What happened before the big bang is irrelevant. It's philosophy, not science. We can only ever study what happened after the big bang (though we have a damn good understanding already from a tiny fraction of a second after onwards). Also, the Heat Death is not going to happen, that scenario is scientifically ruled out since many years.
A very unfortunate thing to say by that scientist. As a particle physicist, he should know we already have CP violation in the Standard Model that explains the matter-antimatter asymmetry partly; we just don't observe enough of it.
How does this get modded insightful!? It's meaningless junk, just some science words linked together grammatically in a sentence, but without utter meaning. Are you like the SCIgen of Slashdot comments?
I would disagree on one point, that it was expected to find a Higgs boson, and nothing else new. This situation makes the hierarchy problem a real and serious thing. Most theories out there expect something new to appear near the weak scale, i.e. within reach of the LHC. The beautiful thing about the diphoton excess which is now gone is that it was such a weakish-scale new physics signal nobody had been expecting. Alas.
The CMS experiment which I am on - only one of the several LHC experiments - went to just this conference being mentioned with ~80 new analyses. These analyses are measurements of particle properties to a greater precision, or explorations of previously unknown territory. Many of these will later be turned into papers and add on the already >400 journal papers by our experiment. Even neglecting the Higgs boson discovery, the scientific output and acquired new knowledge from the LHC has already been immense.
No, gracht is not restricted to urban setting. We use it also for any little creek dug (i.e. man-made) alongside the road, a fierce obstacle when drunk on foot or in the car... Where I live in Flanders we have them alongside almost every other road.
Last year I attended the ICHEP conference in Valencia, Spain, the largest and probably most important conference in the field of high-energy physics.
The keynote speaker, Francois Englert, noble prize physics 2013, couldn't come, and rather last minute Alan Guth from MIT was upgraded to that main talk. He's one of the fathers of ithe theory of inflation, and with the BICEP results around a fitting match for a keynote talk.
He gave an excellent first half of his talk. After that, he wandered into the multiverse, unfortunately. To me, and to many others, we had left physics, and entered philosophy. After the talk the question, which I have no doubt many had in mind, was readily asked: what about the experimental testability of it all. The answer was quite unsatisfactory, unfortunately.
Tachyons are nasty negative mass states; really just weird mathematical solutions. You would expect the Spanish inquisition more than the observation of a tachyon anytime soon.
Travelling faster than light in a medium is not that hard. The blue light in the water surrounding nuclear reactors is a result of neutrons doing exactly that: they travel faster than light in the water. Nothing fancy.
> The Eurozone nations have opted for a degree of financial integration that the UK doesn't want or need. > Obviously that hasn't worked out very well recently, at least for the economically stronger EU nations.
You mean, it hasn't worked out well at all for the economically weaker, right? They are trapped in a system of expensive debt in hands of the richer out of which they can't devaluate themselves, since they share the same currency.
Coordinator: Crucifixion? Mr. Cheeky: Er, no, freedom actually. Coordinator: What? Mr. Cheeky: Yeah, they said I hadn't done anything and I could go and live on an island somewhere. Coordinator: Oh I say, that's very nice. Well, off you go then. Mr. Cheeky: No, I'm just pulling your leg, it's crucifixion really. Coordinator: [laughing] Oh yes, very good. Well... Mr. Cheeky: Yes I know, out of the door, one cross each, line on the left.
This has nothing to do with allergies. You don't feed babies honey to avoid the very rare cases where it actually causes immediate problems. After a year it is perfectly fine. It's like some of the things that are excluded while being pregnant (cats, game meat,...), just a precaution for the possible rare, but severe consequences of an unwanted contamination.
For the same reasons the stop is expected light (naturalness, i.e. SUSY as a solution to the hierarchy problem), also the gluino is expected light. What is light? Some put it at 400GeV for the stop, and 1.5 TeV for the gluino. But it's a bit of a subjective point. So if you like natural SUSY, you expect the gluino to be around the corner, and the stop to be within reach, but probably decaying softly and therefore having escaped detection so far. How likely is such a scenario? There is no good metrci for the likelihood of models. Therefore I prefer to look at it experimentally, i.e. wrt our current limits. If the gluino and stop are just beyond our current limits, then, according to my previous posts (which apparenntly completely missed the point...) the gluino will jump in our face, while the stop will take more time.
I referred to the current limits (~1.2TeV for gluino versus 700GeV for stop), which is more or less corresponding to a couple of events on a small background - for both gluino and stop searches at their high-mass extremes. Production probability (cross section) plot for 8TeV can be seen here: http://inspirehep.net/record/1... Couldn't find a 13TeV version quickly; but the trends are the same: much higher probability for gluino paris (~g~g in red) than for stop pairs (blue curve). Now, when we move from 8TeV to 13TeV, for a gluino just at the limit, the production probability goes up much more than for a stop at its own somewhat lower limit. So I'm not assuming same mass, I'm assuming a heavier gluino actually. Of course, for a 5TeV gluino, no chance; but the same goes for a 2TeV stop - production rate too low.
