LHCb experiment squeezes the space for expected new physics

March 6, 2012

(PhysOrg.com) -- Results presented by the LHCb collaboration this evening at the annual ‘Rencontres de Moriond’ conference, held this year in La Thuile, Italy, have put one of the most stringent limits to date on the current theory of particle physics, the Standard Model. 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 CERN.

“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 Physical Review Letters on 20 March.

Explore further: Large Hadron Collider achieves 2011 data milestone

More information: Quantum diaries: LHCb finds a few very special events out of 10 billion

Related Stories

Large Hadron Collider achieves 2011 data milestone

June 19, 2011

Today at around 10:50 CEST, the amount of data accumulated by Large Hadron Collider experiments ATLAS and CMS clicked over from 0.999 to 1 inverse femtobarn, signalling an important milestone in the experiments' quest for ...

Rare particle decay could mean new physics

August 23, 2011

(PhysOrg.com) -- An incredibly rare sub-atomic particle decay might not be quite as rare as previously predicted, say Cornell researchers. This discovery, culled from a vast data set at the Collider Detector at Fermilab (CDF), ...

CERN's LHCb experiment takes precision physics to a new level

August 29, 2011

(PhysOrg.com) -- Results presented by CERN1's LHCb experiment at the biennial Lepton-Photon conference in Mumbai, India on Saturday 27 August are becoming the most precise yet on particles called B mesons, which provide a ...

The importance of statistics in high-energy physics

January 20, 2012

“If you remember, Mark Twain once said, ‘There are three kinds of lies: lies, damned lies, and statistics.’ If you use statistics in an improper way, you could get pretty much any result,” says Greg Landsberg, ...

Recommended for you

A quantum of light for materials science

December 1, 2015

Computer simulations that predict the light-induced change in the physical and chemical properties of complex systems, molecules, nanostructures and solids usually ignore the quantum nature of light. Scientists of the Max-Planck ...

Quantum dots used to convert infrared light to visible light

December 1, 2015

(Phys.org)—A team of researchers at MIT has succeeded in creating a double film coating that is able to convert infrared light at modest intensities into visible light. In their paper published in the journal Nature Photonics, ...

Test racetrack dipole magnet produces record 16 tesla field

November 30, 2015

A new world record has been broken by the CERN magnet group when their racetrack test magnet produced a 16.2 tesla (16.2T) peak field – nearly twice that produced by the current LHC dipoles and the highest ever for a dipole ...

Turbulence in bacterial cultures

November 30, 2015

Turbulent flows surround us, from complex cloud formations to rapidly flowing rivers. Populations of motile bacteria in liquid media can also exhibit patterns of collective motion that resemble turbulent flows, provided the ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.