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!
Electrocatalysis can advance green transition
23.01.2017 | Technical University of Denmark
Quantum optical sensor for the first time tested in space – with a laser system from Berlin
23.01.2017 | Ferdinand-Braun-Institut Leibniz-Institut für Höchstfrequenztechnik
For the first time ever, a cloud of ultra-cold atoms has been successfully created in space on board of a sounding rocket. The MAIUS mission demonstrates that quantum optical sensors can be operated even in harsh environments like space – a prerequi-site for finding answers to the most challenging questions of fundamental physics and an important innovation driver for everyday applications.
According to Albert Einstein's Equivalence Principle, all bodies are accelerated at the same rate by the Earth's gravity, regardless of their properties. This...
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
23.01.2017 | Health and Medicine
23.01.2017 | Physics and Astronomy
23.01.2017 | Process Engineering