Lattice study for conformal windows of SU(2) and SU(3) gauge theories with fundamental fermions
Abstract not provided
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Engineering topics
Ramos, A
Publications and source records attributed to Ramos, A.
Open-charm mesons in nuclear matter at finite temperature beyond the zero-range approximation
The properties of open charm mesons, D, D, D{sub s}, and D{sub s} in nuclear matter at finite temperature are studied within a self-consistent coupled-channel approach. The interaction of the low-lying pseudoscalar mesons with the ground-state baryons in the charm sector is derived from a t-channel vector-exchange model. The in-medium scattering amplitudes are obtained by solving the Lippmann-Schwinger equation at finite temperature including Pauli blocking effects, baryon dressing, as well as D, D, D{sub s}, and D{sub s} self-energies taking their mutual influence into account. We find that the in-medium properties of the D meson are affected by the D{sub s}-meson self-energy through the intermediate D{sub s}Y loops coupled to DN states. Similarly, dressing the D meson in the DY loops has an influence over the properties of the D{sub s} meson.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Analyticity constraints on the in-medium spectrum of mesons
Analyticity constraints in the form of energy weighted sum rules for the spectral function of mesons are derived, both in cold nuclear matter and at finite temperature, by matching the Dyson propagator with its spectral Lehmann representation at low and high energies. We illustrate our results by calculating the sum rules for specific models of the kaon and pion self-energy in a nuclear medium. We find satisfactory results from the lower energy weight sum rules, which reflect the contributions from the different quasi-particle and collective modes of the meson spectral function, and show examples of the sensitivity of the sum rules to model approximations. Finally, we discuss applications in asymmetric nuclear matter and in the study of the spectral properties of vector mesons.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Radiative decays of dynamically generated charmed baryons
In this work we study the radiative decay of dynamically generated J{sup P}=(1{sup -}/2) charm baryons into the ground state J{sup P}=(1{sup +}/2) baryons. Since different theoretical interpretations of these baryonic resonances and, in particular, of the {Lambda}{sub c}(2595), give different predictions, a precise experimental measurement of these decays would be an important step for understanding their nature.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Experimental status of deeply bound kaonic states in nuclei
We review recent claims of the existence of deeply bound kaonic states in nuclei. Also we study in details the (K{sup -},p) reaction on {sup 12}C with 1 GeV/c momentum kaon beam, based on which a deep kaon nucleus optical potential was claimed in [1]. In our Monte Carlo simulation of this reaction we include not only the quasi-elastic K{sup -}p scattering, as in [1], but also K{sup -} absorption by one and two nucleons followed by the decay of the hyperon in {pi}N, which can also produce strength in the region of interest. The final state interactions in terms of multiple scattering of the K{sup -},p and all other primary particles on their way out of the nucleus is also considered. We will show that all these additional mechanisms allow us to explain the observed spectrum with a ''standard'' shallow kaon nucleus optical potential obtained in chiral models.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Spectral properties of mesons in hot and dense matter from energy weighted sum rules
Energy weighted sum rules for the spectral function of mesons are derived, both in cold nuclear matter and at finite temperature, by matching the Dyson propagator with its spectral Lehmann representation at low and high energies. We illustrate our results by calculating the sum rules for specific models of the kaon and pion self-energy in a nuclear medium. We find satisfactory results from the lower energy weight sum rules, which reflect the contributions from the different quasi-particle and collective modes of the meson spectral function, and show examples of the sensitivity of the sum rules to model approximations. Finally, we discuss applications in asymmetric nuclear matter and in the study of the spectral properties of vector mesons.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Nucleon correlations and the equation of state of nuclear matter
The self-consistent Green's function method within the ladder approximation provides a microscopic description of correlated nuclear systems which properly treats the nucleon-nucleon correlations induced by the short-range and tensor components present in any realistic interaction. These correlations produce a sizable depletion of low momenta below the Fermi surface as well as the occupation of high momenta in the nuclear ground state. A few representative results for nuclear matter are presented to illustrate the present progress in the application of this method to nuclear systems.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Suppression of Tritium Retention in Remote Areas of ITER by Nonperturbative Reactive Gas Injection
A technique based on reactive gas injection in the afterglow region of the divertor plasma is proposed for the suppression of tritium-carbon codeposits in remote areas of ITER when operated with carbon-based divertor targets. Experiments in a divertor simulator plasma device indicate that a 4 nm/min deposition can be suppressed by addition of 1 Pa{center_dot}m{sup 3} s{sup -1} ammonia flow at 10 cm from the plasma. These results bolster the concept of nonperturbative scavenger injection for tritium inventory control in carbon-based fusion plasma devices, thus paving the way for ITER operation in the active phase under a carbon-dominated, plasma facing component background.
70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
K-bar* mesons in dense matter
We study the properties of K-bar* mesons in nuclear matter using a unitary approach in coupled channels within the framework of the local hidden gauge formalism and incorporating the K-bar{pi} decay channel in matter. The in-medium K-bar*N interaction accounts for Pauli blocking effects and incorporates the K-bar* self-energy in a self-consistent manner. We also obtain the K-bar* (off-shell) spectral function and analyze its behavior at finite density and momentum. At a normal nuclear matter density, the K-bar* meson feels a moderately attractive potential, while the K-bar* width becomes five times larger than in free space. We estimate the transparency ratio of the {gamma}A{yields}K{sup +}K*{sup -}A{sup '} reaction, which we propose as a feasible scenario at the present facilities to detect changes in the properties of the K-bar* meson in nuclear medium.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Vector baryon interaction and dynamically generated resonances
The formalism for the interaction of vector mesons with baryons within the local hidden gauge formalism is presented and it is shown to lead to a large amount of dynamically generated baryonic resonances, many of which can be associated to known states, while others represent predictions for new resonances.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Charmed mesons in nuclear matter
We obtain the properties of charmed mesons in dense matter using a coupled-channel approach which accounts for Pauli blocking effects and meson self-energies in a self-consistent manner. We study the behaviour of dynamically-generated baryonic resonances together with the open-charm meson spectral functions in this dense nuclear environment. We discuss the implications of the in-medium properties of open-charm mesons on the D{sub s0}(2317) and the predicted X(3700) scalar resonances, and on the formation of D-mesic nuclei.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Kaon absorption in flight and the binding of K-bar in nuclei
We make a theoretical study of the kaon absorption in flight on nuclei with a kaon beam of 1 GeV momentum, paying special attention to the forward and energetic emitted protons, which were used to claim a deep kaon nucleus optical potential in a recent experiment. We perform a Monte Carlo simulation of this reaction, which allows to account not only for quasi-elastic K{sup -}p scattering, but also for the other processes which contribute to the proton spectra and which are not taken into account by the ordinary Green's function method analysis. The experiment looks for fast protons, but in coincidence with at least one charged particle in a decay counters sandwiching the target. The coincidence requirement is assumed not to distort the shape of the proton spectra, but we show that this is not the case and as a consequence the conclusions drawn from the experimental analysis do not hold.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