Constraints on a possible dibaryon from combined analysis of the $pn\to d{\pi }^{+}{\pi }^{-}$ and $pn\to pn{\pi }^{+}{\pi }^{-}$ cross sections

Abstract

We use recent data that show a narrow peak around $\sqrt{s}=2.37\text{GeV}$ in the $pn\to d{\pi }^{+}{\pi }^{-}$ cross section, with about double strength at the peak than in the analogous $pn\to d{\pi }^0{\pi }^0$ reaction, and, assuming that it is due to the excitation of a dibaryon resonance, we evaluate the cross section for the $pn\to pn{\pi }^{+}{\pi }^{-}$ reaction, with the final $pn$ unbound but with the same quantum numbers as the deuteron. We use accurate techniques to determine the final state interaction in the case of the $pn$ forming a deuteron or a positive energy state, which allow us to get the $pn\to pn{\pi }^{+}{\pi }^{-}$ cross section with $pn$ in I=0 and S=1, that turns out to be quite close or saturates the experimental $pn\to pn{\pi }^{+}{\pi }^{-}$ total cross section around $\sqrt{s}=2.37\text{GeV}$, depending on the angular momentum assumed. We then parametrize a background with different methods, and the sum of the resonant and background contributions is fitted to present data. The resulting cross section exceeds the experimental results in the region of the resonant peak, showing a problem in the dibaryon hypothesis. Yet, in view of the dispersion of present experimental data, and the scarce information around $\sqrt{s}=2.37\text{GeV}$, a call is made for precise measurements of the $pn\to pn{\pi }^{+}{\pi }^{-}$ reaction around this energy, to further clarify this issue.

References in corpus (3)

• ABC Effect in Basic Double-Pionic Fusion --- Observation of a new resonance?
• Double-Pionic Fusion of Nuclear Systems and the ABCEffect -- Aproaching a Puzzle by Exclusive and Kinematically Complete Measurements
• Couplings in coupled channels versus wave functions in the case of resonances: application to the two $\Lambda (1405)$ states

Cited by in corpus (16)

• On the History of Dibaryons and their Final Observation
• Novel Six-Quark Hidden-Color Dibaryon States in QCD
• Measurement of the $pn\to pp{\pi }^0{\pi }^{-}$ Reaction in Search for the Recently Observed Resonance Structure in $d{\pi }^0{\pi }^0$ and $d{\pi }^{+}{\pi }^{-}$ systems
• Measurement of the $np\to np{\pi }^0{\pi }^0$ Reaction in Search for the Recently Observed $d^{\ast }(2380)$ Resonance
• QCD sum rule Study of the $d^{\ast }(2380)$
• A study of $d^{\ast }(2380)\to d\pi \pi$ decay width
• Decay width of $d^{\ast }(2380)\to NN\pi \pi$ processes
• The $d^{\ast }$(2380) dibaryon resonance width and decay branching ratios
• Triangle singularity mechanism for the $pp\to {\pi }^{+}d$ fusion reaction
• Study of the quasi-free $np\to np{\pi }^{+}{\pi }^{-}$ reaction with a deuterium beam at 1.25 GeV/nucleon
• On a Possible Explanation of the DLS-Puzzle
• Dibaryons: Molecular versus Compact Hexaquarks
• ${\tau }^{-}\to {\nu }_{\tau }{M}_1{M}_2$, with $M_1,M_2$ pseudoscalar or vector mesons
• From CELSIUS to COSY: on the observation of a dibaryon resonance
• Sequential single pion production explaining the dibaryon "$d^{\ast }(2380)$" peak
• Reply to "Comment on Sequential Single-pion Production Explaining the dibaryon $d^{\ast }(2380)$ peak''