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    Physics Forecasts For 2011
    By Tommaso Dorigo | December 26th 2010 05:35 AM | 13 comments | Print | E-mail | Track Comments
    About Tommaso

    I am an experimental particle physicist working with the CMS experiment at CERN. In my spare time I play chess, abuse the piano, and aim my dobson...

    View Tommaso's Profile
    Betting a grand on the existence or not of new physics is cool, but one does not need to be that daring (or to be that daring every other day) to enjoy the game of making predictions for what the fundamental research in experimental particle physics will discover or measure in a future close enough that we can reasonably expect to experience ourselves. So here I am, at the end of this eventful 2010, to look forward rather than backward, with no additional grand to invest but some insight to use, some reputation to waste, and a bit of humour to stuff between the lines.

    2011 to me means the summer conferences here. The 2011 winter conferences will happen in just a few months and make any prediction rather dull (I know pretty well what the collaborations are going to show there already), while the 2012 winter conference -well, they're in 2012, duh. Summer 2011 conferences will occur in the summer of 2011 (this is already a quite definite prediction) and more precisely in July and August. Physicists from the Tevatron and LHC experiments will push hard to produce the best results they can in time for their (or their bosses') talks. What will they show there ?

    The data

    First of all, what data will they be analysing: this is the mother of all questions. The Tevatron has been running very steadily and it is by no means hard to predict that CDF and DZERO will be presenting results based on up to 9 inverse femtobarns of collisions; actually let me be precise; I believe they will barely arrive at 8.5 /fb or so in the most straightforward searches (like those for a Z' boson) and in just a bit less (8/fb) in the most important ones (like those for H->WW), while they will be anywhere between 6 and 8/fb in less "data-hungry" analyses.

    As for the LHC, the prediction is much harder to put together: we do not know yet even what exactly will the proton energy be, nor when will LHC restart colliding. The predictions are 8 TeV for the centre-of-mass energy, and end of March for the restart; I foresee that by July ATLAS and CMS will present analyses based on integrated lumiinosities of 200 to 500 inverse picobarns of data.

    So with the quoted data what will they be showing ? Let us go in order.

    Higgs, Higgs

    No signal of course, but slightly improved limits on its existence.

    The Tevatron will produce a new combined limit for the Standard Model Higgs boson which will look similar to the one seen last year (see right), but with 25% more data and some additional small improvement in the analysis strategy they can reach down a bit further. I believe they will NOT be excluding the LEP II "signal" yet, although they will get very close to doing so; their 95% CL limit will extend to 153-182 GeV in the high-mass region.

    ATLAS and CMS will not combine their results on the Higgs instead. Their 95% confidence-level limits will surpass those of the Tevatron, and will extend from 145 to 180 GeV. I do not foresee big differences between the results that the two experiments will produce: their sensitivity is similar.

    Z', compositeness, and other high-mass stuff

    No signal here either, but the LHC will discourage any further attempt by the Tevatron on searches for Z' bosons or other high-mass resonances. The limits that the LHC experiments will place on a Z' will likely reach out to 2 TeV, while the limits on compositeness of quarks will exceed 5 TeV. (On the left is the most constraining limit set so far, that of the CDF collaboration, which excludes Z' bosons with mass below a TeV or so).

    Top quark mass measurements

    Here we will see the first shy attempts of ATLAS and CMS to challenge CDF and DZERO on their favourite battling ground. The precision measurements of the top quark mass benefit from the excellent understanding that the Tevatron experiments have obtained of their detectors, as well as on the large datasets so far collected. The total error on the top quark mass will fall for the first time below 1 GeV, something like 173.0+-0.9 GeV or so. In Europe, measurements with a precision of 2-3 GeV will be possible, but not much below that, due to the still large uncertainty on the jet energy scale.

    New effects, anomalies, and puzzles

    The Tevatron has recently published anomalous asymmetries in the top pair production. These will continue to hold, a sign that the effect is systematic and not statistical. However, I do not believe that the source of the discrepancy will be understood in just six more months of work.

