Nuclear Theory·nucl-th

Friday·March 13, 2020

8 papers—4 primary·4 cross-listed

05
[Submitted on 12 Mar 2020] (cross-list from hep-ph)
$D^{(*)} N$ interaction and the structure of $Σ_{c} (2800)$ and $Λ_{c} (2940)$ in chiral effective field theory
Bo Wang🇨🇳 · Lu Meng🇨🇳 · Shi-Lin Zhu🇨🇳
We study the $D N$ and $D^{*} N$ interactions to probe the inner structure of $Σ_{c} (2800)$ and $Λ_{c} (2940)$ with the chiral effective field theory to the next-to-leading order. We consider the contact term, one-pion-exchange and two-pion-exchange contributions to characterize the short-, long- and mid-range interactions of the $D^{(*)} N$ systems. The low energy constants of the $D^{(*)} N$ systems are related to those of the $N N ˉ$ interaction with quark level Lagrangian that inspired by the resonance saturation model. The $Δ (1232)$ degree of freedom is also included in the loop diagrams. The attractive potential in the $[D N]_{J = 1/2}^{I = 1}$ channel is too weak to form bound state, which indicates the explanation of $Σ_{c} (2800)$ as the compact charmed baryon is more reasonable. Meanwhile, the potentials of the isoscalar channels are deep enough to yield the molecular states. We obtain the masses of the $[D N]_{J = 1/2}^{I = 0}$ , $[D^{*} N]_{J = 1/2}^{I = 0}$ and $[D^{*} N]_{J = 3/2}^{I = 0}$ systems to be $2792.0$ MeV, $2943.6$ MeV and $2938.4$ MeV, respectively. The $Λ_{c} (2940)$ is probably the isoscalar $D^{*} N$ molecule considering its low mass puzzle. Besides, the $Λ_{c} (2940)$ signal might contain the spin- $\frac{1}{2}$ and spin- $\frac{3}{2}$ two structures, which can qualitatively explain the significant decay ratio to $D^{0} p$ and $Σ_{c} π$ . We also study the $B ˉ^{(*)} N$ systems and predict the possible molecular states in the isoscalar channels. We hope experimentalists could hunt for the open charmed molecular pentaquarks in the $Λ_{c}^{+} π^{+} π^{-}$ final state.
Comments:
11 pages, 4 figures and 4 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2003.05688 [pdf]
PRD(2020)·42 citations
06
[Submitted on 12 Mar 2020] (cross-list from hep-ph)
X17: A new force, or evidence for a hard $γ + γ$ process?
Benjamin Koch🇨🇱
It is investigated whether the "X17 puzzle" might be explained by a nuclear decay chain and a conversion of the two resulting highly energetic $γ$ s into an electron-positron pair. It is found that the corresponding kinematics fits perfectly to the experimental result. Also the conversion rates of this process are reasonable. However, the assumed nuclear chain reaction is not favored in the established nuclear models and no explanation for the isospin structure of the signal can be given. Thus, it has to be concluded that the process studied in this paper does not give a completely satisfying explanation of the "X17 puzzle".
Comments:
13 pages, 7 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2003.05722 [pdf]
NPA(2021)·18 citations
07
[Submitted on 12 Mar 2020] (cross-list from hep-lat)
The Roper Resonance in a finite volume
Daniel Severt🇩🇪 · Ulf-G. Meißner🇩🇪
We calculate the energy levels corresponding to the Roper resonance based on a two-flavor chiral effective Lagrangian for pions, nucleons, deltas and the Roper resonance at leading one-loop order. We show that the Roper mass can be extracted from these levels for not too large lattice volumes.
Comments:
22 pages, 5 figures, some minor modifications, accepted for publication in Comm. Theo. Phys
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2003.05745 [pdf]
Commun.Theor.Phys.(2020)·10 citations
08
[Submitted on 12 Mar 2020] (cross-list from hep-ph)
On the Interpretation of the Balance Function
V. Vechernin🇷🇺
We construct a simple toy model and explicitly demonstrate that the Balance Function (BF) can become negative for some values of the rapidity separation and hence can not have any probabilistic interpretation. In particular, the BF can not be interpreted as the probability density for the balancing charges to occur separated by the given rapidity interval.
Comments:
11 pages
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2003.05881 [pdf]
Symmetry(2022)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE

D(∗)N interaction and the structure of Σc​(2800) and Λc​(2940) in chiral effective field theory

X17: A new force, or evidence for a hard γ+γ process?

The Roper Resonance in a finite volume

On the Interpretation of the Balance Function

Affiliations

$D^{(*)} N$ interaction and the structure of $Σ_{c} (2800)$ and $Λ_{c} (2940)$ in chiral effective field theory

X17: A new force, or evidence for a hard $γ + γ$ process?