CP-violating top quark couplings at future linear e+e- colliders

• Published in: The European physical journal. C, Particles and fields Vol. 78; no. 2; pp. 1 - 21
• Main Authors: Bernreuther, W., Chen, L., García, I., Perelló, M., Poeschl, R., Richard, F., Ros, E., Vos, M.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 2018; Springer Nature B.V; Springer Verlag (Germany)
• Subjects: Astronomy; Astrophysics and Cosmology; Computer simulation; Couplings; CP violation; Dipole moments; Elementary Particles; Form factors; Hadrons; Heavy Ions; Higgs bosons; High Energy Physics - Experiment; High Energy Physics - Phenomenology; Large Hadron Collider; Leptons; Measurement Science and Instrumentation; Nuclear Energy; Nuclear Physics; Pair production; Physics; Physics and Astronomy; Quantum Field Theories; Quantum Field Theory; Quarks; Special Article - Tools for Experiment and Theory; String Theory; Higgs particle: doublet; proposed experiment; top: form factor; top: coupling; form factor: dipole; electron positron: annihilation; symmetry: CP; numerical calculations: Monte Carlo; ILC Coll; electron positron: colliding beams; CP: violation; top: pair production; CERN CLIC; jet: final state; CERN LHC Coll: upgrade; sensitivity; coupling: anomaly; final state: ((n)jet lepton)
• ISSN: 1434-6044; 1434-6052
• DOI: 10.1140/epjc/s10052-018-5625-3

We study the potential of future lepton colliders to probe violation of the CP symmetry in the top quark sector. In certain extensions of the Standard Model, such as the two-Higgs-doublet model (2HDM), sizeable anomalous top quark dipole moments can arise, which may be revealed by a precise measurement of top quark pair production. We present results from detailed Monte Carlo studies for the ILC at
500
GeV
and CLIC at
380
GeV
and use parton-level simulations to explore the potential of high-energy operation. We find that precise measurements in
e
+
e
-
→
t
t
¯
production with subsequent decay to lepton plus jets final states can provide sufficient sensitivity to detect Higgs-boson-induced CP violation in a viable two-Higgs-doublet model. The potential of a linear
e
+
e
-
collider to detect CP-violating electric and weak dipole form factors of the top quark exceeds the prospects of the HL-LHC by over an order of magnitude.