"We feel this is the right combination for the World Cup," chairman of selectors Asantha de Mel told AFP soon after the 15-man squad was approved by the sports ministry on Monday.
"The team has got a nice blend of youth and experience. We are well prepared and we feel this team can go all the way to win the World Cup."
Mahela Jayawardene will lead the squad which includes veteran opener Sanath Jayasuriya and spin wizard Muttiah Muralitharan.
The selectors decided on the World Cup squad soon after Sri Lanka recorded a thrilling five-run win over India in the second one-dayer in Rajkot on Sunday.
Sri Lanka lead the four-match series 1-0 after the opening game in Kolkata was abandoned due to rain after 18.2 overs.
Arnold and Silva took the last two batting spots and Kulasekara was included as the fifth member of the pace attack led by the seasoned Chaminda Vaas.
Silva earned a place due to his excellent form in New Zealand in January and Arnold and Kulasekara returned to the squad after good performances for Sri Lanka 'A' on a recent tour of the Caribbean.
De Mel was confident the squad can help Sri Lanka to repeat their World Cup triumph of 1996.
"The side has got firepower at the top of the order and there's a solid middle order too," he said. "Add to that we have the kind of bowlers who can contain and bowl sides out.
"The squad has variation and most players are experienced as well."
Since a tour of India in 2005 when Sri Lanka were routed 1-6 in the one-dayers, Jayawardene's men have won 21 of their 41 one-dayers and six out of 11 Tests, a majority of them away from home.
"We are competing much better overseas," said Jayawardene.
"India actually started our revival. When we lost those six matches badly we had a chat and asked ourselves where we wanted to be in one year's time.
"Today we are in a different situation, performing consistently. We have grown up as a team and we have put a lot of results together."
Sri Lanka are drawn with India, Bangladesh and first-timers Bermuda in group B of the World Cup preliminary league where the top two advance to the second round.
Sri Lanka's World Cup squad:
Mahela Jayawardene (capt), Kumar Sangakkara, Sanath Jayasuriya, Upul Tharanga, Marvan Atapattu, Tillakaratne Dilshan, Russel Arnold, Chamara Silva, Chaminda Vaas, Farveez Maharoof, Lasith Malinga, Dilhara Fernando, Nuwan Kulasekara, Muttiah Muralitharan, Malinga Bandara.