Total pion-proton cross-section from the new LHCf data on leading neutrons spectra
R. A. Ryutin
备注：
5 pages, 6 figures, 1 table, results of this version are more correct than in the version 2. Figs 3, 6 and Table 1 are changed. Minor changes in the text. One reference is added. Erratum is sent to the EPJC
In the light of the latest data by LHCf collaboration of the LHC on leading neutrons spectra it is possible to obtain total pion-proton cross-sections in the TeV energy region. In this work the exact extraction procedure is shown. Final numbers for the pion-proton cross-section are collected at several different values of the colliding energy and compared with some popular theoretical predictions. Errors of results are estimated.
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I critically review the status of computations of threshold pion production in proton-proton collisions in the framework of effective field theory approaches or variants thereof. I also present the results of a novel diagrammatic scheme.
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We derive a closed, model independent, expression for the electromagnetic correction factor to a phenomenological hadronic scattering length extracted from a hydrogenic atom. It is obtained in a non-relativistic approach and in the limit of a short ranged hadronic interaction to terms of order ((alpha)**2)(log(alpha)) using an extended charge distribution. A hadronic negatively charged pion-proton scattering length of 0.0870(5), in units of inverse charged pion-mass, is deduced, leading to a pion-nucleon coupling constant from the GMO relation equals to 14.04(17).
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We report on a detailed investigation of four-body $p p \to p p π^+ π^-$ and $p \bar{p} \to p \bar{p} π^+ π^-$) reactions which constitute an irreducible background to three-body processes $p p \to p p M$, where $M$ is a broad resonance in the $π^+ π^-$ channel, e.g. $M=σ, ρ^{0}, f_{0}(980), f_{2}(1275), f_{0}(1500)$. We include double-diffractive contribution (both pomeron and reggeon exchanges) as well as the pion-pion rescattering contributions. The first process dominates at higher energies and small pion-pion invariant masses while the second becomes important at lower energies and higher…
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We compare calculations for the production of charged pions by pion or proton beams off nuclei calculated within our coupled channel transport model (GiBUU) with recent data of the HARP collaboration for beam energies from 3 up to 13 GeV. Predictions for the 30 GeV data for pions and kaons from the NA61/SHINE experiment are included.
Present availability of high brilliance photon beams as those produced by X-ray Free Electron Lasers in combination with intense TeV proton beams typical of the Large Hadron Collider makes it possible to conceive the generation of pion beams via photo-production in a highly relativistic Lorentz boosted frame: the main advantage is the low emittance attainable and a TeV-class energy for the generated pions, that may be an interesting option for the production of low emittance muon and neutrino beams. We will describe the kinematics of the two classes of dominant events, i.e. the pion photo-prod…
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The production of charged pion pairs via multiphoton absorption from an intense X-ray laser wave colliding with an ultrarelativistic proton beam is studied. Our calculations include the contributions from both the electromagnetic and hadronic interactions where the latter are described approximately by a phenomenological Yukawa potential. Order-of-magnitude estimates for $π^+π^-$ production on the proton by two- and three-photon absorption from the high-frequency laser field are obtained and compared with the corresponding rates for $μ^+μ^-$ pair creation.
Inclusive cross sections for pion production in proton-proton collisions are calculated for the first time based on unintegrated parton (gluon, quark, antiquark) distributions (uPDF). We use Kwieciński uPDF's and phenomenological fragmentation functions from the literature. In addition to the $gg \to g$ diagram used recently for applications at RHIC we include also $g q \to q$ and $q g \to q$ diagrams. We find that the new contributions are comparable to the purely gluonic one at midrapidities and dominate in the fragmentation region. The new mechanisms are responsible for $π^+ - π^-$ asymmetr…
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