126 research outputs found
Neutrino Masses, Leptogenesis, and Unification in the Absence of Low Energy Supersymmetry
We explore generating the dimension five operator leading to neutrino masses
by integrating out heavy SU(2)_L triplet fermions. We exhibit a model that has
a neutrino mass matrix consistent with observations. In addition, the model is
capable of producing the observed baryon asymmetry, and unification can be
achieved without dangerous proton decay. Supersymmetry can be broken at the
fundamental scale with no supersymmetric signal at low energies.Comment: 26 pages, 3 figures, typos corrected and references added, published
in JHE
Flux Tube Spectra from Approximate Integrability at Low Energies
We provide a detailed introduction to a method we recently proposed for
calculating the spectrum of excitations of effective strings such as QCD flux
tubes. The method relies on the approximate integrability of the low energy
effective theory describing the flux tube excitations and is is based on the
Thermodynamic Bethe Ansatz (TBA). The approximate integrability is a
consequence of the Lorentz symmetry of QCD. For excited states the convergence
of the TBA technique is significantly better than that of the traditional
perturbative approach. We apply the new technique to the lattice spectra for
fundamental flux tubes in gluodynamics in D=3+1 and D=2+1, and to k-strings in
gluodynamics in D=2+1. We identify a massive pseudoscalar resonance on the
world sheet of the confining strings in SU(3) gluodynamics in D=3+1, and
massive scalar resonances on the world sheet of k=2,3 strings in SU(6)
gluodynamics in D=2+1.Comment: 44 pages, 19 figures, v2: references added, to appear in special
issue of JETP dedicated to Valery Rubakov's 60th birthda
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