Brane curvature and supernovae Ia observations

Inter-University Centre for Astronomy and Astrophysics,Post Bag 4, Ganeshkhind, Pune-411 007, INDIA.It is well known that modifications to the Friedmann equation on a warped brane in an anti deSitter bulk do not provide any low energy distinguishing feature from standard cosmology. However,addition of a brane curvature scalar in the action produces effects which can serve as a distinctivefeature of brane world scenarios and can be tested with observations. The fitting of such a modelwith supernovae Ia data (including SN 1997ff at z ≈ 1.7) comes out very well and predicts anaccelerating universe.