18. December 2010, 15:07
As Peter Woit pointed out, there is a nice talk from the guys at CMS given at the LHC end-of-year jamboree.
Here’s my little summary of their 2010 results:
- they already reproduced much stuff from the Standard Model, including resonances from J/Ψ, Ψ’, Υ(1,2,3S) particles and Z bosons
- they also have seen top quarks with masses coherent with theory (see this paper)
- the infamous ridge (see here) seen in proton-proton collisions is also in the talk. This ridge might be an indication that the LHC already produced a state of matter called quark-gluon plasma, which is also thought to have existed in the early universe. But no really conclusive explanation for this ridge has been published so far.
- they have excluded quark substructure for energies < 4.0 TeV. This means that quarks are smaller than 5×10^-18 cm – the former limit was 10^-16 cm.
- they also put limits on new particles, which can decay into parton pairs: string resonances > 2.5 TeV, excited quarks > 1.58 TeV
- also, there’s now a lower bound of 3.5-4.5 TeV on the mass of micro black holes:
In this plot, the big black dots are the data acquired by CMS. The dashed lines are the predictions for various black hole masses. As one can easily see, no micro black holes so far.
- what’s quite impressive is that they put new limits on the mass of the supersymmetric partner of the gluon, which is responsible for the mediation of the strong force. The last limits were from the DØ collaboration, which put the limit at around 250 GeV. CMS has now put the limits at around 650 GeV.
- they also saw a massive imbalance in the production of two jets while doing heavy ion collisions. This is called jet quenching and might be another indication for the existence of the quark-gluon plasma.
- they also saw the first ever Z bosons produced in a heavy ion collider (LEP and Tevatron of course produced Z bosons before, but was only using protons, not heavy ions).
28. October 2009, 15:01
There are many unpleasant situations in your life: illness, loss of friends, failing exams, etc. Many of them are such disturbing incidents that the mere thought of them invokes a feeling of uneasiness and slight fear in us. Thinking about some of them even strikes us with plain fear and terror. One of these is failure or in other words not meeting expectations.
Fear of failure becomes an increasing problem in academic life. It is estimated that about a third of all students have to deal with such severe forms of this fear that they are not able to cope with it on their own. Reasons for this are manifold: some students depend on student loans, others fear to disappoint their parents or their advisors, some just fear failure itself.
The results of these fears are diminished living quality in terms of stress, doubts, less self esteem etc. Moreover fear of failure may lead to failure itself when causing blackouts in exams. This rises the question: How to cope with failure, how to live with the fear of it?
Failure occurs when we are not able to meet expectations in one form or another. Either we don’t meet the expectations of others or of ourselves. A delicate situation is the one where we encounter the feeling of having failed although we met the expectations of others, despite the fact that we succeeded we are disappointed because “we could have done even better”.
Then there is something which may be called “pseudo failure” or “induced failure”. The feeling of inferiority when we observe that somebody is doing the same thing as we but in a better way and with more success under harder circumstances (at least according to our perception).
There are two ways to deal with this: 1.) Avoid failure at any cost. 2.) Change the perception of failure.
It seems somewhat obvious that way one is bound to fail. Our limited resources of time, money and resilience do not permit us to go out of failure’s way for indefinit amounts of time and “induced failure” will happen every once in a while even if we shield us from it as efficiently as possible.
Therefore the way we cope with failure deals with the way we perceive it. For example: We tried to solve an equation but there are some complicated details about manipulating the various parts of the equation. Let us assume that we did not know of a specific rule A and therefore ended up with the wrong result, ergo we failed. There is a variety of ways to deal with this situation. We may think that we are worthless and it is futile to give into the illusion that we may become something desirable in the long run (this is an extreme case but it happens all to often) or we could say that we worked correctly under the given conditions (the not knowing of rule A) and that we will simply recalculate everything with bearing rule A in mind and see whether we will come up with the right result or not. These are two very different ways and there lie many in between but the point is that one is self destructive whereas the other regards failure as a constructive device. Which one helps you more at becoming a content and successful individual you may decide for yourself.
An interesting observation is that one seems to be more prone to deal with failure in a self destructive way the more one desires to be a helping hand for others and the more one tries to not bother others with one’s own shortcomings. Failure of others is regarded as acceptable while own failures are perceived as tokens of personal inferiority. You may compare this to certain languages which use different words for the actions of others and of yourself.
Moreover they seem to demand of themselves to achieve the same goals as others even if they are in a far less advantageous situation to begin with. Furthermore the wish to not bother anyone leads to a tendency of declining favors rendering one of man’s best aspects useless: the will to cooperate. Rejection of a helping hand may convince the owner of that hand to stop being helpful and even refuse to deal with you because rejection in itself is a very unpleasant feeling. In extreme cases this may lead to social isolation which will demand increasing investments of energy because you have to do everything yourself.
19. August 2009, 20:39
… world and welcome to the Strange Theorists of Light Matters!
This is our inaugural post, and in the future we hope to entertain you with nice little insights into science, generic geekery and the world from two theoretically inclined students of physics, Felix and Ulrik.
We currently do not have any schedule for postings, but we hope to write something new every few days, so check back regularly.
If something does not work, you get error messages, etc, please feel free to contact us, as work is currently going on on this blog, we’re straightening out the edges and will also update the design soon.
Enjoy this blog!
Felix & Ulrik
21. June 2009, 15:51
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