H-->WW as the discovery mode for a light Higgs boson

The production cross section for a m_H=115 GeV, SM Higgs boson in weak boson fusion at the LHC is sizable. However, the branching fraction for H-->WW is expected to be relatively small. The signal, with its two forward jets, is sufficiently different from the main backgrounds that a signal to background ratio of better than 1:1 can nevertheless be obtained, with large enough rate to allow for a 5 sigma signal with 35 fb^{-1} of data. The H-->WW signal in weak boson fusion may thus prove to be the discovery mode for the Higgs boson at the LHC.Comment: 10 pages, 4 figures, uses revte

Finding the Leptonic WWWW Decay Mode of a Heavy Higgs Boson

We reanalyze the extraction of the heavy Higgs boson signal $H\rightarrow W^+W^-\rightarrow \bar\ell\nu,\ell\bar\nu$ $(\ell=e\hbox{ or }\mu)$ from the Standard Model background at hadron supercolliders, taking into account revised estimates of the top quark background. With new acceptance criteria the detection of the signal remains viable. Requiring a forward jet-tag, a central jet-veto, and a large relative transverse momentum of the two charged leptons yields $S/\sqrt B>6$ for one year of running at the SSC or LHC.Comment: LaTex(Revtex), 9 pages, 6 figures (available upon request), MAD/PH/75

Supersymmetry Phenomenology at Hadron Colliders

The phenomenology of a low-energy supersymmetry at hadron colliders is discussed with consideration of the minimal supergravity model, with a large top quark Yukawa coupling at the grand unification mass scale, and gauge mediated symmetry breaking models. Possible supersymmetry interpretations of some unexplained events are mentioned.Comment: 11 pages, Latex2.09, uses sprocl.sty (included) and epsf.sty. 5 postscript figures. Talk presented at COSMO 97: International Workshop on Particle Physics and the Early Universe, Lancaster, UK, Sept. 1997. Postscript file of complete paper also available at http://pheno.physics.wisc.edu/pub/preprints/1998/madph-98-1034.ps.Z or at ftp://pheno.physics.wisc.edu/pub/preprints/1998/madph-98-1034.ps.

Testing the LMA solution with solar neutrinos independently of solar models

We perform a comparative study of two methods of determining the survival probabilities of low, intermediate, and high energy solar neutrinos that emphasizes the general agreement between the Large Mixing Angle (LMA) solution and extant solar neutrino data. The first analysis is oscillation parameter-independent and the second analysis involves an approximate calculation of the survival probabilities in the three energy ranges that depends only on oscillation parameters. We show that future experiments like BOREXino, CLEAN, Heron, LENS and MOON, that measure $pp$ and $^7$Be neutrinos, will facilitate a stringent test of the LMA solution independently of the Standard Solar Model (SSM), without recourse to earth-matter effects. Throughout, we describe the role of SSM assumptions on our results. If the LMA solution passes the test without needing to be modified, it may be possible to establish that $\theta_x$ is nonzero at more than $2\sigma$ assuming the SSM prediction for the $pp$ flux is correct.Comment: Final SNO salt-phase data included in analysis. Version to appear in PL

Supersymmetry vis-a-vis Muon Colliders

The potential of muon colliders to study a low-energy supersymmetry is addressed in the framework of the minimal supergravity model, whose predictions are first briefly surveyed. Foremost among the unique features of a muon collider is s-channel production of Higgs bosons, by which Higgs boson masses, widths, and couplings can be precisely measured to test the predictions of supersymmetry. Measurements of the threshold region cross sections of W^+ W^-, t t-bar, Zh, chargino pairs, slepton and sneutrino pairs will precisely determine the corresponding masses and test supersymmetric radiative corrections. At the high-energy frontier a 3 to 4 TeV muon collider is ideally suited to study heavy scalar supersymmetric particles.Comment: 14 pages, Latex2.09, uses aipproc.sty and espf.sty. 10 postscript figures. Invited talk presented at the Workshop on Physics at the First Muon Collider and at the Front End of a Muon Collider, Fermilab, November 1997. Postscript file of complete paper also available from the UW-Madison Phenomenology preprint archives at ftp://pheno.physics.wisc.edu/pub/preprints/1998/madph-98-1038.ps.Z o

Higgs Physics and Supersymmetry

The quest for the physics underlying the breaking of the electroweak symmetry and the generation of mass is surveyed.Comment: 14 pages, Latex2.09, uses sprocl.sty and epsf.sty, 13 postscript files included. Talk presented at the Richard Arnowitt Fest: A Symposium on Supersymmetry and Gravitation, College Station, Texas, April 1998. Local-no: MADPH-98-106

Neutrino Masses and Mixing at the Millennium

Recent evidence for neutrino oscillations has revolutionized the study of neutrino masses and mixing. This report gives an overview of what we are learning from the neutrino oscillation experiments, the prospects for the near term, and the bright future of neutrino mass studies.Comment: References added. Latex2.09, uses epsf.sty and aipproc.sty, 16 pages, 14 figures. Talk presented at the 5th International Conference on Physics Potential and Development of mu^+ mu^- Colliders, San Francisco, December 199

Heavy quark production via supersymmetric interaction at a neutrino factory

We investigate b-quark production in both charged and neutral current channels through neutrino-nucleon scattering at a neutrino factory, mediated by the lepton flavour violating interactions present in a supersymmetric theory with broken R-parity. Using values of the effctive interaction strengths well below the current and projected experimental bounds, we are still able to predict markedly enhanced event rates, especially for the neutral current events which are not allowed at the lowest order in the standard model (SM). Data from neutrino factories can therefore be used to probe strengths of such interactions to considerably higher precision than what can be envisioned in other experiments.Comment: Few typos are corrected in this versio

Lepton Flavor Violating Era of Neutrino Physics

The physics agenda for future long-baseline neutrino oscillation experiments is outlined and the prospects for accomplishing those goals at future neutrino facilities are considered. Neutrino factories can deliver better reach in the mixing and mass-squared parameters but conventional super-beams with large water or liquid argon detectors can probe regions of the parameter space that could prove to be interesting.Comment: 12 pages, Latex, uses sprocl.sty and epsf.sty. 5 postscript figures. Talk presented at Joint U.S./Japan Workshop On New Initiatives In Lepton Flavor Violation and Neutrino Oscillation With High Intense Muon and Neutrino Sources, Honolulu, Hawaii, October 200