Another poll confirms that the Massachusetts Senate race is currently shaping up to be one of the closest races in 2012 and could potentially be the race that decides which party controls the chamber. According to a new UMass Lowell-Boston Herald poll of registered voters, incumbent Republican Scott Brown holds a narrow 41 percent to 38 percent lead over Democrat Elizabeth Warren.

Looking at the internals Warren is in slightly better shape than the top line numbers would indicate. The poll found more undecided Democrats than undecided Republicans. As the Warren campaign increases her name recognition, it is likely that most of the undecided Democrats will gravitate to her in the general election.

Brown does extremely well with independents, winning them 48 percent to 29 percent and is even impressively strong among Democrats, getting 16 percent of them compared to Warren’s 65 percent. The only reason the race is so close right now despite Brown’s broad appeal with independents is that the Democratic party holds a huge registration advantage in deep blue Massachusetts.

The poll also tested the Democratic primary and found Warren with an impressive lead over all other Democrats. Warren is currently polling at 36 percent in the primary with all other Democratic hopefuls in single digits. Thomas Conroy is in second with 5 percent, Marisa DeFranco is in third with 4 percent.