In the most complex and impressive experiment ever conducted, 2 LHC collaborations found a new particle near 125 GeV. The main signature of this particle is its disintegration into two photons. The new particle was observed about 400 times out of 1,000,000,000,000,000 collision events (each collaboration has found about 200 events above a background of about 3000 events).
I wish to do the following in this post:
* Suggest what was found in the LHC
* Make a short analysis of the new particle alternatives
* Suggest a decisive test
* Compare the two alternatives – which one is more plausible?
The missing meson
We all know that several known particles were not observed yet and one of them is the Top-Anti-Top meson (tt). Creating two top quarks in one collision event requires a lot of energy and the probability of creating them is very small. Indeed, previous experiments showed that the top quark tends to decay by the weak interaction and that its mean lifetime is nearly 10-25 seconds. This short half life time reduces the probability that a tt pair will make the bound system of a meson. However, this probability is not zero and such a meson can be created and be detected.
Let’s see why the tt meson is the natural candidate for the new 125 GeV particle.
Finding the difference
A tt meson belongs to a group of composite particles which contains an elementary spin-1/2 fermion and its anti-fermion. We know a lot about other particles in this family, like the positronium, π0 and others. Therefore, we can predict many of the tt system properties. In order to distinguish between tt and the Higgs we should look for a property which can differentiate between them. Measuring such a property can tell us whether we found the God Particle or an innocent tt meson.
The electric charge of the tt and the Higgs are both zero. Therefore, their electric charge cannot distinguish between the two.
A tt system has several angular momentum (spin) possibilities. It may be zero (e.g.: in its ground state) or non-zero. The mass difference between the ground state and other states of a meson that contain heavy quarks, is very small (here), so we can assume that around 125 GeV we will find a mixture of several states of tt with different spins.
However, a disintegration into two photons holds for a spin-zero state of the tt system. This is also the spin of the Higgs boson. Therefore, measuring the spin is not an effective method for differentiating between the two candidates.
tt decay modes can be deduced from other quark-antiquark pairs, like π0. There are additional decay channels which contribute to the quick weak decay of the top quark. Therefore, it is reasonable to deduce that the following are possible decay modes of the tt:
Photon-Photon. Most of the observed decays of the new 125 GeV particle are photon-photon. A photon-photon decay channel is well known in nature, and we know the following:
– EVERY composite particle which consists of a charged spin-1/2 particle and its anti-particle and has an appropriate spin and parity may decay into photon-photon. For example, for the ground state of the positronium (electron+positron) this is the only decay channel. Regarding π0, this is close to 99% of the π0 decays. The photon-photon decay channel is also seen in the eta and the f0(500) mesons, etc.
– ALL the known particles which decay into a photon-photon pair consist of a charged spin-1/2 particle and its anti-particle.
– tt consists of a charged spin-1/2 particle and its anti-particle.
– The Higgs is not.
I want to add a theoretical remark for physicists: like the positronium and the π0, a tt meson is a composite neutral system which is made of charged particles. Its coupling to the electromagnetic fields is thus a self-evident phenomenon. On the other hand, the Higgs boson is an elementary particle. As such, it must be pointlike. Therefore, there is no direct coupling of the chargeless pointlike Higgs boson to the electromagnetic fields. For this reason, one must use a two-step process where the Higgs decays into a charged particle-antiparticle system and this pair disintegrates into two photons in a way which is analogous to that of a composite neutral system like the positronium and the π0.
A decay into Photon + lepton-antilepton, and a decay into 2 lepton-antilepton pairs. The decay to photon+lepton-antilepton exists even in the quite low energy system of the π0 (around 1% of π0s decay into one photon and a pair of electron-positron). An analogous decay should also exist in tt as well. Furthermore, the decay of tt into 2 lepton-antilepton pairs should be significantly less frequent than its decay into one photon+lepton+antilepton.
The photon+lepton+antilepton decay channel is not reported in the LHC experimental Higgs search. Probably because it is not an expected decay channel of the Higgs and therefore scientists didn’t look for such decay mode.
There might be other tt decay channels involving other kinds of weak interactions. Such channels should be explored as well.
A decisive test
From the simple analysis described above, a decisive test for telling which particle was observed near 125 GeV is rather clear. LHC should measure 2 numbers:
A – the number of one photon+lepton-antilepton decay events.
B – the number of 2 pairs of lepton-antilepton decay events.
If A>B then it is not the Higgs. If A<B then it is not tt.
It is possible that the suggested decay mode of photon+lepton-antilepton was not even considered so far. I hope that CERN scientists will look in the near future for this decay channel near 125GeV.
Why it is not the Higgs
The new observed particle certainly walks like tt and quacks like tt: the very small number of observed events is compatible with this heavy meson. The decay of the new particle into two photons strongly suggests that it is a composition of charged spin-1/2 particle-antiparticle, like tt. The very small number of 2 pairs of lepton-antilepton decay is also compatible with the expected tt decay channels.
Furthermore, it cannot be the Higgs, without introducing a new and very complicated mechanism which creates two photons out of a chargeless elementary pointlike particle via an intermediate particle-antiparticle state.
And last but not least – it cannot be the Higgs because the Higgs equations are inconsistent. Anyone who is interested can read 3 proofs showing these flaws in chapter 4 in the following article: Physical Consequences of Mathematical Principles.
The top quark is by far the heaviest quark and therefore a tt bound state belongs to the heaviest meson family. But I’m afraid that tt is not as attractive as the God particle. Let’s hope that the LHC physicists will make the decisive test which I mentioned above. After all, scientists look for the scientific truth. Doing this test obviously will tell us more about the new observed particle, no matter what our expectations are.