Triple and quartic interactions of Higgs bosons in the two-Higgs-doublet model with CP violation

We consider the two-Higgs-doublet model with explicit CP-violation, where the effective Higgs potential is not CP-invariant at the tree-level. Three neutral Higgs bosons of the model are the mixtures of CP-even and CP-odd bosons which exist in the CP-conserving limit of the theory. The mass spectrum and tree-level couplings of the neutral Higgs bosons to gauge bosons and fermions are significantly dependent on the parameters of the Higgs boson mixing matrix. We calculate the Higgs-gauge boson, Higgs-fermion, triple and quartic Higgs self-interactions in the MSSM with explicit CP-violation in the Higgs sector and CP-violating Yukawa interactions of the third generation scalar quarks. In some regions of the MSSM parameter space substantial changes of the self-interaction vertices take place, leading to significant suppression or enhancement of the multiple Higgs boson production cross sections.Comment: 29 pages, 4 figures. Minor changes in section 3, misprints in (47) corrected. Version accepted by EPJ

MSSM-inspired multifield inflation

Despite the fact that experimentally with a high degree of statistical significance only a single Standard Model--like Higgs boson is discovered at the LHC, extended Higgs sectors with multiple scalar fields not excluded by combined fits of the data are more preferable theoretically for internally consistent realistic models of particle physics. We analyze the inflationary scenarios which could be induced by the two-Higgs doublet potential of the Minimal Supersymmetric Standard Model (MSSM) where five scalar fields have nonminimal couplings to gravity. Observables following from such MSSM-inspired multifield inflation are calculated and a number of consistent inflationary scenarios are constructed. Cosmological evolution with different initial conditions for the multifield system leads to consequences fully compatible with observational data on the spectral index and the tensor-to-scalar ratio. It is demonstrated that the strong coupling approximation is precise enough to describe such inflationary scenarios.Comment: 27 pages, 4 figures, 5 tables. Version to appear in JHEP. Additions made to the text of the Introduction dealing with the issues of conformity of this multifield model and models of N=1 supergravity (pages 2-3). Added new inflationary scenarios, which are an artifact of such analysis (pages 11-12, Tables 1-4). Additional comments on page 9 and page 13. New references adde

Higgs Boson Discovery Potential of LHC in the Channel pp→γγ+jetpp \to\gamma\gamma+jet

We discuss the SM Higgs discovery potential of LHC in the reaction $pp\to H+ jet\to\gamma\gamma+jet$ when the jet is observed at sufficiently high $E_t$ to be reliably identified. We conclude that this channel gives promising discovery possibilities for the Higgs boson mass range 100-140 GeV, during LHC operation at a low luminosity. With 30 fb$^{-1}$ of accumulated data and for $M_H=120$ GeV about 100 signal events could be observed with the number of background events larger by a factor of 2 only, showing a signal significance $S/\sqrt{B}\sim 7$. We use the difference of distributions in the partonic subprocess energy $\sqrt{\hat s}$ for the signal and background for a better separation of the signal.Comment: 15 pages including 6 figures, LaTeX, use epsfig.sty. To appear in Phys.Lett.B. In this replacement minor LaTeX improvements are mad

Search for Higgs Boson at LHC in the Reaction pp->gamma+gamma+jet at a Low Luminosity

We discuss the SM Higgs discovery potential of the LHC in the channel pp->H+jet->gamma+gamma+jet when the jet is observed at sufficiently high Pt and a small rapidity to be reliably identified. We calculate all the signal subprocesses and the irreducible background with realistic kinematical cuts. The reducible QCD background is also estimated. We conclude that the channel gamma+gamma+jet can give about 120-200 signal events for Higgs mass MH=100-140 GeV at the integrated luminosity of 30 inverse fb. This signal rate should be compared with only 330-600 events for the irreducible background per two-photon invariant mass interval of 2 GeV. We estimate the QCD reducible background at the level of 20% of the irreducible one. Thus, one may hope that the Higgs boson can be discovered already during the LHC operation at a low luminosity. At a high luminosity the observation of several hundreds of high Pt Higgs bosons in this channel will be possible with significance higher than 15 for L=100 inverse fb.Comment: 21 pages (LaTeX code, epsf.sty), 2 tables, 9 figures; to appear in the Proceedings of XIIth International Workshop on High Energy Physics and Quantum Field Theory (QFTHEP-97), Samara, Russia, September 4-10, 199