The symmetry of the universe
CERN: Most precise measurement of mass and charge of light nuclei and anti-nuclei
2015-09-02
(Press-News.org) This news release is available in German.
What did the universe look like shortly after it came into being? The ALICE experiment (A Large Ion Collider Experiment) at CERN in Switzerland concerns itself with this question. At the largest particle accelerator in the world, the Large Hadron Collider (LHC), researchers let lead nuclei and protons collide at the highest beam energies to date. The temperatures thereby created are 100,000 times higher than those in the center of the Sun. "A state is created that is very similar to the one after the Big Bang," explains Laura Fabbietti, Professor in the Physics Department. She and Dr. Torsten Dahms head the two experimental ALICE groups at the TU Munich.
The so-called quark-gluon-plasma (QGP) probably formed one microsecond after the Big Bang, a point in time when the universe was expanding at great speed. The QGP produced in the laboratory is stable only for a fraction of a second, but, during this very short time, the researchers have the opportunity to look back into the past of the universe.
Matter-antimatter asymmetrie remains a mystery
Furthermore, the ALICE experiment makes it possible to get to the bottom of one of mankind's biggest mysteries. According to the CPT theorem (charge, parity, time), there is a fundamental symmetry between particles and antiparticles in our Universe. Specifically, there should be no difference between our Universe and one where all particles are exchanged with antiparticles (and vice versa), if the Universe is also inverted in time and space.
There must be a difference nevertheless, because the theory says that equal quantities of matter and antimatter should have been produced during the Big Bang. When particles and antiparticles meet, they annihilate each another. However, nowadays we almost only observe particles - there must therefore have been an imbalance.
Most accurate measurements to date
Physicists are looking for a violation of the CPT theorem which would help to explain the existing matter-antimatter asymmetry. "ALICE is attempting to find a difference by means of high-precision measurements of the properties of particles and their antiparticles which are produced in particle collisions at the LHC," explains Dahms. In the current study, the researchers investigated the mass-to-charge ratio of helium-3 nuclei and deuterium nuclei and their respective antiparticles. Charge and mass are determined by measuring the particle traces and the particle's specific energy loss within a gas detector called the TPC (Time Projection Chamber). The TCP is thus the heart of the ALICE detector system. The results published in "Nature Physics" are the most accurate measurements to date in this field and at the moment confirm the CPT theorem.
The researchers are currently working on improvements to the ALICE detectors with the aim of making the investigations even more precise. "At the moment we are able to record 500 collisions per second," explains Fabbietti. "Soon it should be 50,000 collisions per second." The TUM groups are working on an upgrade of the TPC read out. The existing multi-wire chambers are being replaced by state of the art GEM foils that provide better spatial resolution as well. The TUM group heads the GEM-TPC upgrade project for ALICE as part of an international collaboration. The installation of the new detectors is planned for 2018.
INFORMATION:
Publication:
ALICE Collaboration: Precision measurement of the mass difference between light nuclei and anti-nuclei; Nature Physics, doi: 10.1038/nphys3432
Contact:
Prof. Dr. Laura Fabbietti
Technical University of Munich
Physik-Department
+49 (89) 289 - 12431
laura.fabbietti@ph.tum.de
ELSE PRESS RELEASES FROM THIS DATE:
2015-09-02
(Boston)--There is strong evidence that the protein complex APC/C may function as a tumor suppressor in multiple cancers including lymphoma, colorectal and breast cancer, and now melanoma. A new study has revealed that a genetic mutation leading to repression of a specific protein, Cdh1, which interacts with APC/C, is present in melanoma cancer cells.
The study, led by researchers at Boston University School of Medicine (BUSM), reports sporadic mutations in the APC/C protein complex, specifically in the essential protein component Cdh1, which may predispose humans to ...
2015-09-02
The study, published in the journal Financial Stability, introduces a new method that allows researchers to estimate the systemic risk that emerge from multiple layers of connectivity.
"Systemic risk is the risk that a significant part of the financial system stops working--that it cannot perform its function," says IIASA Advanced Systems Analysis program researcher Sebastian Poledna, who led the study. For example if a major bank fails, it could trigger the failure of other financial institutions that are linked to it through loans, derivatives, securities, and foreign ...
