Energy transparency and symmetries in the beam-beam interaction
We have modified the beam-beam simulation code CBI to handle asymmetric beams and used it to look at energy transparency and symmetries in the beam-beam interaction. We find that even a small violation of energy transparency, or of the symmetry between the two beams, changes the character of the col...
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| Format: | Article |
| Language: | English |
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American Physical Society
2000-02-01
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| Series: | Physical Review Special Topics. Accelerators and Beams |
| Online Access: | http://doi.org/10.1103/PhysRevSTAB.3.024401 |
| _version_ | 1818266175705972736 |
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| author | S. Krishnagopal |
| author_facet | S. Krishnagopal |
| author_sort | S. Krishnagopal |
| collection | DOAJ |
| description | We have modified the beam-beam simulation code CBI to handle asymmetric beams and used it to look at energy transparency and symmetries in the beam-beam interaction. We find that even a small violation of energy transparency, or of the symmetry between the two beams, changes the character of the collective (coherent) motion; in particular, period-n oscillations are no longer seen. We speculate that the one-time observation of these oscillations at LEP, and the more ubiquitous observation of the flip-flop instability in colliders around the world, may be a consequence of breaking the symmetry between the electron and positron beams. We also apply this code to the asymmetric collider PEP-II, and find that for the nominal parameters of PEP-II, in particular, the nominal tune-shift parameter of ξ_{0}=0.03, there are no collective beam-beam issues. Collective quadrupole motion sets in only at ξ_{0}=0.06 and above, consistent with earlier observations for symmetric beams. |
| first_indexed | 2024-12-12T20:02:32Z |
| format | Article |
| id | doaj.art-92724c36e4bb440b93f76a74f127f85d |
| institution | Directory Open Access Journal |
| issn | 1098-4402 |
| language | English |
| last_indexed | 2024-12-12T20:02:32Z |
| publishDate | 2000-02-01 |
| publisher | American Physical Society |
| record_format | Article |
| series | Physical Review Special Topics. Accelerators and Beams |
| spelling | doaj.art-92724c36e4bb440b93f76a74f127f85d2022-12-22T00:13:43ZengAmerican Physical SocietyPhysical Review Special Topics. Accelerators and Beams1098-44022000-02-013202440110.1103/PhysRevSTAB.3.024401Energy transparency and symmetries in the beam-beam interactionS. KrishnagopalWe have modified the beam-beam simulation code CBI to handle asymmetric beams and used it to look at energy transparency and symmetries in the beam-beam interaction. We find that even a small violation of energy transparency, or of the symmetry between the two beams, changes the character of the collective (coherent) motion; in particular, period-n oscillations are no longer seen. We speculate that the one-time observation of these oscillations at LEP, and the more ubiquitous observation of the flip-flop instability in colliders around the world, may be a consequence of breaking the symmetry between the electron and positron beams. We also apply this code to the asymmetric collider PEP-II, and find that for the nominal parameters of PEP-II, in particular, the nominal tune-shift parameter of ξ_{0}=0.03, there are no collective beam-beam issues. Collective quadrupole motion sets in only at ξ_{0}=0.06 and above, consistent with earlier observations for symmetric beams.http://doi.org/10.1103/PhysRevSTAB.3.024401 |
| spellingShingle | S. Krishnagopal Energy transparency and symmetries in the beam-beam interaction Physical Review Special Topics. Accelerators and Beams |
| title | Energy transparency and symmetries in the beam-beam interaction |
| title_full | Energy transparency and symmetries in the beam-beam interaction |
| title_fullStr | Energy transparency and symmetries in the beam-beam interaction |
| title_full_unstemmed | Energy transparency and symmetries in the beam-beam interaction |
| title_short | Energy transparency and symmetries in the beam-beam interaction |
| title_sort | energy transparency and symmetries in the beam beam interaction |
| url | http://doi.org/10.1103/PhysRevSTAB.3.024401 |
| work_keys_str_mv | AT skrishnagopal energytransparencyandsymmetriesinthebeambeaminteraction |