A search for new physics: The Belle II experiment
At the beginning of the universe there were equal quantities of matter and anti-matter and yet 13.7 billion years later, the universe is completely dominated by matter. How did this happen? Asymmetries in the interactions of fundamental matter particles and their anti-matter counterparts are likely to be responsible for the matter dominance of the universe and our own existence. However, the known asymmetries do not seem to be sufficient and seem to require new particles or new interactions beyond the Standard Model of Particle Physics. A team of University of Hawaiʻi at Mānoa Department of Physics and Astronomy researchers and those from 23 nations seek to answer these questions and other mysteries of the Universe with the Belle II experiment.
A milestone was reached on April 11 as the Belle II detector was “rolled-in” to the collision point of the SuperKEKB particle accelerator. The UH Belle II team plays a leading role in the beam background commissioning detector (BEAST II) and the readout systems of the iTOP (imaging Time Of Propagation) detector and the KLM (KLong Muon) detector. Following the roll-in, the UH team is preparing for the 2017 summer cosmic ray run in which all of the components of the Belle II outer detector are integrated. The first run with collisions of the electron and positron particle beams will start in February 2018.
The term “roll-in” refers to the operation of moving the entire 1,400 ton Belle II detector system, following the completion of the assembly and integration of the various components, from its assembly area to the beam collision point. The Belle II detector and the SuperKEKB accelerator are now an integrated unit.
International team explores the beginning of the universe
The Belle II experiment is an international collaboration hosted by KEK in Tsukuba, Japan. Using a state-of-the-art experimental apparatus, Belle II explores the mysteries of the beginning of the universe. The Belle II detector precisely measures elementary particle interactions artificially created with the upgraded SuperKEKB accelerator.
- Related: Belle II super-B factory experiment takes shape at KEK, CERN Courier, August 12, 2016
In the Belle II experiment, researchers will observe various elementary particles generated from high energy electron-positron collisions using the 8-meter tall Belle II detector consisting of seven types of subdetectors and investigate the various kinds of elementary particles that emerge from these collisions. The detector will provide measurements of the directions, momenta and energies of the newly produced particles. Compared to the earlier Belle experiment, Belle II has much improved measurement precision and can handle an order of magnitude higher rate from accelerator induced background.
More than 700 researchers from around the world participate in the Belle II experiment. Their goal is to find a significant “deviation” from the Standard Model of particle physics and perhaps determine which of the many proposed new theories describes the world of elementary particles.
UH Mānoa Professors Tom Browder, Sven Vahsen and Gary Varner along with other UH Mānoa postdoctoral researchers and graduate students participated in the first Belle experiment at Tsukuba, Japan’s KEK B factory. It is celebrated for its critical role in experimentally verifying the theoretical scheme of Kobayashi and Maskawa, winners of the 2008 Nobel Prize in Physics.
Browder is now the Belle II spokesperson, Vahsen is leading the BEAST II beam background group and Varner is leading the U.S. readout electronics efforts. UH Mānoa is responsible for major components of the Belle II particle identification readout systems using Varner’s renowned “oscilloscope on a chip” application specific integrated circuits (ASICs) as well as the BEAST II background commissioning system, which detects neutrons with Vahsen’s innovative micro-time projection chambers
In addition to the three UH Mānoa faculty members, current members of the Belle II project are postdoctoral scholars Oscar Hartbrich, Dmitri Kotchetkov, Peter Lewis, Tobias Weber and engineers Matt Andrew, Isar Mostafanezhad and Luca Macchiarulo and graduate students Shawn Dubey, Michael Hedges, Chris Ketter and Ilsoo Seong.
Belle II collaborators
The other U.S. institutions collaborating on Belle II are Carnegie-Mellon University, University of Cincinnati, Luther College, Kennesaw State, Indiana University, University of Pittsburgh, University of South Alabama, University of South Carolina, Virginia Polytechnic Institute, Wayne State University and Pacific Northwest National Lab.
The University of Hawaiʻi at Mānoa is located in a lush paradise, but professor Peter Gorham’s work takes him to the frozen expanse of a faraway continent searching for the elusive neutrino, a tiny particle capable of traveling at light speed, with ANITA.
“ANITA stands for the Antarctic Impulsive Transient Antenna,” said Gorham, professor of physics and astronomy. “It flies over the Antarctic continent as a stratospheric balloon payload and looks for the signatures of high-energy neutrinos that crash into some atom in the ice.”
