The CMB power spectra are studied for different families of single field new and chaotic inflation models in the effective field theory approach to inflation .
We implement a systematic expansion in 1 / N _ { e } where N _ { e } \sim 50 is the number of e-folds before the end of inflation .
We study the dependence of the observables ( n _ { s } , r and dn _ { s } / d \ln k ) on the degree of the potential ( 2 n ) and confront them to the WMAP3 and large scale structure data : This shows in general that fourth degree potentials ( n = 2 ) provide the best fit to the data ; the window of consistency with the WMAP3 and LSS data narrows for growing n .
New inflation yields a good fit to the r and n _ { s } data in a wide range of field and parameter space .
Small field inflation yields r < 0.16 while large field inflation yields r > 0.16 ( for N _ { e } = 50 ) .
All members of the new inflation family predict a small but negative running -4 ( n + 1 ) \times 10 ^ { -4 } \leq dn _ { s } / d \ln k \leq - 2 \times 10 ^ { -4 } .
( The values of r, n _ { s } , dn _ { s } / d \ln k for arbitrary N _ { e } follow by a simple rescaling from the N _ { e } = 50 values ) .
A reconstruction program is carried out suggesting quite generally that for n _ { s } consistent with the WMAP3 and LSS data and r < 0.1 the symmetry breaking scale for new inflation is | \phi _ { 0 } | \sim 10 ~ { } M _ { Pl } while the field scale at Hubble crossing is | \phi _ { c } | \sim M _ { Pl } .
The family of chaotic models feature r \geq 0.16 ( for N _ { e } = 50 ) and only a restricted subset of chaotic models are consistent with the combined WMAP3 bounds on r, n _ { s } , dn _ { s } / d \ln k with a narrow window in field amplitude around | \phi _ { c } | \sim 15 ~ { } M _ { Pl } .
We conclude that a measurement of r < 0.16 ( for N _ { e } = 50 ) distinctly rules out a large class of chaotic scenarios and favors small field new inflationary models .
As a general consequence , new inflation emerges more favoured than chaotic inflation .