dorsal/arxiv
View SchemaCoherent Beam-Beam Tune Shift of Unsymmetrical Beam-Beam Interactions with Large Beam-Beam Parameter
| Authors | Lihui Jin, Jicong Shi, Georg H. Hoffstaetter |
|---|---|
| Categories | |
| ArXiv ID | physics/0409054 |
| URL | https://arxiv.org/abs/physics/0409054 |
| DOI | 10.1103/PhysRevE.71.036501 |
| Journal | Phys.Rev.E71:036501,2005 |
Abstract
Coherent beam-beam tune shift of unsymmetrical beam-beam interactions was studied experimentally and numerically in HERA where the lepton beam has a very large beam-beam parameter (up to $\xi_y=0.272$). Unlike the symmetrical case of beam-beam interactions, the ratio of the coherent and incoherent beam-beam tune shift in this unsymmetrical case of beam-beam interactions was found to decrease monotonically with increase of the beam-beam parameter. The results of self-consistent beam-beam simulation, the linearized Vlasov equation, and the rigid-beam model were compared with the experimental measurement. It was found that the coherent beam-beam tune shifts measured in the experiment and calculated in the simulation agree remarkably well but they are much smaller than those calculated by the linearized Vlasov equation with the single-mode approximation or the rigid-beam model. The study indicated that the single-mode approximation in the linearization of Vlasov equation is not valid in the case of unsymmetrical beam-beam interactions. The rigid-beam model is valid only with a small beam-beam parameter in the case of unsymmetrical beam-beam interactions.
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"abstract": "Coherent beam-beam tune shift of unsymmetrical beam-beam interactions was\nstudied experimentally and numerically in HERA where the lepton beam has a very\nlarge beam-beam parameter (up to $\\xi_y=0.272$). Unlike the symmetrical case of\nbeam-beam interactions, the ratio of the coherent and incoherent beam-beam tune\nshift in this unsymmetrical case of beam-beam interactions was found to\ndecrease monotonically with increase of the beam-beam parameter. The results of\nself-consistent beam-beam simulation, the linearized Vlasov equation, and the\nrigid-beam model were compared with the experimental measurement. It was found\nthat the coherent beam-beam tune shifts measured in the experiment and\ncalculated in the simulation agree remarkably well but they are much smaller\nthan those calculated by the linearized Vlasov equation with the single-mode\napproximation or the rigid-beam model. The study indicated that the single-mode\napproximation in the linearization of Vlasov equation is not valid in the case\nof unsymmetrical beam-beam interactions. The rigid-beam model is valid only\nwith a small beam-beam parameter in the case of unsymmetrical beam-beam\ninteractions.",
"arxiv_id": "physics/0409054",
"authors": [
"Lihui Jin",
"Jicong Shi",
"Georg H. Hoffstaetter"
],
"categories": [
"physics.acc-ph",
"physics.class-ph"
],
"doi": "10.1103/PhysRevE.71.036501",
"journal_ref": "Phys.Rev.E71:036501,2005",
"title": "Coherent Beam-Beam Tune Shift of Unsymmetrical Beam-Beam Interactions with Large Beam-Beam Parameter",
"url": "https://arxiv.org/abs/physics/0409054"
},
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