arXiv subjects

H. Behnamian

Publications and source records attributed to H. Behnamian.

3 recordsLinked to original sources

arXiv2021

First Direct Measurement of an Astrophysical p-Process Reaction Cross Section Using a Radioactive Ion Beam

We have performed the first direct measurement of the 83Rb(p,g) radiative capture reaction cross section in inverse kinematics using a radioactive beam of 83Rb at incident energies of 2.4 and 2.7 A MeV. The measured cross section at an effective relative kinetic energy of Ecm = 2.393 MeV, which lies within the relevant energy window for core collapse supernovae, is smaller than the prediction of statistical model calculations. This leads to the abundance of 84Sr produced in the astrophysical p process being higher than previously calculated. Moreover, the discrepancy of the present data with theoretical predictions indicates that further experimental investigation of p-process reactions involving unstable projectiles is clearly warranted.

nucl-ex↗

arXiv2014

Design, fabrication and characterization of the first AC-coupled silicon microstrip sensors in India

This paper reports the design, fabrication and characterization of single-sided silicon microstrip sensors with integrated biasing resistors and coupling capacitors, produced for the first time in India. We have first developed a prototype sensor on a four-inch wafer. After finding suitable test procedures for characterizing these AC coupled sensors, we have fine-tuned various process parameters in order to produce sensors with the desired specifications.

physics.ins-det↗

arXiv2009

Remarks on generalized scalar-tensor models of dark energy

The generalized scalar-tensor models with Lagrangian $F(ϕ,R)-U(ϕ)(\nablaϕ)^2$ are considered. It is shown that the phantom-divide-line crossing and the deceleration to acceleration transition generally occurr in these models. Two specific examples, the coupled quintessence model and the Brans-Dicke model are considered. For the first example, it is shown that for the models with $ξ>3/16$, the $ω=-1$ transition exists. This is verified numerically for some special cases. For the Brans-Dicke model, it is shown that the transition does not occur, a result which can be verified by using the exact solution of this model. Finally the contribution of quantum effects on these phenomena is investigated. It is shown that for some special cases where the $ω=-1$ transition is classically forbidden, the quantum effects can induce transition. The $ξ=1/6$ of coupled quintessence model is an example of this. The quantum effects are described via the account of conformal anomaly.

gr-qc↗