This experiment examined the effectiveness of one-group and dual-identity recategorization strategies on reducing intergroup bias among 180 European Portuguese and African Portuguese 9- and 10-year-old children. Results revealed that each of these recategorization strategies, relative to one that emphasized separate group identities, was successful in producing positive attitudes toward the outgroup children present during the session, the outgroup as a whole, and the outgroup as a whole three weeks later. Consistent with a functional perspective regarding which representation would most effectively promote their group’s goals, a dual identity was more effective for the European Portuguese majority group, whereas a one-group identity was more effective for the African Portuguese minority group. Additional analyses explored a model of the process of generalization that formally links attitudes toward the outgroup as a whole to the attitudes toward outgroup members present during contact.

We explore some aspects of models with two and three SU(2) scalar doublets that lead to mass degeneracies among some of the physical scalars. In Higgs sectors with two scalar doublets, the exact degeneracy of scalar masses, without an artificial fine-tuning of the scalar potential parameters, is possible only in the case of the inert doublet model (IDM), where the scalar potential respects a global U(1) symmetry that is not broken by the vacuum. In the case of three doublets, we introduce and analyze the replicated inert doublet model, which possesses two inert doublets of scalars. We then generalize this model to obtain a scalar potential, first proposed by Ivanov and Silva, with a CP4 symmetry that guarantees the existence of pairwise degenerate scalar states among two pairs of neutral scalars and two pairs of charged scalars. Here, CP4 is a generalized CP symmetry with the property that (CP4) n is the identity operator only for integer n values that are multiples of 4. The form of the CP4-symmetric scalar potential is simplest when expressed in the Higgs basis, where the neutral scalar field vacuum expectation value resides entirely in one of the scalar doublet fields. The symmetries of the model permit a term in the scalar potential with a complex coefficient that cannot be removed by any redefinition of the scalar fields within the class of Higgs bases (in which case, we say that no real Higgs basis exists). A striking feature of the CP4-symmetric model is that it preserves CP even in the absence of a real Higgs basis, as illustrated by the cancellation of the contributions to the CP violating form factors of the effective ZZZ and ZW W vertices. *

We point out that hints of deviations from unitarity in the first row of the CKM matrix may be explained by the presence of a single vector-like top. We study how the stringent experimental constraints arising from CP Violation in the kaon sector and from meson mixing such as $$ {D}^0\hbox{-} {\overline{D}}^0,{K}^0\hbox{-} {\overline{K}}^0 $$ D 0 ‐ D ¯ 0 , K 0 ‐ K ¯ 0 and $$ {B}_{d,s}^0\hbox{-} {\overline{B}}_{d,s}^0 $$ B d , s 0 ‐ B ¯ d , s 0 can be satisfied in the proposed framework. In order for the deviations from unitarity to be of the required size while keeping the theory perturbative, the new top quark should have a mass mT ≲ 7 TeV which could be probed in upcoming experiments at the energy frontier.

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This experiment explored whether the benefits of a complete recategorization and a dual identity might effectively be translated into an intervention program designed to reduce prejudice among European Portuguese and African Portuguese 9‐ to 11‐year‐old children. Participants interacted for 45 minutes in weekly sessions for a month. One month after the last interaction, measures were administered to the children. Results revealed that only recategorization reduced prejudice over time relative to the control condition. Consistent with a functional perspective regarding which representation would most effectively promote their group's goals, a one‐group representation was more effective for the African Portuguese minority group.