相关论文: Delta Delta Excitation in Proton-Proton Induced pi…
The two-pion production in pp-collisions has been investigated at CELSIUS in exclusive measurements from threshold up to $T_p$ = 1.36 GeV. Total and differential cross sections have been obtained for the channels $pn\pi^+\pi^0$,…
The pp -> {pp}_s pi0 differential cross section has been measured with the ANKE spectrometer at COSY-Juelich for seven proton beam energies T_p between 0.5 and 1.97 GeV. By selecting proton pairs with an excitation energy of less than 3 MeV…
Exclusive measurements of the reaction pp -> dpi+pi0 have been carried out at T_p = 1.1 GeV at the CELSIUS storage ring using the WASA detector. The isovector pi+pi0 channel exhibits no enhancement at low invariant pipi masses, i. e. no ABC…
The reaction pp->pppi0pi0 has been investigated at a beam energy of 1.4 GeV using the WASA-at-COSY facility. The total cross section is found to be (324 +- 21_systematic +- 58_normalization) mub. In order to to study the production…
The charge-exchange break-up of polarised deuterons pol{d}p -> {pp}n, where the final {pp} diproton system has a very low excitation energy and hence is mainly in the 1S0 state, is a powerful tool to probe the spin-flip terms in the…
The 2H(p,n) charge exchange reaction at T_p=790 MeV is used to study the Delta(1232)-nucleon interaction in the Delta resonance excitation energy region. For the Delta-N potential, a meson exchange model is adopted where pi, rho, omega, and…
Mechanisms of the charge exchange reaction $dp\to \{pp\}_{\!s} N\pi$, where $\{pp\}_{\!s}$ is a two-proton system at low excitation energy, are studied at beam energies 1 -- 2 GeV and for invariant masses $M_X$ of the final $N\pi $ system…
Exclusive measurements of the quasi-free $pp \to pp\pi^+\pi^-$ 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…
First exclusive data for the $pp \to nn\pi^+\pi^+$ reaction have been obtained at CELSIUS with the WASA detector setup at a beam energy of $T_p$ = 1.1 GeV. Total and differential cross sections disagree with theoretical calculations, which…
COSY-ANKE data on the cross section of the reactions $pp\to \{pp\}_s\pi^0$ and $pp\to \{pp\}_s\gamma$, where $\{pp\}_s$ is the proton pair in the $^1S_0$ state at small excitation energy $E_{pp}<3$ MeV, are analyzed at beam energies $0.5 -…
Exclusive measurements of the quasi-free $pp \to pp\pi^+\pi^-$ reaction have been carried out at WASA@COSY by means of $pd$ collisions at $T_p$ = 1.2 GeV. Total and differential cross sections have been extracted covering the energy region…
The deuteron spectrum in n+p -> 2 H(pi pi) at k_n = 1.88 GeV/c and theta_d = 0^o is explained by considering a Delta Delta excitation as the dominant reaction mechanism for the 2 pi production. We present a new theoretical approach based on…
The two-pion production in nucleon-nucleon collisions has been studied by exclusive and kinematically complete experiments from threshold up to $T_p$ = 1.36 GeV at CELSIUS-WASA. At near-threshold energies the total and differential…
COSY data on the cross section of the reaction pp -> {pp}_s pi^0, where {pp}_s is the proton pair in the 1S0 state at small excitation energy E_{pp}=0-3 MeV, recently obtained for beam energies 0.5 - 2.0 GeV are analyzed within the one-pion…
The pp -> pp pi0 differential cross section has been measured with the ANKE spectrometer at COSY-Juelich for pion cms angles between 0 and 15.4 degrees at a proton beam energy of 0.8 GeV. The selection of diproton pairs with an excitation…
The deuteron spectrum in n+p -> d+pi+pi at k_n = 1.88 GeV/c and theta_d = 0 deg is explained by considering a Delta-Delta excitation as the reaction mechanism for the 2pi production. We study the influence of intermediate Delta-Delta and…
The single-pion production reactions $pp\to d\pi^+$, $pp\to np\pi^+$ and $pp\to pp\pi^0$ were measured at a beam momentum of 0.95 GeV/c ($T_p \approx$ 400 MeV) using the short version of the COSY-TOF spectrometer. The central calorimeter…
The cross section for prompt neutral and charged three pion production in pp interactions was measured at excess energies in the range 160 - 217 MeV. That comprises the first measurement of the pp->pp pi0pi0pi0 reaction and the comparison…
The large variety of experimental data around the pion-production threshold are compared with a meson-exchange isobar model which includes the pion-nucleon interaction in s-- and p-waves. Theoretical results obtained with two different NN…
We present the first measurement of the induced proton polarization P_n in pi^0 electroproduction on the proton around the Delta resonance. The measurement was made at a central invariant mass and a squared four-momentum transfer of W=1231…