Constraints on time variation of fine structure constant from WMAP-3yr data
نویسنده
چکیده
This paper presents the constraints on the time variation of the fine structure constant at recombination relative to its present value, ∆α = (αrec − α0)/α0, obtained from the analysis of the WMAP-3yr Cosmic Microwave Background (CMB) data, with an additional prior on the Hubble expansion rate from HST Hubble Key Project. I found out that −0.039 < ∆α < 0.010 at 95% C.L., which brings a 30% improvement to the previous limits from WMAP-1yr data. The corresponding recombination redshift, zrec = 1075 +40 −63, shows a delayed recombination epoch compared with the results from WMAP-1yr data.
منابع مشابه
Intracluster Medium through three years of WMAP
Wilkinson Microwave Anisotropy Probe (WMAP) has provided us with the highest resolution all-sky maps of the Cosmic Microwave Background. As a result of thermal Sunyaev-Zel’dovich effect, clusters of galaxies are imprinted as tiny, poorly resolved dips on top of primary CMB anisotropies in these maps. Here, I describe different efforts to extract the physics of Intracluster Medium (ICM) from the...
متن کاملConstraints on Field Theoretical Models for Variation of the Fine Structure Constant
Recent theoretical ideas and observational claims suggest that the fine structure constant α may be variable. We examine a spectrum of models in which α is a function of a scalar field. Specifically, we consider three scenarios: oscillating α, monotonic time variation of α, and time-independent α that is spatially varying. We examine the constraints imposed upon these theories by cosmological o...
متن کاملImplications of Gauge Unification for Time Variation of the Fine Structure Constant
Unification of the gauge couplings would imply that time variations of the fine structure constant are accompanied by calculable and very significant time variations in the QCD scale parameter ΛQCD. Since ΛQCD is the dominant factor in setting the hadron masses, estimates made by simple variations of the fine structure constant may not provide meaningful limits. There may also be related variat...
متن کاملLead-Lag Controllers Coefficients Tuning to Control Fuel Cell Based on PSO Algorithm
One of the most important Fuel cells (FCs) is Proton Exchange Membrane Fuel Cells (PEMFCs). The outputvoltage of this FC depends on current loads. This paper tries to introduce, implement and control the voltage ofPEMFC, during load variations. The output voltage of fuel cell should be constant during load variation. Toachieve this goal, a controller should be designed. Here, the Lead-Lag contr...
متن کاملBekenstein Model and the Time Variation of the Strong Coupling Constant
We propose to generalize Bekenstein model for the time variation of the fine structure “constant” αem to QCD strong coupling constant αS . We find that, except for a “fine tuned” choice of the free parameters, the extension can not be performed trivially without being in conflict with experimental constraints and this rules out αS variability. This is due largely to the huge numerical value of ...
متن کامل