In this Letter , we propose a new generalized Ricci dark energy ( NGR ) model to unify Ricci dark energy ( RDE ) and XCDM .
Our model can distinguish between RDE and XCDM by introducing a parameter \beta called weight factor .
When \beta = 1 , NGR model becomes the usual RDE model .
The XCDM model is corresponding to \beta = 0 .
Moreover , NGR model permits the situation where neither \beta = 1 nor \beta = 0 .
We then perform a statefinder analysis on NGR model to see how \beta effects the trajectory on the r - s plane .
In order to know the value of \beta , we constrain NGR model with latest observations including type Ia supernovae ( SNe Ia ) from Union2 set ( 557 data ) , baryonic acoustic oscillation ( BAO ) observation from the spectroscopic Sloan Digital Sky Survey ( SDSS ) data release 7 ( DR7 ) galaxy sample and cosmic microwave background ( CMB ) observation from the 7-year Wilkinson Microwave Anisotropy Probe ( WMAP7 ) results .
With Markov Chain Monte Carlo ( MCMC ) method , the constraint result is \beta = 0.08 _ { -0.21 } ^ { +0.30 } ( 1 \sigma ) _ { -0.28 } ^ { +0.43 } ( 2 \sigma ) , which manifests the observations prefer a XCDM universe rather than RDE model .
It seems RDE model is ruled out in NGR scenario within 2 \sigma regions .
Furthermore , we compare it with some of successful cosmological models using AIC information criterion .
NGR model seems to be a good choice for describing the universe .