KLOE (or the LOng Experiment) was both an experiment studying ϕ meson decays, and the particle detector used to conduct it. It was located in the DAϕNE collider at the

INFN The Istituto Nazionale di Fisica Nucleare (INFN; "National Institute for Nuclear Physics") is the coordinating institution for nuclear, particle, theoretical and astroparticle physics in Italy. History INFN was founded on 8 August 1951, to furth ...

Frascati Frascati () is a city and ''comune'' in the Metropolitan City of Rome Capital in the Lazio region of central Italy. It is located south-east of Rome, on the Alban Hills close to the ancient city of Tusculum. Frascati is closely associated wit ...

Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical ...

. It ceased operation in 2006 and was replaced by the KLOE-2 detector, which began operation in 2014, and continues to operate to this day.

Etymology

Both the DAϕNE collider and the KLOE detector were named after the two titular characters of the

ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic p ...

play

Daphnis and Chloe ''Daphnis and Chloe'' ( el, Δάφνις καὶ Χλόη, ''Daphnis kai Chloē'') is an ancient Greek novel written in the Roman Empire, the only known work of the second-century AD Greek novelist and romance writer Longus. Setting and styl ...

, written in the second century AD. In the story, the two grow up and fall in love, experiencing various hardships before living

happily ever after Happily Ever After may refer to: Film and television Film * ''Happily Ever After'' (1985 film), a Brazilian romantic drama film directed by Bruno Barreto * ''Happily Ever After'' (1989 film), an animated movie continuing the adventures of Snow ...

. The DAϕNE collider was designed with the KLOE experiment as its primary goal, leading to the two to be named as a pair.

KLOE

The KLOE experiment was the first experiment performed by the DAϕNE collider. It began in ernest when the detector began taking data in 2000 and ended when data collection stopped in 2006. The KLOE detector was designed to witness the decays of mesons that were created by colliding

electrons The electron (, or in nuclear reactions) 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 partic ...

and

positrons The positron or antielectron is the antiparticle or the antimatter counterpart of the electron. It has an electric charge of +1 '' e'', a spin of 1/2 (the same as the electron), and the same mass as an electron. When a positron collides ...

at high speeds to generate large numbers of mesons, of which then decay into the pair, following the second most common decay mode. The detector was cylindrical in shape. It had a length of 6 meters and a

diameter In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints lie on the circle. It can also be defined as the longest chord of the circle. Both definitions are also valid fo ...

of 7 meters and was composed of a drift chamber surrounded by an electromagnetic calorimeter, both of which were kept within a constant

magnetic field A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular to its own velocity and t ...

. The interior drift chamber had a length of 3.3 meters and a diameter of 4 meters, within which it contained 52,000 wires, making it the largest drift chamber ever constructed at the time. The computer interpreting its data was able to calculate reconstructed particle

trajectories A trajectory or flight path is the path that an object with mass in motion follows through space as a function of time. In classical mechanics, a trajectory is defined by Hamiltonian mechanics via canonical coordinates; hence, a complete traj ...

with a precision of within 0.3%. The electromagnetic calorimeter had a length of 4.5 meters and a diameter of 4 meters. It used alternating layers of

lead Lead is a chemical element with the Symbol (chemistry), symbol Pb (from the Latin ) and atomic number 82. It is a heavy metals, heavy metal that is density, denser than most common materials. Lead is Mohs scale of mineral hardness#Intermediate ...

with 15,000 kilometers of scintillating fibers before passing the energy from the fibers through 4880

photomultiplier A photomultiplier is a device that converts incident photons into an electrical signal. Kinds of photomultiplier include: * Photomultiplier tube, a vacuum tube converting incident photons into an electric signal. Photomultiplier tubes (PMTs for s ...

s. It was able to determine the energy released by a given particle to within 15% precision, and was able to distinguish between particles occurring at least 0.2 nano seconds apart, but was limited to the computer's ability to calculate a maximum of 2000 events per second.

KLOE-2

KLOE-2 began taking data in November 2014 and is scheduled to continue taking data until at least 2018. Its first run, Run-I was begun in November 2014 and continued until July 2015, observing a total of 1 billion neutral kaon decays. The second experiment, Run-II is still in progress and aims to reach 5 billion such observations. Its drift chamber has the same dimensions as KLOE. It also uses lead and scintillating fibers and the same number of photomultiplier tubes. It uses a magnetic field strength of 0.52 T.

References

{{reflist Experiments