The Higgs Boson Mass as a Probe of the Minimal Supersymmetric Standard Model

Recently, the LEP collaborations have reported a lower bound on a Standard Model-like Higgs boson of order 89 GeV. We discuss the implications of this bound for the minimal supersymmetric extension of the Standard Model (MSSM). In particular, we show that the lower bound on $\tan\beta$, which can be obtained from the presently allowed Higgs boson mass value, becomes stronger than the one set by the requirement of perturbative consistency of the theory up to scales of order $M_{GUT}$ (associated with the infrared fixed-point solution of the top quark Yukawa coupling) in a large fraction of the allowed parameter space. The potentiality of future LEP2 searches to further probe the MSSM parameter space is also discussed.Comment: 15 pages, 5 figures, LateX, psfi

CPsuperH2.3: an Updated Tool for Phenomenology in the MSSM with Explicit CP Violation

We describe the Fortran code CPsuperH2.3, which incorporates the following updates compared with its predecessor CPsuperH2.0. It implements improved calculations of the Higgs-boson masses and mixing including stau contributions and finite threshold effects on the tau-lepton Yukawa coupling. It incorporates the LEP limits on the processes e^+ e^- to H_i Z, H_i H_j and the CMS limits on H_i to tau^+ tau^- obtained from 4.6/fb of data at a centre-of-mass energy of 7 TeV. It also includes the decay mode H_i to Z gamma and the Schiff-moment contributions to the electric dipole moments of Mercury and Radium225, with several calculational options for the case of Mercury. These additions make CPsuperH2.3 a suitable tool for analyzing possible CP-violating effects in the MSSM in the era of the LHC and a new generation of EDM experimentsComment: 31 pages, 10 eps figures, 7 tables; H to Z gamma and SM BRs included; To appear in CPC; Typos in Eq.(A.2) corrected;The program may be obtained from http://www.hep.man.ac.uk/u/jslee/CPsuperH.html, or by contacting the first author at [email protected]; A comment added after Eq.(15) and a typo in Eq.(A.4) correcte

Large mass splittings between charged and neutral Higgs bosons in the MSSM

We show that large ($> 100$ GeV) mass splittings between the charged Higgs boson ($H^\pm$) and the neutral Higgs bosons ($H^0$ and $A^0$) are possible in the Minimal Supersymmetric Standard Model (MSSM). Such splittings occur when the $\mu$ parameter is considerably larger than the common SUSY scale, $M_{SUSY}$, and have significant consequences for MSSM Higgs searches at future colliders.Comment: 11 pages, LaTex, 5 figures, version to appear in Phys. Lett.

A 125 GeV SM-like Higgs in the MSSM and the γγ\gamma \gamma rate

We consider the possibility of a Standard Model (SM)-like Higgs in the context of the Minimal Supersymmetric Standard Model (MSSM), with a mass of about 125 GeV and with a production times decay rate into two photons which is similar or somewhat larger than the SM one. The relatively large value of the SM-like Higgs mass demands stops in the several hundred GeV mass range with somewhat large mixing, or a large hierarchy between the two stop masses in the case that one of the two stops is light. We find that, in general, if the heaviest stop mass is smaller than a few TeV, the rate of gluon fusion production of Higgs bosons decaying into two photons tends to be somewhat suppressed with respect to the SM one in this region of parameters. However, we show that an enhancement of the photon decay rate may be obtained for light third generation sleptons with large mixing, which can be naturally obtained for large values of $\tan\beta$ and sizable values of the Higgsino mass parameter.Comment: 14 pages, 4 figures. Corrected small typos and added reference

Light Charged Higgs Boson and Supersymmetry

A possible discovery of a relatively light charged Higgs boson H^+ in near future experiments, with a mass M_{H+} ~< 110 GeV, together with the present LEP2 direct limits on the chargino and neutral Higgs sectors, would disfavour the minimal supersymmetric standard model as well as its frequently discussed next-to-minimal supersymmetric extension. We show that a supersymmetric origin can naturally be ascribed to the existence of such a light charged Higgs scalar within the context of the recently introduced minimal nonminimal supersymmetric standard model.Comment: 12 pages, LaTeX file, one reference adde

Single Higgs boson production at future linear colliders including radiative corrections

The next generation of high energy e+ e- linear colliders is expected to operate at \sqrt{s} \gtsim 500 GeV. In this energy range the WW fusion channel dominates the Higgs boson production cross section e+ e- -> \bar\nu \nu h^0/H^0. We calculate the one-loop corrections to this process due to fermion and sfermion loops within the MSSM. We perform a detailed numerical analysis of the total cross section and the distributions of the rapidity, the transverse momentum and the production angle of the Higgs boson. The fermion-sfermion correction is substantial being of the order of -10% and is dominated by the fermion loops. In addition, we explore the possibility of polarized e+ / e- beams. In the so-called "intense coupling" scenario the production of the heavy Higgs boson H^0 is also discussed.Comment: 23 pages, 9 figures, to be published in Nucl. Phys.

Probing Supersymmetric Parameters With Astrophysical Observations

A wide range of techniques have been developed to search for particle dark matter, including direct detection, indirect detection, and collider searches. The prospects for the detection of neutralino dark matter is quite promising for each of these three very different methods. Looking ahead to a time in which these techniques have successfully detected neutralino dark matter, we explore the ability of these observations to determine the parameters of supersymmetry. In particular, we focus on the ability of direct and indirect detection techniques to measure the parameters $\mu$ and $m_A$. We find that $\mu$ can be much more tightly constrained if astrophysical measurements are considered than by LHC data alone. In supersymmetric models within the $A$-funnel region of parameter space, we find that astrophysical measurements can determine $m_A$ to roughly $\pm100$ GeV precision.Comment: Prepared for the 7th international UCLA symposium on sources and detection of dark matter and dark energy in the universe (DM 2006) 2006, Marina del Rey, California, 22-24 Feb 200

Decoupling and the radiatively-corrected MSSM Higgs sector

In the decoupling limit of a non-minimal Higgs sector, the lightest CP-even Higgs boson (h) is indistinguishable from the Standard Model (SM) Higgs boson. In the two-Higgs-doublet sector of the MSSM, the approach to the decoupling limit (for m_A>>m_Z) persists, even in the presence of potentially large (tan(beta)-enhanced) radiative corrections to the hbb coupling. Radiative corrections can also generate an accidental cancellation between tree-level and one-loop terms, resulting in a SM-like Higgs boson for moderate m_A outside the decoupling regime.Comment: 6 pages, 1 figure, LaTeX with npb.sty, talk at RADCOR-2002 - Loops and Legs 2002, Kloster Banz, Germany, 8-13 September 200