Non-strange dibaryons studied in the γd → π0π0d reaction

In order to confirm the existence of the dibaryon state observed at WASA@COSY, we estimate the cross section for production of the possible dibaryon and anti-dibaryon pair in the energy region of the upcoming experiments at anda. Based on some qualitative properties of extracted from the analyses in the non-relativistic quark model, the production cross section for this spin-3 particle pair are calculated with the help of a phenomenological effective relativistic and covariant Lagrangian approach.

Section: Introductionsupporting

confidence: 53%

Possible dibaryon production at anda with a Lagrangian approach *

Dong¹,

Shen²

2022

“…The authors mention that " " has been observed in the and reactions. In fact, in [41,42], one can observe a deviation of the experimental cross section from the theoretical results reported by [43,44] at low photon energies. These calculations are based on the impulse approximation, and the π rescattering terms are neglected.…”

Section: Discussionmentioning

confidence: 71%

“…Let us further extend this discussion. The authors of [41,42] also studied the reaction [45,46]. This reaction was throughly studied theoretically in [47], and the authors discovered that the pion rescattering mechanisms were particularly important, and the most striking feature of the reaction, i.e., the shift of the shape of the invariant mass distributions, was well reproduced.…”

Section: Discussionmentioning

confidence: 99%

Sequential single pion production explaining the dibaryon "d(2380)" peak

Peralta

Ikeno

2023

We study the two step sequential one pion production mechanism, $np(I=0)\to \pi^-pp$, followed by the fusion reaction $pp\to \pi^+d$, in order to describe the $np\to \pi^+\pi^-d$ reaction with $\pi^+\pi^-$ in $I=0$, where a narrow peak, so far identified with a ``$d(2380)$'' dibaryon, has been observed. We find that the second step $pp\to \pi^+d$ is driven by a triangle singularity that determines the position of the peak of the reaction and the large strength of the cross section. The combined cross section of these two mechanisms produce a narrow peak with the position, width and strength compatible with the experimental observation within the approximations done. This novel interpretation of the peak without invoking a dibaryon explains why the peak is not observed in other reactions where it has been searched for.

“…Very recently, the first report on data for the reaction also appeared, reaching in energy down to the region. The measurements conducted at ELPH, Japan, only reach down to the high-energy side of the region [55,56]. Measurements performed at MAMI even reach below the region [57].…”

Section: Electromagnetic Excitation Of (2380)mentioning

confidence: 99%

“…There have been a huge number of dibaryon predictions in the past. The oldest one dates back to 1964, when based on SU(6) symmetry considerations, Dyson and Xuong [12] [11,[53][54][55][56][57] are compared to those from theoretical calculations [52,58], starting from the theoretical wave function and including isospin breaking effects. They are also compared to the values expected from pure isospin recoupling of the various channels.…”

Section: Electromagnetic Excitation Of (2380)mentioning

confidence: 99%

Dibaryons: Molecular versus compact hexaquarks *

Clement

Skorodko

2021

Hexaquarks constitute a natural extension of complex quark systems, just as tetra- and pentaquarks do. To this end, the current status of in both experiment and theory is reviewed. Recent high-precision measurements in the nucleon-nucleon channel and analyses thereof have established as an indisputable resonance in the long-sought dibaryon channel. Important features of this state are its narrow width and deep binding relative to the threshold. Its decay branchings favor theoretical calculations predicting a compact hexaquark nature of this state. We review the current status of experimental and theoretical studies on as well as new physics aspects it may bring in future. In addition, we review the situation at the and thresholds, where evidence for a number of resonances of presumably molecular nature has been found – similar to the situation in charmed and beauty sectors. Finally, we briefly discuss the situation of dibaryon searches in the flavored quark sectors.