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Author |
Roca, L.; Oset, E. |
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Title |
Scattering of unstable particles in a finite volume: The case of pi rho scattering and the a(1)(1260) 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 |
5 |
Pages |
054507 - 13pp |
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Keywords |
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Abstract |
We present a way to evaluate the scattering of unstable particles quantized in a finite volume with the aim of extracting physical observables for infinite volume from lattice data. We illustrate the method with the pi rho scattering which generates dynamically the axial-vector a(1)(1260) resonance. Energy levels in a finite box are evaluated both considering the rho as a stable and unstable resonance and we find significant differences between both cases. We discuss how to solve the problem to get the physical scattering amplitudes in the infinite volume, and hence phase shifts, from possible lattice results on energy levels quantized inside a finite box. |
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Address |
[Roca, L.] Univ Murcia, Dept Fis, E-30071 Murcia, Spain |
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Publisher |
Amer Physical Soc |
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Language |
English |
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Series Volume |
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Edition |
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ISSN |
1550-7998 |
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Conference |
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Notes |
WOS:000301706700004 |
Approved |
no |
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Is ISI |
yes |
International Collaboration  |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
941 |
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Author |
Hernandez, P. |
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Title |
CP violation in the neutrino sector: The new frontier |
Type |
Journal Article |
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Year |
2012 |
Publication |
Comptes Rendus Physique |
Abbreviated Journal |
C. R. Phys. |
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Volume |
13 |
Issue |
2 |
Pages |
186-192 |
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Keywords |
Flavour physics; Neutrino physics; Matter-antimatter asymmetry |
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Abstract |
The discovery of neutrino masses has revealed a new flavour sector in the Standard Model. Just like the quark flavour sector, it contains a seed of CP violation, resulting in an asymmetric behaviour of matter and antimatter. It is argued that this new source of leptonic CP violation may be discovered in more precise neutrino oscillation experiments involving neutrino beams with energies in the GeV range that will be sent to distances of a few thousand kilometres. |
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Address |
[Hernandez, Pilar] Dpto Fis Teor UV, Valencia 46071, Spain, Email: m.pilar.hernandez@uv.es |
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Publisher |
Elsevier France-Editions Scientifiques Medicales Elsevier |
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Language |
English |
Summary Language |
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Original Title |
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Series Volume |
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Edition |
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ISSN |
1631-0705 |
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Conference |
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Notes |
WOS:000301037700015 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
934 |
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Author |
Cabello, J.; Rafecas, M. |
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Title |
Comparison of basis functions for 3D PET reconstruction using a Monte Carlo system matrix |
Type |
Journal Article |
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Year |
2012 |
Publication |
Physics in Medicine and Biology |
Abbreviated Journal |
Phys. Med. Biol. |
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Volume |
57 |
Issue |
7 |
Pages |
1759-1777 |
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Keywords |
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Abstract |
In emission tomography, iterative statistical methods are accepted as the reconstruction algorithms that achieve the best image quality. The accuracy of these methods relies partly on the quality of the system response matrix (SRM) that characterizes the scanner. The more physical phenomena included in the SRM, the higher the SRM quality, and therefore higher image quality is obtained from the reconstruction process. High-resolution small animal scanners contain as many as 10(3)-10(4) small crystal pairs, while the field of view (FOV) is divided into hundreds of thousands of small voxels. These two characteristics have a significant impact on the number of elements to be calculated in the SRM. Monte Carlo (MC) methods have gained popularity as a way of calculating the SRM, due to the increased accuracy achievable, at the cost of introducing some statistical noise and long simulation times. In the work presented here the SRM is calculated using MC methods exploiting the cylindrical symmetries of the scanner, significantly reducing the simulation time necessary to calculate a high statistical quality SRM and the storage space necessary. The use of cylindrical symmetries makes polar voxels a convenient basis function. Alternatively, spherically symmetric basis functions result in improved noise properties compared to cubic and polar basis functions. The quality of reconstructed images using polar voxels, spherically symmetric basis functions on a polar grid, cubic voxels and post-reconstruction filtered polar and cubic voxels is compared from a noise and spatial resolution perspective. This study demonstrates that polar voxels perform as well as cubic voxels, reducing the simulation time necessary to calculate the SRM and the disk space necessary to store it. Results showed that spherically symmetric functions outperform polar and cubic basis functions in terms of noise properties, at the cost of slightly degraded spatial resolution, larger SRM file size and longer reconstruction times. However, we demonstrate that post-reconstruction smoothing, usually applied in emission imaging to reduce the level of noise, can produce a spatial resolution degradation of similar to 50%, while spherically symmetric basis functions produce a degradation of only similar to 6%, compared to polar and cubic voxels, at the same noise level. Therefore, the image quality trade-off obtained with blobs is higher than that obtained with cubic or polar voxels. |
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Address |
[Cabello, Jorge; Rafecas, Magdalena] Univ Valencia, Inst Fis Corpuscular, CSIC, Valencia, Spain, Email: jorge.cabello@ific.uv.es |
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Corporate Author |
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Publisher |
Iop Publishing Ltd |
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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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 |
0031-9155 |
ISBN |
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Area |
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Conference |
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Notes |
WOS:000302121000004 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
955 |
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Author |
Carames, T.F.; Valcarce, A.; Vijande, J. |
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Title |
Too many X's, Y's and Z's? |
Type |
Journal Article |
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Year |
2012 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
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Volume |
709 |
Issue |
4-5 |
Pages |
358-361 |
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Keywords |
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Abstract |
A large number of new states have been reported during the last few years in charmonium spectroscopy above the charmed meson production threshold. They have been called X's, Y's, and Z's. We reflect on the influence of thresholds on heavy meson spectroscopy comparing different flavor sectors and quantum numbers. The validity of a quark-model picture above open-flavor thresholds would severely restrict the number of channels that may lodge meson-meson molecules. |
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Address |
[Carames, T. F.; Valcarce, A.] Univ Salamanca, Dept Fis Fundamental, E-37008 Salamanca, Spain, Email: valcarce@usal.es |
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Corporate Author |
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Thesis |
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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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Area |
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Conference |
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Notes |
WOS:000302454700005 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
978 |
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Author |
Bernal, A.; Perez, A. |
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Title |
Analytic behavior of the QED polarizability function at finite temperature |
Type |
Journal Article |
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Year |
2012 |
Publication |
AIP Advances |
Abbreviated Journal |
AIP Adv. |
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Volume |
2 |
Issue |
1 |
Pages |
012152 - 9pp |
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Keywords |
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Abstract |
We revisit the analytical properties of the static quasi-photon polarizability function for an electron gas at finite temperature, in connection with the existence of Friedel oscillations in the potential created by an impurity. In contrast with the zero temperature case, where the polarizability is an analytical function, except for the two branch cuts which are responsible for Friedel oscillations, at finite temperature the corresponding function is non analytical, in spite of becoming continuous everywhere on the complex plane. This effect produces, as a result, the survival of the oscillatory behavior of the potential. We calculate the potential at large distances, and relate the calculation to the non-analytical properties of the polarizability. |
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Address |
[Bernal, A.] Univ Barcelona, Dept Matemat Aplicada & Anal, E-08028 Barcelona, Spain |
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Corporate Author |
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Thesis |
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Publisher |
Amer Inst Physics |
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 |
2158-3226 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000302225400070 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
983 |
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