Eta-Mesic Nucleus and COSY-GEM Data

The experimental data of the COSY-GEM Collaboration for the recoil-free transfer reaction p (27Al, 3He) \pi - p' X, leading to the formation of bound state of eta (\eta) meson in 25Mg nucleus, is reanalyzed in this paper. In particular, predicted values of binding energy and half-width of the \eta -mesic nucleus 25Mg\eta, given by different theoretical approaches, are compared with the ones obtained from the experimental missing mass spectrum. It is found that the spectrum can be explained reasonably well if interference effect of another process, where \eta is not bound in 25Mg but is scattered by the nucleus and emerge as a pion, is taken into account. The data also indicate that the interaction between N*(1535) and a nucleus is attractive in nature.Comment: Invited talk at the International Symposium on Mesic Nuclei, Krakow, 16 June 201

Eta-mesic nuclei: past, present, future

Eta-mesic nucleus or the quasibound nuclear state of an eta ($\eta$) meson in a nucleus is caused by strong-interaction force alone. This new type of nuclear species, which extends the landscape of nuclear physics, has been extensively studied since its prediction in 1986. In this paper, we review and analyze in great detail the models of the fundamental $\eta$--nucleon interaction leading to the formation of an $\eta$--mesic nucleus, the methods used in calculating the properties of a bound $\eta$, and the approaches employed in the interpretation of the pertinent experimental data. In view of the successful observation of the $\eta$--mesic nucleus $^{25}$Mg$_{\eta}$ and other promising experimental results, future direction in searching for more $\eta$--mesic nuclei is suggested.Comment: 41 pages, 8 figure

Composite vertices that lead to soft form factors

The momentum-space cut-off parameter $\Lambda$ of hadronic vertex functions is studied in this paper. We use a composite model where we can measure the contributions of intermediate particle propagations to $\Lambda$. We show that in many cases a composite vertex function has a much smaller cut-off than its constituent vertices, particularly when light constituents such as pions are present in the intermediate state. This suggests that composite meson-baryon-baryon vertex functions are rather soft, i.e., they have \Lambda considerably less than 1 GeV. We discuss the origin of this softening of form factors as well as the implications of our findings on the modeling of nuclear reactions.Comment: REVTex, 19 pages, 5 figs(to be provided on request

General method for extracting the quantum efficiency of dispersive qubit readout in circuit QED

We present and demonstrate a general three-step method for extracting the quantum efficiency of dispersive qubit readout in circuit QED. We use active depletion of post-measurement photons and optimal integration weight functions on two quadratures to maximize the signal-to-noise ratio of the non-steady-state homodyne measurement. We derive analytically and demonstrate experimentally that the method robustly extracts the quantum efficiency for arbitrary readout conditions in the linear regime. We use the proven method to optimally bias a Josephson traveling-wave parametric amplifier and to quantify different noise contributions in the readout amplification chain.Comment: 10 pages, 6 figure

Parameter Inference in the Pulmonary Circulation of Mice

This study focuses on parameter inference in a pulmonary blood cir- culation model for mice. It utilises a fluid dynamics network model that takes selected parameter values and aims to mimic features of the pulmonary haemody- namics under normal physiological and pathological conditions. This is of medical relevance as it allows monitoring of the progression of pulmonary hypertension. Constraint nonlinear optimization is successfully used to learn the parameter values

Deconfinement Phase Transition in an Expanding Quark system in Relaxation Time Approximation

We investigated the effects of nonequilibrium and collision terms on the deconfinement phase transition of an expanding quark system in Friedberg-Lee model in relaxation time approximation. By calculating the effective quark potential, the critical temperature of the phase transition is dominated by the mean field, while the collisions among quarks and mesons change the time structure of the phase transition significantly.Comment: 7 pages, 7 figure

The Role of Δ(1232)\Delta(1232) in Two-pion Exchange Three-nucleon Potential

In this paper we have studied the two-pion exchange three-nucleon potential $(2\pi E-3NP)$ using an approximate $SU(2) \times SU(2)$ chiral symmetry of the strong interaction. The off-shell pion-nucleon scattering amplitudes obtained from the Weinberg Lagangian are supplemented with contributions from the well-known $\sigma$-term and the $\Delta(1232)$ exchange. It is the role of the $\Delta$-resonance in $2\pi E-3NP$, which we have investigated in detail in the framework of the Lagrangian field theory. The $\Delta$-contribution is quite appreciable and, more significantly, it is dependent on a parameter Z which is arbitrary but has the empirical bounds $|Z| \leq 1/2$. We find that the $\Delta$-contribution to the important parameters of the $2\pi E-3NP$ depends on the choice of a value for Z, although the correction to the binding energy of triton is not expected to be very sensitive to the variation of Z within its bounds.Comment: 14 pages, LaTe

Toward a unified description of hadro- and photoproduction: S-wave pi- and eta-photoproduction amplitudes

The Chew-Mandelstam parameterization, which has been used extensively in the two-body hadronic sector, is generalized in this exploratory study to the electromagnetic sector by simultaneous fits to the pion- and eta-photoproduction S-wave multipole amplitudes for center-of-mass energies from the pion threshold through 1.61 GeV. We review the Chew-Mandelstam parameterization in detail to clarify the theoretical content of the SAID hadronic amplitude analysis and to place the proposed, generalized SAID electromagnetic amplitudes in the context of earlier employed parameterized forms. The parameterization is unitary at the two-body level, employing four hadronic channels and the gamma-N electromagnetic channel. We compare the resulting fit to the MAID parameterization and find qualitative agreement though, numerically, the solution is somewhat different. Applications of the extended parameterization to global fits of the photoproduction data and to global fits of the combined hadronic and photoproduction data are discussed.Comment: 9 pages, 9 figures; added figures and tex