STATE HOUSE, BOSTON, OCT. 3, 2011…..U.S. Sen. Scott Brown’s lead over Democrat Elizabeth Warren in a poll of more than 1,000 registered Massachusetts voters is so small that it falls within the survey’s margin of error, resulting in a tie between the Wrentham Republican and the Harvard law professor from Cambridge.

The UMass-Lowell/Boston Herald poll results, released Sunday night in advance of a debate in Lowell Tuesday among Democratic contenders for the seat Brown holds, showed Brown as the choice of 41 percent, with Warren at 38 percent. Brown held a 48-29 percent edge among independents, according to the poll, and more support among Democrats than Warren is attracting so far from Republicans.

The remaining Democratic candidates checked in at 5 percent or lower, with pollsters noting Warren’s rivals on the Democratic side have room to gain since 28 percent of potential Democratic primary voters surveyed said they don’t know whom they’d prefer and 11 percent say they wouldn’t vote for any of the announced candidates. The other Democrats in the race are State Rep. Thomas Conroy, attorney Marisa DeFranco, City Year co-founder Alan Khazei, former lieutenant governor candidate Bob Massie, and engineer Herb Robinson.

Warren’s strong showing came despite another significant poll finding – 37 percent of those surveyed had not even heard of Warren yet. Warren recently returned to Massachusetts after helping the Obama administration build a new consumer protection bureau and is slowing building her public profile.

A campaign source told the News Service Monday that an afternoon event in Lowell scheduled by Warren is centered around an endorsement from U.S. Rep. Niki Tsongas, the only female member of the state’s Congressional delegation.

In hypothetical presidential matchups, Massachusetts voters polled between Sept. 22 and Sept. 28 preferred President Barack Obama over Republican Rick Perry 62-25 and over Mitt Romney 57-33.

Additional poll findings will be released Monday.

Tuesday’s debate at UMass-Lowell begins at 7 p.m. and will be streamed live at www.uml.edu andwww.bostonherald.com. The hashtag on Twitter is #UMLDebate.

With Republicans focused on the nation’s weak economic recovery and hoping to take control of the Senate next year, Democratic Party operatives released a memo Monday morning hyping the Senate race.

“With incumbent Democratic Senators locked in tough-reelection battles around the country, it’s not hard to imagine a scenario where the winner of the Massachusetts Senate race determines which party will control the Senate,” party communications director Kevin Franck wrote in a memo to “interested parties” in which he played up his take on what a Republican-controlled Senate might bring.

Brown was at the State House Monday for a Congressional hearing on fishing industry issues while Gov. Deval Patrick was away from the capitol, attending a Democratic Governors Association meeting in North Carolina.