1 QuickSim - brief introduction - Akiya Miyamoto KEK 22 June 2005 GLD meeting See also

A.Miyamoto, GLD meeting 22 June Components in QuickSim Beam pipe N layers of Vertex Detector M layers of Intermediate Tracker Materials between IT and central tracker Central tracker with L sampling EM Calorimeter in Barrel and End-Cap HD Calorimeter in Barrel and End-Cap Location and sizes of these detectors are specified by input data card Tracker : To get smeared track parameter, a equally-spaced ( N, L) sampling tracker with fixed  r  and  z in solenoid is assumed. Multiple scattering in materials are considered. Energy loss is not considered For IT, only exact hits are saved

A.Miyamoto, GLD meeting 22 June Procedure in QuickSim Start track  At beam pipe : modify track direction by multiple scattering  At 1 st vertex layer:  Estimate the number of vertex hits, then –modify track direction by multiple scattering –Calculate smeared VTX track parameter using the diagonalized error matrix if number of VTX hits > 2.  From 2 nd vertex layer to the support tube ( CDC inner mat. )  Modify track momentum direction based on the effect of MS.  Creates hit in IT, if it traverse IT.  At first meas. Layer of CDC  Estimate the number of CDC hits.  Calculate smeared CDC track parameter, using the diagonalized error matrix  Pivot of CDC track parameters are moved to 1 st layer of VTX, where track parameters of CDC and VTX are averaged with weights given by the error matrixes.  Then pivot of track parameter is moved to IP.

A.Miyamoto, GLD meeting 22 June Limitation of track smearing Error matrix  A term for measurement error  Cyclic trajectory  Parabolic trajectory assuming high mom. Not good for low momentum tracks.  A term for multiple scattering  MS effects in CDC for low momentum tracks  QuickSim resolution was about factor 2 smaller than the results of Geant3 simulation (JLC-I case).

A.Miyamoto, GLD meeting 22 June Generation of Calorimeter signals Tracks are extrapolated to Calorimeter and  Generate signals in EM calorimeter, if e or   Generate signals in HD calorimeter, if hadron  No signals at all in calorimeter, if  or Calorimeter are segmented to small cells. Formula to define lateral spread. Signals collected to the cell: Energy deposit in each cells are smeared according to given resolution parameters.

A.Miyamoto, GLD meeting 22 June Parameters for lateral spread Elemag Cal.Hadron Cal. a1a b1b a2a b2b For hadron Calorimeter: Not compared with data yet!

A.Miyamoto, GLD meeting 22 June Cal Clustering Cal calorimeter: Clustering Algorithm  Find highest energy counter BL1 whose energy larger than ETH.  Neighbor counter BL2 is included if E(BL2) > c1 x E(BL1)  Include BL3 which is neighbour to BL2, if E(BL3) < c2 x E(BL1) and E(BL3) < c3 x E(BL2) Clustering parameters (Eth, c1, c2, c3) : Needs to be tuned to reconstruct single EM particle as single cluster double EM particles as double cluster

A.Miyamoto, GLD meeting 22 June Typical EM tuning: example Two photons are generated with 50mrad separation and efficiency to reconstruct as two clusters are studied as a function of parameters

A.Miyamoto, GLD meeting 22 June Cal. –Track matching Eg – Ec < n  : 1-1 track-cluster match Eg – Ec > n  : Charged track + neutral All connected cells are clustered into a global cluster. If charged track touches a global cluster, total energy of cluster(Eg) and track energy of track(Ec) are compared. Parameter, n, has to be tuned depending on processes. -- small n  ghost neutral cluster -- large n  less observed energy

A.Miyamoto, GLD meeting 22 June Dependance of n : ZH process N=1.0 Mh~117.6 N=3.0 Mh~116.0 N=1.5 Mh~116.8 N=2.5 Mh~116.2 N=2.0 Mh~116.3 Process: e+e-  ZH  X Observed particle masses are plotted. Input Mh=120GeV

A.Miyamoto, GLD meeting 22 June Summary In QuickSim, detector parameters can be modified by a input data card. Correctness of parameters are not guaranteed. Comparison with performance studies by full simulator and parameter tuning are always necessary. Yoshioka san and Fujikawa san are tuning QuickSim for a GLD configuration