Exclusive D s Semileptonic decays using kinematic fitting
Exclusive Ds semileptonic decays2 Analysis Techniques e+ e- (1 -- ) D s +* (D s + ) +...D s - (D s -* ) e + and K* 0 (K + - ) e + n SIGNAL SIDE TAGGED SIDE: + CC Event
Exclusive Ds semileptonic decays3 Analysis Techniques Define the beam constrained mass: Cut “loose” on M bc then look at the invariant mass. We do NOT require one candidate per event based on “best” M bc since M bc and the invariant mass are correlated. Evaluate missing mass-squared (MM 2 ) on the signal side:
Exclusive Ds semileptonic decays4 Selection criteria Track Quality Cuts: Hit fraction > 0.5 Good fit |d0|<0.5cm and |Z0|<5.0cm |cosθ| < 0.93 |p| >0.04 GeV Particle ID Both dE/dX & RICH PID if |p| > 0.7GeV, dE/dX PID if |p| < 0.7 PID for the 1st and/or 2 nd kaon. | Mass-PDG|<0.02 GeV PID for Pion and/or kaon. | Mass-PDG|<0.100 GeV e electron ID. |p| > 0.2GeV. F RICH ≥ 0.8
Exclusive Ds semileptonic decays5 Kinematical constraints Mass of the tag is constrained to the D S mass Total of 7 constraints 4 Missing variables in the fit (Energy and Momentum of the ). 2 is then determined for both -tag or -he hypotheses for any legitimate photon candidates.
Exclusive Ds semileptonic decays6 MM 2 resolution improvements Fitted Not fitted
Exclusive Ds semileptonic decays7 Invariant mass of D s tag
Exclusive Ds semileptonic decays8 MM 2 for D s + e + Ds + e + nu K + K - mass [1.010,1.030] GeV MM 2 [GeV 2 ] m [GeV] Inv mass
Exclusive Ds semileptonic decays9 MM 2 for D s + K* 0 e + Ds + e + nu K + p - mass [0.7761,0.9761] GeV Inv mass MM 2 [GeV 2 ]m [GeV]
Exclusive Ds semileptonic decays10 Efficiencies dependences e Effic.Err. w/ PID w/o 1st PID w/o both w/o 2nd PID K* e Effic.Err. w/ PID w/o PID on K
Exclusive Ds semileptonic decays11 Next … Will remove the PID on the K in K*(Kπ). Run on Generic MC. Run on data.