Download or read book Measurement of Branching Fractions of Rare Semi-leptonic Ds Decays Ds → ; Π ; 0 L Ν ; , Ds → ; Ρ ; L Ν ; , Ds → ; Ks L Ν ; (near ϒ ; (4s), ϒ ; (5s)) At Belle written by Sudeshna Ganguly and published by . This book was released on 2014 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: In Particle physics, a flavor-less meson whose constituents are a quark and an anti-quark is known as quarkonium. Mesons which are formed by a bound state of charm quark and anti-charm quark are known as charmonium states. Different inspections of exotic charmonium states have been understood as 4-quark states. Charmonium states are produced via e+e− annihilation. We search at Belle, based on 119000 tagged events in the Υ (4S) and Υ (5S) energy regions, to look for Ds → π0 l ν, Ds →ρ l ν, Ds →Ks l ν ; considering the electron candidates as well the heavy electron counterpart muon candidates as the leptons. The reconstruction of e+ e- → cc ̅ containing Ds meson events proceeds in two steps. In the first step the inclusive Ds events are reconstructed and in the second step we look for the exclusive decays of our interests. We intend to probe the 4-quark content of Ds by looking for decays Ds → π0 l ν, Ds →ρ l ν. Also we look for Ds →Ks l ν decay because it is a Cabibbo suppressed decay and Ks shares the same final states with ρ. The Ds →Ks l ν is the world's best. Our final results are presented and discussed.