Primary gamma-ray spectra in 44Ti of astrophysical interest

TL;DR

This paper presents primary gamma-ray spectra for 44Ti obtained from particle-gamma coincidence data, which inform models of nuclear decay and improve reaction rate calculations relevant to astrophysics.

Contribution

It introduces a method to extract and analyze primary gamma-ray spectra of 44Ti, constraining nuclear models for astrophysical reaction rate predictions.

Findings

Spectra reveal gamma-decay patterns of 44Ti

Models must be coherently normalized to match data

Spectral shape constrains level density and strength function models

Abstract

Primary gamma-ray spectra for a wide excitation-energy range have been extracted for 44Ti from particle-gamma coincidence data of the 46Ti(p,t gamma)44Ti reaction. These spectra reveal information on the gamma-decay pattern of the nucleus, and may be used to extract the level density and radiative strength function applying the Oslo method. Models of the level density and radiative strength function are used as input for cross-section calculations of the 40Ca(alpha,gamma)44Ti reaction. Acceptable models should reproduce data on the 40Ca(alpha,gamma)44Ti reaction cross section as well as the measured primary gamma-ray spectra. This is only achieved when a coherent normalization of the slope of the level density and radiative strength function is performed. Thus, the overall shape of the experimental primary gamma-ray spectra puts a constraint on the input models for the rate calculations.