B-Factory
Encyclopedia
In particle physics
, a B-factory, or sometimes a beauty
factory, is a collider
-based scientific machine designed to produce a large number (of the order of 109) of B meson
s and analyze their properties. The tauons and D meson
s are also copiously produced at B-factories, which allows precise studies of their properties.
Two B-factories were designed and built in the 1990s. They are both based on electron-positron colliders with the centre of mass energy tuned to the ϒ(4S) resonance peak, which is just above the threshold for decay into two B mesons (with short data taking periods at different energies). Of the two, the only one currently running is the Belle experiment
at the KEKB collider in Tsukuba, Japan
. The other one, the BaBar experiment
at the PEP-II collider at SLAC laboratory
in California
, which was assembled in the late 1990s and conducted data taking operations from 1999 till early 2008, is currently being decommissioned.
The B-factories yielded a rich harvest of results, including the first observation of CP violation
outside of the kaon
system, measurements of the CKM parameters |Vub| and |Vcb|, and measurements of purely leptonic B meson decays.
Proposals for next-generation B-factories include the SuperB
designed to be built in Frascati
near Rome
in Italy, and Belle II in Japan.
Particle physics
Particle physics is a branch of physics that studies the existence and interactions of particles that are the constituents of what is usually referred to as matter or radiation. In current understanding, particles are excitations of quantum fields and interact following their dynamics...
, a B-factory, or sometimes a beauty
Bottomness
In physics, bottomness also called beauty, is a flavour quantum number reflecting the difference between the number of bottom antiquarks and the number of bottom quarks that are present in a particle: B^\prime = -Bottom quarks have a bottomness of −1 while bottom antiquarks have a...
factory, is a collider
Collider
A collider is a type of a particle accelerator involving directed beams of particles.Colliders may either be ring accelerators or linear accelerators.-Explanation:...
-based scientific machine designed to produce a large number (of the order of 109) of B meson
B meson
B mesons are mesons composed of a bottom quark or 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 short lifetime...
s and analyze their properties. The tauons and D meson
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 were called the "F mesons" prior to 1986.-Overview:...
s are also copiously produced at B-factories, which allows precise studies of their properties.
Two B-factories were designed and built in the 1990s. They are both based on electron-positron colliders with the centre of mass energy tuned to the ϒ(4S) resonance peak, which is just above the threshold for decay into two B mesons (with short data taking periods at different energies). Of the two, the only one currently running is the Belle experiment
Belle experiment
The Belle experiment is a particle physics experiment conducted by the Belle Collaboration, an international collaboration of more than 400 physicists and engineers investigating CP-violation effects at the High Energy Accelerator Research Organisation in Tsukuba, Ibaraki Prefecture, Japan.The...
at the KEKB collider in Tsukuba, Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
. The other one, the BaBar experiment
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 . Its design was motivated by the investigation of CP violation...
at the PEP-II collider at SLAC laboratory
SLAC National Accelerator Laboratory
The SLAC National Accelerator Laboratory, originally named 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...
in California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
, which was assembled in the late 1990s and conducted data taking operations from 1999 till early 2008, is currently being decommissioned.
The B-factories yielded a rich harvest of results, including the first observation of CP violation
CP violation
In particle physics, CP violation is a violation of the postulated CP-symmetry: the combination of C-symmetry and P-symmetry . CP-symmetry states that the laws of physics should be the same if a particle were interchanged with its antiparticle , and left and right were swapped...
outside of the kaon
Kaon
In particle physics, a kaon is any one of a group of four mesons distinguished by the fact that they carry a quantum number called strangeness...
system, measurements of the CKM parameters |Vub| and |Vcb|, and measurements of purely leptonic B meson decays.
Proposals for next-generation B-factories include the SuperB
SuperB Experiment
SuperB is a high-luminosity electron-positron collider that will be dedicated to elucidating new physics through precision studies of rare or suppressed decays. The collider will be built near Rome, Italy, under the supervision of Istituto Nazionale di Fisica Nucleare...
designed to be built in Frascati
Frascati
Frascati is a town and comune in the province of Rome 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 with science, being the location of several international scientific...
near Rome
Rome
Rome is the capital of Italy and the country's largest and most populated city and comune, with over 2.7 million residents in . The city is located in the central-western portion of the Italian Peninsula, on the Tiber River within the Lazio region of Italy.Rome's history spans two and a half...
in Italy, and Belle II in Japan.
External links
- B Factories in 60 seconds from symmetry magazine