New, higher precision data that could only have been gathered at the Department of Energy’s Thomas Jefferson National Accelerator Facility (Jefferson Lab) shows the Theta-plus pentaquark doesn’t appear in another place it was expected. This intriguing finding contradicts evidence previously presented by Jefferson Lab researchers that they had sighted a pentaquark, a particle built of five quarks. Volker Burkert, a Jefferson Lab Experimental Hall Leader, will present this preliminary result in a talk reviewing world pentaquark data at Lepton-Photon, the XXII International Symposium on Lepton-Photon Interactions at High Energy, in Uppsala, Sweden, on Friday, July 1.
Researchers sent photons into deuterium nuclei to try to produce pentaquarks. If pentaquarks had been produced, sensitive detectors would have measured a particular mix of Kaons (K-mesons) and protons; neutrons could have been inferred from the data. The researchers did not detect this reaction. Image credit: JLab
The result comes from a very carefully crafted experiment that was designed to repeat Jefferson Lab’s original pentaquark search with a factor of ten higher statistics. Researchers in Jefferson Lab’s CEBAF Large Acceptance Spectrometer (CLAS) collaboration took data with a high-energy photon beam on a deuterium target March 13 – May 16, 2004. Deuterium is an isotope of hydrogen with one proton and one neutron in its nucleus. An earlier probe of this same region by CLAS revealed a possible signal for a pentaquark with mass 1542 MeV.
The new experiment searched for pentaquarks in this same channel at a level of precision at least 10 times higher, or one order of magnitude better, than the previous published result and found no pentaquarks. “The earlier results on the Theta-plus can not be reproduced in the analysis of the high-statistics run,” Burkert says.
Kandice Carter | EurekAlert!
NASA's Fermi catches gamma-ray flashes from tropical storms
25.04.2017 | NASA/Goddard Space Flight Center
DGIST develops 20 times faster biosensor
24.04.2017 | DGIST (Daegu Gyeongbuk Institute of Science and Technology)
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
25.04.2017 | Physics and Astronomy
25.04.2017 | Materials Sciences
25.04.2017 | Life Sciences