Prospects for the discovery of the next new element: Influence of projectiles with Z > 20

TL;DR

This paper explores the potential for discovering new superheavy elements using projectiles with atomic number greater than 20, analyzing experimental reactions and their implications for future element synthesis.

Contribution

It provides experimental data on reactions involving Z > 20 projectiles and discusses their impact on superheavy element production, extending beyond calcium-48 based methods.

Findings

No evidence contradicts theoretical cross section predictions.

Experimental results align with predicted maximum cross sections.

Study suggests alternative projectiles could aid future superheavy element discovery.

Abstract

The possibility of forming new superheavy elements with projectiles having Z > 20 is discussed. Current research has focused on the fusion of 48Ca with actinides targets, but these reactions cannot be used for new element discoveries in the future due to a lack of available target material. The influence on reaction cross sections of projectiles with Z > 20 have been studied in so-called analog reactions, which utilize lanthanide targets carefully chosen to create compound nuclei with energetics similar to those found in superheavy element production. The reactions 48Ca, 45Sc, 50Ti, 54Cr + 159Tb, 162Dy have been studied at the Cyclotron Institute at Texas A&M University using the Momentum Achromat Recoil Spectrometer. The results of these experimental studies are discussed in terms of the influence of collective enhancements to level density for compound nuclei near closed shells, and the implications for the production of superheavy elements. We have observed no evidence to contradict theoretical predictions that the maximum cross section for the 249Cf(50Ti, 4n)295120 and 248Cm(54Cr, 4n)298120 reactions should be in the range of 10-100 fb.