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KEKB, the B-Factory Accelerator at KEK, Positrons Circulate at Near the Speed-Of-Light in Opposite

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KEKB, the B-Factory Accelerator at KEK, Positrons Circulate at Near the Speed-Of-Light in Opposite The world’ The KEKB The KEKB Accelerator world history Improvements in the power of KEKB Accelerator world history Improvements in the power of KEKB Installation of crab cavities Installation of crab cavities y y 34 34 1034 2.0 Peak Luminosity 2.11×10 1034 2.0 Peak Luminosity 2.11×10 ] ] -1 -1 B-Factory s B-Factory s -2 -2 ) 1.5 ) 1.5 -1 -1 cm cm s s 33 34 33 34 A Double-Ring Collider Delivering the World’s Highest Luminosity -2 10 1.0 A Double-Ring Collider Delivering the World’s Highest Luminosity -2 10 1.0 [×10 [×10 0.5 0.5 ak Luminosity in a Da ak Luminosity in a Da s most power 1032 1032 Pe 0 Pe 0 2000 LER 2000 LER y HER y HER The world’s most 31 1500 The world’s most 31 1500 10 10 ak Luminosity (cm 1000 ak Luminosity (cm 1000 Pe Pe 30 30 10 [mA] 500 10 [mA] 500 advanced collider. DCI advanced collider. DCI 0 0 ak Currents in a Da ak Currents in a Da 29 2000 2002 2004 2006 2008 2010 29 2000 2002 2004 2006 2008 2010 10 Pe 10 Pe 1971 1976 1981 1986 1991 1996 2001 2006 2011 1971 1976 1981 1986 1991 1996 2001 2006 2011 KEKB is a particle accelerator that produces a great number normal-conducting radio-frequency cavities called ARES KEKB is a particle accelerator that produces a great number normal-conducting radio-frequency cavities called ARES The graph shows peak luminosity (top) and integrated luminosity (bottom) The graph shows peak luminosity (top) and integrated luminosity (bottom) of pairs of B mesons and anti-B mesons by colliding (Accelerator Resonantly coupled with Energy Storage). KEKB’s luminosity surpassed that of its rival B-Factory PEP-II in the U.S. of pairs of B mesons and anti-B mesons by colliding (Accelerator Resonantly coupled with Energy Storage). KEKB’s luminosity surpassed that of its rival B-Factory PEP-II in the U.S. from the start of the experiment in 1999 until December 2009. All luminosity from the start of the experiment in 1999 until December 2009. All luminosity in April 2001, and has been recording new world records ever since. in April 2001, and has been recording new world records ever since. electrons and positrons -- thus the name, “B-Factory.” An Another key to higher luminosity is to focus the beams as world records are held by KEKB. electrons and positrons -- thus the name, “B-Factory.” An Another key to higher luminosity is to focus the beams as world records are held by KEKB. electron ring and a positron ring are installed inside KEKB’s tightly as possible. KEKB utilizes superconducting magnets electron ring and a positron ring are installed inside KEKB’s tightly as possible. KEKB utilizes superconducting magnets circular tunnel, which is 3 kilometers in circumference and to compress the beam size down to 110 micrometers in circular tunnel, which is 3 kilometers in circumference and to compress the beam size down to 110 micrometers in 11 meters underground. In these rings, electrons and width, and 2 micrometers in height at the collision point. 11 meters underground. In these rings, electrons and width, and 2 micrometers in height at the collision point. positrons circulate at near the speed-of-light in opposite KEKB, the B-Factory accelerator at KEK, positrons circulate at near the speed-of-light in opposite direction at energies of 8 billion electron-Volts and 3.5 KEKB was upgraded by installing the world’s first crab ful accelerator produces high luminosity colliding beams direction at energies of 8 billion electron-Volts and 3.5 KEKB was upgraded by installing the world’s first crab billion electron-Volts, respectively. The two beams collide at cavities in February 2007, and skew sextupole magnets in Discovery of CP Violation in B Meson Decays for the Belle experiment. The Belle billion electron-Volts, respectively. The two beams collide at cavities in February 2007, and skew sextupole magnets in Discovery of CP Violation in B Meson Decays experiment has achieved many notable the interaction point, where the Belle detector is installed March 2009. As the result, KEKB achieved a luminosity of In 2001, the Belle experiment at KEKB discovered a violation and the degree of the CP violation agrees with the prediction the interaction point, where the Belle detector is installed March 2009. As the result, KEKB achieved a luminosity of In 2001, the Belle experiment at KEKB discovered a violation and the degree of the CP violation agrees with the prediction 34 -2 -1 scientific results, including the experimental 34 -2 -1 to observe the particle interactions. 