Ερευνητικό υλικό ΕΚΠΑ

DETERMINATION OF ALPHA(S) FOR B-QUARKS AT THE Z(0) RESONANCE

Αγγλικά

The strong coupling constant for b quarks has been determined, and its
flavour independence, as predicted by QCD, investigated. The analysis
involved events with lepton candidates selected from approximately 356
000 hadronic decays of the Z0, collected by the DELPHI detector at LEP
in 1990 and 199 1. A method based on a direct comparison of the
three-jet fraction in a b enriched sample, selected by requiring leptons
with large momenta and transverse momenta, to that of the entire
hadronic sample, illustrated the significant effect of the b quark mass
on the multi-jet cross section, and verified the flavour independence of
the strong coupling constant to an accuracy of +/- 6%. A second
procedure based on a fit to the momentum and transverse momentum spectra
of the lepton candidates in both two-jet and three (or more)-jet event
samples simultaneously determined the b content in each, and, using
second order QCD calculations, gave an absolute measurement of alpha(s)
for b quarks of 0. 1 18 +/- 0.004 (stat.) +/- 0.003 (syst.) +/- 0.008
(scale). A comparison with a, for all quark flavours, as measured from
the three-jet fraction in all hadronic events, further allowed the
coupling strength for b quarks to be expressed in terms relative to that
for udsc quarks, thereby cancelling certain common systematic
uncertainties, and yielded alpha(s)b/alpha(s)udsc = 1.00 +/- 0.04
(stat.) +/- 0.03 (syst.).

