| 词条 | Belle II experiment |
| 释义 |
The Belle II experiment is a particle physics experiment designed to study the properties of B mesons (heavy particles containing a bottom quark). Belle II is the successor to the Belle experiment, and is currently being 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 due mostly to a factor 40 increase in instantaneous luminosity provided by SuperKEKB over the original KEKB accelerator.[1] Detector upgradeMuch of the original Belle detector has been upgraded[4] to cope with the higher instantaneous luminosity provided by the SuperKEKB accelerator.[1] Close to the beam pipe, the two innermost layers of Belle's silicon vertex detector have been replaced by a depleted field effect transistor (DEPFET) pixel detector, and a larger the silicon vertex detector.[4][5] A larger central tracking system – a wire drift chamber, has been installed.[4] Two new particle identification systems have been installed in the forward endcap (consisting of an aerogel ring-imaging Cherenkov detector)[4][6] and in the barrel (consisting of quartz bars utilising totally internally reflected Cherenkov photons and measuring the time of propagation).[4][7] The original CsI(Tl) electromagnetic calorimeter has been re-used (a new pure CsI calorimeter is being designed for the forward endcap[8] to be installed at a later stage[8][9]). The calorimeter readout electronics have been upgraded.[4] Finally, scintillators have been installed in the forward endcap and inner layers of Belle's {{Subatomic Particle|K-long0|link=yes}} and muon detector, the original resistive plate chambers (RPCs) from Belle are reused in the outer layers of the barrel.[4][10] The target dataset is 50ab−1 at Belle II[4] compared to 988fb−1 (with 711fb−1 at the Υ(4S) energy) at Belle.[11] TimelineThe Belle II data taking is separated into three phases[12]:
On March 25th 2019 the first collisions of the real physics programm could be detected with the nearly complete Belle II detector (only half of the pixel detector is installed [13]. The installation of the full pixel detector is planned for 2020. See also
References1. ^1 2 3 {{Cite web |url=http://www-superkekb.kek.jp/ |title=SuperKEKB |website=www-superkekb.kek.jp |access-date=2017-04-28}} 2. ^{{Cite news |url=https://twitter.com/belle2collab/status/851683547517657088 |title=Belle II Experiment on Twitter |work=Twitter |access-date=2017-05-07 }} 3. ^{{Cite web|url=http://cerncourier.com/cws/article/cern/68775|title=Belle II rolls in - CERN Courier|website=cerncourier.com|language=en-GB|access-date=2017-05-22}} 4. ^1 2 3 4 5 6 7 {{cite arxiv|last=Abe|first=T.|display-authors=etal|date=October 2010|title=Belle II Technical Design Report|eprint=1011.0352|class=physics.ins-det}} 5. ^{{Cite conference |last=Casarosa |first=Giulia |year=2015 |chapter=Inner tracking devices at the Belle II experiment |url=https://inspirehep.net/record/1430598 |title=Proceedings, 2015 European Physical Society Conference on High Energy Physics (EPS-HEP 2015) : Vienna, Austria, July 22-29, 2015 |page=255}} 6. ^{{Cite journal |last=Nishida |first=S. |display-authors=etal |year=2014 |title=Aerogel RICH for the Belle II forward PID |journal=Nuclear Instruments and Methods in Physics Research Section A |volume=766 |pages=28–31 |bibcode=2014NIMPA.766...28N |doi=10.1016/j.nima.2014.06.061}} 7. ^{{Cite journal |last=Inami |first=Kenji |year=2014 |title=TOP counter for particle identification at the Belle II experiment |journal=Nuclear Instruments and Methods in Physics Research Section A |volume=766 |pages=5–8 |bibcode=2014NIMPA.766....5I |doi=10.1016/j.nima.2014.07.006}} 8. ^1 {{Cite journal |last=Manoni |first=E. |display-authors=etal |year=2017 |title=The upgrade of the Belle II forward calorimeter |journal=Nuclear Instruments and Methods in Physics Research Section A |volume=845 |pages=524–527 |bibcode=2017NIMPA.845..524M |doi=10.1016/j.nima.2016.06.074}} 9. ^{{Cite web |url=http://belle2.jp/electromagnetic-calorimeter/ |title=Electromagnetic Calorimeter {{!}} Belle II Experiment |website=belle2.jp |access-date=2017-05-07}} 10. ^{{Cite journal |last=Aushev |first=T. |display-authors=etal |year=2015 |title=A scintillator based endcap KL and muon detector for the Belle II experiment |journal=Nuclear Instruments and Methods in Physics Research Section A |volume=789 |pages=134–142 |bibcode=2015NIMPA.789..134A |doi=10.1016/j.nima.2015.03.060|arxiv = 1406.3267 }} 11. ^{{Cite journal|last=Bevan|first=A. J.|last2=Golob|first2=B.|last3=Mannel|first3=Th|last4=Prell|first4=S.|last5=Yabsley|first5=B. D.|last6=Aihara|first6=H.|last7=Anulli|first7=F.|last8=Arnaud|first8=N.|last9=Aushev|first9=T.|date=2014-11-01|title=The Physics of the B Factories|journal=The European Physical Journal C|language=en|volume=74|issue=11|pages=3026|doi=10.1140/epjc/s10052-014-3026-9|issn=1434-6044|arxiv = 1406.6311 |bibcode = 2014EPJC...74.3026B }} 12. ^[https://indico.nucleares.unam.mx/event/1180/session/11/contribution/76 N.Braun - Hadron Spectroscopy Studies at Belle II] 13. ^[https://www.kek.jp/en/newsroom/2019/03/25/2030/ Kick-off of the Belle II Phase 3 Physics Run] External links{{Commonscat}}
4 : Particle experiments|Particle physics|Experimental particle physics|B physics |
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