Yes, the stop (and sbottom) squark is a prime target too. But it will come again a little later than the gluino. The reason is that we have excluded the gluino in most scenarios already wel beyond 1.2TeV, while the stop squark is unlimited above ~700GeV (and that's assuming ideal decays). Now, with the increase in energy, the heavier is the particle, the higher the increase in production probability. This is visualised in the following (M_X being the "mass" of the produced system, in this case twice the gluino or stop mass, since they come in paris; and the solid line being the most relevant here for strong production): http://www.hep.ph.ic.ac.uk/~ws... For a gluino at the limit of what we could exclude until now, a ~ fifteenfold increase in production probability is expected, while for stops it will be more a factor 6 or 7. A final argument why stops take a little longer is that the main backgrounds (top quark pairs, mainly) are looking quite similar even in the easier decay modes, while many of the possible gluino decays lead to signals that have a tiny background (like four-top final states).
True. But, if we are going to discover a SUSY particle in the first months after turning on, it is indeed very likely to be the gluino. Just because the probability of creating it, if it is within kinematical reach, will be large, compared to many other SUSY particles. All weakly produced particles will take more data to get hold of because they are rarer. In addition, in most models, the gluino decays give rise to spectacular collisions, that are relatively easy to distinnguish from known backgrounds.
You only need one extra symmetry (so-called R parity) to protext the proton from decay. Such a symmetry is not far-fetched, and arises in some GUT models even dynamically. Imposing this R parity yields also automatically a stable lightest supersymmetric particle, and it turns out that that can be a really plausible dark-matter candidate. This said, studies also go on about models where this R parity is not conserved, still keeping the proton's lifetime within the stringent experimental bounds.
A 126 GeV Higgs boson as we (also CMS did, btw) have observed it, and studied its properties in detail, is no problem to be accomodated in even the minimal versions of supersymmetry. What makes you say it was not expected at that mass? It's on the high side, but the higher the mass, the more that Higgs boson with or without supersymmetry would look the same in our detectors...
And you chose to ignore all the content in his/her arguments, by distorting context (the comics arguemnt) trying to undermine the credibility of GP. Who's the weak-ass, AC?
Slashdot Mirror
What happened before the big bang is irrelevant. It's philosophy, not science. We can only ever study what happened after the big bang (though we have a damn good understanding already from a tiny fraction of a second after onwards).
Also, the Heat Death is not going to happen, that scenario is scientifically ruled out since many years.
A very unfortunate thing to say by that scientist. As a particle physicist, he should know we already have CP violation in the Standard Model that explains the matter-antimatter asymmetry partly; we just don't observe enough of it.
How does this get modded insightful!? It's meaningless junk, just some science words linked together grammatically in a sentence, but without utter meaning. Are you like the SCIgen of Slashdot comments?
Sources could not confirm whether taking the taxi would land you on an Alp meadow, or among the kangaroos.
A fan of Samuel Beckett's "Waiting for Godot"! Good luck with that!
I would disagree on one point, that it was expected to find a Higgs boson, and nothing else new. This situation makes the hierarchy problem a real and serious thing. Most theories out there expect something new to appear near the weak scale, i.e. within reach of the LHC.
The beautiful thing about the diphoton excess which is now gone is that it was such a weakish-scale new physics signal nobody had been expecting. Alas.
The CMS experiment which I am on - only one of the several LHC experiments - went to just this conference being mentioned with ~80 new analyses. These analyses are measurements of particle properties to a greater precision, or explorations of previously unknown territory. Many of these will later be turned into papers and add on the already >400 journal papers by our experiment. Even neglecting the Higgs boson discovery, the scientific output and acquired new knowledge from the LHC has already been immense.
No, gracht is not restricted to urban setting. We use it also for any little creek dug (i.e. man-made) alongside the road, a fierce obstacle when drunk on foot or in the car... Where I live in Flanders we have them alongside almost every other road.
Last year I attended the ICHEP conference in Valencia, Spain, the largest and probably most important conference in the field of high-energy physics.
The keynote speaker, Francois Englert, noble prize physics 2013, couldn't come, and rather last minute Alan Guth from MIT was upgraded to that main talk. He's one of the fathers of ithe theory of inflation, and with the BICEP results around a fitting match for a keynote talk.
He gave an excellent first half of his talk. After that, he wandered into the multiverse, unfortunately. To me, and to many others, we had left physics, and entered philosophy. After the talk the question, which I have no doubt many had in mind, was readily asked: what about the experimental testability of it all. The answer was quite unsatisfactory, unfortunately.
IAAPP, and I have trouble parsing your sentences.
Can you give a reference for what you're trying to say?
Tachyons are nasty negative mass states; really just weird mathematical solutions. You would expect the Spanish inquisition more than the observation of a tachyon anytime soon.
TFS doesn't mention the word vacuum, anywhere.
Travelling faster than light in a medium is not that hard. The blue light in the water surrounding nuclear reactors is a result of neutrons doing exactly that: they travel faster than light in the water. Nothing fancy.
> The Eurozone nations have opted for a degree of financial integration that the UK doesn't want or need.
