Lepton-pair production in polarised pp and pp collisions

Ranft, G.; Ranft, J.

doi:10.1088/0305-4616/8/2/006

Cited by 27 publications

(42 citation statements)

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“…To assess this ratio, we made use of available high energy event simulations showing spectator nucleon and pion spectra for Fe-N/p-N collisions at 10 15 and 10 16 eV [543] (summarized in [544]). The pion rapidity spectra in the central plateau are roughly energy independent, except for the widening of the plateau with energy -see [39]-, whereas there is a slow increase of spectator neutrons as one reaches the region of interest (E N ≈ 1 PeV). Allowing for sizeable differences in hadronic interaction models, the secondary populations are roughly 35% π ± , 45% γ, 10% nucleons, and 10% K [544].…”

Section: B Astronomy On Icementioning

confidence: 95%

Astrophysical origins of ultrahigh energy cosmic rays

2004

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In the first part of this review we discuss the basic observational features at the end of the cosmic ray energy spectrum. We also present there the main characteristics of each of the experiments involved in the detection of these particles. We then briefly discuss the status of the chemical composition and the distribution of arrival directions of cosmic rays. After that, we examine the energy losses during propagation, introducing the Greisen-Zaptsepin-Kuzmin (GZK) cutoff, and discuss the level of confidence with which each experiment have detected particles beyond the GZK energy limit. In the second part of the review, we discuss astrophysical environments able to accelerate particles up to such high energies, including active galactic nuclei, large scale galactic wind termination shocks, relativistic jets and hot-spots of Fanaroff-Riley radiogalaxies, pulsars, magnetars, quasar remnants, starbursts, colliding galaxies, and gamma ray burst fireballs. In the third part of the review we provide a brief summary of scenarios which try to explain the super-GZK events with the help of new physics beyond the standard model. In the last section, we give an overview on neutrino telescopes and existing limits on the energy spectrum and discuss some of the prospects for a new (multi-particle) astronomy. Finally, we outline how extraterrestrial neutrino fluxes can be used to probe new physics beyond the electroweak scale. Solicited Review Article Prepared for Reports on Progress in Physics 1 PREFACEReviewing cosmic ray physics is a risky business. Theoretical models continue to appear at an amazing rate, both in the astrophysical and more exotic domains. We warn the reader: we do not (nor we could) intend to make an homogeneous coverage of all the ideas of our fellow colleagues. Reading differently focused reviews on the issue (quoted here along the way) is, in our view, the best approach to such a wide topic of research.2 Contents

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Section: B Astronomy On Icementioning

confidence: 95%

Astrophysical origins of ultrahigh energy cosmic rays

2004

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“…For this reason, Ranft and Nelson [1] introduced a method to estimate the importance of hadron production by energetic photons in the development of electromagnetic showers. This method combines the idea of the vector-meson dominance (VMD) model with a Monte Carlo model based on the dual multistring fragmentation model .…”

Section: Introductionmentioning

confidence: 99%

“…To this end we propose an extension of the method introduced in ref . [1] on the basis of the equivalent photon approximation [4], which has been included into a working version of the FLUKA Monte Carlo code. In the fol lowing two sections we DFICiry UCSCFIUC We 111CUlUU QlIU discuss some results, respectively .…”

Section: Introductionmentioning

confidence: 99%

“…esticn4`e the cross section (and the corresponding mean free path) from the integral of eq. (5) ; 2. sample the energy (x value) of the actual "equivalent" (reale photon according to the distribution of eq" (2); 3. generate hadrons according the photoproduction model [1] already implerirented in the FLM-% rode. To estimate the importance of direct electronuclear reactions we compare the probabilities for hadron generation in electroproduction and photoproduction processes, respectively, for an electron beam incident on a target of length L. For photoproduction of hadrons as a two-step process this probability can be approximated by:…”

Section: Introductionmentioning

confidence: 99%

“…The interaction of the resulting quasireal photons with nuclei is described by the vector-meson dominance model and a Monte Carlo realization of the multistring fragmentation model, as discussed in ref . [1). For thin targets (as compared to the radiation length), hadronic interactions of the incident high-energy electrons on nuclei dominate the generation of high-energy hadrons.…”

