This report summarises the physics opportunities for the study of Higgs bosons and the dynamics of electroweak symmetry breaking at the 100 TeV pp collider.

No abstract

Different mechanisms operate in various regions of the MSSM parameter space to bring the relic density of the lightest neutralino, , assumed here to be the lightest SUSY particle (LSP) and thus the dark matter (DM) particle, into the range allowed by astrophysics and cosmology. These mechanisms include coannihilation with some nearly degenerate next-to-lightest supersymmetric particle such as the lighter stau , stop or chargino , resonant annihilation via direct-channel heavy Higgs bosons H / A, the light Higgs boson h or the Z boson, and enhanced annihilation via a larger Higgsino component of the LSP in the focus-point region. These mechanisms typically select lower-dimensional subspaces in MSSM scenarios such as the CMSSM, NUHM1, NUHM2, and pMSSM10. We analyze how future LHC and direct DM searches can complement each other in the exploration of the different DM mechanisms within these scenarios. We find that the coannihilation regions of the CMSSM, NUHM1, NUHM2 can largely be explored at the LHC via searches for events and long-lived charged particles, whereas their H / A funnel, focus-point and coannihilation regions can largely be explored by the LZ and Darwin DM direct detection experiments. We find that the dominant DM mechanism in our pMSSM10 analysis is coannihilation: parts of its parameter space can be explored by the LHC, and a larger portion by future direct DM searches.

In the presence of CP violation, the Higgs-top coupling may have both scalar and pseudoscalar components, κ t andκ t , which are bounded indirectly but only weakly by the present experimental constraints on the Higgs-gluon-gluon and Higgs-γ-γ couplings, whereas upper limits on electric dipole moments provide strong additional indirect constraints onκ t , if the Higgs-electron coupling is similar to that in the Standard Model and there are no cancellations with other contributions. We discuss methods to measure directly the scalar and pseudoscalar Higgs-top couplings by measurements of Higgs production in association with tt, single t and singlet at the LHC. Measurements of the total cross sections are very sensitive to variations in the Higgs-top couplings that are consistent with the present indirect constraints, as are invariant mass distributions inttH, tH andtH final states. We also investigate the additional information on κ t andκ t that could be obtained from measurements of the longitudinal and transverse t polarization in the different associated production channels, and thett spin correlation inttH events. It is important to characterize the new boson H discovered by the ATLAS [1] and CMS [2]Collaborations. In this paper we refer to this particle as a Higgs boson, since it has some of the expected properties, though others remain to be verified. Tests via H decays into γγ [3], W W * [4] and ZZ * [5,6] are consistent with it having spin zero [7][8][9][10][11], as are measurements of H production in association with W and Z [12]. In particular, these tests exclude gravitonlike spin-two couplings with a high degree of confidence. Assuming that the H spin is indeed zero, the next question is whether it has scalar and/or pseudoscalar couplings.Tests in W W * and ZZ * final states [5][6][7][8][13][14][15][16][17] and production in association with W and Z [12] also disfavour strongly pure pseudoscalar couplings, but do not yet exclude a substantial pseudoscalar admixture. In the presence of CP violation, the ratios of scalar and pseudoscalar couplings may differ from channel to channel, and it is important to measure them in as many different channels as possible. Strategies to measure a CP-violating admixture in H → τ + τ − decays have been proposed [18-20], and other tests are possible in H production in vector-boson fusion [21-25], double-diffractive [26, 27] and γγ collisions [28]. There are already indirect constraints on the scalar and pseudoscalar H-top couplings κ t andκ t from experimental information on the H-gluon-gluon and H-γ-γ couplings [29], but these constraints are relatively weak [40], as we discuss later. Upper limits on electric dipole moments also impose important indirect constraints on a possible pseudoscalar H-top couplingκ t [29], if one assumes that if the Higgs-electron coupling is similar to that in the Standard Model and there are no cancellations with other contributing mechanisms.In this paper we investigate the potential for disentangling scalar and pseudoscalar Htop couplings ...

We use MasterCode to perform a frequentist analysis of the constraints on a phenomenological MSSM model with 11 parameters, the pMSSM11, including constraints from /fb of LHC data at 13 TeV and PICO, XENON1T and PandaX-II searches for dark matter scattering, as well as previous accelerator and astrophysical measurements, presenting fits both with and without the constraint. The pMSSM11 is specified by the following parameters: 3 gaugino masses , a common mass for the first-and second-generation squarks and a distinct third-generation squark mass , a common mass for the first-and second-generation sleptons and a distinct third-generation slepton mass , a common trilinear mixing parameter A , the Higgs mixing parameter , the pseudoscalar Higgs mass and . In the fit including , a Bino-like is preferred, whereas a Higgsino-like is mildly favoured when the constraint is dropped. We identify the mechanisms that operate in different regions of the pMSSM11 parameter space to bring the relic density of the lightest neutralino, , into the range indicated by cosmological data. In the fit including , coannihilations with and the Wino-like or with nearly-degenerate first- and second-generation sleptons are active, whereas coannihilations with the and the Higgsino-like or with first- and second-generation squarks may be important when the constraint is dropped. In the two cases, we present functions in two-dimensional mass planes as well as their one-dimensional profile projections and best-fit spectra. Prospects remain for discovering strongly-interacting sparticles at the LHC, in both the scenarios with and without the constraint, as well as for discovering electroweakly-interacting sparticles at a future linear collider such as the ILC or CLIC.