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تسجيل مستخدم جديدMeasurement of the $pn to pppi^0pi^-$ Reaction in Search for the Recently Observed Resonance Structure in $dpi^0pi^0$ and $dpi^+pi^-$ systems
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Exclusive measurements of the quasi-free $pn to pppi^0pi^-$ reaction have been performed by means of $pd$ collisions at $T_p$ = 1.2 GeV using the WASA detector setup at COSY. Total and differential cross sections have been obtained covering the energy region $sqrt s$ = (2.35 - 2.46) GeV, which includes the region of the ABC effect and its associated resonance structure. No ABC effect, {it i.e.} low-mass enhancement is found in the $pi^0pi^-$-invariant mass spectrum -- in agreement with the constraint from Bose statistics that the isovector pion pair can not be in relative s-wave. At the upper end of the covered energy region $t$-channel processes for Roper, $Delta(1600)$ and $DeltaDelta$ excitations provide a reasonable description of the data, but at low energies the measured cross sections are much larger than predicted by such processes. Adding a resonance amplitude for the resonance at $m$=~2.37 GeV with $Gamma$ =~70 MeV and $I(J^P)=~0(3^+)$ observed recently in $pn to dpi^0pi^0$ and $pn to dpi^+pi^-$ reactions leads to an agreement with the data also at low energies.
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Exclusive measurements of the quasi-free $np to nppi^0pi^0$ reaction have been performed by means of $dp$ collisions at $T_d$ = 2.27 GeV using the WASA detector setup at COSY. Total and differential cross sections have been obtained covering the ener
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We report on a high-statistics measurement of the most basic double pionic fusion reaction $vec{n}p to dpi^0pi^0$ over the energy region of the $d^*(2380)$ resonance by use of a polarized deuteron beam and observing the double fusion reaction in the
quasifree scattering mode. The measurements were performed with the WASA detector setup at COSY. The data reveal substantial analyzing powers and confirm conclusions about the $d^*$ resonance obtained from unpolarized measurements. We also confirm the previous unpolarized data obtained under complementary kinematic conditions.
Along with $pi^0$ and {eta} mesons, a resonance structure in the invariant mass spectrum of two photons at M{gamma}{gamma} = 360 pm 7 pm 9 MeV is observed in the reaction d + C rightarrow {gamma} + {gamma} + X at momentum 2.75 GeV/c per nucleon. Esti
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