Development of a Testing Suite for Event Biasing in GEANT4

Event biasing techniques are used in simulations to generate rare events efficiently. However, their application in GEANT4 has not fully reached its potential. In order to extend their usage in GEANT4, there must be an environment where users and developers can validate their results. In this report, I introduce a prototype testing suite for different biasing techniques. The suite is built on a modification of an existing GEANT4 biasing example. The radiation protection example consists of concrete cells that are stacked in the direction of a neutron beam. Each cell registers several physics variables, which are in turned stored in a ROOT file. The macros read the variables and plot them on two or three-dimensional histograms, which are then compared with the outcome of a non-biasing case. The report provides several plots that are generated from biasing and non-biasing setups and attempts to explain any discrepancy between them. The plots demonstrate that the results of different biasing techniques agree with that of a full simulation. This suite is the first step toward the making of a generic toolkit for users and developers to test a wider variety of configurations

Search for the Higgs boson decays to a ρ0\rho^0, ϕ\phi, or K∗0^{*0} meson and a photon in proton-proton collisions at s\sqrt{s} = 13 TeV

International audienceThree rare decay processes of the Higgs boson to a $\rho$(770)$^0$, $\phi$(1020), or K$^{*}$(892)$^0$ meson and a photon are searched for using $\sqrt{s}$ = 13 TeV proton-proton collision data collected by the CMS experiment at the LHC. Events are selected assuming the mesons decay into a pair of charged pions, a pair of charged kaons, or a charged kaon and pion, respectively. Depending on the Higgs boson production mode, different triggering and reconstruction techniques are adopted. The analyzed data sets correspond to integrated luminosities up to 138 fb$^{-1}$, depending on the reconstructed final state. After combining various data sets and categories, no significant excess above the background expectations is observed. Upper limits at 95% confidence level on the Higgs boson branching fractions into $\rho$(770)$^0$$\gamma$, $\phi$(1020)$\gamma$, and K$^{*}$(892)$^0\gamma$ are determined to be 3.7 $\times$ 10$^{-4}$, 3.0 $\times$ 10$^{-4}$, and 3.0 $\times$ 10$^{-4}$, respectively. In case of the $\rho$(770)$^0$$\gamma$ and $\phi$(1020)$\gamma$ channels, these are the most stringent experimental limits to date

Search for the Higgs boson decays to a ρ0\rho^0, ϕ\phi, or K∗0^{*0} meson and a photon in proton-proton collisions at s\sqrt{s} = 13 TeV

International audienceThree rare decay processes of the Higgs boson to a $\rho$(770)$^0$, $\phi$(1020), or K$^{*}$(892)$^0$ meson and a photon are searched for using $\sqrt{s}$ = 13 TeV proton-proton collision data collected by the CMS experiment at the LHC. Events are selected assuming the mesons decay into a pair of charged pions, a pair of charged kaons, or a charged kaon and pion, respectively. Depending on the Higgs boson production mode, different triggering and reconstruction techniques are adopted. The analyzed data sets correspond to integrated luminosities up to 138 fb$^{-1}$, depending on the reconstructed final state. After combining various data sets and categories, no significant excess above the background expectations is observed. Upper limits at 95% confidence level on the Higgs boson branching fractions into $\rho$(770)$^0$$\gamma$, $\phi$(1020)$\gamma$, and K$^{*}$(892)$^0\gamma$ are determined to be 3.7 $\times$ 10$^{-4}$, 3.0 $\times$ 10$^{-4}$, and 3.0 $\times$ 10$^{-4}$, respectively. In case of the $\rho$(770)$^0$$\gamma$ and $\phi$(1020)$\gamma$ channels, these are the most stringent experimental limits to date