https://doi.org/10.1140/epjc/s10052-023-12193-4
Regular Article -Theoretical Physics
Sensitivity to triple Higgs couplings via di-Higgs production in the 2HDM at the (HL-)LHC
1
Departamento de Física Teórica, Universidad Autónoma de Madrid, Cantoblanco, 28049, Madrid, Spain
2
Instituto de Física Teórica (UAM/CSIC), Universidad Autónoma de Madrid, Cantoblanco, 28049, Madrid, Spain
3
Institute for Theoretical Physics, Karlsruhe Institute of Technology, 76128, Karlsruhe, Germany
4
Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany
Received:
31
July
2023
Accepted:
27
October
2023
Published online:
9
November
2023
An important task of the LHC is the investigation of the Higgs-boson sector. Of particular interest is the reconstruction of the Higgs potential, i.e. the measurement of the Higgs self-couplings. Based on previous analyses, within the 2-Higgs-Doublet Model (2HDM) type I, we analyze several two-dimensional benchmark planes that are over large parts in agreement with all theoretical and experimental constraints. For these planes we evaluate di-Higgs production cross sections at the (HL-)LHC with a center-of-mass energy of 
at next-to-leading order in the heavy top-quark limit with the code HPAIR. We investigate in particular the process 
, with h being the Higgs boson discovered at the LHC with a mass of about 
. The top box diagram of the loop-mediated gluon fusion process into Higgs pairs interferes with the s-channel exchange of the two 
-even 2HDM Higgs bosons h and H. The latter two involve the triple Higgs couplings (THCs) 
and 
, respectively, possibly making them accessible at the HL-LHC. Depending on the size of the involved top-Yukawa and THCs as well as on the mass of H, the contribution of the s-channel H diagram can be dominating or be highly suppressed. We find regions of the allowed parameter space in which the di-Higgs production cross section can differ by many standard deviations from its SM prediction, indicating possible access to deviations in from the SM value 
and/or contributions involving . The sensitivity to the beyond-the-SM (BSM) THC is further analyzed employing the 
distributions. We demonstrate how a possible measurement of depends on the various experimental uncertainties. Depending on the underlying parameter space, the HL-LHC may have the option not only to detect BSM THCs, but also to provide a first rough measurement of their sizes.
© The Author(s) 2023
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