Icecube Rules Out The Sterile Neutrino Model For Lsnd

All babies are beingness killed in addition to embryos are beingness aborted these days.

ATLAS in addition to CMS at the LHC accept basically ruled out all theories predicting novel particle physics phenomena for the offset 10/fb of the \(\sqrt{s}=13\TeV\) data.

Meanwhile, South Dakota-based LUX has improved the limits on the WIMP nighttime thing cross department past times a component of four: nighttime matter, if it exists, is harder to move straight detected than previously thought. (Dark thing may also move composed of LIGO-style dark holes inward which illustration nosotros volition hopefully non play with it hither on Earth.) I must cite that well-nigh simultaneously, a China-based experiment PandaX-II has basically matched the results of LUX. See a comparison of the ii charts.

Lots of form hypothetical novel particles in addition to processes were killed or postponed. What happened to the evil ones? They were killed or postponed, too. This also applies to sterile neutrinos, a detail identify unit of measurement of beasts that are totally plausible but non dear past times people similar me.



IceCube is based on the 86-string theory.

At the South Pole, The IceCube Neutrino Observatory was designed to regain \({\rm TeV}\)-scale high-energy cosmic muon neutrinos. Those instruct converted to muons in addition to IceCube is especially sensitive to those.




In 1996, the LSND collaboration inward Los Alamos announced the evidence for some form of novel neutrino oscillations, \(\bar\nu_\mu\to \bar\nu_e\), that differed from the to a greater extent than established solar in addition to atmospheric neutrino oscillations.

The LSND anomaly was controversial, a betoken oftentimes repeated past times my Rutgers graduate teacher of practical particle physics, Glennys Farrar. In 1998, I was working on a term newspaper on neutrinos in addition to this "duty" has only about doubled my cognition of neutrino physics.




While the oscillation betwixt the muon in addition to electron flavors was originally proposed past times LSND, physicists apace realized that the wavelengths of the oscillations needed to explicate the LSND observation disagree with the parameters (squared majority differences) obtained from the other, to a greater extent than well-known oscillations.

The most pop mental attitude alongside the pro-LSND phenomenologists was to ask some other season of the neutrinos but 1 that has no associated charged lepton – because nosotros haven't seen a 4th charged lepton species – the sterile neutrino. The discussion "sterile" way that it is impotent to breed a charged lepton through interactions involving a virtual \(W\)-boson.



IceCube drilling tower in addition to hose reel inward 2009.

You may selection the simplest model of this sort in addition to claim that the observed oscillation was genuinely changing muon neutrinos into the new, sterile neutrinos. That gives y'all a well-defined model that may move tested. And it only happens that IceCube has tested it. IceCube wasn't designed to examination sterile neutrinos – instead, only those ordinary ones inward the cosmic rays. But it only turns out that due to some luck inward the numbers, IceCube is sensitive just to these hypothetical sterile neutrinos proposed to explicate the LSND anomaly.

Well, inward May 2016, IceCube released a preprint

Searches for Sterile Neutrinos with the IceCube Detector

which only appeared inward PRL in addition to where they excluded some slice of the parameter infinite of theories with sterile neutrinos. In particular, the best betoken fitted to explicate the LSND anomaly was ruled out at some 99% confidence level. The disappearance of the muon neutrinos could accept been seen but it wasn't.

Because of the publication inward PRL, the story was covered inward ii semi-technical articles published past times the Symmetry Magazine in addition to Physics.APS.org. Some paragraphs inward these articles instruct beyond my text. I also liked the factoid that 1 banana (the most pop radioactive fruit) emits some 10 neutrinos a second.



This negative outcome doesn't grade what is the true explanation of the LSND anomaly. Obviously, 1 possible uncomplicated explanation is that the LSND members were intoxicated past times LSD – there's some linguistic evidence supporting this hypothesis. Am I the offset 1 to accept noticed? :-) I don't desire to claim authoritatively that the outcome was wrong. LSND made some other claim inward 2001 in addition to Fermilab's MiniBooNE published a potentially related anomaly a decade later. Add a 2011 neutrino anomaly from reactors in addition to a 1994 anomaly from radioactive sources.

So at that topographic point is some potential evidence inward favor of novel neutrino species. On the other hand, at that topographic point are also lots of experiments with negative results, oftentimes well-nigh straight contradicting the "positive" claims above.

In the theoretical picture, I believe that sterile neutrinos are basically unmotivated – both inward quantum champaign theory in addition to string theory – but sterile neutrinos may move particles that may accept other names, e.g. "modulinos", superpartners of the scalar moduli inward string theory, or something else. So land I am basically unexcited past times the proposal to trust the sterile neutrinos without farther explanations – it is an ugly theory – I am real far from beingness able to evidence a no-go theorem of whatever sort. They're plausible in addition to their regain would move a game-changer of course.

However, at this moment, the "negative" results – exclusions – seem to move the kings of the day.