Spin-Density Matrix Elements and Regge Cuts

1970 ◽  
Vol 1 (6) ◽  
pp. 1847-1848
Author(s):  
Robert L. Thews
Keyword(s):  
Density Matrix ◽  
Spin Density ◽  
Spin Density Matrix ◽  
Matrix Elements

scholarly journals Spin Density Matrix Elements in Exclusive Production of Omega Mesons at HERMES

2016 ◽  
Vol 40 ◽  
pp. 1660063
Author(s):  
Hrachya Marukyan
Keyword(s):  
Density Matrix ◽  
Spin Density ◽  
Cross Section ◽  
Transverse Cross Section ◽  
Spin Density Matrix ◽  
Pion Pole ◽  
Matrix Elements ◽  
Unnatural Parity ◽  
Proton Data ◽  
Parity Exchange

Exclusive electroproduction of [Formula: see text] mesons on unpolarized hydrogen and deuterium targets is studied at HERMES in the kinematic region of [Formula: see text], [Formula: see text], and [Formula: see text]. The data were accumulated during the 1996-2007 running period using the [Formula: see text] longitudinally polarized electron or positron beams at HERA. The determination of the virtual-photon longitudinal-to-transverse cross-section ratio shows that a considerable part of the cross section arises from transversely polarized photons. Spin density matrix elements are derived and presented in projections of [Formula: see text] or [Formula: see text]. Violation of s-channel helicity conservation is observed for some of these elements. A sizable contribution from unnatural-parity-exchange amplitudes is found and the phase shift between those amplitudes that describe transverse [Formula: see text] production by longitudinal and transverse virtual photons is determined for the first time. Good agreement is found between the HERMES proton data and results of a pQCD-inspired phenomenological model that includes pion-pole contributions.

scholarly journals Measurement of spin-density matrix elements forϕ-meson photoproduction from protons and deuterons near threshold

2010 ◽  
Vol 82 (1) ◽  
Author(s):  
W. C. Chang ◽  
D. S. Ahn ◽  
J. K. Ahn ◽  
H. Akimune ◽  
Y. Asano ◽  
...  
Keyword(s):  
Density Matrix ◽  
Spin Density ◽  
Spin Density Matrix ◽  
Matrix Elements ◽  
Meson Photoproduction ◽  
Near Threshold

Drell-Yan representation for vector-meson spin-density matrix elements in semi-inclusive electroproduction

JETP Letters ◽  
2002 ◽  
Vol 76 (3) ◽  
pp. 119-126
Author(s):  
G. I. Gakh ◽  
N. P. Merenkov
Keyword(s):  
Density Matrix ◽  
Vector Meson ◽  
Spin Density ◽  
Spin Density Matrix ◽  
Matrix Elements

scholarly journals Spin density matrix elements in exclusive ρ 0 electroproduction on 1H and 2H targets at 27.5 GeV beam energy

2009 ◽  
Vol 62 (4) ◽  
pp. 659-695 ◽  
Author(s):  
A. Airapetian ◽  
◽  
N. Akopov ◽  
Z. Akopov ◽  
A. Andrus ◽  
...  
Keyword(s):  
Density Matrix ◽  
Spin Density ◽  
Beam Energy ◽  
Spin Density Matrix ◽  
Matrix Elements

scholarly journals Measurement of the spin-density matrix elements in exclusive electroproduction of $\rho^0$ mesons at HERA

2000 ◽  
Vol 12 (3) ◽  
pp. 393-410 ◽  
Author(s):  
J. Breitweg et al. ◽  
Keyword(s):  
Density Matrix ◽  
Spin Density ◽  
Spin Density Matrix ◽  
Matrix Elements

Test of Veneziano Model Usingρ-Meson Spin-Density Matrix Elements

1970 ◽  
Vol 1 (7) ◽  
pp. 2113-2115 ◽  
Author(s):  
Richard A. Morrow
Keyword(s):  
Density Matrix ◽  
Spin Density ◽  
Spin Density Matrix ◽  
Veneziano Model ◽  
Matrix Elements

scholarly journals Spin Density Matrix Elements from diffractive φ meson production at HERMES

2008 ◽  
Author(s):  
Witold Augustyniak ◽  
A Borissov ◽  
S Manayenkov
Keyword(s):  
Density Matrix ◽  
Spin Density ◽  
Meson Production ◽  
Spin Density Matrix ◽  
Matrix Elements
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