The beam-beam effects in a hadron collider with an unprecedented energy scale were studied.These effects are strongly related to the attainable luminosity of the collider.Long-range interactions were identified as the major factor limiting the dynamic aperture,which is strongly dependent on the crossing angle,β*,and bunch population.Different mitigation methods of the beam-beam effects were addressed,with a focus on the com-pensation of long-range interactions by electric current wires.The CEPC-SPPC project is a two-stage large cir-cular collider,with a first-stage circular electron-positron collider(CEPC)and a second-stage super proton-proton collider(SPPC).The design of the SPPC aims to achieve a center-of-mass energy of 75 TeV and peak luminosity of approximately 1×1035 cm-2 s-1.We studied the beam-beam effects in the SPPC and tested the effectiveness of the mitigation methods.We found that with compensation using electric current wires,the dynamic aperture is at an acceptable level.Moreover,considering the significant emittance damping in this future proton-proton collider,the beam-beam effects and compensation are more com-plicated and are studied using long-term tracking.It was found that with a smaller emittance,the head-on interac-tions with a crossing angle become more prominent in reducing the beam stability,and combined head-on and long-range compensation is needed to improve the beam quality.When the reduction in population owing to burn-off was included,it was found that the coupling between the transverse and longitudinal planes at smaller emittance is the main driving source of the instabilities.Thus,crab cavities and emittance control are also necessary than just the compensation of the long-range interactions to improve the beam stability.This study serves as an example for studying the beam-beam effects in future proton-proton colliders.

Li-Jiao Wang;Tanaji Sen;Jing-Yu Tang;Lin-Hao Zhang

Institute of High Energy Physics,CAS,Yuquan Road 19B,Beijing 100049,China;University of Chinese Academy of Sciences,CAS,19A Yuquan Road,Beijing 100049,China;Spallation Neutron Source Science Center,Dongguan 523803,China;Fermi National Accelerator Laboratory,P.O.Box 500,Batavia,IL 60510,USA

核技术（英文版）

[1]Li-Jiao Wang;Tanaji Sen;Jing-Yu Tang;Lin-Hao Zhang-.Beam-beam effects and mitigation in a future proton-proton collider)[J].核技术（英文版）,2022(10):90-105

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