A search for nonresonant Higgs boson pair production in the b ¯bb ¯b final state is presented. The analysis
uses 126 fb−1 of pp collision data at ffiffiffi
s
p ¼ 13 TeV collected with the ATLAS detector at the Large Hadron
Collider, and targets both the gluon-gluon fusion and vector-boson fusion production modes. No evidence
of the signal is found and the observed (expected) upper limit on the cross section for nonresonant Higgs
boson pair production is determined to be 5.4 (8.1) times the Standard Model predicted cross section at
95% confidence level. Constraints are placed on modifiers to the HHH and HHVV couplings. The
observed (expected) 2σ constraints on the HHH coupling modifier, κ λ, are determined to be ½−3.5; 11.3Š
(½−5.4; 11.4Š), while the corresponding constraints for the HHVV coupling modifier, κ2V , are ½−0.0; 2.1Š
(½−0.1; 2.1Š). In addition, constraints on relevant coefficients are derived in the context of the Standard
Model effective field theory and Higgs effective field theory, and upper limits on the HH production cross
section are placed in seven Higgs effective field theory benchmark scenarios

Title

PHYSICAL REVIEW D

Publisher

APS

Publisher Country

United States of America

Indexing

Scopus

Impact Factor

None

Publication Type

Prtinted only

Volume

--

Year

--

Pages

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