Elastic electroproduction of rho mesons at HERA.

The H1 collaboration Adloff, C. ; Andreev, V. ; Andrieu, B. ; et al.
Eur.Phys.J.C 13 (2000) 371-396, 2000.
Inspire Record 495311 DOI 10.17182/hepdata.44043

The elastic electroproduction of rho mesons is studied at HERA with the H1 detector for a photon virtuality in the range 1 < Q^2 < 60 GeV^2 and for a hadronic centre of mass energy in the range 30 < W < 140 GeV. The shape of the pipi mass distribution in the rho resonance region is measured as a function of Q^2. The full set of rho spin density matrix elements is determined, and evidence is found for a helicity flip amplitude at the level of 8 +- 3 % of the non-flip amplitudes. Measurements are presented of the dependence of the cross section on Q^2, W and t (the four-momentum transfer squared to the proton). They suggest that, especially at large Q^2, the gamma^*p cross section develops a stronger W dependence than that expected from the behaviour of elastic and total hadron-hadron cross sections.

15 data tables

Average values of the spin density matrix elements measured for the 1996 data sample.

Spin density matrix elements measured for 3 Q**2 values for the 1996 data sample.

Spin density matrix elements measured for 3 W values for the 1996 data sample.

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Diffraction Dissociation of Photons on Hydrogen

Chapin, T.J. ; Cool, R.L. ; Goulianos, Konstantin A. ; et al.
Phys.Rev.D 31 (1985) 17-30, 1985.
Inspire Record 216071 DOI 10.17182/hepdata.4332

We report results from a measurement of the inclusive diffraction dissociation of photons on hydrogen, γp→Xp, in the range 75<pγ<148 GeV/c, 0.02<‖t‖<0.1 (GeV/c)2, and MX2/s<0.1. Our data show an exponential t dependence and a dominant 1/MX2 behavior for MX2>4 GeV2. We test the finite-mass sum rule and, by comparing γp with π−p data obtained in the same apparatus, we test factorization.

18 data tables

EXTRACTED ELASTIC CROSS SECTIONS.

EXTRACTED ELASTIC CROSS SECTIONS.

RESULTS OF EXPONENTIAL FITS TO ELASTIC CROSS SECTIONS.

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Measurements of Elastic Rho and Phi Meson Photoproduction Cross-Sections on Protons from 30 GeV to 180 GeV

Egloff, R.M. ; Davis, P.J. ; Luste, G. ; et al.
Phys.Rev.Lett. 43 (1979) 657, 1979.
Inspire Record 141059 DOI 10.17182/hepdata.20740

The elastic photoproduction cross sections for ρ and ϕ mesons from protons have been measured from 30 to 180 GeV. The energy dependences agree well with predictions made by using vector-meson dominance and an additive quark model. The ρ cross section is approximately constant with energy while the ϕ cross section rises from 0.5 to 0.7 μb with increasing energy.

1 data table

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