36°9′28″N 140°4′30″E / 36.15778°N 140.07500°E
The Belle II experiment is a particle physics experiment designed to study the properties of B mesons (heavy particles containing a beauty quark) and other particles. Belle II is the successor to the Belle experiment, and commissioned at the SuperKEKB [1] accelerator complex at KEK in Tsukuba, Ibaraki prefecture, Japan. The Belle II detector was "rolled in" (moved into the collision point of SuperKEKB) in April 2017. [2] [3] Belle II started taking data in early 2018. [1] Over its running period, Belle II is expected to collect around 50 times more data than its predecessor, mostly due to a 40-fold increase in an instantaneous luminosity provided by SuperKEKB as compared to the previous KEKB accelerator. [1]
Many interesting analyses of the Belle and BaBar experiments were limited by statistical uncertainties, which was the main motivation to build a new generation of B-factory - Belle II.
The target dataset is 50 ab−1 at Belle II [4] compared to 988 fb−1 (with 711 fb−1 at the Υ(4S) energy) at Belle. [5] The dataset of good runs from Belle II before Long shutdown 1 was 424 fb−1 (with 363 fb−1 at the Υ(4S) energy.) [6]
This immense dataset would allow studies of rare physics processes, which were out of reach for the previous e+ e− experiments and improve precision on the already measured physics observables.
The physics program of Belle II includes the studies of the following particles or processes: [7]
The majority of the Belle II dataset will be recorded at Upsilon(4S) center-of-mass energy, while a small portion of it will be taken at Upsilon(5S) and as energy scans.
Belle II is a general purpose high-energy particle detector with almost full solid angle coverage. It has a cylindrical shape to cover the e+ e− collisions happening on the central axis of the detector. The detector is asymmetric in beam direction, because the initial energy of the electron beam is larger than the positron beam. Much of the original Belle detector has been upgraded [4] to cope with the higher instantaneous luminosity provided by the SuperKEKB accelerator. [1]
The main components are the following, from the innermost to the outermost systems.: [4]
The Belle II experiment data taking is separated into three phases: [14]
On November 22, 2018, the Belle II detector was completed with the installation of the VerteX Detector (VXD). [16] On March 25, 2019, the first collisions of the actual physics program were detected. [17]
On 15 June 2020, the SuperKEKB reached an instantaneous luminosity of 2.22×1034 cm−2s−1 — surpassing the LHC's record of 2.14×1034 cm−2s−1 set with proton–proton collisions in 2018. A few days later, SuperKEKB pushed the luminosity record to 2.4×1034 cm−2s−1. [18] In June 2022 the luminosity record was nearly doubled to 4.7×1034 cm−2s−1. [19]
The Belle II experiment is being governed by Belle II Collaboration, [20] which is an international worldwide scientific community.
The Belle II Collaboration has designed, produced, assembled and is currently operating the Belle II experiment. The collaboration handles the collision data recorded at the experiment, performs the data analysis and delivers the results in form of scientific journal articles, conference talks, etc.
As on October 5, 2023, it included 1,174 members from 124 institutes and 27 countries around the globe. [21]
In October 2021 the Software development team within the Belle II Collaboration has published Belle II Analysis Software Framework or basf2, [22] as open-source software on GitHub. [23]
This is the main package used to simulate, reconstruct and analyse the recorded collision events at the Belle II experiment and there are several other separate satellite packages, used for DAQ, computation of the systematic uncertainties, etc.
The backend of the reconstruction and analysis libraries are written in C++, [24] while the analysis steering and facade are implemented in Python [24] language.
To coordinate the software development, the Belle II Collaboration uses industrial collaboration tools such as Atlassian Jira, Confluence and git-based BitBucket service.
This section is empty. You can help by
adding to it. (January 2022) |
36°9′28″N 140°4′30″E / 36.15778°N 140.07500°E
The Belle II experiment is a particle physics experiment designed to study the properties of B mesons (heavy particles containing a beauty quark) and other particles. Belle II is the successor to the Belle experiment, and commissioned at the SuperKEKB [1] accelerator complex at KEK in Tsukuba, Ibaraki prefecture, Japan. The Belle II detector was "rolled in" (moved into the collision point of SuperKEKB) in April 2017. [2] [3] Belle II started taking data in early 2018. [1] Over its running period, Belle II is expected to collect around 50 times more data than its predecessor, mostly due to a 40-fold increase in an instantaneous luminosity provided by SuperKEKB as compared to the previous KEKB accelerator. [1]
Many interesting analyses of the Belle and BaBar experiments were limited by statistical uncertainties, which was the main motivation to build a new generation of B-factory - Belle II.
The target dataset is 50 ab−1 at Belle II [4] compared to 988 fb−1 (with 711 fb−1 at the Υ(4S) energy) at Belle. [5] The dataset of good runs from Belle II before Long shutdown 1 was 424 fb−1 (with 363 fb−1 at the Υ(4S) energy.) [6]
This immense dataset would allow studies of rare physics processes, which were out of reach for the previous e+ e− experiments and improve precision on the already measured physics observables.
The physics program of Belle II includes the studies of the following particles or processes: [7]
The majority of the Belle II dataset will be recorded at Upsilon(4S) center-of-mass energy, while a small portion of it will be taken at Upsilon(5S) and as energy scans.
Belle II is a general purpose high-energy particle detector with almost full solid angle coverage. It has a cylindrical shape to cover the e+ e− collisions happening on the central axis of the detector. The detector is asymmetric in beam direction, because the initial energy of the electron beam is larger than the positron beam. Much of the original Belle detector has been upgraded [4] to cope with the higher instantaneous luminosity provided by the SuperKEKB accelerator. [1]
The main components are the following, from the innermost to the outermost systems.: [4]
The Belle II experiment data taking is separated into three phases: [14]
On November 22, 2018, the Belle II detector was completed with the installation of the VerteX Detector (VXD). [16] On March 25, 2019, the first collisions of the actual physics program were detected. [17]
On 15 June 2020, the SuperKEKB reached an instantaneous luminosity of 2.22×1034 cm−2s−1 — surpassing the LHC's record of 2.14×1034 cm−2s−1 set with proton–proton collisions in 2018. A few days later, SuperKEKB pushed the luminosity record to 2.4×1034 cm−2s−1. [18] In June 2022 the luminosity record was nearly doubled to 4.7×1034 cm−2s−1. [19]
The Belle II experiment is being governed by Belle II Collaboration, [20] which is an international worldwide scientific community.
The Belle II Collaboration has designed, produced, assembled and is currently operating the Belle II experiment. The collaboration handles the collision data recorded at the experiment, performs the data analysis and delivers the results in form of scientific journal articles, conference talks, etc.
As on October 5, 2023, it included 1,174 members from 124 institutes and 27 countries around the globe. [21]
In October 2021 the Software development team within the Belle II Collaboration has published Belle II Analysis Software Framework or basf2, [22] as open-source software on GitHub. [23]
This is the main package used to simulate, reconstruct and analyse the recorded collision events at the Belle II experiment and there are several other separate satellite packages, used for DAQ, computation of the systematic uncertainties, etc.
The backend of the reconstruction and analysis libraries are written in C++, [24] while the analysis steering and facade are implemented in Python [24] language.
To coordinate the software development, the Belle II Collaboration uses industrial collaboration tools such as Atlassian Jira, Confluence and git-based BitBucket service.
This section is empty. You can help by
adding to it. (January 2022) |