HERA-B
Encyclopedia
HERA-B was an innovative, but ultimately unsuccessful, particle physics
detector of the HERA
accelerator at DESY
.
Its primary aim was to measure CP violation
in the decays of heavy B-mesons in the late 1990s, several years ahead of the Large Hadron Collider
and B Factory programs. Unlike most particle physics detectors, the particles were produced not by colliding two circulating beams head-on, nor by slamming the beam into a stationary target, but by moving a thin wire target directly into the waste 'halo' of the circulating proton beam of the HERA
accelerator. The beam was unaffected by this 'scraping' but the collision rate produced could be made extremely high, around 5 to 10 million interactions per second (5-10 MHz). A novel scheme for moving the wires and the vertex detectors very close to the beam (less than one centimetre), using a vacuum chamber and motorised 'arms', had to be developed.
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...
detector of the HERA
Hera
Hera was the wife and one of three sisters of Zeus in the Olympian pantheon of Greek mythology and religion. Her chief function was as the goddess of women and marriage. Her counterpart in the religion of ancient Rome was Juno. The cow and the peacock were sacred to her...
accelerator at DESY
DESY
The DESY is the biggest German research center for particle physics, with sites in Hamburg and Zeuthen....
.
Its primary aim was to measure 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...
in the decays of heavy B-mesons in the late 1990s, several years ahead of the Large Hadron Collider
Large Hadron Collider
The Large Hadron Collider is the world's largest and highest-energy particle accelerator. It is expected to address some of the most fundamental questions of physics, advancing the understanding of the deepest laws of nature....
and B Factory programs. Unlike most particle physics detectors, the particles were produced not by colliding two circulating beams head-on, nor by slamming the beam into a stationary target, but by moving a thin wire target directly into the waste 'halo' of the circulating proton beam of the HERA
Hera
Hera was the wife and one of three sisters of Zeus in the Olympian pantheon of Greek mythology and religion. Her chief function was as the goddess of women and marriage. Her counterpart in the religion of ancient Rome was Juno. The cow and the peacock were sacred to her...
accelerator. The beam was unaffected by this 'scraping' but the collision rate produced could be made extremely high, around 5 to 10 million interactions per second (5-10 MHz). A novel scheme for moving the wires and the vertex detectors very close to the beam (less than one centimetre), using a vacuum chamber and motorised 'arms', had to be developed.