We compute the free energy density for pure non-Abelian gauge theory at high temperature and zero chemical potential. The three-loop result to o (~~) is where T is the temperature, C is the Riemann zeta function, g~ g(,ii)~i'2, ji is the MS renormalization scale, g(p) is the corresponding coupling constant, and d~ and CA are the dimension and Casimir number of the adjoint representation. We examine the sensitivity of this result to the choice of renormalization scale ,ii. We also give a result for the free energy of scalar d4 theory, correcting a result previously given in the literature. PACS number(s): ll.lO.Wx, 12.38.B~ PETER ARNOLD AND CHENGXING ZHAI 50 -
[1] Using NASA's A-Train satellite measurements, we evaluate the accuracy of cloud water content (CWC) and water vapor mixing ratio (H 2 O) outputs from 19 climate models submitted to the Phase 5 of Coupled Model Intercomparison Project (CMIP5), and assess improvements relative to their counterparts for the earlier CMIP3. We find more than half of the models show improvements from CMIP3 to CMIP5 in simulating column-integrated cloud amount, while changes in water vapor simulation are insignificant. For the 19 CMIP5 models, the model spreads and their differences from the observations are larger in the upper troposphere (UT) than in the lower or middle troposphere (L/MT). The modeled mean CWCs over tropical oceans range from $3% to $15Â of the observations in the UT and 40% to 2Â of the observations in the L/MT. For modeled H 2 Os, the mean values over tropical oceans range from $1% to 2Â of the observations in the UT and within 10% of the observations in the L/MT. The spatial distributions of clouds at 215 hPa are relatively well-correlated with observations, noticeably better than those for the L/MT clouds. Although both water vapor and clouds are better simulated in the L/MT than in the UT, there is no apparent correlation between the model biases in clouds and water vapor. Numerical scores are used to compare different model performances in regards to spatial mean, variance and distribution of CWC and H 2 O over tropical oceans. Model performances at each pressure level are ranked according to the average of all the relevant scores for that level.Citation: Jiang, J. H., et al. (2012), Evaluation of cloud and water vapor simulations in CMIP5 climate models using NASA "A-Train" satellite observations,
We compute the free energy density F for gauge theories, with fermions, at high temperature and zero chemical potential. In the expansion, we determine c ′ 5 and c 5 analytically by calculating two-and three-loop diagrams. The g 5 term constitutes the first correction to the g 3 term and is for the non-Abelian case the last power of g that can be computed within perturbation theory.We find that the g 5 term receives no contributions from overlapping double-frequency sums and that c ′ 5 vanishes.
We compute the free energy density for gauge theories, with fermions, at high temperature and zero chemical potential. Specifically, we analytically compute the free energy through O(g 4 ), which requires the evaluation of threeloop diagrams. This computation extends our previous result for pure gauge QCD.
We obtained spectra in the wavelength range λ = 995-1769 nm of all four known planets orbiting the star HR 8799. Using the suite of instrumentation known as Project 1640 on the Palomar 5 m Hale Telescope, we acquired data at two epochs. This allowed for multiple imaging detections of the companions and multiple extractions of low-resolution (R ∼ 35) spectra. Data reduction employed two different methods of speckle suppression and spectrum extraction, both yielding results that agree. The spectra do not directly correspond to those of any known objects, although similarities with L and T dwarfs are present, as well as some characteristics similar to planets such as Saturn. We tentatively identify the presence of CH 4 along with NH 3 and/or C 2 H 2 , and possibly CO 2 or HCN in varying amounts in each component of the system. Other studies suggested red colors for these faint companions, and our data confirm those observations. Cloudy models, based on previous photometric observations, may provide the best explanation for the new data presented here. Notable in our data is that these presumably co-eval objects of similar luminosity have significantly different spectra; the diversity of planets may be greater than previously thought. The techniques and methods employed in this paper represent a new capability to observe and rapidly characterize exoplanetary systems in a routine manner over a broad range of planet masses and separations. These are the first simultaneous spectroscopic observations of multiple planets in a planetary system other than our own.
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