CDF report 327 GeV anomaly in 4l channel

In a presentation at EPS-HEP today CFD will show a surprising cluster of 4 events in the 4 lepton “golden channel” consistent with a particle at 327GeV. There are four other events also consistent with decays via two Z bosons but at lower masses. The background expectation was 0.01 events for events over 300 GeV so the four 327GeV events are an exceptional find in 6/fb of data. The others are consistent with the background.

Other excesses at these matters have been seen elsewhere, but has D0, ATLAS or CMS seen anything simialr in the 4 lepton channel? Hopefully we will find out in the next two days.

See The Reference Frame for further details


18 Responses to CDF report 327 GeV anomaly in 4l channel

  1. Marc Sher says:

    Doesn’t think seem to be in conflict with the CMS leak from 900/pb a week ago? It showed a DEFICIT at about 325 GeV, IIRC.

    • Philip Gibbs says:

      It looks that way. The lower mass events are more in line with CMS but the 327GeV is out. We need to see the individual CMS channels I think

    • Marc Sher says:

      Never mind. It clearly isn’t a Higgs, since the production rate of a 327 GeV Higgs at the Tevatron is much, much smaller, and there is apparently no signal in the jjll mode (and CMS would be in conflict in any event). Who knows what it is?

      • Luboš Motl says:

        Dear Marc, the particle decaying to ZZ and 4 leptons wasn’t ever believed or meant to be a Higgs. It’s a search for heavy Randall-Sundrum massive gravitons and their various imitators.

      • Philip Gibbs says:

        Excuse what may be a dumb question, but how do they distinguish between what could be a massive graviton and what could be a Higgs boson in the Z -> 4l channel?

      • Luboš Motl says:

        There’s no qualitative difference in their behavior and no simple way to distinguish them. It’s just that a Higgs above 200 GeV or so is considered unlikely so the relative importance of the more exotic alternatives goes up.

      • Philip Gibbs says:

        I suppose the cross section of the Higgs is firmly predicted so if anything exceeds that it is not a Higgs.

      • Luboš Motl says:

        Well, Phil, I would say it’s not a Standard Model Higgs and other results indicate that the SM Higgs isn’t above 185 GeV. Other theories’ Higgs cross sections may be larger. If you have multiple Higgses, you may have enhancements such as the tan(beta)^2 enhancement in SUSY.

        It’s general because the individual Higgs vevs in a multi-Higgs model are lower, so their couplings have to be higher for the product – the generated masses – to be still equal to the observed ones.

        On the other hand, when you divide the role of giving masses to several Higgses, some of them may have couplings to certain matter species much smaller than the SM single Higgs, too.

  2. The peak gives additional support for M_89 hadron physics predicted by TGD. Assuming that 145 GeV CDF bump not detected by D0 is real represents M_89 pion, one can predict the mass of M_89 rho and omega and they are in good accuracy equal to 325 GeV.

    There are many other indications for M_89 hadron physics (see the summarizing article) and little summary at my blog.

  3. Walter says:

    To make it even more odd, look at the table of event properties on the last slide. Two of the 4 events in the 325 GeV region have one jet, the other two have two jets! In other words, a jet veto would remove all four!! The events not in the 325 GeV region have no extra jets….

  4. Daniel de França MTd2 says:

    Could those be resonance modes of a bootstrap model?

  5. […] the most talked about presentation so far will be the CDF search for ZZ resonances (Robson) with this striking peek at 327 GeV. This is the only talk so far that has not seen everything […]

  6. […] Finally, some theoreticians believe that some other symmetry could explain the gravitational force. Its mediator would be a spin-2 boson called graviton. So far, nor this symmetry nor any graviton have ever been seen (or is it?). […]

%d bloggers like this: