Spin Density Matrix Elements from diffractive φ meson production at HERMES
نویسنده
چکیده
Exclusive production of φ mesons on hydrogen and deuterium targets is studied in the HERMES kinematic region 1 < Q < 7 GeV and 3.0 < W < 6.3 GeV. Spin density matrix elements and their Q and t dependences are presented. These data are consistent with s-channel helicity conservation in exclusive φ meson production. No significant evidence for the contribution of unnatural-parity-exchange amplitudes is found.
منابع مشابه
QED radiative correction to spin-density matrix elements in exclusive vector meson production
QED radiative effects are considered in the case of measurement of spin-density matrix elements of diffractive ρ-meson electroproduction. Large radiative correction for r5 00 is found in the kinematics of collider experiments at HERA. The extension of the kinematical region of lepton-nucleon deep inelastic scattering to the domain of the diffractive processes provides hadronic nature of the pho...
متن کاملExclusive meson production at HERMES
mesons on unpolarized hydrogen and deuterium targets is studied in the kinematic region of Q2 > 1.0 GeV2, 3.0 GeV < W < 6.3 GeV, and −t ′ < 0.2 GeV2, while for ρ0-meson production on a transversely polarized hydrogen target −t ′ < 0.4 GeV2 is used. Spin-density matrix elements for ω production are presented in projections of Q2 or −t ′, while the ratios of the helicity amplitudes for the reacti...
متن کاملSpin Dependence of Diffractive Vector Meson Production
I review the recent progress in the theory of s-channel helicity nonconservation (SCHNC) effects in diffractive DIS. SCHNC in diffractive vector meson production is an unique probe of the spin-orbit coupling and Fermi motion of quarks in vector mesons. Photoand electroproduction of the φ and its radial and angular excitations at Jlab is perfectly posed to probe SCHNC in QCD pomeron exchange. I ...
متن کاملDiffractive Photoproduction of Vector Mesons at Large Momentum Transfer
Diffractive photoproduction of ρ, φ and J/ψ was studied in the BFKL approach to hard colour singlet exchange. Differential cross sections, the energy dependence and spin density matrix elements were calculated and compared to data from HERA. The overall description of data is reasonably good, except of the single flip amplitude which has the wrong sign. Importance of chiral odd components of th...
متن کاملDiffractive Ρ Meson Electroproduction at High Q 2 and High |t|
The electroproduction of ρ mesons is studied at HERA with the H1 detector at high Q and high |t|. Cross sections are measured as a function of Q, W and t. The W dependence of the γ∗p cross section is observed to increase with Q from values compatible with soft Pomeron exchange at low Q to a hard dependence at large Q. Spin density matrix elements are measured and their dependence is compared wi...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2008