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Author |
Hiller Blin, A.N.; Ledwig, T.; Vicente Vacas, M.J. |
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Title |
Chiral dynamics in the (gamma)over-right-arrowp -> p pi(0) reaction |
Type |
Journal Article |
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Year |
2015 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
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Volume |
747 |
Issue ![sorted by Issue field, ascending order (up)](img/sort_asc.gif) |
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Pages |
217-222 |
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Abstract |
We investigate the neutral pion photoproduction on the proton near threshold in covariant chiral perturbation theory with the explicit inclusion of A degrees of freedom. This channel is specially sensitive to chiral dynamics and the advent of very precise data from the Mainz microtron has shown the limits of the convergence of the chiral series for both the heavy baryon and the covariant approaches. We show that the inclusion of the Delta resonance substantially improves the convergence leading to a good agreement with data for a wider range of energies. |
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Address |
[Vicente Vacas, M. J.] Univ Valencia, Ctr Mixto, CSIC, Dept Fis Teor,Inst Invest Paterna, E-46071 Valencia, Spain, Email: manuel.j.vicente@uv.es |
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Publisher |
Elsevier Science Bv |
Place of Publication |
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Language |
English |
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Series Editor |
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Series Volume |
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Edition |
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ISSN |
0370-2693 |
ISBN |
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Expedition |
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Conference |
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Notes |
WOS:000358624800038 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
2330 |
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Permanent link to this record |
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Author |
Ren, X.L.; Alvarez-Ruso, L.; Geng, L.S.; Ledwig, T.; Meng, J.; Vicente Vacas, M.J. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
Consistency between SU(3) and SU(2) covariant baryon chiral perturbation theory for the nucleon mass |
Type |
Journal Article |
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Year |
2017 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
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Volume |
766 |
Issue ![sorted by Issue field, ascending order (up)](img/sort_asc.gif) |
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Pages |
325-333 |
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Keywords |
Baryon chiral perturbation theory; Lattice QCD; Nucleon mass and sigma term |
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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. |
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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 |
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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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ISSN |
0370-2693 |
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Conference |
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Notes |
WOS:000396438300043 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3003 |
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Permanent link to this record |
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Author |
Ledwig, T.; Nieves, J.; Pich, A.; Ruiz Arriola, E.; Ruiz de Elvira, J. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
Large-N-c naturalness in coupled-channel meson-meson scattering |
Type |
Journal Article |
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Year |
2014 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
90 |
Issue ![sorted by Issue field, ascending order (up)](img/sort_asc.gif) |
11 |
Pages |
114020 - 17pp |
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Abstract |
The analysis of hadronic interactions with effective field theory techniques is complicated by the appearance of a large number of low-energy constants, which are usually fitted to data. On the other hand, the large-N-c limit helps to impose natural short-distance constraints on these low-energy constants, providing a parameter reduction. A Bayesian interpretation of the expected 1/N-c accuracy allows for an easy and efficient implementation of these constraints, using an augmented chi(2). We apply this approach to the analysis of meson-meson scattering, in conjunction with chiral perturbation theory to one loop and coupled-channel unitarity, and show that it helps to largely reduce the many existing ambiguities and simultaneously provide an acceptable description of the available phase shifts. |
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Address |
[Ledwig, T.; Nieves, J.; Pich, A.] Univ Valencia, CSIC, IFIC, Dept Fis Teor, Valencia 46071, Spain |
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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 |
1550-7998 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000348730800008 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2100 |
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Permanent link to this record |
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Author |
Ledwig, T.; Martin-Camalich, J.; Pascalutsa, V.; Vanderhaeghen, M. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
Nucleon and Delta(1232) form factors at low momentum transfer and small pion masses |
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 ![sorted by Issue field, ascending order (up)](img/sort_asc.gif) |
3 |
Pages |
034013 - 25pp |
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Abstract |
An expansion of the electromagnetic form factors of the nucleon and Delta(1232) in small momentum transfer and pion mass is performed in a manifestly covariant EFT framework consistent with chiral symmetry and analyticity. We present the expressions for the nucleon and Delta(1232) electromagnetic form factors, charge radii, and electromagnetic moments in the framework of SU(2) baryon chiral perturbation theory, with nucleon and Delta-isobar degrees of freedom, to next-to-leading order. Motivated by the results for the proton electric radius obtained from the muonic-hydrogen atom and electron-scattering process, we extract values for the second derivative of the electric form factor which is a genuine prediction of the p(3) B chi PT. The chiral behavior of radii and moments is studied and compared to that obtained in the heavy-baryon framework and lattice QCD. The chiral behavior of Delta(1232)-isobar properties exhibits cusps and singularities at the threshold of Delta -> pi N decay, and their physical significance is discussed. |
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Address |
[Ledwig, T.; Pascalutsa, V.; Vanderhaeghen, M.] Johannes Gutenberg Univ Mainz, Inst Kernphys, D-55099 Mainz, Germany, Email: ledwig@kph.uni-mainz.de |
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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 |
1550-7998 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000300093200003 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
894 |
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Permanent link to this record |
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Author |
Alvarez-Ruso, L.; Ledwig, T.; Martin Camalich, J.; Vicente Vacas, M.J. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
Nucleon mass and pion-nucleon sigma term from a chiral analysis of lattice QCD data |
Type |
Journal Article |
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Year |
2013 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
88 |
Issue ![sorted by Issue field, ascending order (up)](img/sort_asc.gif) |
5 |
Pages |
054507 - 20pp |
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Keywords |
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Abstract |
The pion mass dependence of the nucleon mass within the covariant SU(2) baryon chiral perturbation theory both without and with explicit Delta(1232) degrees of freedom up to order p(4) is investigated. By fitting to a comprehensive set of lattice QCD data in 2 and 2 + 1 flavors from several collaborations, for pion masses M-pi < 420 MeV, we obtain low energy constants of natural size that are compatible with pion-nucleon scattering data. Our results are consistent with the rather linear pion mass dependence showed by lattice QCD. In the 2 flavor case we have also performed simultaneous fits to nucleon mass and sigma(pi N) data. As a result of our analysis, which encompasses the study of finite volume corrections and discretization effects, we report a value of sigma(pi N) = 41(5)(4) MeV in the 2 flavor case and sigma(pi N) = 52(3)(8) MeV for 2 + 1 flavors, where the inclusion of the Delta(1232) resonance changes the results by around 9 MeV. In the 2 flavor case we are able to set independently the scale for lattice QCD data, given by a Sommer scale of r(0) = 0.493(23) fm. |
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Address |
[Alvarez-Ruso, L.] Univ Valencia, Ctr Mixto, CSIC, Inst Fis Corpuscular IFIC, E-46071 Valencia, Spain, Email: alvarez@ific.uv.es; |
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Corporate Author |
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Thesis |
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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 |
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:000324636100005 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1603 |
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Permanent link to this record |