Precise measurement of the [Lambda][sup 0] and [bar [Lambda]][sup 0] masses and a test of [ital CPT] invariance

Journal Article · Mon Feb 28 04:00:00 EST 1994 · Physical Review Letters; (United States)

DOI:https://doi.org/10.1103/PhysRevLett.72.1322· OSTI ID:5014267

Hartouni, E P; Jensen, D A; Kreisler, M N; Uribe, J ^[1]; Church, M D; Gottschalk, E E; Knapp, B C; Stern, B J; Wiencke, L R ^[2]; Christian, D C; Gutierrez, G; Wehmann, A ^[3]; Avilez, C ^[4]; Forbush, M; Huson, F R; White, J T ^[5]

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1. Department of Physics and Astronomy, University of Massachusetts, Amherst Massachusetts 01003 (United States)
2. Columbia University, Nevis Laboratories, Irvington, New York 10533 (United States)
3. Fermilab, Batavia, Illinois 60510 (United States)
4. Instituto de Fisica, Universidad de Guanajuato, Leon, Guanajuato (Mexico)
5. Department of Physics, Texas A M University, College Station, Texas 77843 (United States)

A precision measurement of the masses of the [Lambda][sup 0] and [bar [Lambda]][sup 0] hyperons is obtained from Gaussian fits to the invariant mass distributions for 20 138 [Lambda][sup 0]'s and 18 309 [bar [Lambda]][sup 0]'s. The Gaussians have standard deviations of 0.49 and 0.51 MeV/[ital c][sup 2] for the [Lambda][sup 0] and [bar [Lambda]][sup 0], respectively. Systematic errors were reduced by calibrating the spectrometer with 60 000 exclusive events containing a [ital K][sub [ital S]][sup 0]. We find [ital M][sub [Lambda]]=1115.678[plus minus]0.006[plus minus]0.006 MeV/[ital c][sup 2] and [ital M][sub [bar [Lambda]]]=1115.690[plus minus]0.008[plus minus]0.006 MeV/[ital c][sup 2]. The [Lambda][sup 0-][bar [Lambda]][sup 0] mass difference testing [ital CPT] invariance is [minus]0.012[plus minus]0.010 MeV/[ital c][sup 2].

• DOE Contract Number: AC02-76CH03000; AS05-87ER40356
• OSTI ID: 5014267
• Journal Information: Physical Review Letters; (United States), Journal Name: Physical Review Letters; (United States) Vol. 72:9; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: English

Related Subjects

662120 -- General Theory of Particles & Fields-- Symmetry
Conservation Laws
Currents & Their Properties-- (1992-)
662410* -- Properties of Baryons & Baryon Resonances-- (1992-)
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANTIBARYONS
ANTIHYPERONS
ANTILAMBDA PARTICLES
ANTIMATTER
ANTIPARTICLES
BARYONS
BOSONS
CPT THEOREM
ELEMENTARY PARTICLES
FERMIONS
HADRONS
HYPERONS
INVARIANCE PRINCIPLES
KAONS
KAONS NEUTRAL
KAONS NEUTRAL SHORT-LIVED
LAMBDA BARYONS
LAMBDA PARTICLES
MASS
MASS DIFFERENCE
MATTER
MEASURING INSTRUMENTS
MESONS
NEUTRAL PARTICLES
PARTICLE PROPERTIES
PARTICLES
PSEUDOSCALAR MESONS
SPECTROMETERS
STRANGE MESONS
STRANGE PARTICLES
TESTING