# Forward physics at the LHC; Elastic scattering

R. Fiore, L. Jenkovszky, R. Orava, E. Predazzi, A. Prokudin, O. Selyugin

Research output: Contribution to journalArticle

51 Citations (Scopus)

### Abstract

The following effects in the nearly forward ("soft") region of the LHC are proposed to be investigated: • At small |t| the fine structure of the cone (Pomeron) should be scrutinized: (a) a break of the cone near t ≈ -0.1 GeV2, due to the two-pion threshold, and required by t-channel unitarity, and (b) possible small-period oscillations between t = 0 and the dip region. • In measuring the elastic pp scattering and total pp cross-section at the LHC, the experimentalists are urged to treat the total cross-section σt, the ratio ρ of real to imaginary part of the forward scattering amplitude, the forward slope B and the luminosity ${\mathcal L}$ as free parameters, and to publish model-independent results on dN/dt. • Of extreme interest are the details of the expected diffraction minimum in the differential cross-section. Its position, expected in the interval 0.4 < -t < 1 GeV2 at the level of about 10 -2 mb · GeV-210-1 mb · GeV -2, cannot be predicted unambiguously, and its depth, i.e. the ratio of dσ/dt at the minimum to that at the subsequent maximum (about -t = 5 GeV2, which is about 5) is of great importance. • The expected slow-down with increasing |t| of the shrinkage of the second cone (beyond the dip-bump), together with the transition from an exponential to a power decrease in -t, will be indicative of the transition from "soft" to "hard" physics. Explicit models are proposed to help in quantifying this transition. • In a number of papers a limiting behavior, or saturation of the black disk limit (BDL), was predicted. This controversial phenomenon shows that the BDL may not be the ultimate limit, instead a transition from shadow to antishadow scattering may by typical of the LHC energy scale.

Original language English (US) 2551-2599 49 International Journal of Modern Physics A 24 14 https://doi.org/10.1142/S0217751X09044255 Published - Jun 10 2009

### Fingerprint

elastic scattering
cones
physics
cross sections
forward scattering
shrinkage
scattering amplitude
pions
fine structure
luminosity
slopes
intervals
saturation
oscillations
thresholds
scattering
diffraction
energy

### All Science Journal Classification (ASJC) codes

• Atomic and Molecular Physics, and Optics
• Nuclear and High Energy Physics
• Astronomy and Astrophysics

### Cite this

Fiore, R., Jenkovszky, L., Orava, R., Predazzi, E., Prokudin, A., & Selyugin, O. (2009). Forward physics at the LHC; Elastic scattering. International Journal of Modern Physics A, 24(14), 2551-2599. https://doi.org/10.1142/S0217751X09044255
Fiore, R. ; Jenkovszky, L. ; Orava, R. ; Predazzi, E. ; Prokudin, A. ; Selyugin, O. / Forward physics at the LHC; Elastic scattering. In: International Journal of Modern Physics A. 2009 ; Vol. 24, No. 14. pp. 2551-2599.
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Fiore, R, Jenkovszky, L, Orava, R, Predazzi, E, Prokudin, A & Selyugin, O 2009, 'Forward physics at the LHC; Elastic scattering', International Journal of Modern Physics A, vol. 24, no. 14, pp. 2551-2599. https://doi.org/10.1142/S0217751X09044255

Forward physics at the LHC; Elastic scattering. / Fiore, R.; Jenkovszky, L.; Orava, R.; Predazzi, E.; Prokudin, A.; Selyugin, O.

In: International Journal of Modern Physics A, Vol. 24, No. 14, 10.06.2009, p. 2551-2599.

Research output: Contribution to journalArticle

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AU - Fiore, R.

AU - Jenkovszky, L.

AU - Orava, R.

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