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  • Open Access

First observation in the LHC of beam-beam-induced crabbing

A. Fornara

R. B. Appleby

X. Buffat, M. Hostettler, T. Levens, G. Sterbini, and G. Trad

  • CERN, Meyrin, Switzerland

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Phys. Rev. Accel. Beams 29, 093503 – Published 29 September, 2026

DOI: https://doi.org/10.1103/jm2q-k1g9

Abstract

The first experimental observation of a crabbing orbit induced by beam-beam interaction in the presence of a finite crossing angle in a high-energy proton beam is presented. This measurement required both the design of a dedicated experiment in the large hadron collider (LHC) and careful calibration and optimization of the beam instrumentation to produce and detect such a subtle effect. To also measure the dependence of this effect on the crossing angle, this parameter is varied from positive to negative values, further showing the reproducibility of the effect. Tracking simulations were performed to corroborate the experimental results, showing good agreement with the measured crabbing amplitudes. This experiment highlights the potential of the existing wideband beam position monitors to diagnose crabbing effects, which will be crucial in the High-Luminosity LHC (HL-LHC) upgrade.

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Phys. Rev. Accel. Beams 29, 093503– Published 29 September, 2026
  • Received 7 December 2025
  • Accepted 6 August 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.

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