Ritson, D.
H1
GAMMA P --> RHO0 P
Max results
Sort by Reverse order

Showing 2 of 2 results

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
Table 1

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

Table 2

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

Table 3

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

More…

Elastic Photoproduction of $\rho~{0}$ Mesons at HERA

The H1 collaboration Aid, S. ; Andreev, V. ; Andrieu, B. ; et al.
Nucl.Phys.B 463 (1996) 3-32, 1996.
Inspire Record 415281 DOI 10.17182/hepdata.44784

The cross section for the elastic photoproduction of \r0\ mesons ($\gamma p \rightarrow \rho~0 p$) has been measured with the H1 detector at HERA for two average photon-proton centre-of-mass energies of 55 and 187GeV. TheFcenterline lower energy point was measured by observing directly the $\rho~{0}$ decay giving a cross section of $9.1\pm 0.9\,(\stat)\pm 2.5\,(\syst)\;\mu$b. The logarithmic slope parameter of the differential cross section, ${\rm d}\sigma/{\rm d}t$, is found to be $10.9 \pm 2.4\,(\stat) \pm 1.1\,(\syst)\;$GeV$~{-2}$. The \r0\ decay polar angular distribution is found to be consistent with s-channel helicity conservation. The higher energy cross section was determined from analysis of the lower part of the hadronic invariant mass spectrum of diffractive photoproduction and found to be $13.6\pm 0.8\,(\stat)\pm 2.4\,(\syst)\;\mu$b.

6 data tables
Table 1

PI+ PI- cross section.

Table 2

RHO0 cross section by selecting Mpipi to lie between 2Mpi and Mrho + 5width0.

Table 3

No description provided.

More…