Neutrinos are fundamental particles of the universe, born in the incredible energy of the Big Bang. They can tell us about everything from the birth of the universe to the nuclear reactions that power our cities. And, Antarctica is a perfect place to study them.
ANITA’s 48 antennas on a 25-foot-tall gondola fly pointed down to capture radio waves in the Antarctic ice, which are signs of high-energy neutrino reactions.
“Antarctica has several properties that make it really ideal for what we want to do, and ice has an amazing property in Antarctica of being almost completely clear to radio waves, that, if you flew over Antarctica with radio eyes, you could see right through the ice several miles deep into it and see the subcontinent below,” said Gorham.
One of the ways UH has supported ANITA research is by building a copper enclosed, foam finger filled laboratory that is “anechoic” (with no radio echoes) to test Gorham’s scientific equipment before sending it to Antarctica.
ANITA attracts cutting edge researchers
The ANITA project continues to attract some of the best minds, as well as research dollars, to UH to do cutting edge research at the vanguard of science.
“The University of Hawaiʻi has been incredibly supportive of this effort—the chance to put laboratories like this together and to allow them to be operated. It gives students tremendous opportunities,” said Gorham. “We’re actually the lead institution for ANITA. We’ve developed a great relationship with NASA, brought in something like 10 or 12 million dollars. We’re participating in something which I think is one of the best efforts of humanity.”
UH Physics Professor Philip von Doetinchem's Cosmic Ray Antiparticle Balloon Experiment funded by NASA
Philip von Doetinchem, a University of Hawaiʻi at Mānoa physicsassistant professor, is part of a team working on the design of a next-generation cosmic-ray balloon antiparticle experiment called General AntiParticle Spectrometer (GAPS). This fall, the National Aeronautics and Space Administration selected the experiment for funding and awarded the project $487,259 for the next five years.
The GAPS team includes researchers from Columbia University; University of California, Berkeley; University of California, Los Angeles; Massachusetts Institute of Technology and the Japan Aerospace Exploration Agency.
The creation of cosmic rays
Cosmic rays are created in very energetic events in our galaxy, such as Supernova explosions, and include familiar particles such as electrons and protons. However, antimatter particles including much rarer species such as positrons (antielectrons) or antiprotons can also be created in other processes.
The search for cosmic-ray antideuterons goes even further as they are believed to make up only one out of 10 billion protons. Antideuterons, a bound state of antiprotons and antineutrons, are a particularly promising approach to shed some light on the nature of the mysterious dark matter in the universe. Dark matter is more than five times more abundant than the matter that the solar system and stars are made of, but its exact nature is unknown.
GAPS is forecast to find low-energy cosmic-ray antideuterons with a novel detection approach through the creation of exotic atoms. GAPS is designed to achieve its goals via a series of long duration balloon flights from Antarctica.
The next four years will be used to design, construct and test the payload before the first flight at the end of 2020. The University of Hawaiʻi group will coordinate the simulation tools and analysis pipeline development as well as qualify and calibrate half of the individual tracker detector modules.
Two UH Physics Professors celebrate five years of data taking on the International Space Station
The Alpha Magnetic Spectrometer (AMS), which includes the work of University of Hawaiʻi at Mānoa faculty members and students, presented its major scientific results to date from the first five years of experiments on the International Space Station. AMS is a Department of Energy high-energy physics experiment for the spectroscopy of cosmic rays.
AMS researchers at UH Mānoa include Department of Physics and AstronomyAssociate Professor Veronica Bindi; Assistant Professor Philip Von Doetinchem; postdocs Christina Consolandi, Amaresh Datta and Matteo Palermo; PhD students Claudio Corti, Travis Nelson and Katie Whitman; and other undergraduate students.
Bindi’s main research topics are the study of Dark Matter, Cosmic Rays, Solar Physics and Space Radiation. Since 2002, she has been part of the team at CERN that led the construction, integration and testing of AMS. She is the PI of two grants, one funded by the NASA Space Radiation Group involved in the future manned mission to Mars and an NSF CAREER Award to study Solar Energetic Particles with the AMS experiment. The major results from her research group are shown in the “Solar Physics” paragraph of the attached press release. In summary, they analyzed cosmic ray fluxes of different particle species continuously over five years of AMS operation, showing with unprecedented accuracy how these particles are affected by the solar activity. Furthermore, they proved that positive and negative particles show a different behavior related to the change of the solar magnetic field polarity. This intriguing result, never observed before in such detail, will require improvements of theoretical models to be understood.
