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pro vyhledávání: '"Oller J. A."'
We pursue the calculation of the model-independent component of the axion-photon-photon coupling in the $U(3)$ chiral perturbation theory up to next-to-leading order, with the emphasis on the isospin breaking effect. The mixing of the $\pi^0$-$\eta$-
Externí odkaz:
http://arxiv.org/abs/2411.06737
We study the equation of state (EoS) of a neutron star (NS) accounting for new advances. In the low energy density, $n\leq 0.1 n_s$, with $n_s$ the saturation density, we use a new pure neutron matter EoS that is regulator independent and expressed d
Externí odkaz:
http://arxiv.org/abs/2410.14776
Autor:
Oller, J. A.
These lectures treat scattering theory from a non-perturbative point of view. The course begins with a review of formal aspects in scattering theory, discussing the in/out states and the $S$ matrix that connects them. Unitarity relations, phase space
Externí odkaz:
http://arxiv.org/abs/2409.16790
Autor:
Oller, J. A., Peláez, Marcela
From the graviton-graviton scattering amplitudes calculated perturbatively in quantum gravity to the one-loop order, we develop further a formalism that allows one to calculate infrared-finite partial-wave amplitudes fulfilling perturbative unitarity
Externí odkaz:
http://arxiv.org/abs/2407.16538
Autor:
Oller, J. A., Peláez, Marcela
We have calculated the one-loop scattering amplitude of an electron by an external Coulomb potential in QED free of infrared divergences. This feature is achieved by applying the Faddeev-Kulish formalism, which implies a redefinition of both the asym
Externí odkaz:
http://arxiv.org/abs/2407.15382
We study a family of separable potentials with and without added contact interactions by solving the associated Lippmann-Schwinger equation with two coupled partial waves. The matching of the resulting amplitude matrix with the effective-range expans
Externí odkaz:
http://arxiv.org/abs/2403.05486
Autor:
Oller, J. A.
When a resonance lies near the threshold of a heavier channel, an interesting feature can occur. The paradigmatic example employed here is the scalar isoscalar $f_0(980)$ resonance that couples to the lighter $\pi\pi$ and heavier $K\bar{K}$ channels.
Externí odkaz:
http://arxiv.org/abs/2403.00135
Autor:
Alarcón, J. M., Oller, J. A.
Infinite nuclear matter is studied by resuming the series of ladder diagrams based on the results developed by us in Ann. Phys. 437, 168741 (2022). The master formula for the energy density is explicitly solved for the case of contact interactions, w
Externí odkaz:
http://arxiv.org/abs/2212.05092
We study the mixing of the QCD/QCD-like axion and light-flavor mesons $\pi^0, \eta, \eta'$ within the framework of $U(3)$ chiral perturbation theory up to next-to-leading order in this work. The axion-meson mixing formulas are calculated order by ord
Externí odkaz:
http://arxiv.org/abs/2211.02867
Autor:
Oller, J. A., Guo, Z. -H.
Several methods for studying the nature of a resonance are applied to resonances recently discovered in the bottonomium and charmonium sectors. We employ the effective-range expansion, the saturation of the width and compositeness of a resonance, as
Externí odkaz:
http://arxiv.org/abs/2211.02090