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Simulations of coherent beam-beam modes at the Large Hadron Collider

The transverse coherent motion of two colliding proton beams at the Large Hadron Collider is studied by multiparticle tracking. We use the beam-beam force for a Gaussian beam distribution with variable barycenters and rms beam sizes, and optionally include the effect of long-range collisions and ext...

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Detalles Bibliográficos
Autores principales: Zorzano-Mier, M P, Zimmermann, Frank
Lenguaje:eng
Publicado: 2000
Materias:
Acceso en línea:https://dx.doi.org/10.1103/PhysRevSTAB.3.044401
http://cds.cern.ch/record/446334
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author Zorzano-Mier, M P
Zimmermann, Frank
author_facet Zorzano-Mier, M P
Zimmermann, Frank
author_sort Zorzano-Mier, M P
collection CERN
description The transverse coherent motion of two colliding proton beams at the Large Hadron Collider is studied by multiparticle tracking. We use the beam-beam force for a Gaussian beam distribution with variable barycenters and rms beam sizes, and optionally include the effect of long-range collisions and external impedance. The simulation yields the coherent and incoherent oscillation frequencies, the emittance growth of either beam, and evidence for the existence or lack of Landau damping. For head-on collisions of beams with equal sizes, we find that the pi -mode frequency lies outside of the continuum frequency spread, if the ratio of the beam-beam parameters exceeds 0.6, in accordance with predictions. For smaller ratios of the beam- beam parameters, or if, for equal beam-beam parameters, the beam sizes are widely different, the pi mode is Landau damped. When long- range collisions are also included, undamped coherent modes do still exist outside the continuum, both with and without alternating crossing planes at two interaction points. However, separating the tunes of the two beams restores the Landau damping, provided the external impedance is sufficiently small. (19 refs).
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institution Organización Europea para la Investigación Nuclear
language eng
publishDate 2000
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spelling cern-4463342019-09-30T06:29:59Zdoi:10.1103/PhysRevSTAB.3.044401http://cds.cern.ch/record/446334engZorzano-Mier, M PZimmermann, FrankSimulations of coherent beam-beam modes at the Large Hadron ColliderAccelerators and Storage RingsThe transverse coherent motion of two colliding proton beams at the Large Hadron Collider is studied by multiparticle tracking. We use the beam-beam force for a Gaussian beam distribution with variable barycenters and rms beam sizes, and optionally include the effect of long-range collisions and external impedance. The simulation yields the coherent and incoherent oscillation frequencies, the emittance growth of either beam, and evidence for the existence or lack of Landau damping. For head-on collisions of beams with equal sizes, we find that the pi -mode frequency lies outside of the continuum frequency spread, if the ratio of the beam-beam parameters exceeds 0.6, in accordance with predictions. For smaller ratios of the beam- beam parameters, or if, for equal beam-beam parameters, the beam sizes are widely different, the pi mode is Landau damped. When long- range collisions are also included, undamped coherent modes do still exist outside the continuum, both with and without alternating crossing planes at two interaction points. However, separating the tunes of the two beams restores the Landau damping, provided the external impedance is sufficiently small. (19 refs).oai:cds.cern.ch:4463342000
spellingShingle Accelerators and Storage Rings
Zorzano-Mier, M P
Zimmermann, Frank
Simulations of coherent beam-beam modes at the Large Hadron Collider
title Simulations of coherent beam-beam modes at the Large Hadron Collider
title_full Simulations of coherent beam-beam modes at the Large Hadron Collider
title_fullStr Simulations of coherent beam-beam modes at the Large Hadron Collider
title_full_unstemmed Simulations of coherent beam-beam modes at the Large Hadron Collider
title_short Simulations of coherent beam-beam modes at the Large Hadron Collider
title_sort simulations of coherent beam-beam modes at the large hadron collider
topic Accelerators and Storage Rings
url https://dx.doi.org/10.1103/PhysRevSTAB.3.044401
http://cds.cern.ch/record/446334
work_keys_str_mv AT zorzanomiermp simulationsofcoherentbeambeammodesatthelargehadroncollider
AT zimmermannfrank simulationsofcoherentbeambeammodesatthelargehadroncollider