Introduction to High Energy Physics

Neutron measurements around a beam dump bombarded by high energy protons and lead ions

“…Although one can expect that this assumption is valid for any projectile, it would be interesting to confirm it by measurements with another ion species. Whilst in a thick target the development of the hadronic cascade results in a variation of the neutron yield with energy as given above, with a thin target the high energy cross-sections vary much slower and are roughly equal to the geometrical value [18]. An experimental investigation of the neutron yield from high energy lead ions on a thin lead target is presently in progress.…”

Search for the Rare Decay $K_L \to \pi^0 \pi^0 \mu^+ \mu^-$

“…Essentially, anytime a state of pure CP within K L or K S decays into a state of different CP, this is referred to as direct CP violation and is denoted by the parameter . According to the Standard Model, direct CP violation arises due to interference between the tree diagram in figure 1.2(i) and the penguin diagram in figure 1.2(ii) [14].…”

Measurement of single top quark production in the tau+jets channnel using boosted decision trees at D0

“…In the comparison, the BDT algorithm (see Section 6 for more about the algorithm) used is provided by the TMVA package 4 . The BDT training parameters are 50 tree cycles (1 original tree + 49 boosting trees), β = 0.5, N min.…”