Resonance-like coherent production of a pion pair in the reaction $pd\to pd\pi \pi$ in the GeV region

Abstract

The reaction $p+d\to p+d+X$ was studied at 0.8-2.0 GeV proton beam energies with the ANKE magnetic spectrometer at the COSY synchrotron storage ring. The proton-deuteron pairs emerging with high momenta, 0.6-1.8 GeV/$c$, were detected at small angles with respect to the proton beam. Distribution over the reaction missing mass $M_x$ reveals a local enhancement near the threshold of the pion pair production specific for the so-called ABC effect. The enhancement has a structure of a narrow bump placed above a smooth continuum. The invariant mass of the $d\pi \pi$ system in this enhancement region exhibits a resonance-like peak at $M_{d\pi \pi }\approx 2.36$ GeV/$c^2$ with the width $\Gamma \approx 0.10$ GeV/$c^2$. A possible interpretation of these features is discussed.

arXiv comment14 pages, 16 figures, submitted to Eur. Phys. J. A. v2: Added references [42,43] in section IV.A. v3: revised version according to referee remarks v4: revised version according to referee remarks

References in corpus (24)

• Evidence that the a0(980) and f0(980) are not elementary particles
• ABC Effect in Basic Double-Pionic Fusion --- Observation of a new resonance?
• Quark-model study of few-baryon systems
• Double-Pionic Fusion of Nuclear Systems and the ABCEffect -- Aproaching a Puzzle by Exclusive and Kinematically Complete Measurements
• Evidence for a New Resonance from Polarized Neutron-Proton Scattering
• A Precursor of Chiral Symmetry Restoration in the Nuclear Medium
• On the History of Dibaryons and their Final Observation
• Novel Six-Quark Hidden-Color Dibaryon States in QCD
• Three-body calculation of the Delta-Delta dibaryon candidate D(03) at 2.37 GeV
• Three-body model calculations of Nucleon-Delta and Delta-Delta dibaryon resonances
• Parity doublets and chiral symmetry restoration in baryon spectrum
• Quark models of dibaryon resonances in nucleon-nucleon scattering
• A study of $d^{\ast }(2380)\to d\pi \pi$ decay width
• ABC effect as a signal of chiral symmetry restoration in hadronic collisions
• Decay width of $d^{\ast }(2380)\to NN\pi \pi$ processes
• The $d^{\ast }$(2380) dibaryon resonance width and decay branching ratios
• The role of the Roper resonance in n p --> d (pi pi)
• Excess low energy photon pairs from pion annihilation at the chiral phase transition
• ABC Effect and Resonance Structure in the Double-Pionic Fusion to ${}^3$He
• Observation of an ABC effect in proton-proton collisions
• Structure in two_pion production in the d d -> alpha X reaction
• Energy dependence of forward 1S0 diproton production in the pp -> pp pi0 reaction
• On the width of N-Delta and Delta-Delta states
• Energy dependence of hard bremsstrahlung production in proton-proton collisions in the Delta(1232) region

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