particle physics Particle physics or high energy physics is the study of fundamental particles and forces that constitute matter and radiation. The fundamental particles in the universe are classified in the Standard Model as fermions (matter particles) an ...

, a B-factory, or sometimes a

beauty Beauty is commonly described as a feature of objects that makes these objects pleasurable to perceive. Such objects include landscapes, sunsets, humans and works of art. Beauty, together with art and taste, is the main subject of aesthetics, o ...

factory, is a particle

collider A collider is a type of particle accelerator which brings two opposing particle beams together such that the particles collide. Colliders may either be ring accelerators or linear accelerators. Colliders are used as a research tool in particl ...

experiment designed to produce and detect a large number of

B meson In particle physics, B mesons are mesons composed of a bottom antiquark and either an up (), down (), strange () or charm quark (). The combination of a bottom antiquark and a top quark is not thought to be possible because of the top quark' ...

s so that their properties and behavior can be measured with small statistical

uncertainty Uncertainty refers to epistemic situations involving imperfect or unknown information. It applies to predictions of future events, to physical measurements that are already made, or to the unknown. Uncertainty arises in partially observable ...

. Tau leptons and

D meson The D mesons are the lightest particle containing charm quarks. They are often studied to gain knowledge on the weak interaction. The strange D mesons (Ds) were called "F mesons" prior to 1986. Overview The D mesons were discovere ...

s are also copiously produced at B-factories.

History and development

A sort of "prototype" or "precursor" B-factory was the HERA-B experiment at

DESY The Deutsches Elektronen-Synchrotron (English ''German Electron Synchrotron''), commonly referred to by the abbreviation DESY, is a national research center in Germany. It operates particle accelerators used to investigate the structure of mat ...

that was planned to study B-meson physics in the 1990–2000s, before the actual B-factories were constructed/operational. However, usually HERA-B is not considered a B-factory. Two B-factories were designed and built in the 1990s, and they operated from late 1999 onward: the

Belle experiment The Belle experiment was a particle physics experiment conducted by the Belle Collaboration, an international collaboration of more than 400 physicists and engineers, at the High Energy Accelerator Research Organisation (KEK) in Tsukuba, Ibarak ...

at the KEKB collider in

Tsukuba is a city located in Ibaraki Prefecture, Japan. , the city had an estimated population of 244,528 in 108,669 households and a population density of 862 persons per km². The percentage of the population aged over 65 was 20.3%. The total ar ...

, Japan, and the

BaBar experiment The BaBar experiment, or simply BaBar, is an international collaboration of more than 500 physicists and engineers studying the subatomic world at energies of approximately ten times the rest mass of a proton (~10 GeV). Its design was motivat ...

at the

PEP-II SLAC National Accelerator Laboratory, originally named the Stanford Linear Accelerator Center, is a United States Department of Energy National Laboratory operated by Stanford University under the programmatic direction of the U.S. Departme ...

collider at

SLAC SLAC National Accelerator Laboratory, originally named the Stanford Linear Accelerator Center, is a United States Department of Energy National Laboratory operated by Stanford University under the programmatic direction of the U.S. Departme ...

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

, United States. They were both electron-positron colliders with the center of mass energy tuned to the ϒ(4S) resonance peak, which is just above the threshold for decay into two B mesons (both experiments took smaller data samples at different center of mass energies). BaBar prematurely ceased data collection in 2008 due to budget cuts, but Belle ran until 2010, when it stopped data collection both because it had reached its intended integrated luminosity and because construction was to begin on upgrades to the experiment (see below).

Current experiments

Three "next generation" B-factories were to be built in the 2010s and 2020s:

SuperB Superb may refer to: *Škoda Superb car *, nine Royal Navy ships *The Superb The ''Superb'' was used as U.S. President Warren G. Harding's personal Pullman railroad car in a cross-country tour in 1923. After Harding's death, the car returned hi ...

near

Rome , established_title = Founded , established_date = 753 BC , founder = King Romulus ( legendary) , image_map = Map of comune of Rome (metropolitan city of Capital Rome, region Lazio, Italy).svg , map_caption ...

in Italy;

Belle II The BelleII experiment is a particle physics experiment designed to study the properties of B mesons (heavy particles containing a beauty quark) and other particles. BelleII is the successor to the Belle experiment, and commissioned at the Super ...

, an upgrade to Belle, and SuperPEP-II, an upgrade to the PEP-II accelerator. SuperB was canceled, and the proposal for SuperPEP-II was never acted upon. However, Belle II successfully started taking data in 2018 and is currently the only next-generation B-factory in operation. In addition to Belle II there is the

LHCb The LHCb (Large Hadron Collider beauty) experiment is one of eight particle physics detector experiments collecting data at the Large Hadron Collider at CERN. LHCb is a specialized b-physics experiment, designed primarily to measure the paramet ...

-experiment at the LHC (CERN), which started operations in 2010 and studies primarily the physics of bottom-quark containing hadrons, and thus could be understood to be a B-factory of this "next generation." But LHCb is not usually referred to as a B-factory as the experiment and (perhaps more importantly) the corresponding collider (that is, the LHC) are not used solely for the study of b-quark particles but have other purposes beside b-quark physics.

References

{{reflist

External links

BaBar homepage

Belle homepage

Belle II homepage
Experimental particle physics Particle experiments B physics

History and development

Current experiments

See also

References

External links