yayu

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Learning from scratch

	1,198 reputation	bio	website		visits	member for	2 years, 2 months
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Feb 22	comment	Time Varying Potential, series solution @MaksimZholudev That was a typo. Thanks for pointing it out.
Feb 13	comment	Degree of freedom paradox for a rigid body Thanks though the number of degrees of freedom comes out to be 3. A rigid body is known to have 6 (3trans+3rot).
Feb 13	comment	Why can't we ascribe a (possibly velocity dependent) potential to a dissipative force? @Anna so velocity dependent potentials are actually used to describe conservative forces, is what you meant, right? I will edit my question.
Dec 19	comment	Decay Amplitudes Notation @DavidZaslavsky Yes It may be $B^- (b\bar{u}) ,B^0(b\bar{d})$ etc. $B_p$ means a b quark with a u/d quark
Dec 13	comment	Physics history book with some math @Qmechanic It reminds me when Sheldon embarked on such a project.
Dec 9	comment	Pauli Matrices in orthogonal space I see. Thanks! To sum it up: "$\sigma $" $= \sigma \otimes \mathbb{I}$ while "$\tau $" $=\mathbb{I}\otimes \sigma$
Dec 8	comment	Pauli Matrices in orthogonal space @DavidZaslavsky I dont have a link but the textbook in which this appears is Georgi's Lie Algebras... , chapters 3 (exercises) and chapter 6 (again, in the exercises)
Nov 24	comment	Fitting to a high density scatter plot Could you provide me a reference to the track density and width model you suggested
Nov 18	comment	What is the rationale behind representing a state function by a complex valued function in QM? Please see: physics.stackexchange.com/questions/8062/…
Oct 25	comment	Mathematically, what is color charge? Great Answer! Thanks.
Aug 22	comment	Different values of same physical quantity in time domain and space domain OR Physical explanation of Cauchy Schwarz result @David they are averaged over the same two events (classically), and represent the same physical quantity. Why are the values different, and in general, why is it an ineuqlaity?
Aug 18	comment	Embrace Physics I upvoted because I would have liked to listen to such a talk when I was an undergrad.
Aug 12	comment	How are the HEP experiments' invariant mass plots generated? this is what I suspected, and tried to do my own PID. But I got stuck.
Aug 11	comment	Fitting to a high density scatter plot Another reason the form of the plot looks different from the released ones is that in ALICE Pb-Pb collisions, the multiplicity of pions is so much higher, that it populates the scatter plot obscuring the curves of the electron and the muon.
Aug 11	comment	Fitting to a high density scatter plot @dmckee I have replaced it by a plot of the actual data, so no MC. I used the version of Bethe Bloch provided for the AOD macros. I also used the default TH1::Fit
Aug 11	comment	Fitting to a high density scatter plot @david and dmckee I had posted a plot from pp collision (which was the same, except much lower multiplicity). I have explained the removal in an email to team+physics email.. Basically, the behaviour at low momentum is the same except that the multiplicity is much much higher. I could not find free-to-distribute plots for heavy ion collisions, maybe some from STAR experiments exist, if anyone knows of any, I can post them as a comparision.
Aug 11	comment	How are the HEP experiments' invariant mass plots generated? I have thought about it, and I think experimenters must have some idea of the identity of the individual tracks. Otherwise, any combinatorial algorithm is meaningless.
Jul 24	comment	$N$-body simulation in General Relativity Have a look at the universe sandbox. Everything is classical gravity though.
Jul 15	comment	Why is pseudorapidity defined as $-\log \tan \theta/2$ Thanks a lot, David. This is a great answer. I had been looking for an involved experimental perspective as well and this is better than most stuff I read.
Jun 30	comment	Does a static electric field and the conservation of momentum give rise to a relationship between $E$, $t$, and some path $s$? It might interest you to look at the following question and the answers provided therein.