1993

ABREU, P
ADAM, W
ADYE, T
AGASI, E
ALEKSAN, R and
ALEKSEEV, GD
ALGERI, A
ALLEN, P
ALMEHED, S
ALVSVAAG, SJ
and AMALDI, U
ANDREAZZA, A
ANTILOGUS, P
APEL, WD and
APSIMON, RJ
ARNOUD, Y
ASMAN, B
AUGUSTIN, JE
AUGUSTINUS,
A
BAILLON, P
BAMBADE, P
BARAO, F
BARATE, R and
BARBIELLINI, G
BARDIN, DY
BARKER, GJ
BARONCELLI, A and
BARRING, O
BARRIO, JA
BARTL, W
BATES, MJ
BATTAGLIA, M
and BAUBILLIER, M
BECKS, KH
BEESTON, CJ
BEGALLI, M and
BEILLIERE, P
BELOKOPYTOV, Y
BELTRAN, P
BENEDIC, D and
BENVENUTI, AC
BERGGREN, M
BERTRAND, D
BIANCHI, F and
BILENKY, MS
BILLOIR, P
BJARNE, J
BLOCH, D
BLYTH, S and
BOCCI, V
BOGOLUBOV, PN
BOLOGNESE, T
BONESINI, M and
BONIVENTO, W
BOOTH, PSL
BORISOV, G
BORNER, H
BOSIO, C
and BOSTJANCIC, B
BOSWORTH, S
BOTNER, O
BOUQUET, B and
BOURDARIOS, C
BOWCOCK, TJV
BOZZO, M
BRAIBANT, S and
BRANCHINI, P
BRAND, KD
BRENNER, RA
BRIAND, H
BRICMAN, C
and BROWN, RCA
BRUMMER, N
BRUNET, JM
BUGGE, L
BURAN, T
and BURMEISTER, H
BUYTAERT, JAMA
CACCIA, M
CALVI, M and
ROZAS, AJC
CAMPION, R
CAMPORESI, T
CANALE, V
CAO, F and
CARENA, F
CARROLL, L
CASO, C
GIMENEZ, MVC
CATTAI, A and
CAVALLO, FR
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CHAN, A
CHARPENTIER, P
and CHAUSSARD, L
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CHELKOV, GA and
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CHOROWICZ, V
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CONTRI, R
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MAESTRO, JC
CZELLAR, S
DAHLJENSEN, E
DALMAGNE,
B
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M
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EKSPONG, G and
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ERSHAIDAT, N
FASSOULIOTIS, D and
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FIRESTONE, A
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FRANEK, B
FRENKIEL, P
FRIES, DC
and FRODESEN, AG
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FURNIVAL, K
and FURSTENAU, H
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GAMBA, D
GARCIA, C
GARCIA, J
and GASPAR, C
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GAVILLET, P
GAZIS, EN
GERBER,
JP
GIACOMELLI, P
GOKIELI, R
GOLOB, B
GOLOVATYUK, VM and
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HAHN, F
HAHN, M
HAIDER, S
HAKANSSON, A and
HALLGREN, A
HAMACHER, K
DEMONCHENAULT, GH
HAO, W
HARRIS,
FJ
HEDBERG, V
HENKES, T
HERNANDEZ, JJ
HERQUET, P and
HERR, H
HESSING, TL
HIETANEN, I
HIGGINS, CO
HIGON, E and
HILKE, HJ
HODGSON, SD
HOFMOKL, T
HOLMES, R
HOLMGREN, SO
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HONORE, PF
HOOPER, JE
HOULDEN, M and
HRUBEC, J
HUET, K
HULTH, PO
HULTQVIST, K
IOANNOU, P and
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JACKSON, JN
JALOCHA, P
JARLSKOG, G
JARRY, P
and JEANMARIE, B
JOHANSSON, EK
JOHNSON, D
JONKER, M and
JONSSON, L
JUILLOT, P
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KALMUS, G
KAPUSTA, F
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KATSOUFIS, EC and
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KESTEMAN, J
KHOMENKO, BA
KHOVANSKI, NN
KING,
B
KJAER, NJ
KLEIN, H
KLOVNING, A
KLUIT, P and
KOCHMEHRIN, A
KOEHNE, JH
KOENE, B
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KORYTOV, AV
KOSTIOUKHINE, V
KOURKOUMELIS, C
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KROLIKOWSKI, J
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KRUPINSKI, W
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MAIO, A
MALTEZOS, A
MANDL, F
MARCO, J and
MARGONI, M
MARIN, JC
MARKOU, A
MARON, T
MARTI, S and
MATHIS, L
MATORRAS, F
MATTEUZZI, C
MATTHIAE, G and
MAZZUCATO, M
MCCUBBIN, M
MCKAY, R
MCNULTY, R
MEOLA, G
and MERONI, C
MEYER, WT
MICHELOTTO, M
MIKULEC, I and
MIRABITO, L
MITAROFF, WA
MITSELMAKHER, GV
MJOERNMARK, U and
MOA, T
MOELLER, R
MOENIG, K
MONGE, MR
MORETTINI, P and
MUELLER, H
MURRAY, WJ
MURYN, B
MYATT, G
NAVARRIA, FL and
NEGRI, P
NICOLAIDOU, R
NIELSEN, BS
NIJJHAR, B and
NIKOLAENKO, V
NILSEN, PES
NISS, P
NOMEROTSKI, A and
OBRAZTSOV, V
OLSHEVSKI, AG
ORAVA, R
OSTANKOV, A and
OSTERBERG, K
OURAOU, A
PAGANONI, M
PAIN, R
PALKA, H and
PAPADOPOULOU, TD
PAPE, L
PARODI, F
PASSERI, A
PEGORARO,
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PENNANEN, J
PERALTA, L
PERNEGGER, H
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PERROTTA, A
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PLASZCZYNSKI, S
PODOBRIN,
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WEIERSTALL, M
WEILHAMMER, P
WERNER,
J
WETHERELL, AM
WICKENS, JH
WILKINSON, GR
WILLIAMS, WSC
and WINTER, M
WITEK, M
WORMSER, G
WOSCHNAGG, K
YAMDAGNI,
N
YEPES, P
ZAITSEV, A
ZALEWSKA, A
ZALEWSKI, P and
ZAVRTANIK, D
ZEVGOLATAKOS, E
ZHANG, G
ZIMIN, NI
ZITO, M
and ZUBERI, R
FUNCHAL, RZ
ZUMERLE, G
ZUNIGA, J

PHYSICS LETTERS B

Elsevier

307

1-2

221-236

https://doi.org/10.1016/0370-2693(93)90213-2

10.1016/0370-2693(93)90213-2

https://pergamos.lib.uoa.gr/uoa/dl/object/3045752