Super symmetry
continues to not be productive and by extension is looking less and less useful. That does happen. The standard theory found useful symmetries
from the data at hand and by direct inference.
Stepping out, it becomes necessary to have a clearer foundation than just
the inferred geometry.
This will not change
until we succeed in modeling the fine detail involved.
Beyond all that it is
good to see that the standard model continues to hold up well.
LHC
Discovery Maims Supersymmetry, Again
JUL
24, 2013 02:45 PM ET // BY IAN O'NEILL
This
is one discovery that will likely excite and disappoint physicists in
equal measure. Large Hadron Collider (LHC) scientists have confirmed the
detection of an ultra-rare subatomic decay for the first time, a decay that is
predicted by the Standard Model. Unfortunately for supersymmetry proponents, that’s
one hefty blow against their theory.
But
before we can understand the bad news, it’s best to start with the good news.
The
Good: Standard Model Glory
On
its ongoing mission to explore the most primordial of matter of the Universe,
the LHC slams particles (usually protons, sometimes higher-mass hadrons like
lead nuclei) together at close to the speed of light. By doing this, for the
briefest of moments, the energy conditions that existed shortly after the Big
Bang are created. From this energetic soup, particles that were last seen
buzzing around the ancient universe some 13.75 billion years ago condense from
the blast of energy, like raindrops condensing inside a raincloud.
By
their nature, these newly-condensed particles buzzing inside the LHC’s
monstrous detectors are unstable, so they quickly decay into other particles.
These decays are extremely important to physics as they provide a very
privileged view into how particle interactions worked during the earliest
moments of the universe and bolster decades of scientific theory.
The
Standard Model of physics is the theoretical framework by how all matter should
act. And in this case, the Standard Model predicts that a very, very rare decay
should occur for a specific particle in a very specific way. The LHC — with its
vast energies, ultra-high resolution detectors and epic computing power — is
the first machine available to mankind that can probe and detect these
extremely rare and specific decays.
So,
after analyzing two years worth of data from the LHC, physicists from two LHC
experiments, LHCb and CMS, have announced the discovery of the decay of the Bs meson
into two muons. (A meson is a hadron and composed of a quark and anti-quark.
Muons are the larger cousins of electrons.)
To
see this Bs decay, however, you need to be patient — the particle only
decays into two muons three times out of every billion decays. For a
particle collider that produces hundreds of millions of collisions every
second, that’s countless trillions of particle interactions that need
to be analyzed to weed out the desired Bs decays to any statistical
significance.
“Finding particle decays this rare makes
hunting for a needle in a haystack seem easy,” the LHC physicists said in this
morning’s news release (July 24).
In
short, the detection of Bs meson decaying into two muons at the exact rate
predicted is a huge triumph for the Standard Model of physics. Add that to the
recent confirmed discovery of the Higgs boson that appears to exist at exactly
the energy predicted by the Standard Model.
This
model may have its restrictions, but it has once again proven that it’s a very
good “recipe book” for how the universe works on a subatomic level.
The
Bad: Supersymmetry Woes
But
it’s not all good news. In fact, it rather depends on your definition of
“good.”
Physicists
have long been concerned by the Standard Model’s inability to account for
gravity, dark matter and dark energy. So, as the Standard Model is pushed to
its limits by particle accelerators like the LHC, physicists have been
carefully watching for any slight oddities in particle collision data. In the
hope that supersymmetry theory (or “SUSY”) may help explain dark matter, for
example, they’ve been expecting small signatures of supersymmetry revealing
itself in experimental results. SUSY should skew the Bs decay rate
slightly, but, as this most recent discovery has once again proven, the
Standard Model isn’t budging and there’s no sign of anyexperimental
evidence for supersymmetry — the Bs meson decay rate is spot-on.
“Measurements of this very rare decay
significantly squeeze the places new physics (i.e. SUSY) can hide,” said Val
Gibson, leader of the Cambridge particle physics group and member of the LHCb
experiment. “It is the dedication of our students and post-docs that make such
measurements possible. The UK LHCb team are now looking forward to the LHC
returning at even higher energy and to an upgrade to the experiment so that we
can investigate why new physics is so shy.”
While
this isn’t the end for supersymmetry, it is a blow for our
understanding of what lies beyond the Standard Model.
The
Ugly: A Dark Dilemma
Understanding
the nature of dark matter and dark energy are two of the biggest challenges for
all of physics, from the quantum world to cosmology. Supersymmetry — which
predicts that for every particle of “normal” matter there’s a “superpartner”
particle — may help explain why 95 percent of the mass-energy of the universe
is invisible. (Dark matter has been detected indirectly by its gravitational
impact on normal matter and dark energy is the invisible force that has been
indirectly observed as the force that accelerates the expansion of the
universe.)
But
if we cannot detect any evidence of supersymmetry, what the heck is dark
matter and dark energy? Let alone gravity; that ‘everyday’ force remains as
mysterious as ever.
Unfortunately,
until the LHC turns up supersymmetry evidence, or spits out some totally
unpredictable exotic dark matter particle, dark matter and dark energy will
remain a mystery.
And as for supersymmetry theory, well, it will
soldier on while physicists push particle accelerators to ever higher energies
in the hope of seeing over the Standard Model horizon and into a new landscape
of exotic physics that may, or may not be, supersymmetrical in nature.
Image:
Simulation of particle collisions and Bs decay inside the LHCb detector.
Credit: CERN/LHCb Collaboration
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