Neutrino flavor ratios as diagnostic of solar WIMP annihilation

We consider the neutrino (and antineutrino) flavors arriving at Earth for neutrinos produced in the annihilation of weakly interacting massive particles (WIMPs) in the Sun's core. Solar-matter effects on the flavor propagation of the resulting \agt GeV neutrinos are studied analytically within a density-matrix formalism. Matter effects, including mass-state level-crossings, influence the flavor fluxes considerably. The exposition herein is somewhat pedagogical, in that it starts with adiabatic evolution of single flavors from the Sun's center, with $\theta_{13}$ set to zero, and progresses to fully realistic processing of the flavor ratios expected in WIMP decay, from the Sun's core to the Earth. In the fully realistic calculation, non-adiabatic level-crossing is included, as are possible nonzero values for $\theta_{13}$ and the CP-violating phase $\delta$. Due to resonance enhancement in matter, nonzero values of $\theta_{13}$ even smaller than a degree can noticeably affect flavor propagation. Both normal and inverted neutrino-mass hierarchies are considered. Our main conclusion is that measuring flavor ratios (in addition to energy spectra) of \agt GeV solar neutrinos can provide discrinination between WIMP models. In particular, we demonstrate the flavor differences at Earth for neutrinos from the two main classes of WIMP final states, namely $W^+ W^-$ and 95% $b \bar{b}$ + 5% $\tau^+\tau^-$. Conversely, if WIMP properties were to be learned from production in future accelerators, then the flavor ratios of \agt GeV solar neutrinos might be useful for inferring $\theta_{13}$ and the mass hierarchy.Comment: 30 pages, including 10 figures and 4 appendice

The cluster environments of radio loud quasars

We have carried out multi-colour imaging of the fields of a statistically complete sample of low-frequency selected radio loud quasars at 0.6<z<1.1, in order to determine the characteristics of their environments. The largest radio sources are located in the field, and smaller steep-spectrum sources are more likely to be found in richer environments, from compact groups through to clusters. This radio-based selection (including source size) of high redshift groups and clusters is a highly efficient method of detecting rich environments at these redshifts. Although our single filter clustering measures agree with those of other workers, we show that these statistics cannot be used reliably on fields individually, colour information is required for this.Comment: 5 pages, 3 figures, contribution to "Tracing Cosmic Evolution with Galaxy Clusters" (Sesto 2001), ASP Conference Serie

Estimate of heating effects in Raman microspectroscopy and the accuracy of stokes/anti-stokes thermometry

Нагрев образца значительно увеличивает неопределенность условий получения спектров в Рамановской микроспектроскопии. В работе теоретически оценен максимальный рост температуры внутри образца при воздействии лазерного излучения. Результат моделирования роста температуры представлен аналитически в виде функции свойств пробы (показатель рефракции, коэффициент абсорбции, теплопроводность), мощности лазера и значения апертуры фокусирующего объектива. Показано, что достигаемая точность определения температуры по соотношению интенсивностей стоксовской и антистоксовских полос может быть оценена теоретически, что имеет большую практическую значимость. Получена функциональная зависимость, связывающая точность определения температуры образца с основными источниками экспериментальных погрешностей. Обсуждены различные практически влияющие факторы, вызывающие ухудшение теоретического отношения dТ/Т

Resolving Phonon Fock States in a Multimode Cavity with a Double-Slit Qubit

We resolve phonon number states in the spectrum of a superconducting qubit coupled to a multimode acoustic cavity. Crucial to this resolution is the sharp frequency dependence in the qubit-phonon interaction engineered by coupling the qubit to surface acoustic waves in two locations separated by $\sim40$ acoustic wavelengths. In analogy to double-slit diffraction, the resulting self-interference generates high-contrast frequency structure in the qubit-phonon interaction. We observe this frequency structure both in the coupling rate to multiple cavity modes and in the qubit spontaneous emission rate into unconfined modes. We use this sharp frequency structure to resolve single phonons by tuning the qubit to a frequency of destructive interference where all acoustic interactions are dispersive. By exciting several detuned yet strongly-coupled phononic modes and measuring the resulting qubit spectrum, we observe that, for two modes, the device enters the strong dispersive regime where single phonons are spectrally resolved.Comment: 9 pages, 8 figures; revised arguments in paragraphs 3 and 8, added Hamiltonian description, and corrected typo