image: This is a working prototype of the silicon micro-vertex detector module designed and assembled by scientists at TIFR Mumbai. view more
Credit: Gagan Mohanty, TIFR
A new electron-positron collider, SuperKEKB, at the KEK laboratory in Tsukuba, Japan has achieved "First Turns" and is now in the test operation stage. This is the first new "atom-smasher" since the LHC, which is located at the CERN laboratory in Switzerland. The achievement of "first turns", which means storing the highly energetic beam in the ring through many revolutions, is a major milestone for any new particle accelerator. In the SuperKEKB, the electron and positron beams have separate rings and different energies (7 GeV and 4 GeV, respectively. GeV or Gigaelectron Volt is a unit of energy equivalent to the rest mass of a proton).
On February 10, 2016, the SuperKEKB collider was able to circulate and store a positron beam moving close to the speed of light through over a thousand magnets in a narrow tube around the 3.1-km circumference of its main ring. Recently, on February 26, the machine succeeded in circulating and storing a 7-GeV electron beam around its ring of magnets in the opposite direction. During the full operation of SuperKEKB, the beams of electrons and positrons will collide and produce large numbers of new particles.
In contrast to the LHC at CERN, which is the world's highest energy machine, SuperKEKB is designed to have the world's highest particle beam intensity (a factor of 40 higher than the earlier KEKB machine that holds many of the current world records for accelerator performance). Thus, SuperKEKB will soon be the leading accelerator on the "intensity frontier". This will enable the Belle-II experiment, a detector placed at the interaction point of SuperKEKB, to probe the next fundamental theory beyond the Standard Model by measuring extremely rare decays of subatomic particles such as beauty and charm hadrons and tau leptons.
The Belle II detector at SuperKEKB was designed and built by an international collaboration of over 600 physicists from 23 countries in Asia, Europe and North America. A team of about 30 physicists, engineers and technicians from all over India (see below) is playing a major role in this international enterprise. Led by the group at the Tata Institute of Fundamental Research (TIFR) in Mumbai, the Indian team is involved in the design and assembly of one of the four layers of the silicon micro-vertex detector (SVD) of the experiment. Almost coinciding with the historic occasion of the "first turns" milestone for SuperKEKB, the team has received the go ahead to start the building of production-grade SVD modules after successfully assembling a number of prototypes and meeting the stringent quality requirements of an international technical review. The production will continue until the middle of 2017, followed by installation and commissioning of the detector.
Prof. Thomas Browder of University of Hawaii (Belle-II spokesperson) has congratulated the SuperKEKB team on this achievement and expects that this will be the first of many good things to follow. Prof. Gagan Mohanty (TIFR) says, "This is a historic occasion for all us in India as we are eagerly looking forward to harvest the pristine electron-positron collision data to unlock some of the fundamental mysteries of universe."
The Indian institutes and universities that are participating in the Belle and Belle II experiments are IIT Bhubaneswar, IIT Guwahati, IIT Hyderabad, IIT Madras, IISER Mohali, IMSc Chennai, Panjab University Chandigarh, Punjab Agricultural University Ludhiana, and TIFR Mumbai.
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