An alternative scheme for effective range corrections in pionless EFT

We discuss an alternative scheme for including effective range corrections in pionless effective field theory. The standard approach treats range terms as perturbative insertions in the T-matrix. In a finite volume this scheme can lead to singular behavior close to the unperturbed energies. We consider an alternative scheme that resums the effective range but expands the spurious pole of the T-matrix created by this resummation. We test this alternative expansion for several model potentials and observe good convergence.

A novel way of constraining the α-attractor chaotic inflation through Planck data

Defining a scale of k-modes of the quantum fluctuations during inflation through the dynamical horizon crossing condition k = aH we go from the physical t variable to k variable and solve the equations of cosmological first-order perturbations self consistently, with the chaotic α-attractor type potentials. This enables us to study the behaviour of ns , r, nt and N in the k-space. Comparison of our results in the low-k regime with the Planck data puts constraints on the values of the α parameter through microscopic calculations. Recent studies had already put model-dependent constraints on the values of α through the hyperbolic geometry of a Poincaré disk: consistent with both the maximal supergravity model 𝒩 = 8 and the minimal supergravity model 𝒩 = 1, the constraints on the values of α are 1/3, 2/3, 1, 4/3, 5/3, 2, 7/3. The minimal 𝒩 = 1 supersymmetric cosmological models with B-mode targets, derived from these supergravity models, predicted the values of r between 10-2 and 10-3. Both in the E-model and the T-model potentials, we have obtained, in our calculations, the values of r in this range for all the constrained values of α stated above, within 68% CL. Moreover, we have calculated r for some other possible values of α both in low-α limit, using the formula r = 12α/N 2, and in the high-α limit, using the formula r = 4n/N, for n = 2 and 4. With all such values of α, our calculated results match with the Planck-2018 data with 68% or near 95% CL.

Further Results on the Proportional Vitalities Model

In contrast to many survival models such as proportional hazard rates and proportional mean residual lives, the proportional vitalities model has also been introduced in the literature. In this paper, further stochastic ordering properties of a dynamic version of the model with a random vitality growth parameter are investigated. Examples are presented to illustrate different established properties of the model. Potentials for inference about the parameters in proportional vitalities model with possibly time-varying effects are also argued and discussed.

An investigation of the effects of level density models and alpha optical model potentials on the cross-section calculations for the production of the radionuclides 62Cu, 67Ga, 86Y and 89Zr via some alpha induced reactions

Theoretical studies via nuclear reaction models have an undeniable importance and impact in terms of better understanding of reaction processes and their nature. In this study, by considering the importance of these models and the medical radionuclides, the effects of six level density models and eight alpha optical model potentials on the cross-section calculations for the production of the radionuclides 62Cu, 67Ga, 86Y and 89Zr via 59Co(α,n)62Cu, 60Ni(α,np)62Cu, 65Cu(α,2n)67Ga, 64Zn(α,p)67Ga, 85Rb(α,3n)86Y, 86Sr(α,n)89Zr, 87Sr(α,2n)89Zr and 88Sr(α,3n)89Zr reactions were investigated. Calculations for each reaction route were performed by using the TALYS v1.9 code. The most consistent model with the literature data taken from the Experimental Nuclear Reaction Database (EXFOR), was identified by using the reduced chi-squared statistics in addition to an eyeball estimation. Also, the effects of combinational use of selected models and potentials were investigated by comparing the calculational results with the experimental data.