Oops-Leon is the name given by

particle physicist Particle physics or high energy physics is the study of Elementary particle, fundamental particles and fundamental interaction, forces that constitute matter and radiation. The fundamental particles in the universe are classified in the Standa ...

s to what was thought to be a new subatomic particle "discovered" at

Fermilab Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a United States Department of Energy national laboratory specializing in high-energy particle physics. Since 2007, Fermilab has been opera ...

in 1976. The

E288 experiment E, or e, is the fifth letter and the second vowel letter in the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is ''e'' (pronounced ); plur ...

team, a group of physicists led by

Leon Lederman Leon, Léon (French) or León (Spanish) may refer to: Places Europe * León, Spain, capital city of the Province of León * Province of León, Spain * Kingdom of León, an independent state in the Iberian Peninsula from 910 to 1230 and again f ...

who worked on the E288

particle detector In experimental and applied particle physics, nuclear physics, and nuclear engineering, a particle detector, also known as a radiation detector, is a device used to detect, track, and/or identify ionizing particles, such as those produced by nu ...

, announced that a particle with a

mass Mass is an intrinsic property of a body. It was traditionally believed to be related to the quantity of matter in a physical body, until the discovery of the atom and particle physics. It was found that different atoms and different eleme ...

of about 6.0

GeV GEV may refer to: * ''G.E.V.'' (board game), a tabletop game by Steve Jackson Games * Ashe County Airport, in North Carolina, United States * Gällivare Lapland Airport, in Sweden * Generalized extreme value distribution * Gev Sella, Israeli-Sou ...

, which decayed into an

electron The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no ...

and a positron, was being produced by the Fermilab

particle accelerator A particle accelerator is a machine that uses electromagnetic fields to propel charged particles to very high speeds and energies, and to contain them in well-defined beams. Large accelerators are used for fundamental research in particle ...

. The particle's initial name was the

greek letter The Greek alphabet has been used to write the Greek language since the late 9th or early 8th century BCE. It is derived from the earlier Phoenician alphabet, and was the earliest known alphabetic script to have distinct letters for vowels as ...

Upsilon Upsilon (, ; uppercase Υ, lowercase υ; el, ''ýpsilon'' ) or ypsilon is the 20th letter of the Greek alphabet. In the system of Greek numerals, grc, Υʹ, label=none has a value of 400. It is derived from the Phoenician waw . E ...

(

\Upsilon\,

). After taking further data, the group discovered that this particle did not actually exist, and the "discovery" was named "Oops-Leon" as a

pun A pun, also known as paronomasia, is a form of word play that exploits multiple meanings of a term, or of similar-sounding words, for an intended humorous or rhetorical effect. These ambiguities can arise from the intentional use of homophoni ...

on the original name and the first name of the E288 collaboration leader. The original publication was based on an apparent peak (

resonance Resonance describes the phenomenon of increased amplitude that occurs when the frequency of an applied Periodic function, periodic force (or a Fourier analysis, Fourier component of it) is equal or close to a natural frequency of the system ...

) in a histogram of the invariant mass of electron-positron pairs produced by protons colliding with a stationary

beryllium Beryllium is a chemical element with the symbol Be and atomic number 4. It is a steel-gray, strong, lightweight and brittle alkaline earth metal. It is a divalent element that occurs naturally only in combination with other elements to form m ...

target, implying the existence of a particle with a mass of 6 GeV which was being produced and decaying into two leptons. An analysis showed that there was "less than one chance in fifty" that the apparent resonance was simply the result of a coincidence. Subsequent data collected by the same experiment in 1977 revealed that the resonance had been such a coincidence after all. However, a new resonance at 9.5 GeV was discovered using the same basic logic and greater statistical certainty, and the name was reused (see

Upsilon particle The Upsilon meson () is a quarkonium state (i.e. Flavour (particle physics), flavourless meson) formed from a bottom quark and its antiparticle. It was discovered by the E288 experiment team, headed by Leon Lederman, at Fermilab in 1977, and was t ...

). Today's commonly accepted standard for announcing the discovery of a particle is that the number of observed events is 5 standard deviations (σ) above the expected level of the background. Since for a normal distribution of data, the measured number of events will fall within 5σ over 99.9999% of the time, this means a less than one in a million chance that a statistical fluctuation would cause the apparent resonance. Under this standard, the Oops-Leon "discovery" might have gone unpublished.

References

{{reflist Mesons 1976 in science Error