Archive for December 16, 2015

Winter: A Dirge

Posted in Poetry with tags on December 16, 2015 by telescoper

The wintry west extends his blast,
  And hail and rain does blaw;
Or the stormy north sends driving forth
  The blinding sleet and snaw:
While, tumbling brown, the burn comes down,
  And roars frae bank to brae;
And bird and beast in covert rest,
  And pass the heartless day.

“The sweeping blast, the sky o’ercast,”
  The joyless winter day
Let others fear, to me more dear
  Than all the pride of May:
The tempest’s howl, it soothes my soul,
  My griefs it seems to join;
The leafless trees my fancy please,
  Their fate resembles mine!

Thou Power Supreme, whose mighty scheme
  These woes of mine fulfil,
Here firm I rest; they must be best,
  Because they are Thy will!
Then all I want—O do Thou grant
  This one request of mine!—
Since to enjoy Thou dost deny,
  Assist me to resign.

by Robert Burns (1759-1796)

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A Bump at the Large Hadron Collider

Posted in Bad Statistics, The Universe and Stuff with tags , , , on December 16, 2015 by telescoper

Very busy, so just a quickie today. Yesterday the good folk at the Large Hadron Collider announced their latest batch of results. You can find the complete set from the CMS experiment here and from ATLAS here.

The result that everyone is talking about is shown in the following graph, which shows the number of diphoton events as a function of energy:

Atlas_Bump

Attention is focussing on the apparent “bump” at around 750 GeV; you can find an expert summary by a proper particle physicist here and another one here.

It is claimed that the “significance level” of this “detection” is 3.6σ. I won’t comment on that precise statement partly because it depends on the background signal being well understood but mainly because I don’t think this is the right language in which to express such a result in the first place. Experimental particle physicists do seem to be averse to doing proper Bayesian analyses of their data.

However if you take the claim in the way such things are usually presented it is roughly equivalent to a statement that the odds against this being a real detection are greater that 6000:1. If any particle physicists out there are willing to wager £6000 for £1 of mine that this result will be confirmed by future measurements then I’d happily take them up on that bet!

P.S. Entirely predictably there are 10 theory papers on today’s ArXiv offering explanations of the alleged bump, none of which says that it’s a noise feature..