From @aurora.physics.utoronto.ca:"UIHEP::TKW"@FNALD.FNAL.GOV Tue Nov 17 13:31:50 1992 Received: from aurora.physics.utoronto.ca by cepheid.physics.utoronto.ca id AA28467; Tue, 17 Nov 92 13:31:50 EST Received: from FNALI.FNAL.GOV ([131.225.108.3]) by aurora.physics.utoronto.ca with SMTP id <23345>; Tue, 17 Nov 1992 13:31:50 -0500 Date: Tue, 17 Nov 1992 13:31:29 -0500 From: "UIHEP::TKW"@FNALD.FNAL.GOV Message-Id: <921117123129.20803a8d@FNALD.FNAL.GOV> Subject: Facts about top with M(top) = 130 To: pekka@physics.utoronto.ca X-Vmsmail-To: FNALD::PEKKA,FNALD::CLAUDIOC,FNALD::LISS,FNALD::WESTHUSING Status: R I've studied M(top) = 130 GeV events in the W(--> l+neu) + 4 jet channel to see how well one can reconstruct various quantities such as the W mass from two jets, etc. The JETS banks are corrected with QDJSCO and I require that there be four with Et > 15 GeV. In the first plot below I identify the two partons from the hadronic decay of the W. I then order the corrected JETS banks in Et and identify which jet contains the partons from the hadronic decay of the W. Plot 1 is the JETS order of the leading parton from the W versus the JETS order of the second parton from the W. In plot 1 you see that the partons from the W decay are almost equally likely to appear in any combination of JETS i.e. jet1-jet2, jet1-jet3, etc so one can't safely use the jet ordering to identify which jets come from the W. I next made a plot of the invariant mass of the two JETS which was second closest to the W mass versus the invariant mass of the two JETS banks which was closest to the W mass (plot 2). Plot 2 says that in a top event there is often more than one two jet combination which will come close to the W mass. This is why dynamical likelihood methods are doomed I think. Taken together plots 1 and 2 say that it's difficult to identify the jets from the hadronic decay of the W without more information. If one can identify one jet as a b with a b tag things might get easier though (I'll check). Finally I think unless it's absolutely crucial that an analysis needs to distinguish all the partons in a top event (I doubt that this is ever necessary but this is another argument for why people need to decide the analysis method before deciding on the cuts), I think going to a cone of R=0.4 is a mistake. Apart from the question of whether the monte carlos can handle such a cone size safely, it appears that QDJSCO will not correct JETS to the parton energy correctly for R=0.4. Plots 3-5 show Et(JETS, corrected)/Et(parton) - 1. for the first three leading jets in the top events assuming a cone size of R=0.4. You see that the JETS is under corrected by almost 15% relative to the true parton energy. Plot 6-8 shows the same plot for R=0.7. QDJSCO does a better job correcting the JETS to the true parton energy for a cone of R=0.7. The QDJSCO corrections include out of cone corrections and underlying event corrections for both R=0.4 and R=0.7 cases. 