Chronology of Milestone Events in Particle Physics

Chronology of Milestone Events in Particle Physics - ALBRECHT 1987P

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ALBRECHT 1987P

ARGUS collaborations; Albrecht, H. et al.
Observation of B^o- anti-B^o Mixing
Phys. Lett. 192B (1987) 245;

Reprinted in
Heavy Flavours, San Miniato (1987) 145.
Hadrons, Quarks and Gluons, Les Arcs (1987) 51.
R. N. Cahn and G. Goldhaber, The Experimental Foundations of Particle Physics, Cambridge Univ. Press (1991) 369.

Abstracts
Using the ARGUS detector at the DORIS II storage ring we have searched in three different ways for B^o- anti-B^o mixing in Υ(4S) decays. One explicitly mixed event, a decay Υ(4S) →B^o B^o, has been completely reconstructed. Futhermore, we observe a 4.0 standard deviation signal of 24.8 events with like-sign lepton pairs and 3.0 standard deviation signal of 4.1 events containing one reconstructed B^o- anti-B^o and an additional fast l⁺( l)^-. This leads to the conclusion that B^o- anti-B^o mixing is substantial. For the mixing parameter we obtain r = 0.21 ± 0.08.

Accelerator DESY-DORIS-II Detectors ARGUS

Related references
See also
M. Kobayashi and T. Maskawa, Progr. of Theor. Phys. 49 (1973) 652;
Particle Data Group, Review of Particle Properties, M. Aguilar-Benitez, Phys. Lett. 170B (1986) 1;
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ARGUS Coll., H. Albrecht et al., Phys. Lett. 134B (1984) 137;
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Reactions

e⁺ e^– Υ(4S)

Υ(4S) B^o anti-B^o

Υ(4S) B⁺ B^–

Υ(4S) B^o e⁺ X

Υ(4S) B^o μ⁺ X

Υ(4S) anti-B^o e^– X

Υ(4S) 2e^– X

Υ(4S) μ^– e^– X

Υ(4S) 2μ^– X

Υ(4S) 2e⁺ X

Υ(4S) μ⁺ e⁺ X

Υ(4S) 2μ⁺ X

Υ(4S) e^– e⁺ X

Υ(4S) μ^– μ⁺ X

Υ(4S) μ^– e⁺ X

Υ(4S) μ⁺ e^– X

B^o anti-B^o

B^o D^*(2010)^– π⁺

B^o D^*(2010)^– π⁺ π^o

B^o D^*(2010)^– 2π⁺ π^–

B^o D^*(2010)^– e⁺ ν_e

B^o D^*(2010)^– μ⁺ ν_μ

anti-B^o D^*(2010)⁺ π^–

anti-B^o D^*(2010)⁺ π^o π^–

anti-B^o D^*(2010)⁺ π⁺ 2π^–

anti-B^o D^*(2010)⁺ e^– anti-ν_e

anti-B^o D^*(2010)⁺ μ^– anti-ν_μ

D^*(2010)^– anti-D_o π^–

D^*(2010)⁺ D^o π⁺

D^o K^– π⁺

D^o K^– π⁺ π^o

D^o K^– 2π⁺ π^–

D^o anti-K^o π⁺ π^–

anti-D_o K⁺ π^–

anti-D_o K⁺ π^o π^–

anti-D_o K⁺ π⁺ 2π^–

anti-D_o K^o π⁺ π^–

Particles studied

B^o mass

anti-B^o mass

Record comments
First evidence for the B^o- anti-B^o mixing.

New Comments List of Comments

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