New determination of the mass of the eta meson at COSY-ANKE

Abstract

A value for the mass of the eta meson has been determined at the COSY-ANKE facility through the measurement of a set of deuteron laboratory beam momenta and associated 3He center-of-mass momenta in the d+p -> 3He+X reaction. The eta was then identified by the missing-mass peak and the production threshold determined. The individual beam momenta were fixed with a relative precision of 3 x 10^-5 for values around 3 GeV/c by using a polarized deuteron beam and inducing an artificial depolarizing spin resonance, which occurs at a well-defined frequency. The final-state momenta in the two-body d+p -> 3He+eta reaction were investigated in detail by studying the size of the 3He momentum ellipse with the forward detection system of the ANKE spectrometer. Final alignment of the spectrometer for this high precision experiment was achieved through a comprehensive study of the 3He final-state momenta as a function of the center-of-mass angles, taking advantage of the full geometrical acceptance. The value obtained for the mass, m(eta)=(547.873 +- 0.005(stat) +- 0.027(syst)) MeV/c^2, is consistent and competitive with other recent measurements, in which the meson was detected through its decay products.

arXiv comment11 pages, 11 figures, 3 tables, published version

References in corpus (7)

• Precision study of the eta-3He system using the d+p->3He+eta reaction
• Precision study of the d+p->3He+eta reaction for excess energies between 20 and 60 MeV
• A precision determination of the mass of the $\eta$ meson
• New measurements of the $\eta$ and $K^0$ masses
• High precision beam momentum determination in a synchrotron using a spin resonance method
• Measurement of the eta-Meson Mass using psi(2S) --> eta J/psi
• Precise measurements of the eta and the neutral kaon meson masses with the KLOE detector

Cited by in corpus (5)

• Few-body aspects of the near threshold pseudoscalar meson production
• Isospin effects in the exclusive dp -> 3Heπ+π- reaction
• The legacy of the experimental hadron physics programme at COSY
• Experimental and theoretical study of deuteron-proton elastic scattering for proton kinetic energies between $T_p=882.2\text{MeV}$ and $T_p=918.3\text{MeV}$
• Total and differential cross sections of the $\mathbf{dp}\to {}^3\text{He}\mathbf{\eta }$ reaction at excess energies between 1 and 15 MeV