1JET ORDER W PARTON 1 VS 2(W+4JET) HBOOK ID = 482 DATE 17/11/92 NO = 137 CHANNELS 10 U 0 1 2 O 1 N 1234567890123456789012345 V ********************************* OVE * * OVE 24 * * 25 23 * * 24 22 * * 23 21 * * 22 20 * * 21 19 * * 20 18 * * 19 17 * * 18 16 * * 17 15 * * 16 14 * * 15 13 * * 14 12 * * 13 11 * * 12 10 * * 11 9 * * 10 8 * * 9 7 * * 8 6 * * 7 5 * * 6 4 * 3+2 + * 5 3 * 25 422 * 4 2 * + 4 A75 * 3 1 * 5 MFM2+ * 2 * * 1 UND * A 222 * UND ********************************* LOW-EDGE 10 111111111122222 1. 123456789012345678901234 * I I * ENTRIES = 132 PLOT ---------I---------I--------- * SATURATION AT= INFINITY 6 I 110 I * SCALE .,+,2,3,.,., A,B, STATISTICS ---------I---------I--------- * STEP = 1.00 * MINIMUM=0.000E+00 10 I 6 I Plot 1 1INV MASS SEC BEST W VS BEST W(W+4JET) HBOOK ID = 477 DATE 17/11/92 NO = 132 CHANNELS 10 U 0 1 2 O 1 N 1234567890123456789012345 V ********************************* OVE * + + + * OVE 116.8 * + * 25 113.6 * + * 24 110.4 * * 23 107.2 * + * 22 104 * + +3 + * 21 100.8 * + * 20 97.6 * ++ ++ + * 19 94.4 * + +2++ +++ * 18 91.2 * + + 2+ * 17 88 * 23+3++ * 16 84.8 * 36 + * 15 81.6 * 53+ * 14 78.4 * + * 13 75.2 * +4+ * 12 72 * 32+62 * 11 68.8 * ++623+ * 10 65.6 * 2+ + * 9 62.4 * 2+22 4+ + * 8 59.2 * +++ + 2 * 7 56 * + +2 * 6 52.8 * + + + * 5 49.6 * + + + * 4 46.4 * + * 3 43.2 * + * 2 40 * * 1 UND * * UND ********************************* LOW-EDGE 100 111111 10 4444555666777888999000111 1. 0369269258258148147047036 0 0246802468024680246802468 * I 3 I * ENTRIES = 132 PLOT ---------I---------I--------- * SATURATION AT= INFINITY I 129 I * SCALE .,+,2,3,.,., A,B, STATISTICS ---------I---------I--------- * STEP = 1.00 * MINIMUM=0.000E+00 I I Plot 2 1ET (JETS(CORRECTED)/ET PARTON 1) - 1 (R=0.4) HBOOK ID = 456 DATE 17/11/92 NO = 264 6.2 6 --- 5.8 I I 5.6 I I 5.4 I I 5.2 I I 5 I I 4.8 I I 4.6 I I 4.4 I I 4.2 I I 4 - -I I 3.8 I I I 3.6 I I I 3.4 I I I 3.2 I I I 3 I- -I I- 2.8 II I I 2.6 II I I 2.4 II I I 2.2 II I I 2 -- II- I I 1.8 II I I I I 1.6 II I I I I 1.4 II I I I I 1.2 II I I I I 1 --II-I I I I-- - - .8 I I I I I I .6 I I I I I I .4 I I I I I I .2 I I I I I I CHANNELS 10 0 1 2 3 4 5 1 12345678901234567890123456789012345678901234567890 CONTENTS 1. 11221432 34666311 1 1 0 00000000000000000000000000000000000000000000000000 INTEGRAT 10 111112234444444444444444444444444 1. 12467146693951456677778888888888888888 LOW-EDGE -------------------------- 1. 