 - 30pp  
  Keywords  
  Abstract Based on a spin-flavor extension of chiral symmetry, a novel s-wave meson-meson interaction involving members of the rho nonet and of the pi octet is introduced, and its predictions are analyzed. The starting point is the SU(6) version of the SU(3)-flavor Weinberg-Tomozawa Lagrangian. SU(6) symmetry-breaking terms are then included to account for the physical meson masses and decay constants in a way that preserves (broken) chiral symmetry. Next, the T-matrix amplitudes are obtained by solving the Bethe-Salpeter equation in a coupled-channel scheme, and the poles are identified with their possible Particle Data Group counterparts. It is shown that most of the low-lying even-parity Particle Data Group meson resonances, especially in the J(P) = 0(+) and 1(+) sectors, can be classified according to multiplets of SU(6). The f(0)(1500), f(1)(1420), and some 0(+)(2(++)) resonances cannot be accommodated within this scheme, and thus they would be clear candidates to be glueballs or hybrids. Finally, we predict the existence of five exotic resonances (I >= 3/2 and/or vertical bar Y vertical bar = 2) with masses in the range of 1.4-1.6 GeV, which would complete the 27(1), 10(3), and 10(3)* multiplets of SU(3) circle times SU(2).  
  Address [Garcia-Recio, C.; Salcedo, L. L.] Univ Granada, Dept Fis Atom Mol & Nucl, E-18071 Granada, 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 1550-7998 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000286765100008 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 585  
Permanent link to this record
 

 
Author Branz, T.; Geng, L.S.; Oset, E. url  doi
openurl 
  Title Two-photon and one-photon-one-vector meson decay widths of the f(0)(1370), f(2)(1270), f(0)(1710), f(2)'(1525), and K-2*(1430) Type Journal Article
  Year 2010 Publication (down) Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 81 Issue 5 Pages 054037 - 10pp  
  Keywords  
  Abstract We calculate the radiative decay widths, two-photon (gamma gamma) and one-photon-one-vector meson (V gamma), of the dynamically generated resonances from vector-meson -vector-meson interaction in a unitary approach based on the hidden-gauge Lagrangians. In the present paper we consider the following dynamically generated resonances: f(0)(1370), f(0)(1710), f(2)(1270), f(2)'(1525) K-2*(1430), two strangeness 0 and isospin 1 states, and two strangeness 1 and isospin 1= 2 states. For the f(0)(1370) and f(2)(1270) we reproduce the previous results for the two-photon decay widths and further calculate their one-photon -one-vector decay widths. For the f(0)(1710) and f(2)'(1525) the calculated two-photon decay widths are found to be consistent with data. The rho 0 gamma, omega gamma and phi gamma decay widths of the f0(1370), f(2)'(1270) f(0)(1710), f(2)'(1525) are compared with the results predicted by other approaches. The K*(+)gamma and K*(0)gamma decay rates of the K-2*(1430) are also calculated and compared with the results obtained in the framework of the covariant oscillator quark model. The results for the two states with strangeness 0, isospin 1 and two states with strangeness 1, isospin 1/ 2 are predictions that need to be tested by future experiments.  
  Address [Branz, T.] Univ Tubingen, Inst Theoret Phys, D-72076 Tubingen, Germany  
  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 1550-7998 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000276194200068 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ elepoucu @ Serial 474  
Permanent link to this record
 

 
Author Garcia-Recio, C.; Geng, L.S.; Nieves, J.; Salcedo, L.L.; Wang, E.; Xie, J.J. url  doi
openurl 
  Title Low-lying even parity meson resonances and spin-flavor symmetry revisited Type Journal Article
  Year 2013 Publication (down) Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 87 Issue 9 Pages 096006 - 18pp  
  Keywords  
  Abstract We review and extend the model derived in Garcia-Recio et al. [Phys. Rev. D 83, 016007 (2011)] to address the dynamics of the low-lying even-parity meson resonances. This model is based on a coupled-channels spin-flavor extension of the chiralWeinberg-Tomozawa Lagrangian. This interaction is then used to study the S-wave meson-meson scattering involving members not only of the pi octet, but also of the rho nonet. In this work, we study in detail the structure of the SU(6)-symmetry-breaking contact terms that respect (or softly break) chiral symmetry. We derive the most general local (without involving derivatives) terms consistent with the chiral-symmetry-breaking pattern of QCD. After introducing sensible simplifications to reduce the large number of possible operators, we carry out a phenomenological discussion of the effects of these terms. We show how the inclusion of these pieces leads to an improvement of the description of the J(P) = 2(+) sector, without spoiling the main features of the predictions obtained in the original model in the JP = 0(+) and J(P) = 1(+) sectors. In particular, we find a significantly better description of the I-G(J(PC)) =0(+)(2(++)), 1(-)(2(++)) and the I(JP)=1/2(2(+)) sectors, which correspond to the f(2)(1270), a(2)(1320), and K-2(*)(1430) quantum numbers, respectively.  
  Address Univ Granada, Dept Fis Atom Mol & Nucl, E-18071 Granada, 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 1550-7998 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000319059500004 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 1450  
Permanent link to this record
 

 
Author Ledwig, T.; Martin Camalich, J.; Geng, L.S.; Vicente Vacas, M.J. url  doi
openurl 
  Title Octet-baryon axial-vector charges and SU(3)-breaking effects in the semileptonic hyperon decays Type Journal Article
  Year 2014 Publication (down) Physical Review D Abbreviated Journal Phys. Rev. D  
  Volume 90 Issue 5 Pages 054502 - 16pp  
  Keywords  
  Abstract The octet-baryon axial-vector charges and the g(1)/f(1) ratios measured in the semileptonic hyperon decays are studied up to O(p(3)) using the covariant baryon chiral perturbation theory with explicit decuplet contributions. We clarify the role of different low-energy constants and find a good convergence for the chiral expansion of the axial-vector charges of the baryon octet, g(1)(0), with O(p(3)) corrections typically around 20% of the leading ones. This is a consequence of strong cancellations between different next-to-leading- order terms. We show that considering only nonanalytic terms is not enough and that analytic terms appearing at the same chiral order play an important role in this description. The same effects still hold for the chiral extrapolation of the axial-vector charges and result in a rather mild quark-mass dependence. As a result, we report a determination of the leading-order chiral couplings, D = 0.623(61)(17) and F = 0.441(47)(2), as obtained from a completely consistent chiral analysis up to O(p(3)). Furthermore, we note that the appearance of an unknown low-energy constant precludes the extraction of the proton octet charge from semileptonic decay data alone, which is relevant for an analysis of the composition of the proton spin.  
  Address [Ledwig, T.; Vicente Vacas, M. J.] Univ Valencia, CSIC, Inst Invest Paterna, Dept Fis Teor, Paterna 46980, Spain, Email: ledwig@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 1550-7998 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000341264600001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 1899  
Permanent link to this record
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