## Sunday, July 12, 2015 ... /////

### LHC matches the whole atmosphere in the number of produced Higgses

The LHC just passed 1,000 inverse microbarns per second [live] (divide 1,000 by 31.69 to get the value in "inverse femtobarns per year" – yes, it would be 30 inverse femtobarns per year). Thanks to Phil Gibbs. So it may be a good time for some musings about "how much stuff the LHC creates".

Jonathan Butterworth of ATLAS just posted a funny little comment in his Guardian blog:

Nature's hadron collider produces Higgs bosons all the time, high in the sky
He mentions the bachelor thesis by Josua Unger who has calculated how many Higgs bosons are created in the atmosphere due to the collisions of the cosmic rays with the air.

To make the story short, and I guess that you came here to get the important information more efficiently than elsewhere, Unger decided that the proton-proton and proton-neutron collisions are the most important ones for the production of the Higgs bosons in the atmosphere. So some protons arrive from the rest of the Universe (probably not neutrons – they are unlikely to live long enough for the astronautic journey) and they collide with the protons and neutrons in the atmosphere (they almost never make it to the surface – the atmosphere is our protective shield).

Microscopically, from the subnuclear point of view, these collisions may be represented as the gluon-gluon fusion, much like the dominant channel at the LHC. When Unger combined the numbers, and I haven't verified the arithmetics, the result for the number of Higgs bosons produced in the atmosphere is$\frac{dN}{dt} \approx 7.2\,\frac{\text{Higgs bosons}}{{\rm minute}}$ The 1-sigma confidence window is between 2 and 9 Higgs bosons per minute. Using the most likely value, it's 430 Higgs bosons per hour, 10,400 Higgs bosons per day, and 3.8 million Higgs bosons per year. At the end of his thesis, Unger quotes the result for a 73-day period to be compared with an active period of the LHC in 2012. He gets 760,000 Higgs bosons in the atmosphere.

To compare, the LHC has produced something like 493,000 Higgs bosons in the 2012 run, almost all of which came in the 73-day period mentioned above. You can see that the rates of the Higgs bosons produced by the LHC and the whole atmosphere are comparable. Nature is a little bit faster but sometime during the 13 TeV or 14 TeV LHC run, the LHC will beat the whole atmosphere in the number of the produced Higgs bosons (per day).

Butterworth spins this result by saying that he is surprised that a loser like Mother Nature is capable of beating the wise guys like him who work at the LHC. Well, it's a possible perspective. I still tend to be impressed by the opposite observation: that a bunch of humans playing with a tube filled with magnets are going to be able to trump the whole blue, not green planet that is playing with the collider made out of the whole Universe around us.

If you were neglecting the short lifetime of the Higgs $1.56\times 10^{-22}\,{\rm sec}$ – the real figure may be even shorter if there are invisible decays of the Higgs, and they can make up to 50 percent of the decays, according to some papers – and you were imagining that the "Higgs boson emissions" are as dangerous as the carbon dioxide emissions (that cause at least 883 terrible things, according to the religious cult that believes these things), you could potentially face some dilemmas.

We have often mocked the LHC alarmists by saying that the LHC is doing something that has been taking place for billions of years. Detectors are usually not waiting around the point in the atmosphere where the cosmic rays produce a Higgs boson. But the Higgs bosons are still being produced over there.

Yes, the total number of the Higgs bosons that the whole atmosphere has created in the 4.6 billion years is much greater than what the LHC has done – the rates are comparable but the LHC has so far operated for 73 "really hectic" days only. But if you construct a somewhat more contrived conspiracy theory – the Higgs bosons are very dangerous if they're close to a solid or something like that – you could end up with the conclusion that the physicists have already created a greater accumulated threat than the cosmic rays in the atmosphere since the formation of the Solar System.

Needless to say, I don't think for a nanosecond that it's possible that the Higgs bosons – or any other objects created by the colliders in the past or in the foreseeable future – may be dangerous. But it is interesting that if you were only relying on the simplest arguments in favor of the safety of the colliders, namely comparisons with the "natural backgrounds", you could get to the point at which the extra LHC collisions would increase certain backgrounds by a large factor.

The mankind has already increased the CO2 concentration in the atmosphere by 40 percent relatively to the pre-industrial era. But as we have seen, that's far from being the only discipline in which the mankind is already matching or beating Mother Nature. We are going to produce more Higgs bosons than the atmosphere per day. There are many other examples like that. For example, the Earth become a completely different object – a bright star – when observed in the high-frequency radio or microwave signals.

Is that a fatal sin for the mankind to have changed the planet from these points of view? I don't think so. The Earth is doing some things it wasn't doing in the past – but they're really a good thing. These changes are testimonies to the human prosperity, skills, creativity, and curiosity. And humans shouldn't be singled out. After all, humans are a part of Nature, too.