[1] INFM, Lab Nazl TASC, I-34012 Trieste, Italy
[2] INFM, Lab Nazl TASC, Lilit Grp, I-34012 Trieste, Italy
[3] Univ Cattolica Sacro Cuore, INFM, I-25121 Brescia, Italy
[4] Univ Cattolica Sacro Cuore, Dipartimento Matemat & Fis, I-25121 Brescia, Italy
[5] Univ Milan, I-20122 Milan, Italy
[6] Politecn Milan, INFM, I-20133 Milan, Italy
[7] Politecn Milan, Dipartimento Ingn Nucl, I-20133 Milan, Italy