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 Jul 22 asked Understanding the argument that local U(1) leads to coupling of EM and matter Jul 16 revised Lev Landau's “Theoretical Minimum” Removed [theoretical-physics] again. I still belive it's fitting, but as long as it's only on one question, it's not very useful. Added [education]. Sorry for bumping :-) Jul 15 reviewed Reject Lev Landau's “Theoretical Minimum” Jul 15 revised Lev Landau's “Theoretical Minimum” edited tags Jul 4 awarded Custodian Jul 4 reviewed Reject Lev Landau's “Theoretical Minimum” Jul 2 accepted Mechanisms of mass generation for Dirac neutrinos May 18 asked Why distinguish between row and column vectors? May 13 answered How to determine the direction of medium's displacement vectors of a standing wave? 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. 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. 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? 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.) May 12 asked List of cross sections? May 12 asked Caveats when using event-by-event reweightings? May 12 awarded Informed 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... 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? Apr 23 answered Why does Hydrogen molar heat capacity reach 7/2 R? 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.