122590503
PROGRESS REPORT FOR A NEW KARLSRUHE-HELSINKI TYPE PION-NUCLEON PARTIAL WAVE ANALYSIS
121630089
Resolution of the multichannel anomaly in the extraction of S-matrix resonance-pole parameters
Within the framework of a mathematically well-defined coupled-channel T-matrix model we have improved the existing multichannel pole-extraction procedure based on the numerical analytic continuation of the channel propagator, and for the first time we present the full set of pole parameters for already published amplitudes. Standard single-channel pole-extraction method (speed plot) was then applied to those amplitudes and resulting sets of T-matrix poles were inspected. The anomaly has been established that in some partial waves the pole values extracted using the standard single-channel methods differ not only from the values obtained using the analytic continuation method, but also change from one reaction to another. Inspired by this peculiarity, we have developed a new single-channel pole-extraction method based solely on the assumption of the partial wave analyticity. Since the speed plot turns out to be the lowest order term of the proposed method, the anomaly is understood and resolved.
115390182
Lambda-Polarization Measurement in pi-p-->K0Lambda in the Framework of `EPECUR' Experiment Proposal
110769680
THE INFLUENCE OF INELASTIC CHANNELS UPON THE POLE STRUCTURE OF PW IN THE COUPLED CHANNEL πN PWA
36126528
PAMELA Satellite Data as a Signal of Non-Thermal Wino LSP Dark Matter
Abstract Satellite and astrophysical data is accumulating that suggests and constrains interpretations of the dark matter of the universe. We argue there is a very well motivated theoretical framework (which existed before data) consistent with the interpretation that dark matter annihilation is being observed by the PAMELA satellite detector. The dark matter is (mainly) the neutral W boson superpartner, the wino. Using the program GALPROP extensively we study the annihilation products and the backgrounds together. A wino mass approximately in the 180–200 GeV range gives a good description of the PAMELA data, with antimatter and gammas from annihilating winos dominating the data below this energy range but not contributing above it. We explain why PAMELA data does not imply no antiproton signal was observed by PAMELA or earlier experiments, and explain why the antiproton analysis was misunderstood by earlier papers. Wino annihilation does not describe the Fermi e + + e − data (except partially below ∼100 GeV). At higher energies we expect astrophysical mechanisms to contribute, and we simply parameterize them without a particular physical interpretation, and check that the combination can describe all the data. We emphasize several predictions for satellite data to test the wino interpretation, particularly the flattening or turndown of the positron and antiproton spectra above 100 GeV. It should be emphasised that most other interpretations require a large rise in the positron and antiproton rates above 100 GeV. We focus on studying this well-motivated and long predicted wino interpretation, rather than comparisons with other interpretations. We emphasize that interpretations also depend very strongly on assumptions about the cosmological history of the universe, on assumptions about the broader underlying theory context, and on propagation of antiprotons and positrons in the galaxy. The winos PAMELA is observing arose from moduli decay or other non-thermal sources rather than a universe that cooled in thermal equilibrium after the big bang. Then it is appropriate to normalize the wino density to the local relic density, and no “boost factors” are needed to obtain the reported PAMELA rates.
16239690
Neutralino Dark Matter from Indirect Detection Revisited
We revisit indirect detection possibilities for neutralino dark matter, emphasizing the complementary roles of different approaches. While thermally produced dark matter often requires large astrophysical "boost factors" to observe antimatter signals, the physically motivated alternative of non-thermal dark matter can naturally provide interesting signals, for example from light wino or Higgsino dark matter. After a brief review of cosmic ray propagation, we discuss signals for positrons, antiprotons, synchrotron radiation and gamma rays from wino annihilation in the galactic halo, and examine their phenomenology. For pure wino dark matter relevant to the LHC, PAMELA and GLAST should report signals.
54967493
Inflation without inflaton(s)
We propose a model for early universe cosmology without the need for fundamental scalar fields. Cosmic acceleration and phenomenologically viable reheating of the universe result from a series of energy transitions, where during each transition vacuum energy is converted to thermal radiation. We show that this 'cascading universe' can lead to successful generation of adiabatic density fluctuations and an observable gravity wave spectrum in some cases, where in the simplest case it reproduces a spectrum similar to slow-roll models of inflation. We also find the model provides a reasonable reheating temperature after inflation ends. This type of model may also be relevant for addressing the smallness of the vacuum energy today.
26247082
Living on a dS brane : effects of KK modes on inflation
We develop a formalism to study non-local higher dimensional effects in braneworld scenarios from a four-dimensional effective theory point of view and check it against the well-known Garriga-Tanaka result in the appropriate limit. We then use this formalism to study the spectrum of density perturbations during inflation as seen from the lower dimensional effective theory. In particular, we find that the gravitational potential is greatly enhanced at short wavelengths. The consequences to the curvature perturbations are nonetheless very weak and will lead to no characteristic signatures on the power spectrum.
35702613
Effective field theory approach to string gas cosmology
We derive the 4D low energy effective field theory for a closed string gas on a time dependent FRW background. We examine the solutions and find that although the Brandenberger–Vafa mechanism at late times no longer leads to radion stabilization, the radion rolls slowly enough that the scenario is still of interest. In particular, we find a simple example of the string inspired dark matter recently proposed by Gubser and Peebles.