Related papers: The $2\pi$ Subsystem in Diffractively Produced $\p…
A new analysis of S-wave production amplitudes for the reaction $\pi^- p_{\uparrow} \rightarrow \pi^+ \pi^- n$ on a transversely polarized target is performed. It is based on the results obtained by the CERN-Cracow -Munich collaboration in…
COMPASS is a multi-purpose fixed-target experiment at CERN's M2 beam line aimed at studying the structure and spectrum of hadrons. It has collected the so far world's largest data set on diffractive production of the $K^-\pi^-\pi^+$ final…
Exclusive measurements of the quasi-free $pn \to pp\pi^0\pi^-$ 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…
Baryon resonance production in proton-proton collisions at a kinetic beam energy of 1.25 GeV is investigated. The multi-differential data were measured by the HADES collaboration. Exclusive channels with one pion in the final state…
The DIRAC experiment at CERN has achieved a sizeable production of $\pi^+\pi^-$ atoms and has significantly improved the precision on its lifetime determination. From a sample of 21227 atomic pairs, a 4% measurement of the S-wave $\pi\pi$…
Using the D0 detector, we have observed events produced in pbar-p collisions that contain W or Z bosons in conjunction with very little energy deposition (``rapidity gaps'') in large forward regions of the detector. The fraction of W boson…
We study the process e+e- -> pi+pi-pi+pi-gamma, with a photon emitted from the initial-state electron or positron, using 454.3 fb^-1 of data collected with the BABAR detector at SLAC, corresponding to approximately 260,000 signal events. We…
Differential cross sections of the exclusive process $e p \to e^\prime \pi^+ n$ were measured with good precision in the range of the photon virtuality $Q^2 = 1.8 - 4.5$ GeV$^2$, and the invariant mass range of the $\pi^+ n$ final state W =…
The exclusive reaction $\gamma p \to p \pi^+ \pi^-$ was studied in the photon energy range 3.0 - 3.8 GeV and momentum transfer range $0.4<-t<1.0$ GeV$^2$. Data were collected with the CLAS detector at the Thomas Jefferson National…
Production of D*+/-(2010) mesons in diffractive deep inelastic scattering has been measured with the ZEUS detector at HERA using an integrated luminosity of 82 pb^{-1}. Diffractive events were identified by the presence of a large rapidity…
Recently, the BES collaboration has published an extensive partial wave analysis of experimental data on J/psi -> phi pi+pi-, J/psi -> omega pi+pi-, J/psi -> phi K+K- and J/psi -> omega K+K-. These new results are analyzed here, with full…
At the COMPASS experiment, diffractive dissociation of the beam proton is one of the dominant processes for the 190GeV/c positive hadron beam impinging on a liquid hydrogen target. The status of the analysis of the reactions pp -> p_f pi^+…
The diffractive dissociation of 500 GeV/c $\pi^-$ into di-jets is described as a way to measure the momentum distribution of quarks in the pion. The measurements of the pion diffractive dissociation were carried out using data from Fermilab…
Study of the elastic scattering can produce a rich information on the dynamics of the strong interaction. The EPECUR collaboration is aimed at the research of baryon resonances in the second resonance region via pion-proton elastic…
Using a sample of 3.8 M psi(2S) events accumulated with the BES detector, the process psi(2S) -> pi^+ pi^- J/psi is studied. The angular distributions are compared with the general decay amplitude analysis of Cahn. We find that the dipion…
The COMPASS collaboration at CERN has investigated pion Compton scattering, $\pi^-\gamma\rightarrow \pi^-\gamma$, at centre-of-mass energy below 3.5 pion masses. The process is embedded in the reaction…
The goal of the COMPASS experiment at CERN is to study the structure and dynamics of hadrons. The two-stage spectrometer used by the experiment has large acceptance and covers a wide kinematic range for charged as well as neutral particles…
A S-wave \pi\pi resonance below 1 GeV/c^2, sigma has been observed in analyses of the phase shift data of \pi\pi scatterings. It is important to observe it in production processes. A huge events of \pi^0\pi^0 below 1 GeV/c^2 is seen in the…
A partial wave analysis (PWA) of the pi-pi-pi+ and pi-pi0pi0 systems produced in the reaction pi- p -> (3pi)-p at 18 GeV/c was carried out using an isobar model assumption. This analysis is based on 3.0M pi-pi0pi0 events and 2.6M pi-pi-pi+…
We show that a single $I=1$ spin-parity $J^{PC}= 1^{++}$ $a_1$ resonance can manifest itself as two separated mass peaks, one decaying into an S-wave $\rho\pi$ system and the second decaying into a P-wave $f_0(980)\pi$ system, with a rapid…