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Diffractive dissociation of quasi-real photons at a photon-proton centre of mass energy of W 200 GeV is studied with the ZEUS detector at HERA. The process under consideration is gamma p -> X N, where X is the diffractively dissociated photon system of mass M_X and N is either a proton or a nucleonic system with mass M_N < 2GeV. The cross section for this process in the interval 3 < M_X < 24 GeV relative to the total photoproduction cross section was measured to be sigma~partial_D / sigma_tot = 6.2 +- 0.2(stat) +- 1.4(syst)%. After extrapolating this result to the mass interval of m_phi~2 < M_X~2 < 0.05 W~2 and correcting it for proton dissociation, the fraction of the total cross section attributed to single diffractive photon dissociation, gamma p -> X p, is found to be sigma_SD / sigma_tot = 13.3 +- 0.5(stat) +- 3.6(syst)%. The mass spectrum of the dissociated photon system in the interval 8 < M_X < 24 GeV can be described by the triple pomeron (PPP) diagram with an effective pomeron intercept of alpha_P(0) = 1.12 +- 0.04(stat) +- 0.08(syst). The cross section for photon dissociation in the range 3 < M_X < 8 GeV is significantly higher than that expected from the triple pomeron amplitude describing the region 8 < M_X < 24 GeV. Assuming that this discrepancy is due to a pomeron-pomeron-reggeon (PPR) term, its contribution to the diffractive cross section in the interval 3 < M_X < 24 GeV is estimated to be f_PPR = 26 +- 3(stat) +- 12(syst)%.

4 data tables match query

Table 1

Fraction of the total photoproduction cross section attributed to the photon dissociation.

Table 2

The fraction of the total photoproduction cross section due to single dif fractive photon dissociation, in the mass range M_phi**2 < M_DD < X >**2 < 0.05 *W**2.

Table 3

Identification of the diffractive processes was performed on the basis of the shape of reconstructed hadronic mass spectrum. No rapidity-gap was required.

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Study of pi- Meson Elastic Scattering by Protons at Small Angles

Apokin, V.D. ; Derevshchikov, A.A ; Matulenko, Yu.A. ; et al.

Yad.Fiz. 21 (1975) 1240-1246, 1975.

Inspire Record 103333 DOI 10.17182/hepdata.19099

None

3 data tables match query

Table 1

No description provided.

Table 2

No description provided.

Table 3

IM(AMP) VIA OPTICAL THEOREM FROM TOTAL CROSS SECTIONS OF L. M. VASILYEV ET AL., PL 36B, 528 (1971).

FORWARD pi- p ELASTIC SCATTERING AT 40-GeV/c

Apokin, V.D. ; Matulenko, Yu.A. ; Nurushev, S.B. ; et al.

Sov.J.Nucl.Phys. 28 (1978) 786, 1978.

Inspire Record 130964 DOI 10.17182/hepdata.18967

None

2 data tables match query

Table 1

No description provided.

Table 2

REAL/IMAG OF FORWARD AMPLITUDE FROM FIT TO D(SIG)/DT.

Small-Angle pi- p Elastic Scattering Measurements

Apokin, V.D. ; Derevshchikov, A.A. ; Matulenko, Yu.A. ; et al.

Phys.Lett.B 56 (1975) 391-394, 1975.

Inspire Record 90800 DOI 10.17182/hepdata.27866

We have measured small angle elastic pion-proton scattering in 40 and 50 GeV c π − beams at Serpukhov. Analysis of the data in the Coulomb interference region yields a value for the ratio of the real to the imaginary part of the strong amplitude, ϱ (0)=−0.074 ± 0.033 at 40 GeV/ c and ϱ (0)=−0.006 ±0.026 at 50 GeV/ c

2 data tables match query

Table 1

STATISTICAL ERRORS ONLY.

Table 2

STATISTICAL ERRORS ONLY.

A measurement of elastic pion-proton scattering at 50 gev

Derevchekov, A.A. ; Golovin, N.I. ; Khodirev, Y.C. ; et al.

Phys.Lett.B 48 (1974) 367-370, 1974.

Inspire Record 95356 DOI 10.17182/hepdata.27998

We have measured elastic pion-proton scattering in a 50 GeV/ c π − beam at the 76 GeV proton synchrotron in Serpukhov. Data are presented for four-momenta transfer squared in the range 0.03 < t < 0.4 (GeV/ c ) 2 .

1 data table match query

Table 1

SLOPE IS 9.1, +0.2, -0.4 GEV**-2 (INCLUDING SYSTEMATIC ERRORS).