    Other standing anomalies include the potential excess of MSSM-like Higgs bosons, for which there is a 2-sigmaish excess both in CDF and DZERO for H->bb resonances at 150 GeV or so. This also is a systematic effect, and I believe that only a better understanding of QCD production of multiple b-quark jets may solve the issue -and this too will have to wait much longer than half a year. Similar excesses will continue to inspire, vacuously, the more credulous minds.

    Finally, CDF has shown a 2-sigma excess in the search for a 4-th generation t' quark. Again, this is in my humble opinion just a misnomer for a ill-understood QCD background shape; so the excess is not going to disappear, unless the authors change their background parametrizations.

    And what will the LHC have to show to inspire us ? This is quite an interesting question. In principle, ATLAS and CMS have the potential to discover a light SUSY signal quite early on -that is, now, or in the next few months. Not being a believer, I can only say that some excess or discrepancy will dutifully appear in one of the hundreds of histograms that will be searched by the CERN experiments. The look-elsewhere effect will have to be enforced without pity in order to attribute those effects to their most likely cause -fluctuations.

    All in all...

    All in all, I do not believe that I need to cancel my long-planned summer vacations to southern Greece in order to show up for the announcement of a new physics discovery. My safest prediction, in fact, remains that we will not see anything extraordinarily sexy in the next few months. Fluctuations, yes; 2- and 3-sigma excesses, yes. But nothing capable of changing my vacations agenda!

    PS: I realize that in the above text I have mentioned several topics which are potentially interesting to you. If you need references, please ask them in the comments thread below.

    Disclaimer of Liability: I do disclaim thee, oh Liability!
    The above text represents the personal opinion of the author. They do not in any way reflect those of the scientific collaborations of which he is a member.



    Comments

    Hi Tommaso.

    I think it is worthwhile adding to the list potential surprises from neutrino physics experiments and Dark Matter searches. Contrary to many expectations, BSM physics may surface sooner in these areas of research.

    Your thoughts?

    Cheers,

    Ervin

    dorigo
    Hi Ervin,

    I was forecasting the results of collider experiments. I have not been clear enough on that... Sorry!
    Cheers,
    T.
    Bonny Bonobo alias Brat
    Tommaso, are you also predicting the discovery of more anti-matter like the anti-hypertriton found at RHIC and STAR earlier this year? Surely these are also the results of particle collider experiments?
    My latest forum article 'Australian Researchers Discover Potential Blue Green Algae Cause & Treatment of Motor Neuron Disease (MND)&(ALS)' Parkinsons's and Alzheimer's can be found at http://www.science20.com/forums/medicine
    Tommaso, your predictions are that, essentially, nothing really new is going to show up.
    But if we have "no signal of course" for Higgs from both LHC and Tevatron, and improved 95% exclusion limits for up to 185 GeV, will this mean that we have to expect a "low mass" Higgs (around 130 GeV), or that we have to prepare to live with a higgsless physics?

    dorigo
    Hi Filippo,

    the fact that the Higgs is excluded does not mean it is not there... Only that we had a downward background fluctuation somewhere! A 95% C.L. limit is something which is wrong 5% of the times.

    In any case I believe the Higgs is light, and in the 115-130 GeV range, where next year nobody will be able to yet see it conclusively.

    Helen, are you trolling ? You well understand I was referring to Tevatron and LHC. There are dozens of colliders around the world apart from those two, but I am not overly interested in what they are presently doing -mainly because of the high interest of what is going on especially at CERN.

    Best,
    T.
    Bonny Bonobo alias Brat
    Sorry Tommaso, I wasn't meaning to troll, I was genuinely wondering if there was any chance of any antimatter or strange matter being created and recorded at Tevatron and /or LHC next year? In the same way that some was created and recorded at RHIC earlier this year, for the very first time on Earth, by smashing gold atoms at each other at super-high speeds in a particle collider.

    If asking these questions is trolling then I apologise and please feel free to delete my comments/questions.
    My latest forum article 'Australian Researchers Discover Potential Blue Green Algae Cause & Treatment of Motor Neuron Disease (MND)&(ALS)' Parkinsons's and Alzheimer's can be found at http://www.science20.com/forums/medicine
    dorigo
    Come on Helen, don't get me wrong. I am slightly unhappy with myself of having called this post "physics forecasts" instead of "hadron collider physics forecasts"... Or to just explain in the text that what I feel entitled to make predictions about are just the results of the LHC and Tevatron colliders.

