LSND anomaly from CPT violation in four-neutrino models

The LSND signal for <f>ν¯μ→ν¯e</f> oscillations has prompted supposition that there may be a fourth light neutrino or that CPT is violated. Neither explanation provides a good fit to all existing neutrino data. We examine the even more speculative possibility that a four-neutrino model with CPT violation can explain the LSND effect and remain consistent with all other data. We find that models with a <f>3+1</f> mass structure in the neutrino sector are viable; a <f>2+2</f> structure is permitted only in the antineutrino sector. [Copyright &y& Elsevier]