LHCb tests the Standard Model by measuring extremely rare processes, in this case a decay pattern predicted to happen just three times out of every billion decays of a particle known as the Bs (B-sub-s) meson. Anything other than that would be evidence for new physics. Measuring the rate of this Bs decay has been a major goal of particle physics experiments in the past decade, with the limit on its decay rate being gradually improved by the CDF and D0 experiments at Fermilab, LHCb, and most recently CMS at CERN1.
“The LHCb result on Bs decaying to two muons pushes our knowledge of the Standard Model to an unprecedented level and tells us the maximum amount of New Physics we can expect, if any, in this very rare decay,” explained LHCb spokesperson, Pierluigi Campana. “We know this is an important result for the theoretical community and also nicely complements the direct searches in ATLAS and CMS.”
The Standard Model is a highly successful theory that has been put to the test by experiments over several decades, and come through unscathed. Nevertheless, it is known to be an incomplete theory, accounting for just the 4% of the Universe that is visible to astronomy. New physics is needed to account for the remaining 96%. Such new physics could manifest itself directly, through the production of new particles that would be detected by the ATLAS and CMS experiments, or indirectly through the influence it would have on rare processes of the kind studied by LHCb.
The LHCb particle detector is a highly specialised instrument specifically designed to study short-lived B mesons, and is systematically investigating the rarest decays of these particles. Since the Standard Model gives very precise predictions for such decays, they provide a very sensitive testing ground for new physics. The latest LHCb result constrains the decay rate for Bs to two muons to be less than 4.5 decays per billion Bs decays. That does not rule out new physics, but does start to constrain theoretical models for it, and helps to set the direction for searches in all the LHC experiments.
“Sometimes we feel like Achilles pursuing the tortoise,” said Campana, “we believe our distance from new physics is steadily halving, but we will eventually reach it!”
This result is scheduled to be submitted to the journal Phys. Rev. Lett. on 20 March
CERN Press Office | Newswise Science News
Computer model predicts how fracturing metallic glass releases energy at the atomic level
20.07.2018 | American Institute of Physics
What happens when we heat the atomic lattice of a magnet all of a sudden?
18.07.2018 | Forschungsverbund Berlin
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
20.07.2018 | Power and Electrical Engineering
20.07.2018 | Information Technology
20.07.2018 | Materials Sciences