SMITHTOWN, N.Y. — Shmuel Blasz died in the Holocaust, but his music has survived.For the first time in the decades since he was killed at Auschwitz, the Hungarian Jewish cantor’s original scores were performed by singers for a live audience.Thursday’s concert at Temple Beth-Shalom in Smithtown was watched hundreds of miles away over the Internet by one of his surviving children, Eva Blasz Egri.Egri had been safeguarding her father’s scores for decades since he died along with her mother and three siblings.The 90-year-old woman’s daughter told Newsday the music provoked mixed feelings for her mother, since she had not heard it since the war.