Total hadronic cross-section of photon-photon interactions at LEP

al., G. Abbiendi et

doi:10.1007/s100520000352

Cited by 43 publications

(4 citation statements)

References 24 publications

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“…This configuration of minimum bias e + e − collision events therefore is very similar in experimental signature as minimum bias events in hadron collisions. Specifically, in experimental analyses of these secondary γγ → hadrons events, they are identified by an anti-tag of energetic electron and positrons [117,118], requiring that the colliding particles are lost down the beam, and a limit on the total energy to remove annihilation events. With these considerations, the minimum bias events in e + e − collisions would enjoy the same power counting and symmetries as described in section 2 and the expansion of the cross section would also follow from that presented there.…”

Section: Electron-positron Collisionsmentioning

confidence: 99%

A large-N expansion for minimum bias

Larkoski

Melia

2021

J. High Energ. Phys.

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Despite being the overwhelming majority of events produced in hadron or heavy ion collisions, minimum bias events do not enjoy a robust first-principles theoretical description as their dynamics are dominated by low-energy quantum chromodynamics. In this paper, we present a novel expansion scheme of the cross section for minimum bias events that exploits an ergodic hypothesis for particles in the events and events in an ensemble of data. We identify power counting rules and symmetries of minimum bias from which the form of the squared matrix element can be expanded in symmetric polynomials of the phase space coordinates. This expansion is entirely defined in terms of observable quantities, in contrast to models of heavy ion collisions that rely on unmeasurable quantities like the number of nucleons participating in the collision, or tunes of parton shower parameters to describe the underlying event in proton collisions. The expansion parameter that we identify from our power counting is the number of detected particles N and as N → ∞ the variance of the squared matrix element about its mean, constant value on phase space vanishes. With this expansion, we show that the transverse momentum distribution of particles takes a universal form that only depends on a single parameter, has a fractional dispersion relation, and agrees with data in its realm of validity. We show that the constraint of positivity of the squared matrix element requires that all azimuthal correlations vanish in the N → ∞ limit at fixed center-of-mass energy, as observed in data. The approach we follow allows for a unified treatment of small and large system collective behavior, being equally applicable to describe, e.g., elliptic flow in PbPb collisions and the “ridge” in pp collisions. We also briefly comment on power counting and symmetries for minimum bias events in other collider environments and show that a possible ridge in e+e− collisions is highly suppressed as a consequence of its symmetries.

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Section: Electron-positron Collisionsmentioning

confidence: 99%

A large-N expansion for minimum bias

Larkoski

Melia

2021

J. High Energ. Phys.

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“…The experimental data are from Refs. [30,33,34]. The probability that in these collisions the photon interacts as a hadron was fixed at P p had ¼ 1=221.…”

Section: ðSþmentioning

confidence: 99%

Nonlinear effects and the behavior of total hadronic and photonic cross sections

Giannini

Durães

2013

Phys. Rev. D

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In this paper we use an eikonalized minijet model where the effects of the first nonlinear corrections to the DGLAP equations are taken into account. The contributions coming from gluon recombination effects are included in the DGLAP þ GLRMQ approach for the free proton in the context of saturation models. The parameters of the model are fixed to fit total pp and "pp cross sections, including the very recent data from LHC, HiRes, and Pierre Auger collaborations. Glauber and multiple scattering approximations are then used to describe the inclusive inelastic proton-Air cross section. Photoproduction cross sections, without change of parameters fixed before, are also obtained from the model using vector meson dominance and the additive quark model. We show and discuss our main results as well as the implications of saturation effects in the behavior of total hadronic and photonic cross sections at very high energies.

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“…In fact, only three parameters A γ γ , s (1) γ γ , s (2) γ γ were fitted. The experimental data on cross sections of γ γ interaction [28,29] are presented in figure 2. The scaling transformated experimental data, that were used for constructing the calibration curve (13), are shown by triangles in the same figure.…”

Section: Reconstruction Of a Cross Section Of γγ Interactionmentioning

confidence: 99%

Multiplicity of photohadronization and photon–hadron scaling violation

Novoseltsev

Novoseltseva

Vereshkov

2008

J. Phys. G: Nucl. Part. Phys.

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The method of scaling transformations permitting to carry out the reconstruction of cross sections of γN and γγ interactions on the basis of cross sections of nucleon-(anti)nucleon interactions is suggested. The photon-hadron scaling violation is a consequence of dependence of scaling transformation parametern(s) on the energy. The universal functionn(s) is interpreted as the multiplicity of photohadronization. This function is established by processing the data on γp cross sections in the low energy region √ s < 20 GeV and is extrapolated to the high energy region up to √ s ∼ 200 GeV. The results of the reconstruction of γN cross sections at high energies and of γγ ones at all energies are in a remarkable agreement with available experimental data.

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Total hadronic cross-section of photon-photon interactions at LEP

Cited by 43 publications

References 24 publications

A large-N expansion for minimum bias

A large-N expansion for minimum bias

Nonlinear effects and the behavior of total hadronic and photonic cross sections

Multiplicity of photohadronization and photon–hadron scaling violation

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