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On the contribution of off-nuclei electroproduction to the generation of energetic hadrons in electromagnetic showers

Möhring¹

1990

Nuclear Instruments and Methods in Physics Research Section A:

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The calculation of high-energy hadron cascades in extended materials induced by electron beams in the GeV energy range is reconsidered. In particular, we estimate the contribution from hadronic interactions of high-energy electrons on nuclei as compared to hadron production by photons.Our estimate relies on the equivalent photon approximation . The interaction of the resulting quasireal photons with nuclei is described by the vector-meson dominance model and a Monte Carlo realization of the multistring fragmentation model, as discussed in ref . [1). For thin targets (as compared to the radiation length), hadronic interactions of the incident high-energy electrons on nuclei dominate the generation of high-energy hadrons. l. IntroductionSo far, hadroproduction by leptons was of no importance for many practical applications in shielding and calorimetry : For example, due to the smallness of the corresponding hadronic cross sections, properties of electromagnetic calorimeters are well understood from the Monte Carlo calculation of purely electromagnetic showers in the detector geometry . However, with the construction of high-energy and/or high-current electron machines, like LEP at CERN, SLC at SLAC or CEBAF, hadron-production processes induced by energetic electrons and photons become important, at least for shielding: The large attenuation length of hadrons as compared to leptons may compensate their small production cross sections .For this reason, Ranft and Nelson [1] introduced a method to estimate the importance of hadron production by energetic photons in the development of electromagnetic showers. This method combines the idea of the vector-meson dominance (VMD) model with a Monte Carlo model based on the dual multistring fragmentation model . It has been included into the coupled hadron-electromagnetic cascade code FLUK.A-EGS [2] îor ;.z-urp'.i^ation in Monte Carlo shower simulations . Note that, due to the restrictions in applicability of both the VMD and the multistring fragmentation models, the method should not be applied to photon energies below 1-2 GeV . As a consequence, reliable results are to be * Permanent address : Sektion Physik, Karl-Marx-Universität, Leipzig, GDR . A292 (1990) 482-486 North-Holland expected only for the production of hadrons with energies above about 1 GeV. A careful comparison of calculations using the FLU KA code, with SLAC data on hadroproduction by 18 GeV electrons on a beryllium target shows a systematic underestimation of hadron yields at high momenta (above 2 GeV) by a factor of order two [3] . This disagreement rises the question for other important hadron-generating mechanisms in electron-photon showers . At least for high-energy electron beams direct electron-induced hadron production on nuclei might be such a process : Although suppressed by a factor of order a/,ir as compared to photoproduction mechanisms, the latter ones represent two-step processes for electron beams -the energetic photons have to be generated via hard bremsstrahlung first .In this note we es...

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How to Deal with Relativistic Heavy Ion Collisions

Hagedorn

2016

Melting Hadrons, Boiling Quarks - From Hagedorn Temperature to Ultra-Relativistic Heavy-Ion Collisions at CERN

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A qualitative review is given of the theoretical problems and possibilities arising when one tries to understand what happens in relativistic heavy ion collisions. The striking similarity between these and pp collisions suggests the use of techniques similar to those used 5-12 years ago in pp collisions to disentangle collective motions from thermodynamics. A very heuristic and qualitative sketch of statistical bootstrap thermodynamics concludes an idealized picture in which a relativistic heavy ion collision appears as a superposition of moving 'fireballs' with equilibrium thermodynamics in the rest frames of these fireballs. The interesting problems arise where this theoretician's picture deviates from reality: non-equilibrium, more complicated motion (shock waves, turbulence, spin) and the collision history. Only if these problems have been solved or shown to be irrelevant can we safely identify signatures of unusual states of hadronic matter as, for example, a quark-gluon plasma or density isomers.

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Lepton-pair production in polarised pp and pp collisions

Cited by 27 publications

References 13 publications

Astrophysical origins of ultrahigh energy cosmic rays

Astrophysical origins of ultrahigh energy cosmic rays

On the contribution of off-nuclei electroproduction to the generation of energetic hadrons in electromagnetic showers

How to Deal with Relativistic Heavy Ion Collisions

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