RIKEN Software Meeting Software Update Takashi Hachiya RIKEN 2019/7/2 RIKEN Software Meeting

RIKEN Software Meeting Things Software Update Plan Add SvxPixelHotDeadMap in SvxParManager and SvxDecode Similar maps for Stripixel is not prepared. Join to the CentralArm-Cluster analysis Make Link of Cluster using Central Track. Skipping dead area using Hot &dead map. Making some additional documentation 2019/7/2 RIKEN Software Meeting

RIKEN Software Meeting 2019/7/2 RIKEN Software Meeting

Algorithm of Standalone Tracking Track Finding Track Fitting QuickPt determination Use first 3 points (2 pixel and 1 strip points) Track Fitting W/O the primary vertex to determine the momentum Fit with multi-circles with R (pT). Multiple scattering are taken into account

Algorithm for Track fitting After Track finding using link method Cluster list (link) includes more than 3 clusters 2 Pixel hits More than 1 Stripixel hits. QuickPt determination Use first 3 points (2 pixel and 1 strip points) Determine the center position (Cx, Cy) and radius (R) of the circle which pass through these 3 points. The circle can be determined uniquely. Fitting these cluster list (link) with multi-circles with pT. Calculate Chi-square Try finding the least Chi-Square Using pT from quickPt funciton Try to calculate chi2 using pT, pT+dpT, pT-dpT. (chi0, chi1, chi2) Compare chi0 with chi1 and chi2. If Chi0 > Chi1 -> Chi1 is good (1.5 pT is good) else if Chi0 > Chi2-> Chi2 is good (0.5 pT) is good) Repeat the chi2 comparison with changing pT and dpT until chi2 is minimum Changing pT to pT + dpT Changing dpT to dpT /2 7 times repeat as maximum. If chi2 is minimum with less number of repeat, loop will be break. (chi0 > chi1 && chi0 > chi2 : this condition should never happen) Calculate Log probability Chi2 – determined above NDF = (Ncluster – 2 ) * 2 – 1 : Each point has 2 NDF (R and Z direction) what is -2 ?

QuickPt determination Determine the center of the rotation and its radius The center of rotation (cx, cy) should be on the perpendicular of both the lines of hit 1 and 2 and hit 2 and 3 which pass at the center of the lines. The center position can be determined by sliding along with the red line from the center btw B-D) A(x1, y1) B(x2, y2) D(x3, y3) C(cx, cy) R         The radius is the length betwenn A and C pT (momentum of this plane (x-y plane) is described as follows: pT = 0.003 * R * B. R=radius(cm), B=Field strength (0.9T) , where 0.003 is the speed of light . Constant B-Field is assumed. pc = q * c *R *B [ j] = 0.3 * R * B [GeV] 1[j] = 1/(q=1.6e-19) [eV]

Calculate Chi-Square Definition of Chi-Square X-Y plane NDF=(N-2)^2-1   Definition of Chi-Square   X-Y plane NDF=(N-2)^2-1 N of defined theta for r and z direction p(pT, pz) vectors is defined along with arc1 and arc2 at the crossing point.                    

Calculate Chi-Square 2 Lr12 is 2D distance btw p1 and p2   Lr12 is 2D distance btw p1 and p2 Lz12 is 3D distance btw p1 and p2 Numerator is unit pixel size in phi and z -direction Sqrt(12) – might be Naverage hit pixels in a cluster   Pixel Strip dr23 dr12 L23 L12

calculate Tangent at hit position calculate_simpleTangent Input : 2 hit positions (p1 and p2) pT2 : pT squared determined by quickPT Output Momentum(p) – scalar value Px-py vector at hit postion 1 and 2 Algorithm Recalculate the center position of the circle where both points are on the circles with radius (R = b*pT, b=const) Calculate the momentum vector (pT1 and pT2) at p1 and p2 along with the direction of tangent.     P2 P1       P12