Measurement of the b baryon lifetime and branching fractions in Z decays

被引：34

作者：

Barate, R ^{[1
]}

Buskulic, D

Decamp, D

Ghez, P

Goy, G

Lees, JP

Lucotte, A

Minard, MN

Nief, JY

Pietrzyk, B

Casado, MP

Chmeissani, M

Comas, P

Crespo, JM

Delfino, M

Fernandez, E

Fernandez-Bosman, M

Garrido, L

Juste, A

Martinez, M

Merino, G

Miquel, R

Mir, LM

Padilla, C

Park, IC

Pascual, A

Perlas, JA

Riu, I

Sanchez, F

Colaleo, A

Creanza, D

de Palma, M

Gelao, G

Iaselli, G

Maggi, G

Maggi, M

Marinelli, N

Nuzzo, S

Ranieri, A

Raso, G

Ruggieri, F

Selvaggi, G

Silvestris, L

Tempesta, P

Tricomi, A

Zito, G

Huang, X

Lin, J

Ouyang, Q

Wang, T

机构：

[1] CNRS, IN2P3, Phys Particules Lab, F-74019 Annecy Le Vieux, France

[2] Univ Autonoma Barcelona, Inst Fis Altes Energies, E-08193 Barcelona, Spain

[3] Ist Nazl Fis Nucl, Dipartimento Fis, I-70126 Bari, Italy

[4] Acad Sinica, Inst High Energy Phys, Beijing, Peoples R China

[5] CERN, European Lab Particle Phys, CH-1211 Geneva 23, Switzerland

[6] Univ Clermont Ferrand, CNRS, IN2P3, Phys Corpusculaire Lab, F-63177 Clermont Ferrand, France

[7] Niels Bohr Inst, DK-2100 Copenhagen, Denmark

[8] Democritos Nucl Res Ctr, Athens, Greece

[9] Ecole Polytech, CNRS, IN2P3, Lab Phys Nucl & Hautes Energies, F-91128 Palaiseau, France

[10] Univ Edinburgh, Dept Phys, Edinburgh EH9 3JZ, Midlothian, Scotland

[11] Univ Florence, Dipartimento Fis, Ist Nazl Fis Nucl, I-50125 Florence, Italy

[12] Florida State Univ, Supercomp Computat Res Inst, Tallahassee, FL 32306 USA

[13] Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy

[14] Univ Glasgow, Dept Phys & Astron, Glasgow G12 8QQ, Lanark, Scotland

[15] Univ Heidelberg, Inst Hochenergiephys, D-69120 Heidelberg, Germany

[16] Univ London Imperial Coll Sci Technol & Med, Dept Phys, London SW7 2BZ, England

[17] Univ Innsbruck, Inst Expt Phys, A-6020 Innsbruck, Austria

[18] Univ Lancaster, Dept Phys, Lancaster LA1 4YB, England

[19] Johannes Gutenberg Univ Mainz, Inst Phys, D-55099 Mainz, Germany

[20] Fac Sci Luminy, CNRS, IN2P3, Ctr Phys Particles, F-13288 Marseille, France

[21] Univ Milan, Dipartimento Fis, I-20133 Milan, Italy

[22] Ist Nazl Fis Nucl, I-20133 Milan, Italy

[23] Max Planck Inst Phys & Astrophys, D-80805 Munich, Germany

[24] Univ Paris 11, CNRS, IN2P3, Lab Accelerateur Lineaire, F-91405 Orsay, France

[25] Univ Pisa, INFN, Dipartimento Fis, I-56010 Pisa, Italy

[26] Scuola Normale Super Pisa, I-56010 Pisa, Italy

[27] Univ London Royal Holloway & Bedford New Coll, Dept Phys, Egham TW20 0EX, Surrey, England

[28] Rutherford Appleton Lab, Particle Phys Dept, Didcot OX11 0QX, Oxon, England

[29] CEA, DAPNIA, Serv Phys Particles, CE Saclay, F-91191 Gif Sur Yvette, France

[30] Univ Calif Santa Cruz, Inst Particle Phys, Santa Cruz, CA 95064 USA

[31] Univ Sheffield, Dept Phys, Sheffield S3 7RH, S Yorkshire, England

[32] Univ Siegen, Fachbereich Phys, D-57068 Siegen, Germany

[33] Univ Trieste, Dipartmento Fis, I-34127 Trieste, Italy

[34] Ist Nazl Fis Nucl, I-34127 Trieste, Italy

[35] Univ Washington, Seattle, WA 98195 USA

[36] Univ Wisconsin, Dept Phys, Madison, WI 53706 USA

[37] Ist Nazl Fis Nucl, Dipartimento Fis, I-95129 Catania, Italy

[38] Univ Turin, Ist Fis Gen, Turin, Italy

[39] CNR, Ist Cosmogeofis, I-10133 Turin, Italy

[40] Kangnung Natl Univ, Kangnung, South Korea

[41] Univ Barcelona, Barcelona 08208, Spain

[42] Univ Sassari, Ist Matemat & Fis, I-07100 Sassari, Italy

[43] Sungkyunkwan Univ, Suwon 440746, South Korea

来源：

EUROPEAN PHYSICAL JOURNAL C | 1998年 / 2卷 / 02期

关键词：

D O I：

10.1007/s100520050133

中图分类号：

O412 [相对论、场论]; O572.2 [粒子物理学];

学科分类号：

摘要：

Using approximately 4 million hadronic Z decays recorded with the ALEPH detector from 1991 through 1995, the lifetime of the b baryon is measured with three independent methods. From the impact parameter distribution of candidate leptons in 1063 events with Lambda l(-) combinations, the average b baryon lifetime is measured to be 1.20 +/- 0.08 +/- 0.06 ps. From a sample of 193 fully reconstructed Lambda(c)(+) candidates correlated with a lepton and a sample of 46 Lambda l(+)l(-) combinations the Lambda(b) lifetime is measured to be 1.21+/-0.11 ps. The product branching fractions to these final states are Br(b-->Lambda(b)) . Br(Lambda(b) --> Lambda l(-)(v) over bar X) = 0.326 +/- 0.016 +/- 0.039% for the first sample and Br(b --> Lambda(b)) . Br(Lambda(b) --> Lambda(c)(+)l(-)(v) over bar X) = 0.86 +/- 0.07 +/- 0.14% for the second and third samples combined.

引用

页码：197 / 211

页数：15

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