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network profile
| bio | website | |
|---|---|---|
| location | ||
| age | ||
| visits | member for | 2 years, 5 months |
| seen | 2 hours ago | |
| stats | profile views | 138 |
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May 18 |
asked | Why distinguish between row and column vectors? |
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May 13 |
answered | How to determine the direction of medium's displacement vectors of a standing wave? |
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May 13 |
comment |
Lagrangian of electromagnetic tensor in light cone coordinates? @kernel_panic: It's hard to tell what you're asking. You're saying you have the Lagrangian in light cone coordinates and would like to get to cartesian coordinates? If you add the formulas you have and describe the problem better, maybe someone could reopen the question. |
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May 13 |
comment |
Caveats when using event-by-event reweightings? Hmm, I'll write up something or look for a reference when I have time. |
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May 13 |
comment |
Caveats when using event-by-event reweightings? (Seems you need 50 reputition to comment...) I was asking about the most general case, since this has many uses: Fixing MC, estimating BGs from data, estimating trigger effects without simulating the trigger, .... You give every event a different weight, and make a certain distribution $y$ match perfectly - but have no predictive power there anymode, since data=BG per construction. You hope that in a somewhat correlated distribution $x$ (maybe with a different selection) you now have a better modelling of the BG, but you'll be able to discern the signal, in the simplest case a bump. |
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May 12 |
comment |
Gravity in other dimensions than 3 and stable orbits I wonder what happens if one just uses a different potental, so that one still has $F \propto 1/r^2$ even in higher dimensions? |
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May 12 |
comment |
Caveats when using event-by-event reweightings? Say your interested in the dilepton invariant mass, so $y=M_{\ell\ell}$. You believe the angle between leptons is not well modeled, so you correct the $\varphi_{\ell\ell}$ MC distribution ($x$). You would do that in bins of $\varphi$, and you have one factor for each bin. One may determine the factor in a sideband, but applies it to all events. You seem to be thinking about normalizing to the Upsilon peak (~10 GeV), however in the case I mean the total normalization often doesn't change. (By the way, you're answer would better be a comment. We should move this discussion there.) |
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May 12 |
asked | List of cross sections? |
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May 12 |
asked | Caveats when using event-by-event reweightings? |
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May 12 |
awarded | Informed |
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Apr 30 |
comment |
How to calculate Riemann and Ricci tensors for a sphere? I'm not sure, can't you just read off the $g_{ij}$, since the differentials are not mixed? For example $g_{\theta\theta} = R^2 \sin^2 \varphi$. I forgot why one is allowed to do that though... |
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Apr 23 |
comment |
Why does Hydrogen molar heat capacity reach 7/2 R? @Georg: I found it in need of an explanation that the 7th degree of freedom is really a separate DOF. Some simple arguments suggest otherwise: Say #6 is the wiggling, or $\dot p$ of the HO, and #7 is the motion of the center of mass, or $\dot x$. Then a) one variable is determined by the other through the HO DGL, thus they are not independent and b) isn't the movement of the center just a translation? |
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Apr 23 |
answered | Why does Hydrogen molar heat capacity reach 7/2 R? |
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Apr 20 |
comment |
How to determine predicted CP violation for a given SUSY point? Thanks. I have some negative mass parameters at the GUT scale (e.g. $M2$), but not negative squared masses, so I don't believe I have complex parameters - at least it was not my intention to introduce them. I was just told in passing by a colleague "Negative mass parameters? That's bad, you'll have too much CP violation!", although he couldn't tell me how exactly, or where he got that. |
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Apr 4 |
asked | How to determine predicted CP violation for a given SUSY point? |
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Mar 4 |
awarded | Enthusiast |
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Feb 27 |
comment |
Local $U(1)$ gauge invariance of QED @Nivalth: Thanks a lot, but you didn't have to accept it if it didn't help you. Qmechanic and twistor59 also deserve some credit, but unfortunately you don't get points for comments. |
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Feb 27 |
answered | Local $U(1)$ gauge invariance of QED |
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Feb 18 |
asked | What dark matter can AMS currently find (or exclude)? |
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Feb 3 |
comment |
What constitutes an observation/measurement in QM? As far as I understand, decoherence is objective, so no, two observers can't disagree. They can disagree over wheter a system is in a pure or a mixed state. Maybe my use of 'observer' is confusing here. I don't mean something deep like different frames of reference, just that different people (experimentators) have different incomplete knowlege, and that is expressed through their density operators / mixed states. Its like statistical mechanics, but QM. |
