Stop rumours!

Meaning that there are rumours going round about stops or scalar tops, not that we should stop spreading rumours. In SUSY theories stops are the lightest sfermions (scalar fermions are bosons not fermions) related to top quarks which are the heaviest leptons and indeed the heaviest particle in the standard model. If stops exist they would help stabilise the Higgs vacuum which could be too unstable if the Higgs mass is around 125 GeV as now expected, but noone has seen one yet and the situation for theorists has been getting a bit desperate because they had expected to see them at the LHC and the so the anti-SUSY bloggers have been poking fun and saying I told you so.

Now rumours have been squarked to the blogotwittersphere via Motl at TRF and Jester of Resonaances that a signal for the stop has been seen in the data. the story so far has been summed up by Cliff Harvey on Google+ so look there for the details. There is a seminar next week that could be relevant to the rumour but Jester’s last tweet says knowingly  “Caution: theorists rumoring about stops is fact, but what is now out on blogs is 100% false. Dont jump unless more reliable rumors appear” so what is going on?

Sooner or later someone is going to start a rumour just to catch us out. So is the greatest news story in the history of science about to break or have we been duped by a revengeful experimentalist who saw the next seminar as an opportunity to get back at us for all those earlier leaks on the theory blogs? Is it indeed a slepton or something we should have slept on?

By the way there is an LHCb seminar about to be webcast and they are the only ones with plausible BSM signals so far so let’s slide back to reality and enjoy that, until next week.


29 Responses to Stop rumours!

  1. What is the difference of signal between a sTop and another W?

    • I just noticed the word, scalar, so instead of W, why not another higgs?

      • Philip Gibbs says:

        I don’t know many details but off the top of my head I know that the stop has the same charge as the top (2/3 e) and is coloured so it must be produced with other quarks or squarks and these can form jets. The W has charge +e or -e and is not coloured so it will look very different. The stop is a scalar so it has spin zero whereas the W has spin 1, so they are going to look very different. The Higgs has the same spin but no charge or colour, even a charged Higgs would be very different.

    • Ray Munroe says:

      In many SUSY scenarios, the stop squark is the lightest squark. Because of its anticipated couplings to top (and bottom) quarks, along with the LSP, we might expect stops to decay into missing mass and momentum (the ‘invisible’ LSP’s) along with many bottom-tagged jets.

      The Wino is a spin-1/2 fermionic particle that may be related to a SUSY m_1/2 mass parameter (>800 GeV), whereas the stop squark is a scalar bosonic particle that may be related to a SUSY m_0 mass parameter (also >800 GeV) reduced by a factor of the top mass-squared. I personally have been anticipating the discovery of the stop squark prior to other SUSY sparticles – due to its lighter mass, and fairly unique signals.

      Have Fun!

  2. Luboš Motl says:

    I like your suggested hypothesis that an experimenter, and perhaps a malicious phenomenologist such as Jester himself, could have fabricated the rumor. That would fully explain Jester’s mysterious tweet, indeed! :-)

    But I don’t think it is a catastrophe if one writes a blog entry about a rumor, calling it a “rumor”, and the rumor turns out very inaccurate or completely false. Many if not most rumors face the same fate.

    • Philip Gibbs says:

      Of course, we can laugh at ourselves and quietly plot our next move to get our own back. :-)

    • Luboš Motl says:

      The move I am personally plotting is thinking about how I will deal with the $10,000 SUSY bet (against $100) that Jester will lose to me, or which methods to enforce justice I will use in the case that he would decide to hesitate with the payment. I really can’t afford to forgive him a penny.

  3. JollyJoker says:

    Apologies for the off topic post, but the official (separate) Atlas and CMS Higgs combinations are available. Doesn’t seem like much of a change at first glance, but the CMS signal might be a bit stronger if I remember the December one correctly.

    Both seem to have far more gammagamma signal than expected, but I have no idea how likely random chance is to do that.

    Dorigo has a post at
    http://www.science20.com/quantum_diaries_survivor/atlas_and_cms_publish_2011_higgs_results-86735

    Obviously, I fully expect you to have finished the combination by the time I click Post… :)

    • Philip Gibbs says:

      Very interesting. This fulfills some recent mini-rumours at NEW and OPS. I will have to update my combinations so that they can be compared properly with the official ones, but not today.

  4. Sometimes a rumor has its grounding in our subconscious intuitions and what forbids it cannot be true.

    I am not saying it is true but thanks for the dynamics of the concepts (scalars as bosons as the only view aside)

    No one will catch you out on this most noble scientific experiment and research, it is not about prestige but actually going to Mars.

    Now, consider this… from my view the gene code begins to be read where something stable and solid starts… and there are the stops. But in an odd way what is start is the stop when we add to the quantum formula the few adjusted inverses.

    Now, the issue is what is the mechanism of mass anyway- and the standard model has its successes on some levels.

    ThePeSla

  5. From the posting of Jester one learns that the signal is indeed twice too strong in gamma+gamma channel to be assigned with standard model Higgs. There is also a signal for WW fusion to Higgs. This signal should not be yet observed for standard model Higgs. Both ATLAS and CMS are explained to have been too “lucky”!

