%O © 2006 The American Physical Society %D 2006 %V 97 %L discovery1308526 %I AMERICAN PHYSICAL SOC %N 24 %A N Gabyshev %A K Abe %A K Abe %A I Adachi %A H Aihara %A Y Asano %A V Aulchenko %A T Aushev %A AM Bakich %A U Bitenc %A I Bizjak %A S Blyth %A A Bondar %A A Bozek %A M Bracko %A J Brodzicka %A TE Browder %A P Chang %A Y Chao %A A Chen %A WT Chen %A BG Cheon %A R Chistov %A SK Choi %A Y Choi %A A Chuvikov %A S Cole %A J Dalseno %A M Danilov %A M Dash %A A Drutskoy %A S Eidelman %A Y Enari %A S Fratina %A T Gershon %A G Gokhroo %A B Golob %A A Gorisek %A T Hara %A H Hayashii %A M Hazumi %A T Hokuue %A Y Hoshi %A S Hou %A WS Hou %A YB Hsiung %A T Iijima %A A Imoto %A K Inami %A A Ishikawa %A R Itoh %A M Iwasaki %A Y Iwasaki %A JH Kang %A JS Kang %A SU Kataoka %A N Katayama %A H Kawai %A T Kawasaki %A HR Khan %A H Kichimi %A HJ Kim %A HO Kim %A SK Kim %A SM Kim %A K Kinoshita %A S Korpar %A P Krokovny %A S Kumar %A CC Kuo %A A Kuzmin %A YJ Kwon %A JS Lange %A G Leder %A T Lesiak %A SW Lin %A F Mandl %A T Matsumoto %A Y Mikami %A W Mitaroff %A H Miyake %A H Miyata %A R Mizuk %A T Nagamine %A Y Nagasaka %A E Nakano %A M Nakao %A H Nakazawa %A Z Natkaniec %A S Nishida %A O Nitoh %A S Ogawa %A T Ohshima %A T Okabe %A S Okuno %A SL Olsen %A Y Onuki %A H Ozaki %A H Palka %A CW Park %A H Park %A N Parslow %A LS Peak %A R Pestotnik %A LE Piilonen %A M Rozanska %A H Sagawa %A Y Sakai %A N Sato %A T Schietinger %A O Schneider %A AJ Schwartz %A K Senyo %A R Seuster %A ME Sevior %A H Shibuya %A V Sidorov %A JB Singh %A A Somov %A R Stamen %A S Stanic %A M Staric %A T Sumiyoshi %A SY Suzuki %A O Tajima %A F Takasaki %A K Tamai %A N Tamura %A M Tanaka %A Y Teramoto %A XC Tian %A T Tsuboyama %A T Tsukamoto %A S Uehara %A T Uglov %A K Ueno %A S Uno %A P Urquijo %A G Varner %A KE Varvell %A S Villa %A CH Wang %A MZ Wang %A QL Xie %A BD Yabsley %A A Yamaguchi %A H Yamamoto %A Y Yamashita %A M Yamauchi %A H Yang %A CC Zhang %A J Zhang %A LM Zhang %A ZP Zhang %A V Zhilich %A D Zontar %A Belle Cobbaration %T Study of decay mechanisms in B-->Lambda(+)(c)p pi(-) decays and observation of low-mass structure in the Lambda(+)(c)p system %J PHYS REV LETT %K BELLE %X Using a sample of 152x10(6) B (B) over bar pairs accumulated with the Belle detector at the KEKB e(+)e(-) collider, we study the decay mechanism of three-body charmed decay B-->Lambda(+)(c)(p) over bar pi(-). The intermediate two-body decay B-->Sigma(c)(2455)(0)(p) over bar is observed for the first time with a branching fraction of (3.7 +/- 0.7 +/- 0.4 +/- 1.0)x10(-5) and a statistical significance of 8.4 sigma. We also observe a low-mass enhancement in the (Lambda(+)(c)(p) over bar) system, which can be parametrized as a Breit-Wigner function with a mass of (3.35(-0.02)(+0.01)+/- 0.02) GeV/c(2) and a width of (0.07(-0.03)(+0.04)+/- 0.04) GeV/c(2). We measure its branching fraction to be (3.9(-0.7)(+0.8)+/- 0.4 +/- 1.0)x10(-5) with a statistical significance of 6.2 sigma. The errors are statistical, systematic, and that of the Lambda(+)(c)-> pK(-)pi(+) decay branching fraction.