2015-09-02
Scientists have developed a simple process to treat waste coffee grounds to allow them to store methane. The simple soak and heating process develops a carbon capture material with the additional environmental benefits of recycling a waste product.
The results are published today, 03 September 2015, in the journal Nanotechnology.
Methane capture and storage provides a double environmental return - it removes a harmful greenhouse gas from the atmosphere that can then be used as a fuel that is cleaner than other fossil fuels.
The process developed by the researchers, ...
2015-09-02
Although most of the world's biodiversity is below ground, surprisingly little is known about how it affects ecosystems or how it will be affected by climate change. A new study demonstrates that soil bacteria and the richness of animal species belowground play a key role in regulating a whole suite of ecosystem functions on Earth. The authors call for far more attention to this overlooked world of worms, bugs and bacteria in the soil.
Ecosystem functions such as carbon storage and the availability of nutrients are linked to the bugs, bacteria and other microscopic ...
2015-09-02
CAMBRIDGE, Mass. (September 2, 2015) - Altering the protein recycling complexes in human cells, including cancer cells, allows the cells to resist treatment with a class of drugs known as proteasome inhibitors, according to Whitehead Institute scientists.
"This is why some cancers can be so difficult to treat with chemotherapy, because the cells can be in different states--some sensitive to treatment and some resistant to treatment, all in the same tumor," says Sandro Santagata, a former visiting scientist in the lab of Whitehead Member Susan Lindquist. Santagata is now ...
2015-09-02
Their pregnancies are carried by the males but, when it comes to breeding, seahorses have more in common with humans than previously thought, new research from the University of Sydney reveals.
Seahorses are famed for being part of the only family in the animal kingdom (Syngnathidae) in which the male is responsible for pregnancy. What hasn't been known until now is the degree to which male seahorses nourish and protect their embryos in their brood pouch during the 24-day gestation period.
Findings co-authored by Dr Camilla Whittington from the University's School of ...
2015-09-02
A new study, published today in the British Journal of Pharmacology, by scientists from Royal Holloway, University of London, St George's, University of London and University of Surrey have identified that a drug related to commonly used diabetes treatments provides protection against terminal blood loss.
Massive blood loss often leads to death, and when blood transfusions are unavailable, drugs are currently being tested that can keep people alive until they get to hospital. Understanding how these drugs work, and finding improved drugs, has up to now proved difficult. ...
2015-09-01
MAYWOOD, Ill. - In carefully selected patients, minimally invasive surgery is enabling physicians to stop strokes in their tracks.
And as more stroke patients undergo such procedures, physicians are debating the best way to anesthetize them. Should patients be put under general anesthesia, rendering them unconscious and motionless? Or should they undergo conscious sedation, in which they remain conscious, but are sedated and do not feel pain?
In the September, 2015 issue of the Journal of Stroke and Cerebrovascular Diseases, Loyola University Medical center anesthesiologists ...
2015-09-01
At the International Conference on Intelligent Robots and Systems in September, members of the Singapore-MIT Alliance for Research and Technology (SMART) and their colleagues will describe an experiment conducted over six days at a large public garden in Singapore, in which self-driving golf carts ferried 500 tourists around winding paths trafficked by pedestrians, bicyclists, and the occasional monitor lizard.
The experiments also tested an online booking system that enabled visitors to schedule pickups and drop-offs at any of 10 distinct stations scattered around the ...
2015-09-01
The incidence of bicycle accidents has increased significantly in the U.S. in recent years, with many serious injuries occurring among riders older than 45, according to a new study led by UC San Francisco.
The researchers used a national injury surveillance database to study trends in bicycle injuries from 1998 to 2013. They found that the rate of hospital admissions associated with bicycle injuries more than doubled during that timeframe, especially with head and torso injuries.
Altogether, the proportion of injuries occurring to riders above age 45 rose 81 percent, ...
LAST 30 PRESS RELEASES:
[Press-News.org] The symmetry of the universe
CERN: Most precise measurement of mass and charge of light nuclei and anti-nuclei
