Giuseppe Roselli (CMS-RPC) Università degli Studi di Bari – INFN RPC Efficiency with Track Reconstruction Giuseppe Roselli

Giuseppe Roselli (CMS-RPC) Università degli Studi di Bari – INFN Muon Reconstruction Four steps:Four steps: 1.Digitization 2.Local Reconstruction 3.Stand Alone Reconstruction 4.Global Reconstruction In the Stand-Alone reconstruction the RPC can be excluded (or DT or CSC) giving the possibility to reconstruct the track on the detector surface and calculate the efficiency. In the Stand-Alone reconstruction the RPC can be excluded (or DT or CSC) giving the possibility to reconstruct the track on the detector surface and calculate the efficiency. Z°-> µ+µ- samples have been used for this analysis. Z°-> µ+µ- samples have been used for this analysis.

Giuseppe Roselli (CMS-RPC) Università degli Studi di Bari – INFN 1- Chamber selection We can see how the chambers are selected in the algorithm without bias:We can see how the chambers are selected in the algorithm without bias: 1.Read Trajectory (not persistent objects, that are deleted at the end of the reconstruction chain and contains all the information on the track propagation  need to run the reconstruction in the same job of analysis) 2.Loop over all the CMS RPC Roll (Barrel + EndCap) 3.Extrapolation of the impact point on each encountered surface 4.Coordinates conversion in the Local Frame 5.Roll selection.

Giuseppe Roselli (CMS-RPC) Università degli Studi di Bari – INFN 2- Efficiency - selection Matching between the extrapolated point and the rechit point, can be calculated residuals distribution, giving the possibility to estimate the RPC resolution and understand which kind of cuts can be applied to decide the efficiency of the single chamber.Matching between the extrapolated point and the rechit point, can be calculated residuals distribution, giving the possibility to estimate the RPC resolution and understand which kind of cuts can be applied to decide the efficiency of the single chamber. Stand-Alone Muon Track RPC extrapolation On surface Residuals Efficiency µ RB1IN RB1out RB2IN RB2out RB3 RB4 x z y Local coordinate

Giuseppe Roselli (CMS-RPC) Università degli Studi di Bari – INFN More rec-hits If there are more than one rec-hit we can select the only one that gives the minimum residual! Best RecHit1 µ 1 µ 2 Best RecHit2

Giuseppe Roselli (CMS-RPC) Università degli Studi di Bari – INFN Parameters We can decide: 1.Kind of track to read: a)StandAloneMuons b)StandAloneMuons + Vertex c)GlobalMuons 2.Set the cut value on the residuals: a)Default cut = 6 cm. 3.Start directly from digi of DT or CSC and RPC. 4.Create the following plots: a)Efficiency b)Residuals c)Real Occupancy and predicted from the track extrapolation d)Residuals vs reconstructed Pt e)Global Residuals and Efficiency

Giuseppe Roselli (CMS-RPC) Università degli Studi di Bari – INFN Results Residuals distribution for all the chambers:

Giuseppe Roselli (CMS-RPC) Università degli Studi di Bari – INFN Pull and error associated to the Rec-Hit To find the functional form of the Resolution, can be investigated the Pull distribution, defined as: If the estimation of σ x on the average value is correct, the Pull distribution must be fitted with a Gaussian curve having a standard deviation of about “ 1 ”.

Giuseppe Roselli (CMS-RPC) Università degli Studi di Bari – INFN Pull Distribution Errors on Rec-Hit overestimated

Giuseppe Roselli (CMS-RPC) Università degli Studi di Bari – INFN Reconstructed Pt Pt distribution calculated in correspondence of the RPC surface.

Giuseppe Roselli (CMS-RPC) Università degli Studi di Bari – INFN GREN Track Reconstruction

Giuseppe Roselli (CMS-RPC) Università degli Studi di Bari – INFN GREN Results Local Efficiency with an average value of about 94% Residuals

Giuseppe Roselli (CMS-RPC) Università degli Studi di Bari – INFN Inefficient cases Real Inefficient case Inefficient case due to the track reconstruction

Giuseppe Roselli (CMS-RPC) Università degli Studi di Bari – INFN Stand Alone Reconstruction The same package can be used also track reconstructed only with the RPC and obtain the “Stand Alone Efficiency”. Status: P. Noli 1.At the moment the RPC seed can be read and from it can be activated the reconstruction chain (there are cases in which it does not works and so the tracks are not reconstructed) (P. Noli)

Giuseppe Roselli (CMS-RPC) Università degli Studi di Bari – INFN Stand Alone options

Giuseppe Roselli (CMS-RPC) Università degli Studi di Bari – INFN RPC Stand Alone Residuals

Giuseppe Roselli (CMS-RPC) Università degli Studi di Bari – INFN RPC Stand Alone Pull Errors on Rec-Hit underestimated

Giuseppe Roselli (CMS-RPC) Università degli Studi di Bari – INFN Work in progress At the moment this algorithm has been tested only on simulated data and a real test can be done with the Cosmic Runs.At the moment this algorithm has been tested only on simulated data and a real test can be done with the Cosmic Runs. The main topic for the future is to evaluate the “intrinsic efficiency” for each chamber using the following method:The main topic for the future is to evaluate the “intrinsic efficiency” for each chamber using the following method: 1.Match between simulated and reconstructed tracks; 2.Calculate the efficiency vs Pt; 3.Calculate the efficiency vs eta.