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Bertulani, C. A.

Publications and source records attributed to Bertulani, C. A..

8 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Production of meson molecules in ultraperipheral heavy ion collisons

In this work we present a calculation of exotic charmonium production in ultraperipheral collisions, in which the exotic state is explicitly treated as a meson molecule. Our formalism is general, but we focus on the lightest possible exotic charmonium state: a 𝐷 + ⁒𝐷 βˆ’ molecular bound state. It was proposed some time ago, and it has been an object of experimental searches. Here we study the production of the open charm pair in the process 𝛾⁒𝛾 β†’ 𝐷 + ⁒𝐷 βˆ’ . Then we use a prescription to project the free pair |𝐷 + ⁒𝐷 βˆ’ ⟩ onto a bound state at the amplitude level and compute the cross section of the process 𝛾⁒𝛾 β†’ 𝐡 (where 𝐡 is the bound state). Finally, we convolute this last cross section with the equivalent photon distributions coming from the projectile and target in an ultraperipheral collision and find the 𝐴⁒𝐴 β†’ 𝐴⁒𝐴⁒𝐡 cross section, which, for 𝑃⁒𝑏 βˆ’π‘ƒβ’π‘ collisions at $\sqrt{s_{NN}}$ =5.02 TeV, is of the order of 3 μ⁒b.

Sobrinho, F. C.β†—
DOE OSTI2024

Thermonuclear 28 P(p, Ξ³ ) 29 S reaction rate and astrophysical implication in ONe nova explosion

An accurate 28 P(p, Ξ³) 29 S reaction rate is crucial to defining the nucleosynthesis products of explosive hydrogen burning in ONe novae. Using the recently released nuclear mass of 29 S, together with a shell model and a direct capture calculation, we reanalyzed the 28 P(p, Ξ³) 29 S thermonuclear reaction rate and its astrophysical implication. We focus on improving the astrophysical rate for 28 P(p, Ξ³) 29 S based on the newest nuclear mass data. Our goal is to explore the impact of the new rate and associated uncertainties on the nova nucleosynthesis. We evaluated this reaction rate via the sum of the isolated resonance contribution instead of the previously used Hauser-Feshbach statistical model. The corresponding rate uncertainty at different energies was derived using a Monte Carlo method. Nova nucleosynthesis is computed with the 1D hydrodynamic code SHIVA. The contribution from the capture on the first excited state at 105.64 keV in 28 P is taken into account for the first time. We find that the capture rate on the first excited state in 28 P is up to more than 12 times larger than the ground-state capture rate in the temperature region of 2.5 Γ— 10 7 K to 4 Γ— 10 8 K, resulting in the total 28 P(p, Ξ³) 29 S reaction rate being enhanced by a factor of up to 1.4 at ~1 Γ— 10 9 K. In addition, the rate uncertainty has been quantified for the first time. It is found that the new rate is smaller than the previous statistical model rates, but it still agrees with them within uncertainties for nova temperatures. The statistical model appears to be roughly valid for the rate estimation of this reaction in the nova nucleosynthesis scenario. Using the 1D hydrodynamic code SHIVA, we performed the nucleosynthesis calculations in a nova explosion to investigate the impact of the new rates of 28 P(p, Ξ³) 29 S. Our calculations show that the nova abundance pattern is only marginally affected if we use our new rates with respect to the same simulations but statistical model rates. Finally, the isotopes whose abundance is most influenced by the present 28 P(p, Ξ³) 29 S uncertainty are 28 Si, 33,34 S, 35,37 Cl, and 36 Ar, with relative abundance changes at the level of only 3% to 4%.

Astronomy & Astrophysics↗
DOE OSTI2024

Nuclear structure opportunities with GeV radioactive beams at FAIR

The Facility for Antiproton and Ion Research (FAIR) is in its final construction stage next to the campus of the Gesellschaft fΓΌr Schwerionenforschung Helmholtzzentrum for heavy-ion research in Darmstadt, Germany. Once it starts its operation, it will be the main nuclear physics research facility in many basic sciences and their applications in Europe for the coming decades. Owing to the ability of the new fragment separator, Super-FRagment Separator, to produce high-intensity radioactive ion beams in the energy range up to about 2 GeV/nucleon, these can be used in various nuclear reactions. This opens a unique opportunity for various nuclear structure studies across a range of fields and scales: from low-energy physics via the investigation of multi-neutron systems and halos to high-density nuclear matter and the equation of state, following heavy-ion collisions, fission and study of short-range correlations in nuclei and hypernuclei. Here, the newly developed reactions with relativistic radioactive beams (R3B) set up at FAIR would be the most suitable and versatile for such studies. An overview of highlighted physics cases foreseen at R3B is given, along with possible future opportunities, at FAIR.

FAIR↗
DOE OSTI2024

New insight into knockout reactions from the two-proton halo nucleus 17 Ne

The unexplained disagreement in the dependence of spectroscopic factors (𝐢2⁒𝑆 exp ) on the binding energy obtained by nucleon knockout using different targets is still a puzzle that needs to be addressed. To find an explanation of this riddle through exclusive measurements using different targets. The exclusive measurements were performed by using a 17 Ne beam with an energy of 500 MeV/u incident on C and CH 2 targets. Through the standard theoretical approach, 𝐢 2⁒ 𝑆 exp were derived from the analysis of the experimental data on proton ejection from the proton halo in 17 Ne as well as from its core 15 O. For the C target, proton ejection from the proton halo gave 𝐢 2 ⁒𝑆 exp about 37% smaller than for the H target. But when protons are ejected from the core of 17 Ne, 𝐢 2 ⁒𝑆 exp are identical within statistical uncertainties. An explanation for the difference in 𝐢 2 ⁒𝑆 exp could be the removal of both halo protons, a more important reaction pathway for the C target. The 𝐢 2 ⁒𝑆 exp values obtained by analyzing the proton ejection from the core indicate that it is not affected by the interaction with the halo protons.

6 ≀ A ≀ 19β†—
DOE OSTI2023

New 26 P( p, Ξ³ ) 27 S Thermonuclear Reaction Rate and Its Astrophysical Implications in the rp -process

Accurate nuclear reaction rates for 26 P(p, Ξ³) 27 S are pivotal for a comprehensive understanding of the rp-process nucleosynthesis path in the region of proton-rich sulfur and phosphorus isotopes. However, large uncertainties still exist in the current rate of 26 P(p, Ξ³) 27 S because of the lack of nuclear mass and energy level structure information for 27 S. We reevaluate this reaction rate using the experimentally constrained 27 S mass, together with the shell model predicted level structure. It is found that the 26 P(p, Ξ³) 27 S reaction rate is dominated by a direct capture reaction mechanism despite the presence of three resonances at E = 1.104, 1.597, and 1.777 MeV above the proton threshold in 27 S. The new rate is overall smaller than the other previous rates from the Hauser–Feshbach statistical model by at least 1 order of magnitude in the temperature range of X-ray burst interest. In addition, we consistently update the photodisintegration rate using the new 27 S mass. The influence of new rates of forward and reverse reaction in the abundances of isotopes produced in the rp-process is explored by postprocessing nucleosynthesis calculations. The final abundance ratio of 27 S/ 26 P obtained using the new rates is only 10% of that from the old rate. The abundance flow calculations show that the reaction path 26 P(p, Ξ³) 27 S(Ξ² + ,Ξ½) 27 P is not as important as previously thought for producing 27 P. The adoption of the new reaction rates for 26 P(p, Ξ³) 27 S only reduces the final production of aluminum by 7.1% and has no discernible impact on the yield of other elements.

79 ASTRONOMY AND ASTROPHYSICS↗