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Nuclear Theory·nucl-th

Friday·June 12, 2020

5 papers—2 primary·3 cross-listed

All5Primary2Cross-lists3
  1. 03

    Strong decays of the as a and molecule

    Yin Huang🇨🇳 · Lisheng Geng🇨🇳

    In this work, we study the strong decays of the newly observed assuming that it is a meson-baryon molecular state of and . We consider four possible spin-parity assignments and for the , and evaluate its partial decay width into via hadronic loops with the help of effective Lagrangians. In comparison with the Belle data, the calculated decay width favors the spin-party assignment while the other spin-parity assignments do not yield a decay width consistent with data in the molecule picture. We find that about - of the total width comes from the channel, while the rest is provided by the channel. As a result, both channels are important in explaining the strong decay of the . This information is helpful to further understand the nature of the .

    ↳ hep-phnucl-thEPJC(2020)·13 citations
  2. 04

    The modified astrophysical S-factor of the C+C fusion reaction at sub-barrier energies

    Y. J. Li · X. Fang · B. Bucher · K. A. Li · L. H. Ru · X. D. Tang

    The C+C fusion reaction plays a crucial role in stellar evolution and explosions. Its open reaction channels mainly include , , , and Be. Despite more than a half century of efforts, large discrepancies remain among the experimental data measured using various techniques. In this work, we analyze the existing data using the statistical model. Our calculation shows: 1) the relative systematic uncertainties of the predicted branching ratios get smaller as the predicted ratios increase; 2) the total modified astrophysical S-factors (S factors) of the and channels can each be obtained by summing the S factors of their corresponding ground-state transitions and the characteristic rays while taking into account the contributions of the missing channels to the latter. After applying corrections based on branching ratios predicted by the statistical model, an agreement is achieved among the different data sets at 4 MeV, while some discrepancies remain at lower energies suggesting the need for better measurements in the near future. We find that the recent S factor obtained from an indirect measurement is inconsistent with the direct measurement at energies below 2.6 MeV. We recommend upper and lower limits for the C+C S factor based on the existing models. A new C+C reaction rate is also recommended.

    ↳ nucl-exastro-ph.SRnucl-thCPC(2020)·13 citations
  3. 05

    Effects of long-range forces on the D-term and the energy-momentum structure

    Mira Varma🇺🇸 · Peter Schweitzer🇺🇸

    The hadronic form factors of the energy-momentum tensor (EMT) have attracted considerable interest in recent literature. This concerns especially the D-term form factor D(t) with its appealing interpretation in terms of internal forces. With their focus on hadron structure, theoretical studies so far have concentrated on strongly interacting systems with short-range forces. Effects on the EMT due to long-range forces like the electromagnetic interaction have not yet been studied. Electromagnetic forces play a small role in the balance of forces inside the proton, but their long-range nature introduces new features which are not present in systems with short-range forces. We use a simple but consistent classical field theoretical model of the proton to show how the presence of long-range forces alters some notions taken for granted in short-range systems. Our results imply that a more careful definition of the D-term is required when long-range forces are present.

    ↳ hep-phnucl-thPRD(2020)·40 citations

Affiliations

first authorsco-authorsvia INSPIRE