Doetinchem joined the AMS collaboration more than a decade ago in 2003 and has been an Assistant Professor at UH Mānoa since 2013. He was involved in the experiment development and testing before the launch and his group is currently conducting the challenging search for a very rare species of cosmic rays that has yet to be found: antideuterons, which are composed of the antiparticles of the proton and neutron, known as the essential building blocks for every known element. A first-time detection of antideuterons in space is a particularly promising way to learn more about the mysterious dark matter, which is more than five times more abundant than the matter that the solar system and stars are made of. Doetinchem received an NSF CAREER award in 2016 for exactly this study with the AMS experiment. Furthermore, he is involved in additional experimental efforts to tackle other aspects of the same question and is part of the team that was just selected from NASA to build the new General AntiParticle Spectrometer (GAPS) experiment.
For more information, visit: http://natsci.manoa.hawaii.edu
Physics Graduate Student Mark Duvall Awarded DOE Scholarship
UH Manoa Physics Graduate Student Mark Duvall of the neutrino group has been awarded a prestigious US Department Of Energy Office of Science Graduate Student Research Award to support a year of work at Lawrence Livermore National Laboratory on studies of electron anti-neutrino directional detectors, with the eventual goal of applying these analyses to data from
the UH miniTimeCube and NuLat experiments. Applications include sterile
neutrino searches and non-proliferation of nuclear weapons and materials. He will reside in Livermore from November 2016 for one year, extendable.
miniTimeCube web site: https://www.phys.hawaii.edu/~mtc/
NuLat collaboration whitepaper: https://arxiv.org/abs/1501.06935
DOE Office of Science SCGSR Program web site: http://science.energy.gov/wdts/scgsr/
UH Physics Prof. Gary Varner has received the 2016 DPF Instrumentation Award
The Division of Particle and Fields (DPF) of the American Physical Society has honored University of Hawai’i at Manoa Physics Professor Gary Varner with the 2016 Instrumentation Award for Experimental Particle Physics.
The award citation reads “For the development of technologies for detection of signals in frontier experiments, especially [the fully depleted charge coupled device] and the ‘oscilloscope on a chip’ integrated circuit.”
This is the second DPF instrumentation award. Prof. Varner shares the award with Dr. Stephen Holland (Lawrence Berkeley National Laboratory). Last year’s award went to Prof. David Nygren (University of Texas at Arlington) and Dr. Veljko Radeka (Brookhaven National Laboratory).
The 2016 DPF Instrumentation Award recognizes Gary Varner’s development of state of the art “oscilloscope on a chip” ASICs (Application Specific Integrated Circuits) and associated readout systems, which have had considerable impact on experiments in high energy and astroparticle physics.
Professor Varner’s readout systems play a critical role in the Belle II experiment located at the KEK laboratory in Tsukuba, Japan. In particular, his IRSX ASIC readout chip, which has a timing resolution of below 50 picoseconds is the basis of the readout system for the Cerenkov particle identification system called the iTOP (imaging Time Of Propagation) detector. Gary Varner not only developed the readout ASIC matched to the pixelated photosensors of the device but the full readout system and the methods for calibration. He also designed and built the TARGETX waveform sampling ASIC, which is the basis of the readout system for the Belle II KLM (K-long and
It is quite remarkable that in addition to his critical contributions to accelerator based experiments, Professor Varner has also developed readout systems based on his fast deep pipeline multi- channel oscilloscopes on a chipfor the ANITA astroparticle missions and for a variety of other experiments (such as the UH-led TimeCube experiment). In all these cases, his contributions were critical to the success of the experiments and the physics results.
In addition to his scientific accomplishments, Professor Varner has mentored and trained an entire generation of graduate students, postdocs and engineers. This is a critical contribution to the entire field of high energy physics.
Varner received a BS in Electrical Engineering from Boston University (BU), a master’s degree from BU in Physics and a Phd in Physics from the University of Hawai’i. He has worked in academia and industry. He was appointed as assistant professor of physics at UH Manoa in 2005 and was promoted to the full professor rank in 2015. While at UH, he received three DOE (Department of Energy) ADR (Advanced Detector Research) awards and a large number of external grants.