    Cheers,
    T.
    Bonny Bonobo alias Brat
    So Tommaso, does that mean that you do not feel entitled to make predictions about antimatter or strange matter like anti-hypertriton being created in the LHC or Tevatron colliders next year, whereas someone else who is working on this area at these establishments might be able to?

    Or is it simply that noone is trying to create or detect antimatter or strange matter at LHC or Tevatron next year, so the detectors and the 3 level trigger system are not programmed or positioned to detect them if they should occur, because they are instead looking for the Higgs boson etc.?
    My latest forum article 'Australian Researchers Discover Potential Blue Green Algae Cause & Treatment of Motor Neuron Disease (MND)&(ALS)' Parkinsons's and Alzheimer's can be found at http://www.science20.com/forums/medicine
    dorigo
    Helen, I mis-read you above, as I already said. Must be the wine I drunk over christmas... However, this post was essentially concentrated on the high-energy frontier.
    Cheers,
    T.
    Bonny Bonobo alias Brat
    Tommaso, couldn't the creation of new but observable antimatter and strange matter such as the anti-hypertritons recently found at STAR also occur in the high-energy frontier where you are making these predictions? I've just read your article on the 'look elsewhere' effect which you say -
    The 'look-elsewhere effect' is very common in physics searches for uncommon events. It is present in all searches for new particles, for instance. A new particle may be discovered by reconstructing its mass from the measured energy and flight direction of all its decay products.
    What I'm trying to understand is if anyone really is 'looking elsewhere' at LHC and Tevatron, let alone making predictions or are they being quite blinkered in their searches? Would they even notice if an old school friend they hadn't seen for 20 years was sitting in a restaurant in a strange country, if they are too busy looking at their amazingly sexy or good-looking waiter or waitress?

    I also agree with Rafael that you don't always need statistical significance from multiple events in a hypothetically, acceptable sample size for it to still mathematically exist and even be predictable. Just because something only occurs very rarely like the Big Bang or the origin of life for example, it is still scientifically significant, provable and predictable, if not easy to reproduce in large numbers.

    Surely the combination of overly focused, statistical analysis and the 'look elsewhere' effect have the potential to blind scientists to the real occurrence of rare but significant events that still have scientifically repeatable causes and effects? Does that make them 'supernatural' and therefore not worth even looking for let alone predicting that at least one will be found next year, according to your logic?
    My latest forum article 'Australian Researchers Discover Potential Blue Green Algae Cause & Treatment of Motor Neuron Disease (MND)&(ALS)' Parkinsons's and Alzheimer's can be found at http://www.science20.com/forums/medicine
    dorigo
    Hi Helen,

    "looking elsewhere" does not mean not looking. It means looking in too many places at once for the same thing, multiplying the chances that some normal statistical fluke resembles a signal.
    I think the LHC experiments can do all that RHIC did, plus more; already we saw things in heavy ion collisions that were never seen before, and we only started looking. Give us time, and all your questions will be answered by ATLAS and CMS...

    Cheers,
    T.
    Bonny Bonobo alias Brat
    Thanks Tommaso, just out of interest can you tell me how much 'missing energy' such as neutrinos is detected or calculated to have occurred on the average run at CMS?
    To accomplish this, a series of "trigger" stages are employed. All the data from each crossing is held in buffers within the detector while a small amount of key information is used to perform a fast, approximate calculation to identify features of interest such as high energy jets, muons or missing energy.
    My latest forum article 'Australian Researchers Discover Potential Blue Green Algae Cause & Treatment of Motor Neuron Disease (MND)&(ALS)' Parkinsons's and Alzheimer's can be found at http://www.science20.com/forums/medicine
    Hi Tommaso.

    By the end of 2011 physicists will find a solution to define god by physics and in few years they will discover GOD .THERE IS A POSSIBILITY TO DO EXPERIMENTS FOR THIS DISCOVERIES. BY 10 YEARS MACHINES WILL BE INVENTED FOR THIS SUPER NATURAL PHYSICS.

    Just it is an adding for you.

    regards,

    Siva prasad kodukula