111111 11111 0 22110099887766554433221100011223344556677889900112 0 50505050505050505050505050505050505050505050505050 * ENTRIES = 48 * ALL CHANNELS = 0.4800E+02 * UNDERFLOW = 0.0000E+00 * OVERFLOW = 0.0000E+00 * BIN WID = 0.5000E-01 * MEAN VALUE =-0.1427E+00 * R . M . S = 0.2290E+00 PLOT 3 1ET (JETS(CORRECTED)/ET PARTON 2) - 1 (R=0.4) HBOOK ID = 457 DATE 17/11/92 NO = 269 6.2 6 - - 5.8 I I 5.6 I I 5.4 I I 5.2 I I 5 - I I 4.8 I I I 4.6 I I I 4.4 I I I 4.2 I I I 4 I I I - 3.8 I I I I 3.6 I I I I 3.4 I I I I 3.2 I I I I 3 I- I-I I 2.8 II I I I 2.6 II I I I 2.4 II I I I 2.2 II I I I 2 - -II I I-I- --- 1.8 I I I I I I I 1.6 I I I I I I I 1.4 I I I I I I I 1.2 I I I I I I I 1 - - I I I-I I-I I - - .8 I I I I I I I .6 I I I I I I I .4 I I I I I I I .2 I I I I I I I CHANNELS 10 0 1 2 3 4 5 1 12345678901234567890123456789012345678901234567890 CONTENTS 1. 1 1 2 25316362421222 1 1 0 00000000000000000000000000000000000000000000000000 INTEGRAT 10 111223333344444444444444444444444 1. 11122224446145140268913556666666666667777777 LOW-EDGE -------------------------- 1. 111111 11111 0 22110099887766554433221100011223344556677889900112 0 50505050505050505050505050505050505050505050505050 * ENTRIES = 47 * ALL CHANNELS = 0.4700E+02 * UNDERFLOW = 0.0000E+00 * OVERFLOW = 0.0000E+00 * BIN WID = 0.5000E-01 * MEAN VALUE =-0.1548E+00 * R . M . S = 0.2958E+00 PLOT 4 1ET (JETS(CORRECTED)/ET PARTON 3) - 1 (R=0.4) HBOOK ID = 458 DATE 17/11/92 NO = 274 7.2 7 - 6.8 I 6.6 I 6.4 I 6.2 I 6 I 5.8 I 5.6 I 5.4 I 5.2 I 5 - I 4.8 I I 4.6 I I 4.4 I I 4.2 I I 4 I - I 3.8 I I I 3.6 I I I 3.4 I I I 3.2 I I I 3 I I--I 2.8 I I I 2.6 I I I 2.4 I I I 2.2 I I I 2 - I- - I I - 1.8 I II I I I I 1.6 I II I I I I 1.4 I II I I I I 1.2 I II I I I I 1 - I II-I-I I-- - I- - .8 I I I I I II I .6 I I I I I II I .4 I I I I I II I .2 I I I I I II I CHANNELS 10 0 1 2 3 4 5 1 12345678901234567890123456789012345678901234567890 CONTENTS 1. 1 2 52121433711 1 21 1 0 00000000000000000000000000000000000000000000000000 INTEGRAT 10 11111223333333333333333333333333 1. 1111133801348141233334467777777777777788 LOW-EDGE -------------------------- 1. 111111 11111 0 22110099887766554433221100011223344556677889900112 0 50505050505050505050505050505050505050505050505050 * ENTRIES = 38 * ALL CHANNELS = 0.3800E+02 * UNDERFLOW = 0.0000E+00 * OVERFLOW = 0.0000E+00 * BIN WID = 0.5000E-01 * MEAN VALUE =-0.7105E-01 * R . M . S = 0.3279E+00 PLOT 5 1ET (JETS(CORRECTED)/ET PARTON 1) - 1 (R=0.7) HBOOK ID = 456 DATE 17/11/92 NO = 264 5.2 5 - - - 4.8 I I I 4.6 I I I 4.4 I I I 4.2 I I I 4 I I - -I 3.8 I I I II 3.6 I I I II 3.4 I I I II 3.2 I I I II 3 --I-I-I II- 2.8 I I I I 2.6 I I I I 2.4 I I I I 2.2 I I I I 2 - -I I-I I 1.8 I I I 1.6 I I I 1.4 I I I 1.2 I I I 1 - - I-I I - - .8 I I I I I I .6 I I I I I I .4 I I I I I I .2 I I I I I I CHANNELS 10 0 1 2 3 4 5 1 12345678901234567890123456789012345678901234567890 CONTENTS 1. 