arXiv subjects

Hans J. Pirner

Publications and source records attributed to Hans J. Pirner.

6 recordsLinked to original sources

arXiv2015

Deformed Flux Tubes Produce Azimuthal Anisotropy in Heavy Ion Collisions

We investigate the azimuthal anisotropy $v_2$ of particle production in nucleus-nucleus collisions in the maximum entropy approach. This necessitates two new phenomenological input parameters $δ$ and $λ_2$ compared with integrated multiplicity distributions. The parameter $δ$ describes the deformation of a flux tube and can be theoretically calculated in a bag model with a bag constant which depends on the density of surrounding flux tubes. The parameter $λ_2$ defines the anisotropy of the particle distribution in momentum space and can be connected to $δ$ via the uncertainty relation. In this framework we compute the anisotropy $v_2$ as a function of centrality, transverse momentum and rapidity in qualitative agreement with LHC data.

nucl-th↗

arXiv2011

Boundary between Hadron and Quark/Gluon Structure of Nuclei

We show that the boundary between quark-dominated and hadron-dominated regions of nuclear structure may be blurred by multi-nucleon quark clusters arising from color percolation. Recent experiments supporting partial percolation in cold nuclei and full percolation in hot/dense nuclear matter include: deep inelastic lepton-nucleus scattering, relativistic heavy-ion collisions and the binding energy in $^5 He_Λ$.

nucl-th↗

arXiv2003

Geometrical Scaling due to Critical Behavior Near the Light Cone

At low $x$ a transition from a dilute parton gas to a dense parton liquid takes place. We derive geometrical scaling for the structure function in deep inelastic scattering at low $x$ from a diverging correlation length $ξ(x)$ of Wilson lines near the light cone. QCD (SU(3)) in 2+1 space - time dimensions near the light cone becomes a critical theory in the limit of $x \to 0$ with a diverging correlation length $ξ(x) \propto x^{-\frac{1}{2 λ_2}}$ where the exponent $λ_2=2.52$ is obtained from the center group Z(3) of SU(3).

hep-ph↗

arXiv2002

Nuclear modifications of fragmentation functions and rescaling models

We discuss nuclear modification of fragmentation functions in the context of the so-called ``rescaling models''. These models implement partial deconfinement inside nuclei by modifying the fragmentation functions perturbatively. We apply these models to the analysis of nuclear hadron production in deep inelastic scattering processes at the HERMES and EMC experiments.

nucl-th↗

arXiv2002

Critical Correlations of Wilson Lines in SU(3) and the High Energy $γ^*p$ Cross Section

We discuss deep inelastic scattering at high energies as a critical phenomenon in 2+1 space - time dimensions. In the limit of Bjorken $x \to 0$, $QCD$ SU(3) with quark fields becomes a critical theory with a diverging correlation length $ξ(x) \propto x^{-\frac{1}{2 λ_2}}$ where the exponent $λ_2=2.52$ is obtained from the center group Z(3) of SU(3). We conjecture that the dipole wave function of the virtual photon for transverse sizes $1/Q<x_{\bot}<ξ$ obeys correlation scaling $Ψ\propto (x_{\bot})^{-(1+n)}$ before exponentially decaying for distances larger than the correlation length. Using this behavior combined with different $x$ -independent dipole proton cross sections we calculate the proton structure function and compare with the experimental data. We take the good agreement with the measured proton structure function F$_2(x,Q^2)$ as an indication that at high energies dimensional reduction to an effective three dimensional theory with a critical point occurs.

hep-ph↗

arXiv2001

Low x Scattering as a Critical Phenomenon

We discuss deep inelastic scattering at low $x$ as a critical phenomenon in 2+1 space-time dimensions. QCD (SU2) near the light cone becomes a critical theory in the limit of $\lim x \to 0$ with a correlation mass $m(x) \propto x^{ν/2}$. We conjecture that the perturbative dipole wave function of the virtual photon in the region $1/Q<x_{\bot}<1/m$ obeys correlation scaling $Ψ\propto (x_{\bot})^{-(1+n)}$ before exponentially decaying for distances larger than the inverse correlation mass. This behavior combined with an $x$ -independent dipole proton cross section gives a longitudinal structure function which shows the dominant features of the experimental data. For SU3 QCD a similar second order phase transition is possible in the presence of quark zero modes on the light cone.

hep-ph↗