> Obviously that hasn't worked out very well recently, at least for the economically stronger EU nations.
You mean, it hasn't worked out well at all for the economically weaker, right? They are trapped in a system of expensive debt in hands of the richer out of which they can't devaluate themselves, since they share the same currency.
Coordinator: Crucifixion?
Mr. Cheeky: Er, no, freedom actually.
Coordinator: What?
Mr. Cheeky: Yeah, they said I hadn't done anything and I could go and live on an island somewhere.
Coordinator: Oh I say, that's very nice. Well, off you go then.
Mr. Cheeky: No, I'm just pulling your leg, it's crucifixion really.
Coordinator: [laughing] Oh yes, very good. Well...
Mr. Cheeky: Yes I know, out of the door, one cross each, line on the left.
The parent said "to learn *well*", and (s)he was right. English is for many people easy to get started with, but it's really hard to master well.
This has nothing to do with allergies. You don't feed babies honey to avoid the very rare cases where it actually causes immediate problems. After a year it is perfectly fine.
It's like some of the things that are excluded while being pregnant (cats, game meat,...), just a precaution for the possible rare, but severe consequences of an unwanted contamination.
A classic by now on SUSY naturalness related to LHC: http://arxiv.org/abs/1110.6926
See Section II.
The gluino plays a similar naturalness role as the stop, at 2-loop level. Now you are aware, though I made that point in my previous post too.
Just beyond the limits is not an arbitrary choice. Given our current limits already, naturalness points to these masses being as low as possible.
For the same reasons the stop is expected light (naturalness, i.e. SUSY as a solution to the hierarchy problem), also the gluino is expected light. What is light? Some put it at 400GeV for the stop, and 1.5 TeV for the gluino. But it's a bit of a subjective point. So if you like natural SUSY, you expect the gluino to be around the corner, and the stop to be within reach, but probably decaying softly and therefore having escaped detection so far. How likely is such a scenario? There is no good metrci for the likelihood of models. Therefore I prefer to look at it experimentally, i.e. wrt our current limits. If the gluino and stop are just beyond our current limits, then, according to my previous posts (which apparenntly completely missed the point...) the gluino will jump in our face, while the stop will take more time.
I referred to the current limits (~1.2TeV for gluino versus 700GeV for stop), which is more or less corresponding to a couple of events on a small background - for both gluino and stop searches at their high-mass extremes.
Production probability (cross section) plot for 8TeV can be seen here:
http://inspirehep.net/record/1...
Couldn't find a 13TeV version quickly; but the trends are the same: much higher probability for gluino paris (~g~g in red) than for stop pairs (blue curve).
Now, when we move from 8TeV to 13TeV, for a gluino just at the limit, the production probability goes up much more than for a stop at its own somewhat lower limit.
So I'm not assuming same mass, I'm assuming a heavier gluino actually.
Of course, for a 5TeV gluino, no chance; but the same goes for a 2TeV stop - production rate too low.
Yes, the stop (and sbottom) squark is a prime target too.
But it will come again a little later than the gluino. The reason is that we have excluded the gluino in most scenarios already wel beyond 1.2TeV, while the stop squark is unlimited above ~700GeV (and that's assuming ideal decays).
Now, with the increase in energy, the heavier is the particle, the higher the increase in production probability. This is visualised in the following (M_X being the "mass" of the produced system, in this case twice the gluino or stop mass, since they come in paris; and the solid line being the most relevant here for strong production):
http://www.hep.ph.ic.ac.uk/~ws...
For a gluino at the limit of what we could exclude until now, a ~ fifteenfold increase in production probability is expected, while for stops it will be more a factor 6 or 7.
A final argument why stops take a little longer is that the main backgrounds (top quark pairs, mainly) are looking quite similar even in the easier decay modes, while many of the possible gluino decays lead to signals that have a tiny background (like four-top final states).
True.
But, if we are going to discover a SUSY particle in the first months after turning on, it is indeed very likely to be the gluino. Just because the probability of creating it, if it is within kinematical reach, will be large, compared to many other SUSY particles. All weakly produced particles will take more data to get hold of because they are rarer. In addition, in most models, the gluino decays give rise to spectacular collisions, that are relatively easy to distinnguish from known backgrounds.
You only need one extra symmetry (so-called R parity) to protext the proton from decay. Such a symmetry is not far-fetched, and arises in some GUT models even dynamically. Imposing this R parity yields also automatically a stable lightest supersymmetric particle, and it turns out that that can be a really plausible dark-matter candidate. This said, studies also go on about models where this R parity is not conserved, still keeping the proton's lifetime within the stringent experimental bounds.
A 126 GeV Higgs boson as we (also CMS did, btw) have observed it, and studied its properties in detail, is no problem to be accomodated in even the minimal versions of supersymmetry. What makes you say it was not expected at that mass? It's on the high side, but the higher the mass, the more that Higgs boson with or without supersymmetry would look the same in our detectors...
And you chose to ignore all the content in his/her arguments, by distorting context (the comics arguemnt) trying to undermine the credibility of GP. Who's the weak-ass, AC?