Diffraction of subnuclear waves

Alberi, G.; Goggi, G.

doi:10.1016/0370-1573(81)90019-3

Cited by 180 publications

(149 citation statements)

References 264 publications

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“…The H1 results indicate that the cross section for this process has the same dependence on Q 2 and W and the same helicity structure as the elastic reaction. These observations support the hypothesis of factorisation of the diffractive vertex [32], which has been extensively studied in hadron-hadron reactions (see e.g. [32]- [37]).…”

Section: Introductionsupporting

confidence: 85%

“…These observations support the hypothesis of factorisation of the diffractive vertex [32], which has been extensively studied in hadron-hadron reactions (see e.g. [32]- [37]). The H1 data also show that the t distribution is exponential but shallower than that for the elastic case.…”

Section: Introductionsupporting

confidence: 85%

“…Although the data extend down to M N = M p + M π , the lack of Monte Carlo events below M p + 2M π is not expected to give a significant effect [32]. The shapes of the two-pion invariant mass distribution and the ρ 0 decay angular distributions were assumed to be the same as those of the elastic events; this assumption is supported by the data, as discussed in section 8.1.…”

Section: Monte Carlo Generators and Acceptance Determinationmentioning

confidence: 70%

“…For both EPSOFT and PYTHIA, the value of M N ranged between M p +2M π and a maximum fixed by the condition discussed above, M 2 N /W 2 ≤ 0.1 [32,40]. Although the data extend down to M N = M p + M π , the lack of Monte Carlo events below M p + 2M π is not expected to give a significant effect [32].…”

Section: Monte Carlo Generators and Acceptance Determinationmentioning

confidence: 90%

“…The limit was chosen following refs. [32,40] and corresponds to the region where diffractive interactions dominate. The distributions of M ππ , W , the polar and azimuthal angles of the pions in the helicity frame and the t dependence of proton-dissociative ρ 0 photoproduction were studied.…”

Section: Introductionmentioning

confidence: 99%

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Elastic and proton-dissociative

Breitweg

1998

Eur. Phys. J. C

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Elastic and proton-dissociative ρ 0 photoproduction (γp → ρ 0 p, γp → ρ 0 N , respectively, with ρ 0 → π + π − ) has been studied in ep interactions at HERA for photon-proton centre-of-mass energies in the range 50 < W < 100 GeV and for |t| < 0.5 GeV 2 , where t is the square of the four-momentum transfer at the proton vertex; the results on the protondissociative reaction are presented for masses of the dissociated proton system in the range M 2 N < 0.1W 2 . For the elastic process, the π + π − invariant mass spectrum has been investigated as a function of t. As in fixed target experiments, the ρ 0 resonance shape is asymmetric; this asymmetry decreases with increasing |t|, as expected in models in which the asymmetry is ascribed to the interference of resonant and non-resonant π + π − production. The cross section has been studied as a function of W ; a fit to the resonant part with the form W a gives a = 0.16 ± 0.06 (stat.) +0.11 −0.15 (syst.). The resonant part of the γp → π + π − p cross section is 11.2 ± 0.1 (stat.) +1.1 −1.2 (syst.) µb at W = 71.7 GeV. The t dependence of the cross section can be described by a function of the type A ρ exp (−b ρ |t| + c ρ t 2 ) with b ρ = 10.9 ± 0.3 (stat.) +1.0 −0.5 (syst.) GeV −2 and c ρ = 2.7 ± 0.9 (stat.) +1.9 −1.7 (syst.) GeV −4 . The t dependence has also been studied as a function of W and a value of the slope of the pomeron trajectory α IP ′ = 0.23 ± 0.15 (stat.) +0.10 −0.07 (syst.) GeV −2 has been deduced. The ρ 0 spin density matrix elements r 04 00 , r 04 1−1 and ℜe[r 04 10 ] have been measured and found to be consistent with expectations based on s-channel helicity conservation. For proton-dissociative π + π − photoproduction in the ρ 0 mass range, the distributions of the two-pion invariant mass, W and the polar and azimuthal angles of the pions in the helicity frame are the same within errors as those for the elastic process. The t distribution has been fitted to an exponential function with a slope parameter 5.8 ± 0.3 (stat.) ± 0.5 (syst.) GeV −2 . The ratio of the elastic to proton-dissociative ρ 0 photoproduction cross section is 2.0 ± 0.2 (stat.) ± 0.7 (syst.).

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Section: Introductionsupporting

confidence: 85%

Section: Introductionsupporting

confidence: 85%

Section: Monte Carlo Generators and Acceptance Determinationmentioning

confidence: 70%

Section: Monte Carlo Generators and Acceptance Determinationmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

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Elastic and proton-dissociative

Breitweg

1998

Eur. Phys. J. C

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Phenomenology of Elastic Hadron Diffraction

Jenkovszky¹

1986

Fortschr. Phys.

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Recent experimental data on high‐energy elastic scattering of hadrons is reviewed in the light of various theoretical models with special emphasize on the dipole (or geometrical) Pomeron. As suggested by its name, this model combines the properties of two different approaches: the analytic and geometric ones. Its virtue is simplicity, which makes possible analytic calculation of many complicated problems.

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Cluster Excitation in Hadron-Nucleus Collisions at Medium and High Energies

1985

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A phenomenological cluster excitation model is proposed to describe the cumulative particle emission in nuclear reactions initiated by energetic projectiles. Clusters consisting of few nucleons are assumed to act as subunits of the nucleus in quasi-free inelastic collisions with the projectile. They absorb considerable energy and momentum in this process and decay statistically into the kinematically allowed exit channels. The dynamical properties of nuclear clusters are assumed to be the same for all target nuclei investigated. Good agreement of model calculations with experimental data is reached for a wide region of the target mass number and for incidence energies from 0.6 GeV to 400 GeV.

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Diffraction of subnuclear waves

Cited by 180 publications

References 264 publications

Elastic and proton-dissociative

Elastic and proton-dissociative

Phenomenology of Elastic Hadron Diffraction

Cluster Excitation in Hadron-Nucleus Collisions at Medium and High Energies

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