The NMSSM Solution to the Fine-Tuning Problem, Precision Electroweak Constraints and the Largest LEP Higgs Event Excess

We present an extended study of how the Next to Minimal Supersymmetric Model easily avoids fine-tuning in electroweak symmetry breaking for a SM-like light Higgs with mass in the vicinity of 100\gev, as beautifully consistent with precision electroweak data, while escaping LEP constraints due to the dominance of $h\to aa$ decays with $m_a<2m_b$ so that a\to \tauptaum or jets. The residual $\sim 10$ branching ratio for h\to b\anti b explains perfectly the well-known LEP excess at \mh\sim 100\gev. Details of model parameter correlations and requirements are discussed as a function $\tan(\beta)$. Comparisons of fine-tuning in the NMSSM to that in the MSSM are presented. We also discuss fine-tuning associated with scenarios in which the $a$ is essentially pure singlet, has mass m_a>30\gev, and decays primarily to \gam\gam leading to an h\to aa\to 4\gam Higgs signal.Comment: 26 pages, 37 figures, published version with minor text and reference improvement

On the D0D^0 -- DsD_s lifetime difference and τ→7π+ντ\tau\to 7\pi + \nu_\tau decays

In this paper we discuss some aspects of inclusive decays of charmed mesons and also decays of the $\tau$ lepton into $\nu_\tau + 7\pi$. We find that phase space effects are likely to explain the observed lifetime ratio $\tau(D_s^+) / \tau(D^0)$ = 1.17. In particular one need not appeal to a large annihilation contribution in the inclusive $D^0$ decay which, being absent in $D_s^+$ decays could also contribute to the enhanced $D^0$ decay rate relative to that of the $D_s^+$. Examining a separate problem, we find that the rate for $\tau\to \nu_\tau + 7\pi$ is almost completely dominated by the tiny phase space for the final eight particle state. Using an effective chiral Lagrangian to estimate the matrix element yields a branching ratio into the channel of interest far smaller than the present upper bound.Comment: No figure

The Interplay Between Collider Searches For Supersymmetric Higgs Bosons and Direct Dark Matter Experiments

In this article, we explore the interplay between searches for supersymmetric particles and Higgs bosons at hadron colliders (the Tevatron and the LHC) and direct dark matter searches (such as CDMS, ZEPLIN, XENON, EDELWEISS, CRESST, WARP and others). We focus on collider searches for heavy MSSM Higgs bosons ($A$, $H$, $H^{\pm}$) and how the prospects for these searches are impacted by direct dark matter limits and vice versa. We find that the prospects of these two experimental programs are highly interrelated. A positive detection of $A$, $H$ or $H^{\pm}$ at the Tevatron would dramatically enhance the prospects for a near future direct discovery of neutralino dark matter. Similarly, a positive direct detection of neutralino dark matter would enhance the prospects of discovering heavy MSSM Higgs bosons at the Tevatron or the LHC. Combining the information obtained from both types of experimental searches will enable us to learn more about the nature of supersymmetry.Comment: 22 pages, 28 figure

Summary on tau Leptonic Branching Ratios and Universality

The large samples of tau decays available from CLEO and the four LEP experiment have resulted in new, precise measurements of the leptonic branching ratios of the $\tau$. The experimental techniques to obtain these results are reviewed with special emphasis on the DELPHI measurement. World averages are found to be Be = (17.81 +/- 0.06) % and Bmu = (17.36 +/- 0.06) %. These results are consistent with universality in the charged current couplings to a precision of about 0.25 %. The branching ratio measurements can also be used to constrain the "low energy parameter" eta. It is shown that the sensitivity to eta depends on details of the momentum acceptance for muon identification in the different experiments. Assuming universality in the couplings, the estimate eta = 0.012 +/- 0.024 is obtained.Comment: 10 pages, LaTeX, including 9 figures, uses epsf and espcrc2. Invited talk at the Fifth Intl. Workshop on Tau Lepton Physics, 14-17 September 1998, Santander (Spain

A Biased Review of Tau Neutrino Mass Limits

After a quick review of astrophysically relevant limits, I present a summary of MeV scale tau neutrino mass limits derived from accelerator based experiments. I argue that the current published limits appear to be too consistent, and that we therefore cannot conclude that the tau neutrino mass limit is as low as usually claimed. I provide motivational arguments calling into question the assumed statistical properties of the usual maxumum likelihood estimators, and provide a prescription for deriving a more robust and understandable mass limit.Comment: 9 pages, 5 figures, 2 tables. To appear in the Proceedings of the Sixth International Workshop on Tau Lepton Physics, Sept 18-21 2000, Victoria (Canada

On three-body B decays to charm

I briefly describe the use of the three-body decay modes $B^0 \to D^{(*)-} D^{(*)0} K^+$ to investigate open issues in charmed meson spectroscopy, and of the time dependent $B^0 (\bar {B^0}) (t) \to D^{-} D^{+} \pi^0$ transitions for a measurement of $\cos (2 \beta)$.Comment: LaTeX, 4 pages, 4 figs. Talk at 5th International Conference on Hyperons, Charm and Beauty Hadrons (BEACH 2002), Vancouver, Canada, 25-29 Jun 200

Puzzles of excited charm meson masses

We attempt a comprehensive analysis of the low lying charm meson states which present several puzzles, including the poor determination of masses of several non-strange excited mesons. We use the well-determined masses of the ground states and the strange first excited states to `predict' the mass of the non-strange first excited state in the framework of heavy hadron chiral perturbation theory, an approach that is complementary to the well-known analysis of Mehen and Springer. This approach points to values for the masses of these states that are smaller than the experimental determinations. We provide a critical assessment of these mass measurements and point out the need for new experimental information.Comment: 9 pages, 1 figure, accepted for publication in Physics Letters

CLEO Contributions to Tau Physics

We review many of the contributions of the CLEO experiment to tau physics. Topics discussed are: branching fractions for major decay modes and tests of lepton universality; rare decays; forbidden decays; Michel parameters and spin physics; hadronic sub-structure and resonance parameters; the tau mass, tau lifetime, and tau neutrino mass; searches for CP violation in tau decay; tau pair production, dipole moments, and CP violating EDM; and tau physics at CLEO-III and at CLEO-c.Comment: Invited talk at the Seventh International Workshop on Tau Lepton Physics (TAU02), Santa Cruz, Ca, USA, Sept 2002, 14 pages, LaTeX, 21 eps figure

Radiative M1-decays of heavy-light mesons in the relativistic quark model

Radiative magnetic dipole decays of heavy-light vector mesons into pseudoscalar mesons V -> P\gamma are considered within the relativistic quark model. The light quark is treated completely relativistically, while for the heavy quark the 1/m_Q expansion is used. It is found that relativistic effects result in a significant reduction of decay rates. Comparison with previous predictions and recent experimental data is presented.Comment: 11 pages, 2 figures, few comments added, version to appear in Phys. Lett.