Cosmological Searches for Photon Velocity Oscillations

We posit a second massless photon, uncoupled to known forms of matter but undergoing Lorentz non-invariant velocity mixing with ordinary photons. Our speculation within a speculation suffers from the sin of implausibility but enjoys the virtue of verifiability. To avoid unacceptable distortion of the well-measured microwave background spectrum, the velocity difference of the photons cannot exceed $\sim10^{-32} c$. Stronger constraints (or observable effects!) can arise from optical measurements of distant sources.Comment: 4 pages, TEX with harvmac macro

Neutrinos and Their Charged Cousins: Are They Secret Sharers?

Masses and mixings of quarks and leptons differ wildly from one another. Thus it is all the more challenging to search for some hidden attribute that they may share.Comment: 6 page

Beating the Standard Model

This report, adapted from my talk at the 1998 Ettore Majorana Subnuclear School at Erice, proffers speculative explanations of the strong CP problem and the existence of cosmic rays beyond the GZK bound. It is based on works done with Sidney Coleman and Howard Georgi.Comment: 8 pages, harvma

Neutrinos with Seesaw Masses and Suppressed Interactions

Mixing between light and heavy neutrino states has been proposed as an explanation (or partial explanation) for the 3-sigma NuTeV anomaly and the 2-sigma departure of the $Z^0$ invisible width from its expected value. I assume herein that neutrino masses and mixings result from the conventional seesaw mechanism involving six chiral neutrino states, the first three being members of weak doublets, the others weak singlets. A finely-tuned choice of both the (bare) Majorana masses and the (Higgs-induced) Dirac masses can fit solar and atmospheric neutrino data and also result in significant (but necessarily flavor-dependent) mixing between singlet and doublet states such as would yield detectable suppression of light neutrino interaction amplitudes. The possibility for this kind of suppressive mixing is constrained by the observed upper limit on radiative muon decay.Comment: 7 pages, harvma

Physics Focus and Fiscal Forces

Two items are reproduced herein: my `Outlook' talk, an amended version of which was presented at the 1991 joint Lepton--Photon and EPS Conference in Geneva, and an Open Letter addressed to HEPAP. One is addressed primarily to the European high--energy physics community, the other to the American. A common theme of these presentations is a plea for the rational allocation of the limited funds society provides for high--energy physics research. If my `loose cannon' remarks may seem irresponsible to some of my colleagues, my silence would be more so.Comment: 11 page

A simple Solution to the Strong CP Problem

We propose a minimal modification of the standard model, remarkable in its simplicity, which may solve the strong CP problem. It employs three Higgs doublets with interactions taken to be invariant under a flavor symmetry. Both CP and the flavor symmetry are softly broken by Higgs boson mass terms. In tree approximation, quark mass matrices are triangular and arg det M vanishes, Radiative corrections yield a tiny and tolerable value of theta-bar.Comment: 4 pages, harvma

Particle Physics in The United States, A Personal View

I present my views on the future of America's program in particle physics. I discuss a variety of experimental initiatives that do have the potential to make transformative impacts on our discipline and should be included in our program, as well as others that do not and should not.Comment: 6 pages, no figure

Atmospheric Neutrino Constraints on Lorentz Violation

Sensitive tests of Lorentz invariance can emerge from the study of neutrino oscillations, particularly for atmospheric neutrinos where the effect is conveniently near-maximal and has been observed over a wide range of energies. We assume these oscillations to be described in terms of two neutrinos with different masses and (possibly) different maximal attainable velocities (MAVs). It suffices to examine limiting cases in which neutrino velocity eigenstates coincide with either their mass or flavor eigenstates. We display the modified mu to tau neutrino transition probability for each case. Data on atmospheric neutrino oscillations at the highest observed energies and pathlengths can yield constraints on neutrino MAV differences (i.e., tests of special relativity) more restrictive than any that have been obtained to date on analogous Lorentz-violating parameters in other sectors of particle physics.Comment: 3 page

A Sinister Extension of the Standard Model to SU(3)XSU(2)XSU(2)XU(1)

This paper describes work done in collaboration with Andy Cohen. In our model, ordinary fermions are accompanied by an equal number `terafermions.' These particles are linked to ordinary quarks and leptons by an unconventional CP' operation, whose soft breaking in the Higgs mass sector results in their acquiring large masses. The model leads to no detectable strong CP violating effects, produces small Dirac masses for neutrinos, and offers a novel alternative for dark matter as electromagnetically bound systems made of terafermions.Comment: 9 pages, adapted from talk at XI Workshop on Neutrino Telescopes, Venic

A Neutrino Mass Matrix with Vanishing μ\mu--μ\mu and τ\tau--τ\tau Entries

We revisit our earlier proposal for the form of the neutrino mass matrix: a two-zero ansatz wherein the CP-violating PMNS phase $\delta$ plays a surprisingly important role. We review its observable consequences and show how our ansatz follows from a softly-broken symmetry (muon number minus tau lepton number) in a see-saw model with three Higgs doublets.Comment: 7 pages, harvma