DDecayAlg#
DDecayAlg
is an algorithm used by BESIII to create NTuple
s to be used in charm
analysis (e.g. \(D\to K_S^0 h^+h^-\).
It is located in BesExamples
of BOSS and mainly uses the DTagTool
package to perform
tagged
analysis of D mesons.
DTagTool#
The algorithm starts the DTagTool
algorithm
DTagTool dtagTool;
DTagTool
has information about tagged decays at BESIII, used at the
\(\psi(3770)\to D^0 \bar{D}^0\) decay mode. We can either look at the “single tag” or
“stag” which looks at the decay \(D^0(\bar{D}^0) \to f\) where we include both \(D^0\) and
\(\bar{D}^0\).
Let’s take the \(K_{S}^{0} \pi^+ \pi^-\) decay, which DTagTool
assigns the decay mode
"100"
:
EvtRecDTag * stag = dtagTool.findSTag(100);
This stag
object now has the information relating to the candidate decay
\(D\to K *S^0 \pi^+ \pi^-\) such as \(\Delta E = E* \text{beam} - E_D\):
deltaE = stag->deltaE();
or the tracks from the event
tracks = stag->tracks();