1 1 21233535342453 1 1 0 00000000000000000000000000000000000000000000000000 INTEGRAT 10 1112223334444444444444444444444 1. 1111122224570381693594777888889999999999999 LOW-EDGE -------------------------- 1. 111111 11111 0 22110099887766554433221100011223344556677889900112 0 50505050505050505050505050505050505050505050505050 * ENTRIES = 49 * ALL CHANNELS = 0.4900E+02 * UNDERFLOW = 0.0000E+00 * OVERFLOW = 0.0000E+00 * BIN WID = 0.5000E-01 * MEAN VALUE =-0.6684E-01 * R . M . S = 0.2544E+00 PLOT 6 1ET (JETS(CORRECTED)/ET PARTON 2) - 1 (R=0.7) HBOOK ID = 457 DATE 17/11/92 NO = 269 6.2 6 - 5.8 I 5.6 I 5.4 I 5.2 I 5 I 4.8 I 4.6 I 4.4 I 4.2 I 4 -I 3.8 II 3.6 II 3.4 II 3.2 II 3 - -II - 2.8 I I I I 2.6 I I I I 2.4 I I I I 2.2 I I I I 2 - --I I I--I- - 1.8 I I I I I I 1.6 I I I I I I 1.4 I I I I I I 1.2 I I I I I I 1 I-I I I I- -I - - - - .8 I I I I II I I I I .6 I I I I II I I I I .4 I I I I II I I I I .2 I I I I II I I I I CHANNELS 10 0 1 2 3 4 5 1 12345678901234567890123456789012345678901234567890 CONTENTS 1. 21223 34622321 12 1 1 1 1 0 00000000000000000000000000000000000000000000000000 INTEGRAT 10 1111222333333333333333333444444 1. 23570037357023346677777889999000000 LOW-EDGE -------------------------- 1. 111111 11111 0 22110099887766554433221100011223344556677889900112 0 50505050505050505050505050505050505050505050505050 * ENTRIES = 40 * ALL CHANNELS = 0.4000E+02 * UNDERFLOW = 0.0000E+00 * OVERFLOW = 0.0000E+00 * BIN WID = 0.5000E-01 * MEAN VALUE =-0.1625E-01 * R . M . S = 0.3195E+00 PLOT 7 1ET (JETS(CORRECTED)/ET PARTON 3) - 1 (R=0.7) HBOOK ID = 458 DATE 17/11/92 NO = 274 4.1 4 - - 3.9 I I 3.8 I I 3.7 I I 3.6 I I 3.5 I I 3.4 I I 3.3 I I 3.2 I I 3.1 I I 3 - -I I-- 2.9 I II I I 2.8 I II I I 2.7 I II I I 2.6 I II I I 2.5 I II I I 2.4 I II I I 2.3 I II I I 2.2 I II I I 2.1 I II I I 2 - I -II-I I - 1.9 I I I I I 1.8 I I I I I 1.7 I I I I I 1.6 I I I I I 1.5 I I I I I 1.4 I I I I I 1.3 I I I I I 1.2 I I I I I 1.1 I I I I I 1 - - --I-I I I --I - .9 I I I I I I I I I .8 I I I I I I I I I .7 I I I I I I I I I .6 I I I I I I I I I .5 I I I I I I I I I .4 I I I I I I I I I .3 I I I I I I I I I .2 I I I I I I I I I .1 I I I I I I I I I CHANNELS 10 0 1 2 3 4 5 1 12345678901234567890123456789012345678901234567890 CONTENTS 1. 1 1 11213 2342433 112 1 0 00000000000000000000000000000000000000000000000000 INTEGRAT 10 111112223333333333333333333333 1. 1112223467002591581112355666666666666666 LOW-EDGE -------------------------- 1. 111111 11111 0 22110099887766554433221100011223344556677889900112 0 50505050505050505050505050505050505050505050505050 * ENTRIES = 36 * ALL CHANNELS = 0.3600E+02 * UNDERFLOW = 0.0000E+00 * OVERFLOW = 0.0000E+00 * BIN WID = 0.5000E-01 * MEAN VALUE =-0.2639E-01 * R . M . S = 0.2732E+00 PLOT 8