    This “luckiness” is turning into a trouble as the statistics improves. I feel it boring to repeat what I have said so many times: there might be no Higgs there and M_89 hadron physics could be the proper explanation for the too strong signal and also other signals which have been suddenly forgotten in fashionable and well-informed blogger circles.

    See my recent and also earlier blog posting.

  6. wl59 says:

    The signal for a possible Higgs is for CMS near 124, for ATLAS near 126-7 , with fast decreasing values at the sides so that each of these experiments exclude the other.

    There may be ‘something’, but not a Higgs, and only in the gammagamma channel

    • Luboš Motl says:

      Dear WL59,

      the signal near 125 GeV appear in many channels, including the ZZ channel, and the discrepancy between the mean value of the mass between both experiments is small and explainable by systematic and statistical errors. It’s surely not true that the experiments exclude the best theories of each other.

      It surely is a Higgs albeit extra collisions may show that it is not just a Standard Model Higgs… Ray links to a Higgs article of mine in the comment below.

      Cheers, LM

  7. Ray Munroe says:

    Hi WL59,

    You might read:
    http://motls.blogspot.com/2012/02/higgs-signal-grew-from-38-to-43-sigma.html

    This blog is supposedly about the possible discovery of the light stop squark. Such news should be as huge as finding a Higgs boson (I say ‘a Higgs boson’ because SUSY requires more than one type of Higgs boson – minimally 5). I guess everyone is waiting for Feb 14, and the hopes of real data, before they get excited.

    I nearly died last month (an aortic dissection and the necessary open-heart surgery put me in intensive care and the cardio unit for 18 days), but I’m excited to be living during such ground-breaking times.

    Have Fun!

    • Dilaton says:

      … I hope You are well again according to the circumstances ;-)

      I look foreward too to what the 14. February will bring :-)

    • Willard Mittelman says:

      Best wishes for a full recovery!

    • Luboš Motl says:

      Good to see you alive, Ray. This would indeed be a bad time to die for any physics-wise curious human so make your life a priority.

    • Lawrence B. Crowell says:

      Sorry to hear about this. I hope you have a full recovery. I don’t think you are that much older than I, and a few years ago a friend of mine my age died of a heart attack. It is uneasy reaching that phase of life, even if I come from a family who on both sides live beyond 80, often into the 100s.

      It is good to see Higgs signal get about 4-sigma. It is somewhat curious to me that this signal should have been so hard to find. It was not that long ago prior to 2009 that people were calling the Higgs a “slam dunk.” There might be something funny about it that we do not understand.

      • Ray Munroe says:

        Thank you all for the good wishes!

        Hi Lawrence,

        I’m 53 years old, but death doesn’t care about such numbers. Most of my family also lives into their 80′s or 90′s, no one else has any serious heart disease, and I thought I had my blood pressure under control with medication.

        My Cardiologist says that my operation was more difficult than a heart transplant, and that in 30 years he hasn’t seen anyone bounce back as quickly from a similar operation as I have so far. I will have permanent lifestyle changes, but I intend to get back to ‘normal’ as fast as possible.

        I hope that Philip has something interesting to post on Feb 14th!

        Have Fun!

  8. publicfunding says:

    Rumors are the best triggers to publish useless papers and mess arXiv lists with speculations and myths. Bad theoretical physicists live on confusions and ambiguities, mixing hypothetical hypothesis like middle age alchemists. Rumors are meant to give them the possibility to survive, unfortunately at the expenses of good physicists and new ideas. Poor physics, it was science once!

  9. anna v says:

    Listening to the talk at CERN at the moment.
    .
    In greek we have an expression : “the treasure was coals”.

    The slides are available in PDF, and everything is within the SM expectations. More limits, but we are told to hold our breath because the analysis is ongoing.

    I guess the spring conferences are the next time rumours can be checked.

  10. Luboš Motl says:

    My understanding is that the ATLAS talk didn’t present any new (unreleased as preprints) results at all so it was clearly unrelated to the rumor if the rumor is material at all.

    • Anonymous says:

      This is not true. The ATLAS talk reported on new results, released simultaneously that day as ATLAS-CONF-2012-003,
      ATLAS-CONF-2012-004, and ATLAS-CONF-2012-005.

  11. Soap_Bubbles says:

    In lure of the superlunimal neutrinos, should velocity terms be normalized when used in quantum field theory?

    In other words what tells us a pound of mass today is equal to a pound of the same mass tomorrow?

  12. Philip Gibbs says:

    There are still many opportunities for things to emerge from the 5/fb dataset beyond what was shown at the seminar, but It is always possible that the rumour was based on real data but that we will never hear what it was because it has gone away with more data or with a correction to the analysis. There must be lots of anomalies discussed within the collaborations that never make it into the public domain.

  13. ondra says:

    Actually if you look at the last slide{55) of the presentation, there used to be interesting anomaly after 1 fb-1 at Gluino Mediated Stop Production, but it looks like its more or less gone after 2 fb-1.

  14. Lubos Motl says:

    In the paper 003.

    http://cdsweb.cern.ch/record/1423598/files/ATLAS-CONF-2012-003.pdf?version=1

    I like the two events at meff=1.7 TeV in Figure 2a left but it’s far from what would lead me to spread a rumor.;-)

Follow

Get every new post delivered to your Inbox.

Join 270 other followers

%d bloggers like this: