Lubos: A new Z prime boson The real question is: Why? There's no excessively good reason for the Z' boson to exist and no reason for it to not exist. We just usually prefer to believe in the non-existence unless we have a reason to do otherwise - unless we see a role that such a new particle could play. We don't know of such a role.
Such a new fifth force would remain a fifth wheel for some time. Imagine - people would say that there are five basic forces. One of them holds galaxies together and keeps us on the Earth; the other is responsible for all of chemistry, biology, and material science, not to speak about electromagnetic communication; the third force keeps atomic nuclei together; the fourth force causes some nuclei to beta-decay; and the fifth force adds 100 bizarre events at the Tevatron. ;-)
They could solve the mu problem in supersymmetric model building; mediate SUSY breaking; and add interesting yet dangerous predictions of flavor changing processes and new interactions with dark matter. The string-derived (beyond ordinary GUT) Z' bosons have also been claimed to be essential for light neutrino masses and proton stability.
Resonaances: The simplest explanation, proposed in this April Fools' paper, involves a 150 GeV Z' boson. A light Zprime with significant couplings to leptons are excluded by LEP and the Tevatron, but if the coupling to leptons is small then the limits are surprisingly weak. In particular, 150 GeV Z' with electroweak size couplings to quarks is perfectly allowed, and would have the right cross section to produce a bump observed by CDF. One should note that Z' with the mass of that order could generate a large forward backward asymmetry of the top production, as observed in another CDF analysis. But one should also note that generating the asymmetry requires a large flavor violating coupling u t Z' which in principle is not related to the coupling to the light quarks.
Washparkprophet: seems to solve problems that is isn't clear that we had in the first place. I'm skeptical, as are most physics bloggers looking at the announcement. Like Motl, I just don't see where the theoretical motivation for a fifth force comes from unless you have something like composite quarks or leptons out there that need to be held together and sometimes decay in high energy environments.
TGD: identification of the new particle would be as an exotic weak boson. The TGD based explanation of family replication phenomenon predicts that gauge bosons come in singlets and octets of a dynamical SU(3) symmetry associated with three fermion generations (fermion families correspond to topologies of partonic wormhole throats characterized by the number of handles attached to sphere). Exotic Z or W boson could be in question. If the symmetry breaking between octet and singlet is due to different value of p-adic prime alone then the mass would come as an multiple of half-octave of the mass of Z or W.
An entirely new interaction. Actually I have talked about entire hierarchy of scaled up variants of hadron physics (Aaaarrrrgggghhh!; do not get scared: it was an expression of extreme irritation by some colleague who believes that physics proceeds by infinitesimal steps) associated with Mersenne primes and strongly suggested by p-adic length scale hypothesis! The natural explanation for preference of quark pairs would be that strong interactions are somehow involved. This suggests a state analogous to a charged pion decaying to W boson and gluon creating the quark pair. This kind of proposal is indeed made in Technicolor at the Tevatron and has as its analog second fundamental prediction of TGD that p-adically scaled up variants of hadron physics should exist.
Resonaances: the new particle should not be too heavy and should couple strongly enough to both the 1st generation quarks and to the top quarks. Otherwise the effect would not show up on top of the QCD top pair production.should couple chirally, that is to say, with a different strength to left- and right-handed quarks. Otherwise it would not generate a forward-backward asymmetry.
A strong force for chirality?? (my comment)
the new particle has to have a large flavor violating coupling to the 1st and the 3rd generation, whereas similar couplings to the 1st and 2nd or to the 2nd and 3rd generations appear to be severely constrained by experiment. If any of these models corresponds to reality then some unexpected flavor structure is being revealed. Flavour = weak force
a new color triplet scalar decays to a top quark plus a light invisible fermion. Sounds much like stop → top + neutralino, although the required couplings do not fit SUSY. As the new particle production cannot of course interfere with the QCD top production, this possibility is somewhat disfavored by the top cross section measurements. On the other hand, such a new particle can be very well disguised, especially when its mass is close to the top mass, and is currently poorly constrained by new physics searches. Strong force again, with dark matter.
Twistor scattering theory for color say Kea.
NY Times: They found that in about 250 more cases than they expected, what came out of the collision were two jets of lightweight particles, like electrons, and a heavy-force-carrying particle called the W boson were produced. The team found that in about 250 times more cases than expected, the total energy of the jets clustered around a value of about 144 billion electron volts, as if they were the decay products of a hitherto unsuspected particle with that mass-energy. For comparison, a proton weighs about one billion electron volts.This could not be the Standard Model Higgs, Dr. Punzi and his colleagues concluded, because the Higgs is predicted to decay into much heavier particles, namely quarks.
The result does not come from a search for new physics (take note of this please) but rather from an attempt to measure the cross section for di-boson production in which one W decays leptonically (e or μ) and the other boson decays to a pair of jets. The invariant mass distribution includes a peak near the W and Z masses – the red peak in the plot above – as it should. The mass resolution is about 12 GeV and hence not good enough to resolve individual W and Z peaks; the W peak dominates anyway.There is a huge continuum background from W bosons produced with two jets.
So we have a nice, statistically-significant bump in this mass spectrum. Some theorists already posted their hypothesis (Buckley, Hooper, Kopp and Niel, arXiv:1103.6035, 31-Mar-2011) — even before the CDF Collaboration released their results! (I agree completely with Gordon Watts’ comments about this.) You can also read a report in the New York Times. I’ll not comment on that.
Of course, the observation requires confirmation. I am very sure that physicists at both ATLAS and CMS are studying their data carefully. Most probably, the D0 Collaboration will try to say something soon about it, too. So let’s pay attention and keep an open mind. Speculation is fun, but fluctuations do come and go….
(Disclosure: I am in inactive member of the CDF Collaboration but played no part in this analysis. I devote all of my research time to CMS.)
Other bloggers have already commented, ahead of me: See Physics and Physicists, Not Even Wrong, The Reference Frame, A Quantum Diaries Survivor and Cosmic Variance. I’m sure there will be lots of discussions on these blogs – and if I am lucky, a little bit here, too.