2.11×10 cm s in June 2009, breaking its own world of the charge-parity symmetry (CP violation) in B meson decays. made by the Kobayashi-Maskawa Theory. to observe the particle interactions. 2.11×10 cm s in June 2009, breaking its own world of the charge-parity symmetry (CP violation) in B meson decays. made by the Kobayashi-Maskawa Theory. confirmation orf the Nobel Physics record again. B mesons decay via various decay modes. In one mode (for In other B meson decay modes, physicists are conducting record again. B mesons decay via various decay modes. In one mode (for In other B meson decay modes, physicists are conducting example, B → J/psi and Ks mesons), when a B meson decays measurement to look for “direct CP violation.” In the mode in Prize-winning Kobayashi-Maskawa theory example, B → J/psi and Ks mesons), when a B meson decays measurement to look for “direct CP violation.” In the mode in One measure of the performance of a collider is a quantity One measure of the performance of a collider is a quantity physicists can measure the decay times of the B meson and which a B meson decays into a pair of charged kaon and charged (2008). (Read: Discovery of CP violation in B physicists can measure the decay times of the B meson and which a B meson decays into a pair of charged kaon and charged called luminosity. The rate of particle interactions, such as The high luminosity generated a large amount of collision anti-B meson that were created as a pair. The difference in the pion, the numbers of B meson decay events and anti-B meson called luminosity. The rate of particle interactions, such as The high luminosity generated a large amount of collision anti-B meson that were created as a pair. The difference in the pion, the numbers of B meson decay events and anti-B meson meson decays) the production of B-mesons and anti-B mesons, is data. The Belle group found evidence for the violation of decay times is then plotted for many B meson decays (the left decays event differ. (In the right figure, the peaks show the the production of B-mesons and anti-B mesons, is data. The Belle group found evidence for the violation of decay times is then plotted for many B meson decays (the left decays event differ. (In the right figure, the peaks show the figure: blue). The distribution changes when the decay time numbers of decay events in this particular decay mode.) This figure: blue). The distribution changes when the decay time numbers of decay events in this particular decay mode.) This proportional to the luminosity. Thus, in order to study rare charge-parity symmetry (CP violation) in B meson decays, differences are plotted for anti-B meson decays, versus for B provides evidence for a new type of CP violation independent of proportional to the luminosity. Thus, in order to study rare charge-parity symmetry (CP violation) in B meson decays, differences are plotted for anti-B meson decays, versus for B provides evidence for a new type of CP violation independent of events, scientists need to produce high luminosity providing experimental confirmation for the meson decays (the left figure: red). This is called CP violation, the CP violation found in the left figure. events, scientists need to produce high luminosity providing experimental confirmation for the meson decays (the left figure: red). This is called CP violation, the CP violation found in the left figure. collisions. Kobayashi-Maskawa Theory of CP violation. This led to the collisions. Kobayashi-Maskawa Theory of CP violation. This led to the Nobel Physics Prize in 2008, half of which was shared by Nobel Physics Prize in 2008, half of which was shared by On May 9, 2003, KEKB’s luminosity reached the world’s Kobayashi and Maskawa. On May 9, 2003, KEKB’s luminosity reached the world’s Kobayashi and Maskawa. Anti-B mesons Anti-B mesons highest record luminosity at 1034cm-2s-1. This luminosity was Anti-B mesons highest record luminosity at 1034cm-2s-1. This luminosity was Anti-B mesons B mesons B mesons thought beyond the reach of accelerators ten years before; As of July 30, 2010, the operation of the KEKB accelerator B mesons thought beyond the reach of accelerators ten years before; As of July 30, 2010, the operation of the KEKB accelerator B mesons in accelerator science, this remarkable accomplishment is has been temporarily suspended in order to carry out in accelerator science, this remarkable accomplishment is has been temporarily suspended in order to carry out ents ents ents ents comparable to the great achievement witnessed by the upgrades for higher performance. ev ev comparable to the great achievement witnessed by the upgrades for higher performance.
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