arXiv subjects

J. Guttmann

Publications and source records attributed to J. Guttmann.

2 recordsLinked to original sources

arXiv2013

Theoretical Analysis of the $p \bar{p}\rightarrow π^0 e^+ e^-$ Process within a Regge Framework

We study the annihilation process $p\bar{p} \to π^0 e^+ e^-$ within a Regge framework, as a means to provide constraints on timelike nucleon form factors. We present results for the $e^+e^-$ angular distributions and the differential cross sections in kinematics which will be accessible by PANDA@FAIR. To check the consistency of the model, we first test the approach on the process of real photon production, $\bar{p} p \to π^0 γ$, where data in the energy range of 2.911 GeV$\leq\sqrt{s} \leq 3.686$ GeV exist. We find that a Regge pole model is able to well reproduce the available data. The analysis is then extended to a timelike virtual photon in the final state.

hep-ph↗

arXiv1994

Low-Temperature Series Expansions for the Spin-1 Ising Model

The finite lattice method of series expansion has been used to extend low-temperature series for the partition function, order parameter and susceptibility of the spin-1 Ising model on the square lattice. A new formalism is described that uses two distinct transfer matrix approaches in order to significantly reduce computer memory requirements and which permits the derivation of the series to 79th order. Subsequent analysis of the series clearly confirms that the spin-1 model has the same dominant critical exponents as the spin-$\frac{1}{2}$ Ising model. Accurate estimates for both the critical temperature and non-physical singularities are obtained. In addition, evidence for a non-analytic confluent correction with exponent $Δ_{1} = 1.1 \pm 0.1$ is found.

hep-lat↗